PostGIS 2.4.

3 Manual i

PostGIS 2.4.3 Manual

PostGIS 2.4.3 Manual ii

Contents

1 Introduction 1
1.1 Project Steering Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Core Contributors Present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Core Contributors Past . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Other Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.5 More Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 PostGIS Installation 4
2.1 Short Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Install Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Getting the Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Compiling and Install from Source: Detailed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4.1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4.2 Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4.3 Building PostGIS Extensions and Deploying them . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4.4 Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4.5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.5 Creating a spatial database using EXTENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.6 Create a spatially-enabled database without using extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.7 Installing and Using the address standardizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.7.1 Installing Regex::Assemble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.8 Installing, Upgrading Tiger Geocoder and loading data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.8.1 Tiger Geocoder Enabling your PostGIS database: Using Extension . . . . . . . . . . . . . . . . . . . . . 23
2.8.1.1 Converting a Tiger Geocoder Regular Install to Extension Model . . . . . . . . . . . . . . . . 25
2.8.2 Tiger Geocoder Enabling your PostGIS database: Not Using Extensions . . . . . . . . . . . . . . . . . . 26
2.8.3 Using Address Standardizer Extension with Tiger geocoder . . . . . . . . . . . . . . . . . . . . . . . . 26
2.8.4 Loading Tiger Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.8.5 Upgrading your Tiger Geocoder Install . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.9 Create a spatially-enabled database from a template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.10 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
PostGIS 2.4.3 Manual iii

2.10.1 Soft upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

2.10.1.1 Soft Upgrade Pre 9.1+ or without extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.10.1.2 Soft Upgrade 9.1+ using extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.10.2 Hard upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.11 Common Problems during installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.12 Loader/Dumper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3 PostGIS Frequently Asked Questions 32

4 Using PostGIS: Data Management and Queries 36

4.1 GIS Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.1.1 OpenGIS WKB and WKT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.1.2 PostGIS EWKB, EWKT and Canonical Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.1.3 SQL-MM Part 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.2 PostGIS Geography Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.2.1 Geography Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.2.2 When to use Geography Data type over Geometry data type . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2.3 Geography Advanced FAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.3 Using OpenGIS Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.3.1 The SPATIAL_REF_SYS Table and Spatial Reference Systems . . . . . . . . . . . . . . . . . . . . . . 42
4.3.2 The GEOMETRY_COLUMNS VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.3.3 Creating a Spatial Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.3.4 Manually Registering Geometry Columns in geometry_columns . . . . . . . . . . . . . . . . . . . . . . 45
4.3.5 Ensuring OpenGIS compliancy of geometries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.3.6 Dimensionally Extended 9 Intersection Model (DE-9IM) . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.3.6.1 Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.4 Loading GIS (Vector) Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.4.1 Loading Data Using SQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.4.2 shp2pgsql: Using the ESRI Shapefile Loader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.5 Retrieving GIS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.5.1 Using SQL to Retrieve Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.5.2 Using the Dumper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.6 Building Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.6.1 GiST Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.6.2 BRIN Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.6.3 Using Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.7 Complex Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.7.1 Taking Advantage of Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.7.2 Examples of Spatial SQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
PostGIS 2.4.3 Manual iv

5 Raster Data Management, Queries, and Applications 66

5.1 Loading and Creating Rasters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.1.1 Using raster2pgsql to load rasters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.1.2 Creating rasters using PostGIS raster functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5.2 Raster Catalogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5.2.1 Raster Columns Catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5.2.2 Raster Overviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.3 Building Custom Applications with PostGIS Raster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.3.1 PHP Example Outputting using ST_AsPNG in concert with other raster functions . . . . . . . . . . . . . 73
5.3.2 ASP.NET C# Example Outputting using ST_AsPNG in concert with other raster functions . . . . . . . . 73
5.3.3 Java console app that outputs raster query as Image file . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.3.4 Use PLPython to dump out images via SQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5.3.5 Outputting Rasters with PSQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6 Using PostGIS Geometry: Building Applications 78

6.1 Using MapServer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.1.1 Basic Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.1.2 Frequently Asked Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.1.3 Advanced Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
6.1.4 Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.2 Java Clients (JDBC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.3 C Clients (libpq) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.3.1 Text Cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.3.2 Binary Cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

7 Performance tips 84
7.1 Small tables of large geometries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.1.1 Problem description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.1.2 Workarounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.2 CLUSTERing on geometry indices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
7.3 Avoiding dimension conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
7.4 Tuning your configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
7.4.1 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
7.4.2 Runtime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
PostGIS 2.4.3 Manual v

8 PostGIS Reference 88
8.1 PostgreSQL PostGIS Geometry/Geography/Box Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
8.1.1 box2d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
8.1.2 box3d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
8.1.3 geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
8.1.4 geometry_dump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
8.1.5 geography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
8.2 PostGIS Grand Unified Custom Variables (GUCs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
8.2.1 postgis.backend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
8.2.2 postgis.gdal_datapath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
8.2.3 postgis.gdal_enabled_drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
8.2.4 postgis.enable_outdb_rasters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
8.3 Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
8.3.1 AddGeometryColumn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
8.3.2 DropGeometryColumn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
8.3.3 DropGeometryTable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
8.3.4 PostGIS_Full_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
8.3.5 PostGIS_GEOS_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
8.3.6 PostGIS_Liblwgeom_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
8.3.7 PostGIS_LibXML_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
8.3.8 PostGIS_Lib_Build_Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
8.3.9 PostGIS_Lib_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
8.3.10 PostGIS_PROJ_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
8.3.11 PostGIS_Scripts_Build_Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
8.3.12 PostGIS_Scripts_Installed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
8.3.13 PostGIS_Scripts_Released . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
8.3.14 PostGIS_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
8.3.15 Populate_Geometry_Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
8.3.16 UpdateGeometrySRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
8.4 Geometry Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
8.4.1 ST_BdPolyFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
8.4.2 ST_BdMPolyFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
8.4.3 ST_Box2dFromGeoHash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
8.4.4 ST_GeogFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
8.4.5 ST_GeographyFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
8.4.6 ST_GeogFromWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
8.4.7 ST_GeomFromTWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
8.4.8 ST_GeomCollFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
8.4.9 ST_GeomFromEWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
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8.4.10 ST_GeomFromEWKT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

8.4.11 ST_GeometryFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
8.4.12 ST_GeomFromGeoHash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
8.4.13 ST_GeomFromGML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
8.4.14 ST_GeomFromGeoJSON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
8.4.15 ST_GeomFromKML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
8.4.16 ST_GMLToSQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
8.4.17 ST_GeomFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
8.4.18 ST_GeomFromWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
8.4.19 ST_LineFromEncodedPolyline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.4.20 ST_LineFromMultiPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.4.21 ST_LineFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.4.22 ST_LineFromWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.4.23 ST_LinestringFromWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
8.4.24 ST_MakeBox2D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8.4.25 ST_3DMakeBox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
8.4.26 ST_MakeLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
8.4.27 ST_MakeEnvelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8.4.28 ST_MakePolygon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8.4.29 ST_MakePoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
8.4.30 ST_MakePointM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.4.31 ST_MLineFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
8.4.32 ST_MPointFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
8.4.33 ST_MPolyFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
8.4.34 ST_Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
8.4.35 ST_PointFromGeoHash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
8.4.36 ST_PointFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
8.4.37 ST_PointFromWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
8.4.38 ST_Polygon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
8.4.39 ST_PolygonFromText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
8.4.40 ST_WKBToSQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
8.4.41 ST_WKTToSQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
8.5 Geometry Accessors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
8.5.1 GeometryType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
8.5.2 ST_Boundary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
8.5.3 ST_CoordDim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
8.5.4 ST_Dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
8.5.5 ST_EndPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
8.5.6 ST_Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
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8.5.7 ST_BoundingDiagonal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

8.5.8 ST_ExteriorRing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
8.5.9 ST_GeometryN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
8.5.10 ST_GeometryType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
8.5.11 ST_InteriorRingN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
8.5.12 ST_IsPolygonCCW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
8.5.13 ST_IsPolygonCW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
8.5.14 ST_IsClosed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
8.5.15 ST_IsCollection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
8.5.16 ST_IsEmpty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
8.5.17 ST_IsRing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
8.5.18 ST_IsSimple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
8.5.19 ST_IsValid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
8.5.20 ST_IsValidReason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
8.5.21 ST_IsValidDetail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
8.5.22 ST_M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
8.5.23 ST_NDims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
8.5.24 ST_NPoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
8.5.25 ST_NRings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
8.5.26 ST_NumGeometries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
8.5.27 ST_NumInteriorRings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
8.5.28 ST_NumInteriorRing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
8.5.29 ST_NumPatches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
8.5.30 ST_NumPoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
8.5.31 ST_PatchN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
8.5.32 ST_PointN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
8.5.33 ST_Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
8.5.34 ST_SRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
8.5.35 ST_StartPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
8.5.36 ST_Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
8.5.37 ST_X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
8.5.38 ST_XMax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
8.5.39 ST_XMin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
8.5.40 ST_Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
8.5.41 ST_YMax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
8.5.42 ST_YMin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
8.5.43 ST_Z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
8.5.44 ST_ZMax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
8.5.45 ST_Zmflag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
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8.5.46 ST_ZMin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

8.6 Geometry Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
8.6.1 ST_AddPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
8.6.2 ST_Affine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
8.6.3 ST_Force2D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
8.6.4 ST_Force3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
8.6.5 ST_Force3DZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
8.6.6 ST_Force3DM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
8.6.7 ST_Force4D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
8.6.8 ST_ForcePolygonCCW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
8.6.9 ST_ForceCollection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
8.6.10 ST_ForcePolygonCW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
8.6.11 ST_ForceSFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
8.6.12 ST_ForceRHR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
8.6.13 ST_ForceCurve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
8.6.14 ST_LineMerge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
8.6.15 ST_CollectionExtract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
8.6.16 ST_CollectionHomogenize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
8.6.17 ST_Multi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
8.6.18 ST_Normalize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
8.6.19 ST_RemovePoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
8.6.20 ST_Reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
8.6.21 ST_Rotate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
8.6.22 ST_RotateX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
8.6.23 ST_RotateY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
8.6.24 ST_RotateZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
8.6.25 ST_Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
8.6.26 ST_Segmentize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
8.6.27 ST_SetPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
8.6.28 ST_SetSRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
8.6.29 ST_SnapToGrid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
8.6.30 ST_Snap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
8.6.31 ST_Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
8.6.32 ST_Translate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
8.6.33 ST_TransScale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
8.7 Geometry Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
8.7.1 ST_AsBinary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
8.7.2 ST_AsEncodedPolyline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
8.7.3 ST_AsEWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
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8.7.4 ST_AsEWKT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

8.7.5 ST_AsGeoJSON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
8.7.6 ST_AsGML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
8.7.7 ST_AsHEXEWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
8.7.8 ST_AsKML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
8.7.9 ST_AsLatLonText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
8.7.10 ST_AsSVG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
8.7.11 ST_AsText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
8.7.12 ST_AsTWKB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
8.7.13 ST_AsX3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
8.7.14 ST_GeoHash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
8.7.15 ST_AsGeobuf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
8.7.16 ST_AsMVTGeom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
8.7.17 ST_AsMVT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
8.8 Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
8.8.1 && . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
8.8.2 &&(geometry,box2df) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
8.8.3 &&(box2df,geometry) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
8.8.4 &&(box2df,box2df) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
8.8.5 &&& . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
8.8.6 &&&(geometry,gidx) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
8.8.7 &&&(gidx,geometry) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
8.8.8 &&&(gidx,gidx) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
8.8.9 &< . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
8.8.10 &<| . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
8.8.11 &> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
8.8.12 << . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
8.8.13 <<| . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
8.8.14 = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
8.8.15 >> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
8.8.16 @ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
8.8.17 @(geometry,box2df) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
8.8.18 @(box2df,geometry) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
8.8.19 @(box2df,box2df) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
8.8.20 |&> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
8.8.21 |>> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
8.8.22 ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
8.8.23 ~(geometry,box2df) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
8.8.24 ~(box2df,geometry) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
PostGIS 2.4.3 Manual x

8.8.25 ~(box2df,box2df) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

8.8.26 ~= . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
8.8.27 <-> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
8.8.28 |=| . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
8.8.29 <#> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
8.8.30 <<->> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
8.8.31 <<#>> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
8.9 Spatial Relationships and Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
8.9.1 ST_3DClosestPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
8.9.2 ST_3DDistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
8.9.3 ST_3DDWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
8.9.4 ST_3DDFullyWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
8.9.5 ST_3DIntersects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
8.9.6 ST_3DLongestLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
8.9.7 ST_3DMaxDistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
8.9.8 ST_3DShortestLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
8.9.9 ST_Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
8.9.10 ST_Azimuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
8.9.11 ST_Centroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
8.9.12 ST_ClosestPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
8.9.13 ST_ClusterDBSCAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
8.9.14 ST_ClusterIntersecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
8.9.15 ST_ClusterKMeans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
8.9.16 ST_ClusterWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
8.9.17 ST_Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
8.9.18 ST_ContainsProperly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
8.9.19 ST_Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
8.9.20 ST_CoveredBy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
8.9.21 ST_Crosses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
8.9.22 ST_LineCrossingDirection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
8.9.23 ST_Disjoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
8.9.24 ST_Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
8.9.25 ST_MinimumClearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
8.9.26 ST_MinimumClearanceLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
8.9.27 ST_HausdorffDistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
8.9.28 ST_FrechetDistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
8.9.29 ST_MaxDistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
8.9.30 ST_DistanceSphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
8.9.31 ST_DistanceSpheroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
PostGIS 2.4.3 Manual xi

8.9.32 ST_DFullyWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

8.9.33 ST_DWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
8.9.34 ST_Equals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
8.9.35 ST_GeometricMedian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
8.9.36 ST_HasArc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
8.9.37 ST_Intersects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
8.9.38 ST_Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
8.9.39 ST_Length2D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
8.9.40 ST_3DLength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
8.9.41 ST_LengthSpheroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
8.9.42 ST_Length2D_Spheroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
8.9.43 ST_LongestLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
8.9.44 ST_OrderingEquals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
8.9.45 ST_Overlaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
8.9.46 ST_Perimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
8.9.47 ST_Perimeter2D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
8.9.48 ST_3DPerimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
8.9.49 ST_PointOnSurface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
8.9.50 ST_Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
8.9.51 ST_Relate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
8.9.52 ST_RelateMatch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
8.9.53 ST_ShortestLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
8.9.54 ST_Touches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
8.9.55 ST_Within . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
8.10 SFCGAL Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
8.10.1 postgis_sfcgal_version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
8.10.2 ST_Extrude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
8.10.3 ST_StraightSkeleton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
8.10.4 ST_ApproximateMedialAxis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
8.10.5 ST_IsPlanar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
8.10.6 ST_Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
8.10.7 ST_ForceLHR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
8.10.8 ST_MinkowskiSum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
8.10.9 ST_3DIntersection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
8.10.10 ST_3DDifference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
8.10.11 ST_3DUnion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
8.10.12 ST_3DArea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343
8.10.13 ST_Tesselate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344
8.10.14 ST_Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
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8.10.15 ST_MakeSolid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347

8.10.16 ST_IsSolid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
8.11 Geometry Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
8.11.1 ST_Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
8.11.2 ST_BuildArea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
8.11.3 ST_ClipByBox2D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
8.11.4 ST_Collect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
8.11.5 ST_ConcaveHull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
8.11.6 ST_ConvexHull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
8.11.7 ST_CurveToLine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
8.11.8 ST_DelaunayTriangles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
8.11.9 ST_Difference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
8.11.10 ST_Dump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
8.11.11 ST_DumpPoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372
8.11.12 ST_DumpRings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
8.11.13 ST_FlipCoordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
8.11.14 ST_GeneratePoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
8.11.15 ST_Intersection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
8.11.16 ST_LineToCurve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
8.11.17 ST_MakeValid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
8.11.18 ST_MemUnion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
8.11.19 ST_MinimumBoundingCircle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
8.11.20 ST_MinimumBoundingRadius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
8.11.21 ST_Polygonize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
8.11.22 ST_Node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
8.11.23 ST_OffsetCurve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
8.11.24 ST_RemoveRepeatedPoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
8.11.25 ST_SharedPaths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
8.11.26 ST_ShiftLongitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
8.11.27 ST_WrapX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
8.11.28 ST_Simplify . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
8.11.29 ST_SimplifyPreserveTopology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
8.11.30 ST_SimplifyVW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
8.11.31 ST_SetEffectiveArea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
8.11.32 ST_Split . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
8.11.33 ST_SymDifference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
8.11.34 ST_Subdivide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
8.11.35 ST_SwapOrdinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406
8.11.36 ST_Union . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
PostGIS 2.4.3 Manual xiii

8.11.37 ST_UnaryUnion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409

8.11.38 ST_VoronoiLines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
8.11.39 ST_VoronoiPolygons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
8.12 Linear Referencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
8.12.1 ST_LineInterpolatePoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
8.12.2 ST_LineLocatePoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
8.12.3 ST_LineSubstring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
8.12.4 ST_LocateAlong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
8.12.5 ST_LocateBetween . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
8.12.6 ST_LocateBetweenElevations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
8.12.7 ST_InterpolatePoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
8.12.8 ST_AddMeasure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
8.13 Temporal Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
8.13.1 ST_IsValidTrajectory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
8.13.2 ST_ClosestPointOfApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
8.13.3 ST_DistanceCPA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
8.13.4 ST_CPAWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
8.14 Long Transactions Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
8.14.1 AddAuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
8.14.2 CheckAuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
8.14.3 DisableLongTransactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
8.14.4 EnableLongTransactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
8.14.5 LockRow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
8.14.6 UnlockRows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
8.15 Miscellaneous Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
8.15.1 ST_Accum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
8.15.2 Box2D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
8.15.3 Box3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
8.15.4 ST_EstimatedExtent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
8.15.5 ST_Expand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
8.15.6 ST_Extent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
8.15.7 ST_3DExtent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
8.15.8 Find_SRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
8.15.9 ST_MemSize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
8.15.10 ST_PointInsideCircle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
8.16 Exceptional Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
8.16.1 PostGIS_AddBBox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
8.16.2 PostGIS_DropBBox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
8.16.3 PostGIS_HasBBox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
PostGIS 2.4.3 Manual xiv

9 Raster Reference 442

9.1 Raster Support Data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
9.1.1 geomval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
9.1.2 addbandarg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
9.1.3 rastbandarg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
9.1.4 raster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444
9.1.5 reclassarg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444
9.1.6 summarystats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
9.1.7 unionarg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
9.2 Raster Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
9.2.1 AddRasterConstraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
9.2.2 DropRasterConstraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
9.2.3 AddOverviewConstraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448
9.2.4 DropOverviewConstraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
9.2.5 PostGIS_GDAL_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
9.2.6 PostGIS_Raster_Lib_Build_Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
9.2.7 PostGIS_Raster_Lib_Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451
9.2.8 ST_GDALDrivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451
9.2.9 UpdateRasterSRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455
9.2.10 ST_CreateOverview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455
9.3 Raster Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
9.3.1 ST_AddBand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
9.3.2 ST_AsRaster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
9.3.3 ST_Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
9.3.4 ST_MakeEmptyCoverage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
9.3.5 ST_MakeEmptyRaster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
9.3.6 ST_Tile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
9.3.7 ST_Retile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
9.3.8 ST_FromGDALRaster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
9.4 Raster Accessors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
9.4.1 ST_GeoReference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
9.4.2 ST_Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
9.4.3 ST_IsEmpty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
9.4.4 ST_MemSize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
9.4.5 ST_MetaData . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
9.4.6 ST_NumBands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
9.4.7 ST_PixelHeight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
9.4.8 ST_PixelWidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473
9.4.9 ST_ScaleX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
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9.4.10 ST_ScaleY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474

9.4.11 ST_RasterToWorldCoord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
9.4.12 ST_RasterToWorldCoordX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
9.4.13 ST_RasterToWorldCoordY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
9.4.14 ST_Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
9.4.15 ST_SkewX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
9.4.16 ST_SkewY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479
9.4.17 ST_SRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
9.4.18 ST_Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
9.4.19 ST_UpperLeftX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
9.4.20 ST_UpperLeftY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
9.4.21 ST_Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
9.4.22 ST_WorldToRasterCoord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
9.4.23 ST_WorldToRasterCoordX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
9.4.24 ST_WorldToRasterCoordY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
9.5 Raster Band Accessors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
9.5.1 ST_BandMetaData . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
9.5.2 ST_BandNoDataValue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
9.5.3 ST_BandIsNoData . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
9.5.4 ST_BandPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
9.5.5 ST_BandPixelType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488
9.5.6 ST_HasNoBand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
9.6 Raster Pixel Accessors and Setters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
9.6.1 ST_PixelAsPolygon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
9.6.2 ST_PixelAsPolygons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490
9.6.3 ST_PixelAsPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491
9.6.4 ST_PixelAsPoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
9.6.5 ST_PixelAsCentroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
9.6.6 ST_PixelAsCentroids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
9.6.7 ST_Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
9.6.8 ST_NearestValue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497
9.6.9 ST_Neighborhood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 499
9.6.10 ST_SetValue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
9.6.11 ST_SetValues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
9.6.12 ST_DumpValues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
9.6.13 ST_PixelOfValue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
9.7 Raster Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
9.7.1 ST_SetGeoReference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
9.7.2 ST_SetRotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
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9.7.3 ST_SetScale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514

9.7.4 ST_SetSkew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
9.7.5 ST_SetSRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516
9.7.6 ST_SetUpperLeft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
9.7.7 ST_Resample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
9.7.8 ST_Rescale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
9.7.9 ST_Reskew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
9.7.10 ST_SnapToGrid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521
9.7.11 ST_Resize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522
9.7.12 ST_Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523
9.8 Raster Band Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525
9.8.1 ST_SetBandNoDataValue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525
9.8.2 ST_SetBandIsNoData . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526
9.9 Raster Band Statistics and Analytics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
9.9.1 ST_Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
9.9.2 ST_CountAgg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
9.9.3 ST_Histogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529
9.9.4 ST_Quantile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
9.9.5 ST_SummaryStats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
9.9.6 ST_SummaryStatsAgg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
9.9.7 ST_ValueCount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
9.10 Raster Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
9.10.1 ST_AsBinary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
9.10.2 ST_AsGDALRaster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
9.10.3 ST_AsJPEG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
9.10.4 ST_AsPNG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
9.10.5 ST_AsTIFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
9.11 Raster Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
9.11.1 Map Algebra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
9.11.1.1 ST_Clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
9.11.1.2 ST_ColorMap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546
9.11.1.3 ST_Intersection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
9.11.1.4 ST_MapAlgebra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551
9.11.1.5 ST_MapAlgebra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
9.11.1.6 ST_MapAlgebraExpr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559
9.11.1.7 ST_MapAlgebraExpr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562
9.11.1.8 ST_MapAlgebraFct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
9.11.1.9 ST_MapAlgebraFct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570
9.11.1.10 ST_MapAlgebraFctNgb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574
PostGIS 2.4.3 Manual xvii

9.11.1.11 ST_Reclass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 576

9.11.1.12 ST_Union . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
9.11.2 Built-in Map Algebra Callback Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
9.11.2.1 ST_Distinct4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
9.11.2.2 ST_InvDistWeight4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
9.11.2.3 ST_Max4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
9.11.2.4 ST_Mean4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 582
9.11.2.5 ST_Min4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 583
9.11.2.6 ST_MinDist4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584
9.11.2.7 ST_Range4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
9.11.2.8 ST_StdDev4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586
9.11.2.9 ST_Sum4ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587
9.11.3 DEM (Elevation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588
9.11.3.1 ST_Aspect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588
9.11.3.2 ST_HillShade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590
9.11.3.3 ST_Roughness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 591
9.11.3.4 ST_Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592
9.11.3.5 ST_TPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594
9.11.3.6 ST_TRI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594
9.11.4 Raster to Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
9.11.4.1 Box3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
9.11.4.2 ST_ConvexHull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
9.11.4.3 ST_DumpAsPolygons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596
9.11.4.4 ST_Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597
9.11.4.5 ST_MinConvexHull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 598
9.11.4.6 ST_Polygon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
9.12 Raster Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
9.12.1 && . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
9.12.2 &< . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
9.12.3 &> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
9.12.4 = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
9.12.5 @ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
9.12.6 ~= . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
9.12.7 ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
9.13 Raster and Raster Band Spatial Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
9.13.1 ST_Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
9.13.2 ST_ContainsProperly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606
9.13.3 ST_Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
9.13.4 ST_CoveredBy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
PostGIS 2.4.3 Manual xviii

9.13.5 ST_Disjoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608

9.13.6 ST_Intersects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609
9.13.7 ST_Overlaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
9.13.8 ST_Touches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611
9.13.9 ST_SameAlignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612
9.13.10 ST_NotSameAlignmentReason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
9.13.11 ST_Within . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614
9.13.12 ST_DWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615
9.13.13 ST_DFullyWithin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615

10 PostGIS Raster Frequently Asked Questions 617

11 Topology 621
11.1 Topology Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621
11.1.1 getfaceedges_returntype . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621
11.1.2 TopoGeometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622
11.1.3 validatetopology_returntype . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622
11.2 Topology Domains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623
11.2.1 TopoElement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623
11.2.2 TopoElementArray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623
11.3 Topology and TopoGeometry Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624
11.3.1 AddTopoGeometryColumn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 624
11.3.2 DropTopology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625
11.3.3 DropTopoGeometryColumn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625
11.3.4 Populate_Topology_Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 626
11.3.5 TopologySummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 627
11.3.6 ValidateTopology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
11.4 Topology Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
11.4.1 CreateTopology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
11.4.2 CopyTopology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629
11.4.3 ST_InitTopoGeo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630
11.4.4 ST_CreateTopoGeo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630
11.4.5 TopoGeo_AddPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
11.4.6 TopoGeo_AddLineString . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
11.4.7 TopoGeo_AddPolygon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
11.5 Topology Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
11.5.1 ST_AddIsoNode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
11.5.2 ST_AddIsoEdge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633
11.5.3 ST_AddEdgeNewFaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634
PostGIS 2.4.3 Manual xix

11.5.4 ST_AddEdgeModFace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634

11.5.5 ST_RemEdgeNewFace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635
11.5.6 ST_RemEdgeModFace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 636
11.5.7 ST_ChangeEdgeGeom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 636
11.5.8 ST_ModEdgeSplit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637
11.5.9 ST_ModEdgeHeal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638
11.5.10 ST_NewEdgeHeal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638
11.5.11 ST_MoveIsoNode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639
11.5.12 ST_NewEdgesSplit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639
11.5.13 ST_RemoveIsoNode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 640
11.5.14 ST_RemoveIsoEdge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641
11.6 Topology Accessors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641
11.6.1 GetEdgeByPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641
11.6.2 GetFaceByPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642
11.6.3 GetNodeByPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643
11.6.4 GetTopologyID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644
11.6.5 GetTopologySRID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644
11.6.6 GetTopologyName . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645
11.6.7 ST_GetFaceEdges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645
11.6.8 ST_GetFaceGeometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
11.6.9 GetRingEdges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647
11.6.10 GetNodeEdges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647
11.7 Topology Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 648
11.7.1 Polygonize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 648
11.7.2 AddNode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
11.7.3 AddEdge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
11.7.4 AddFace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
11.7.5 ST_Simplify . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
11.8 TopoGeometry Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
11.8.1 CreateTopoGeom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
11.8.2 toTopoGeom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654
11.8.3 TopoElementArray_Agg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655
11.9 TopoGeometry Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
11.9.1 clearTopoGeom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
11.9.2 TopoGeom_addElement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
11.9.3 TopoGeom_remElement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
11.9.4 toTopoGeom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
11.10TopoGeometry Accessors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658
11.10.1 GetTopoGeomElementArray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658
PostGIS 2.4.3 Manual xx

11.10.2 GetTopoGeomElements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658

11.11TopoGeometry Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659
11.11.1 AsGML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659
11.11.2 AsTopoJSON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661
11.12Topology Spatial Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662
11.12.1 Equals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662
11.12.2 Intersects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663

12 Address Standardizer 665

12.1 How the Parser Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665
12.2 Address Standardizer Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665
12.2.1 stdaddr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665
12.3 Address Standardizer Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666
12.3.1 rules table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666
12.3.2 lex table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 669
12.3.3 gaz table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 669
12.4 Address Standardizer Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 670
12.4.1 parse_address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 670
12.4.2 standardize_address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 671

13 PostGIS Extras 674

13.1 Tiger Geocoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674
13.1.1 Drop_Indexes_Generate_Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674
13.1.2 Drop_Nation_Tables_Generate_Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 675
13.1.3 Drop_State_Tables_Generate_Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 676
13.1.4 Geocode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677
13.1.5 Geocode_Intersection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 679
13.1.6 Get_Geocode_Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 680
13.1.7 Get_Tract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 681
13.1.8 Install_Missing_Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 682
13.1.9 Loader_Generate_Census_Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 682
13.1.10 Loader_Generate_Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684
13.1.11 Loader_Generate_Nation_Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686
13.1.12 Missing_Indexes_Generate_Script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687
13.1.13 Normalize_Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 688
13.1.14 Pagc_Normalize_Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 689
13.1.15 Pprint_Addy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
13.1.16 Reverse_Geocode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 692
13.1.17 Topology_Load_Tiger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
13.1.18 Set_Geocode_Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695
PostGIS 2.4.3 Manual xxi

14 PostGIS Special Functions Index 697

14.1 PostGIS Aggregate Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697
14.2 PostGIS Window Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697
14.3 PostGIS SQL-MM Compliant Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 698
14.4 PostGIS Geography Support Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703
14.5 PostGIS Raster Support Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 704
14.6 PostGIS Geometry / Geography / Raster Dump Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709
14.7 PostGIS Box Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709
14.8 PostGIS Functions that support 3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710
14.9 PostGIS Curved Geometry Support Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 715
14.10PostGIS Polyhedral Surface Support Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
14.11PostGIS Function Support Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 721
14.12New, Enhanced or changed PostGIS Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 730
14.12.1 PostGIS Functions new or enhanced in 2.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 730
14.12.2 PostGIS Functions new or enhanced in 2.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 732
14.12.3 PostGIS Functions new or enhanced in 2.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 734
14.12.4 PostGIS functions breaking changes in 2.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 736
14.12.5 PostGIS Functions new or enhanced in 2.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737
14.12.6 PostGIS functions breaking changes in 2.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740
14.12.7 PostGIS Functions new, behavior changed, or enhanced in 2.0 . . . . . . . . . . . . . . . . . . . . . . . 741
14.12.8 PostGIS Functions changed behavior in 2.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749
14.12.9 PostGIS Functions new, behavior changed, or enhanced in 1.5 . . . . . . . . . . . . . . . . . . . . . . . 751
14.12.10PostGIS Functions new, behavior changed, or enhanced in 1.4 . . . . . . . . . . . . . . . . . . . . . . . 752
14.12.11PostGIS Functions new in 1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 753

15 Reporting Problems 754

15.1 Reporting Software Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754
15.2 Reporting Documentation Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754

A Appendix 755
A.1 Release 2.4.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755
A.1.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755
A.2 Release 2.4.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755
A.2.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755
A.3 Release 2.4.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755
A.3.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 756
A.4 Release 2.4.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 756
A.4.1 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 756
A.4.2 Enhancements and Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 757
PostGIS 2.4.3 Manual xxii

A.4.3 Breaking Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 757

A.5 Release 2.3.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 757
A.5.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 757
A.6 Release 2.3.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 758
A.6.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 758
A.7 Release 2.3.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 758
A.7.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759
A.8 Release 2.3.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759
A.8.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759
A.9 Release 2.3.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759
A.9.1 Bug Fixes and Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759
A.10 Release 2.3.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 760
A.10.1 Important / Breaking Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 760
A.10.2 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 760
A.10.3 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 761
A.10.4 Performance Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 761
A.11 Release 2.2.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 761
A.11.1 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 761
A.12 Release 2.2.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 761
A.12.1 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
A.13 Release 2.2.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
A.13.1 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
A.13.2 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764
A.14 Release 2.1.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764
A.14.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764
A.15 Release 2.1.7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 765
A.15.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 765
A.16 Release 2.1.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 765
A.16.1 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 765
A.16.2 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 765
A.17 Release 2.1.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 765
A.17.1 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766
A.17.2 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766
A.18 Release 2.1.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766
A.18.1 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766
A.18.2 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766
A.19 Release 2.1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 767
A.19.1 Important changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 767
A.19.2 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 767
PostGIS 2.4.3 Manual xxiii

A.20 Release 2.1.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 767

A.20.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 767
A.20.2 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768
A.21 Release 2.1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768
A.21.1 Important Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768
A.21.2 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 768
A.21.3 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 769
A.22 Release 2.1.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 769
A.22.1 Important / Breaking Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 769
A.22.2 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 769
A.22.3 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 771
A.22.4 Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772
A.22.5 Known Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 773
A.23 Release 2.0.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 773
A.23.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 773
A.23.2 Important Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 774
A.24 Release 2.0.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 774
A.24.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 774
A.24.2 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
A.24.3 Known Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
A.25 Release 2.0.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
A.25.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
A.25.2 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
A.26 Release 2.0.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
A.26.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 776
A.26.2 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
A.27 Release 2.0.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
A.27.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
A.27.2 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 778
A.28 Release 2.0.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 778
A.28.1 Testers - Our unsung heroes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 778
A.28.2 Important / Breaking Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 779
A.28.3 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 779
A.28.4 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 780
A.28.5 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 780
A.28.6 Release specific credits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 780
A.29 Release 1.5.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 780
A.29.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 780
A.30 Release 1.5.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 781
PostGIS 2.4.3 Manual xxiv

A.30.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 781

A.31 Release 1.5.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
A.31.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
A.32 Release 1.5.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
A.32.1 Bug Fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
A.33 Release 1.5.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
A.33.1 API Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
A.33.2 Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
A.33.3 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
A.33.4 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784
A.33.5 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784
A.34 Release 1.4.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784
A.34.1 API Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784
A.34.2 Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785
A.34.3 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785
A.34.4 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785
A.34.5 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
A.35 Release 1.3.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
A.36 Release 1.3.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
A.37 Release 1.3.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
A.38 Release 1.3.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
A.39 Release 1.3.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
A.40 Release 1.3.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
A.41 Release 1.3.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
A.41.1 Added Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
A.41.2 Performance Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
A.41.3 Other Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
A.42 Release 1.2.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
A.42.1 Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787
A.43 Release 1.2.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
A.43.1 Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
A.44 Release 1.1.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
A.44.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
A.44.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
A.44.3 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
A.45 Release 1.1.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
A.45.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
A.45.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
A.45.3 New Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
PostGIS 2.4.3 Manual xxv

A.46 Release 1.1.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789

A.46.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
A.46.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
A.46.3 Java changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
A.47 Release 1.1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
A.47.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
A.47.2 Bug fixes / correctness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
A.47.3 New functionalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
A.47.4 JDBC changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
A.47.5 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
A.48 Release 1.1.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
A.48.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
A.48.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
A.48.3 New functionalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
A.48.4 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
A.49 Release 1.1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
A.49.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
A.49.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
A.49.3 New functionalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
A.50 Release 1.1.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
A.50.1 Credits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
A.50.2 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
A.50.3 New functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793
A.50.4 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793
A.50.5 Function semantic changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793
A.50.6 Performance improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793
A.50.7 JDBC2 works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793
A.50.8 Other new things . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
A.50.9 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
A.51 Release 1.0.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
A.51.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
A.51.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
A.51.3 Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
A.52 Release 1.0.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
A.52.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
A.52.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
A.52.3 Loader changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
A.52.4 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
A.53 Release 1.0.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
PostGIS 2.4.3 Manual xxvi

A.53.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796

A.53.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796
A.53.3 Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796
A.54 Release 1.0.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796
A.54.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796
A.54.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
A.54.3 Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
A.55 Release 1.0.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
A.55.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
A.55.2 Bug fixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
A.55.3 Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
A.56 Release 1.0.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
A.56.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
A.56.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
A.56.3 Other changes/additions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
A.57 Release 1.0.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
A.57.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
A.57.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
A.57.3 Other changes/additions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.58 Release 1.0.0RC6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.58.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.58.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.58.3 Scripts changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.58.4 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.59 Release 1.0.0RC5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.59.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799
A.59.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
A.59.3 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
A.60 Release 1.0.0RC4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
A.60.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
A.60.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
A.60.3 Scripts changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
A.60.4 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
A.61 Release 1.0.0RC3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
A.61.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
A.61.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
A.61.3 Scripts changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
A.61.4 JDBC changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
A.61.5 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
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A.62 Release 1.0.0RC2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802

A.62.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
A.62.2 Library changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
A.62.3 Scripts changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
A.62.4 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
A.63 Release 1.0.0RC1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
A.63.1 Upgrading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
A.63.2 Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
 Abstract

PostGIS is an extension to the PostgreSQL object-relational database system which allows GIS (Geographic Information Sys-
tems) objects to be stored in the database. PostGIS includes support for GiST-based R-Tree spatial indexes, and functions for
analysis and processing of GIS objects.

This is the manual for version 2.4.3

This work is licensed under a Creative Commons Attribution-Share Alike 3.0 License. Feel free to use
this material any way you like, but we ask that you attribute credit to the PostGIS Project and wherever possible, a link back to
http://postgis.net.
PostGIS 2.4.3 Manual 1 / 803

Chapter 1

Introduction

PostGIS was developed by Refractions Research Inc, as a spatial database technology research project. Refractions is a GIS
and database consulting company in Victoria, British Columbia, Canada, specializing in data integration and custom software
development. We plan on supporting and developing PostGIS to support a range of important GIS functionality, including full
OpenGIS support, advanced topological constructs (coverages, surfaces, networks), desktop user interface tools for viewing and
editing GIS data, and web-based access tools.
PostGIS is an incubation project of the OSGeo Foundation. PostGIS is being continually improved and funded by many FOSS4G
Developers as well as corporations all over the world that gain great benefit from its functionality and versatility.

1.1 Project Steering Committee

The PostGIS Project Steering Committee (PSC) coordinates the general direction, release cycles, documentation, and outreach
efforts for the PostGIS project. In addition the PSC provides general user support, accepts and approves patches from the general
PostGIS community and votes on miscellaneous issues involving PostGIS such as developer commit access, new PSC members
or significant API changes.

Mark Cave-Ayland Coordinates bug fixing and maintenance effort, spatial index selectivity and binding, loader/dumper, and
Shapefile GUI Loader, integration of new and new function enhancements.

Regina Obe Buildbot Maintenance, windows production and experimental builds, Documentation, alignment of PostGIS with
PostgreSQL releases, general user support on PostGIS newsgroup, X3D support, Tiger Geocoder Support, management
functions, and smoke testing new functionality or major code changes.
Bborie Park Raster development, integration with GDAL, raster loader, user support, general bug fixing, testing on various OS
(Slackware, Mac, Windows, and more)

Paul Ramsey (Chair) Co-founder of PostGIS project. General bug fixing, geography support, geography and geometry index
support (2D, 3D, nD index and anything spatial index), underlying geometry internal structures, PointCloud (in devel-
opment), GEOS functionality integration and alignment with GEOS releases, alignment of PostGIS with PostgreSQL
releases, loader/dumper, and Shapefile GUI loader.
Sandro Santilli Bug fixes and maintenance, git mirrors management, integration of new GEOS functionality and alignment with
GEOS releases, Topology support, and Raster framework and low level api functions.

1.2 Core Contributors Present

Jorge Arévalo Raster development, GDAL driver support, loader

PostGIS 2.4.3 Manual 2 / 803

Nicklas Avén Distance function enhancements (including 3D distance and relationship functions) and additions, Tiny WKB
output format (TWKB) (in development) and general user support
Dan Baston Geometry clustering function additions, other geometry algorithm enhancements, GEOS enhancements and general
user support
Olivier Courtin Input output XML (KML,GML)/GeoJSON functions, 3D support and bug fixes.
Björn Harrtell MapBox Vector Tile and GeoBuf functions. Gogs testing and GitLab experimentation.
Mateusz Loskot CMake support for PostGIS, built original raster loader in python and low level raster api functions

Darafei Praliaskouski Index improvements, bug fixing and geometry/geography function improvements, GitHub curator, and
Travis bot maintenance.
Pierre Racine Raster overall architecture, prototyping, programming support

1.3 Core Contributors Past

Chris Hodgson Prior PSC Member. General development, site and buildbot maintenance, OSGeo incubation management

Kevin Neufeld Prior PSC Member. Documentation and documentation support tools, buildbot maintenance, advanced user
support on PostGIS newsgroup, and PostGIS maintenance function enhancements.
Dave Blasby The original developer/Co-founder of PostGIS. Dave wrote the server side objects, index bindings, and many of
the server side analytical functions.

Jeff Lounsbury Original development of the Shape file loader/dumper. Current PostGIS Project Owner representative.
Mark Leslie Ongoing maintenance and development of core functions. Enhanced curve support. Shapefile GUI loader.
David Zwarg Raster development (mostly map algebra analytic functions)

1.4 Other Contributors

Individual Contributors In alphabetical order: Alex Bodnaru, Alex Mayrhofer, Andrea Peri, Andreas Forø Tollefsen, An-
dreas Neumann, Anne Ghisla, Barbara Phillipot, Ben Jubb, Bernhard Reiter, Brian Hamlin, Bruce Rindahl, Bruno Wolff
III, Bryce L. Nordgren, Carl Anderson, Charlie Savage, Dane Springmeyer, David Skea, David Techer, Eduin Carrillo,
Even Rouault, Frank Warmerdam, George Silva, Gerald Fenoy, Gino Lucrezi, Guillaume Lelarge, IIDA Tetsushi, Ingvild
Nystuen, Jason Smith, Jeff Adams, Jose Carlos Martinez Llari, Julien Rouhaud, Kashif Rasul, Klaus Foerster, Kris Jurka,
Leo Hsu, Loic Dachary, Luca S. Percich, Maria Arias de Reyna, Mark Sondheim, Markus Schaber, Maxime Guillaud,
Maxime van Noppen, Michael Fuhr, Mike Toews, Nathan Wagner, Nathaniel Clay, Nikita Shulga, Norman Vine, Rafal
Magda, Ralph Mason, Rémi Cura, Richard Greenwood, Silvio Grosso, Steffen Macke, Stephen Frost, Tom van Tilburg,
Vincent Mora, Vincent Picavet
Corporate Sponsors These are corporate entities that have contributed developer time, hosting, or direct monetary funding to
the PostGIS project
In alphabetical order: Arrival 3D, Associazione Italiana per l’Informazione Geografica Libera (GFOSS.it), AusVet, Aven-
cia, Azavea, Cadcorp, CampToCamp, CartoDB, City of Boston (DND), Clever Elephant Solutions, Cooperativa Alveo,
Deimos Space, Faunalia, Geographic Data BC, Hunter Systems Group, Lidwala Consulting Engineers, LisaSoft, Logical
Tracking & Tracing International AG, Maponics, Michigan Tech Research Institute, Natural Resources Canada, Norwe-
gian Forest and Landscape Institute, Boundless (former OpenGeo), OSGeo, Oslandia, Palantir Technologies, Paragon
Corporation, R3 GIS, Refractions Research, Regione Toscana - SITA, Safe Software, Sirius Corporation plc, Stadt Uster,
UC Davis Center for Vectorborne Diseases, University of Laval, U.S Department of State (HIU), Zonar Systems
PostGIS 2.4.3 Manual 3 / 803

Crowd Funding Campaigns Crowd funding campaigns are campaigns we run to get badly wanted features funded that can
service a large number of people. Each campaign is specifically focused on a particular feature or set of features. Each
sponsor chips in a small fraction of the needed funding and with enough people/organizations contributing, we have the
funds to pay for the work that will help many. If you have an idea for a feature you think many others would be willing to
co-fund, please post to the PostGIS newsgroup your thoughts and together we can make it happen.
PostGIS 2.0.0 was the first release we tried this strategy. We used PledgeBank and we got two successful campaigns out
of it.
postgistopology - 10 plus sponsors each contributed $250 USD to build toTopoGeometry function and beef up topology
support in 2.0.0. It happened.
postgis64windows - 20 someodd sponsors each contributed $100 USD to pay for the work needed to work out PostGIS
64-bit issues on windows. It happened. We now have a 64-bit release for PostGIS 2.0.1 available on PostgreSQL stack
builder.
Important Support Libraries The GEOS geometry operations library, and the algorithmic work of Martin Davis in making it
all work, ongoing maintenance and support of Mateusz Loskot, Sandro Santilli (strk), Paul Ramsey and others.
The GDAL Geospatial Data Abstraction Library, by Frank Warmerdam and others is used to power much of the raster
functionality introduced in PostGIS 2.0.0. In kind, improvements needed in GDAL to support PostGIS are contributed
back to the GDAL project.
The Proj4 cartographic projection library, and the work of Gerald Evenden and Frank Warmerdam in creating and main-
taining it.
Last but not least, the PostgreSQL DBMS, The giant that PostGIS stands on. Much of the speed and flexibility of PostGIS
would not be possible without the extensibility, great query planner, GIST index, and plethora of SQL features provided
by PostgreSQL.

1.5 More Information

• The latest software, documentation and news items are available at the PostGIS web site, http://postgis.net.

• More information about the GEOS geometry operations library is available athttp://trac.osgeo.org/geos/.
• More information about the Proj4 reprojection library is available at http://trac.osgeo.org/proj/.
• More information about the PostgreSQL database server is available at the PostgreSQL main site http://www.postgresql.org.

• More information about GiST indexing is available at the PostgreSQL GiST development site, http://www.sai.msu.su/~megera/-
postgres/gist/.
• More information about MapServer internet map server is available at http://mapserver.org.
• The "Simple Features for Specification for SQL" is available at the OpenGIS Consortium web site: http://www.opengeospatial.org/-
.
PostGIS 2.4.3 Manual 4 / 803

Chapter 2

PostGIS Installation

This chapter details the steps required to install PostGIS.

2.1 Short Version

To compile assuming you have all the dependencies in your search path:
tar xvfz postgis-2.4.3.tar.gz
cd postgis-2.4.3
./configure
make
make install

Once postgis is installed, it needs to be enabled in each individual database you want to use it in.

Note
The raster support is currently optional, but installed by default. For enabling using the PostgreSQL 9.1+ extensions
model raster is required. Using the extension enable process is preferred and more user-friendly. To spatially enable
your database:

psql -d yourdatabase -c "CREATE EXTENSION postgis;"

psql -d yourdatabase -c "CREATE EXTENSION postgis_topology;"
-- if you built with sfcgal support --
psql -d yourdatabase -c "CREATE EXTENSION postgis_sfcgal;"

-- if you want to install tiger geocoder --

psql -d yourdatabase -c "CREATE EXTENSION fuzzystrmatch"
psql -d yourdatabase -c "CREATE EXTENSION postgis_tiger_geocoder;"

-- if you installed with pcre

-- you should have address standardizer extension as well
psql -d yourdatabase -c "CREATE EXTENSION address_standardizer;"

Please refer to Section 2.4.3 for more details about querying installed/available extensions and upgrading extensions, or switching
from a non-extension install to an extension install.
For those running who decided for some reason not to compile with raster support, or just are old-fashioned, here are longer
more painful instructions for you:
All the .sql files once installed will be installed in share/contrib/postgis-2.3 folder of your PostgreSQL install
PostGIS 2.4.3 Manual 5 / 803

createdb yourdatabase
createlang plpgsql yourdatabase
psql -d yourdatabase -f postgis.sql
psql -d yourdatabase -f postgis_comments.sql
psql -d yourdatabase -f spatial_ref_sys.sql
psql -d yourdatabase -f topology.sql
psql -d yourdatabase -f topology_comments.sql

-- only if you compiled with raster (GDAL)

psql -d yourdatabase -f rtpostgis.sql
psql -d yourdatabase -f raster_comments.sql

--if you built with sfcgal support --

psql -d yourdatabase -f sfcgal.sql
psql -d yourdatabase -f sfcgal_comments.sql

The rest of this chapter goes into detail each of the above installation steps.
As of PostGIS 2.1.3, out-of-db rasters and all raster drivers are disabled by default. In order to re-enable these, you need to set
the following environment variables POSTGIS_GDAL_ENABLED_DRIVERS and POSTGIS_ENABLE_OUTDB_RASTERS in
the server environment. For PostGIS 2.2, you can use the more cross-platform approach of setting the corresponding Section 8.2.
If you want to enable offline raster:
POSTGIS_ENABLE_OUTDB_RASTERS=1

Any other setting or no setting at all will disable out of db rasters.

In order to enable all GDAL drivers available in your GDAL install, set this environment variable as follows
POSTGIS_GDAL_ENABLED_DRIVERS=ENABLE_ALL

If you want to only enable specific drivers, set your environment variable as follows:
POSTGIS_GDAL_ENABLED_DRIVERS="GTiff PNG JPEG GIF XYZ"

Note
If you are on windows, do not quote the driver list

Setting environment variables varies depending on OS. For PostgreSQL installed on Ubuntu or Debian via apt-postgresql, the
preferred way is to edit /etc/postgresql/9.3/main/environment where 9.3 refers to version of PostgreSQL and main
refers to the cluster.
On windows, if you are running as a service, you can set via System variables which for Windows 7 you can get to by right-
clicking on Computer->Properties Advanced System Settings or in explorer navigating to Control Panel\All Control
Panel Items\System. Then clicking Advanced System Settings ->Advanced->Environment Variables and adding new sys-
tem variables.
After you set the environment variables, you’ll need to restart your PostgreSQL service for the changes to take effect.

2.2 Install Requirements

PostGIS has the following requirements for building and usage:

Required
PostGIS 2.4.3 Manual 6 / 803

• PostgreSQL 9.3 or higher. A complete installation of PostgreSQL (including server headers) is required. PostgreSQL is
available from http://www.postgresql.org .
For a full PostgreSQL / PostGIS support matrix and PostGIS/GEOS support matrix refer to http://trac.osgeo.org/postgis/wiki/-
UsersWikiPostgreSQLPostGIS
• GNU C compiler (gcc). Some other ANSI C compilers can be used to compile PostGIS, but we find far fewer problems when
compiling with gcc.
• GNU Make (gmake or make). For many systems, GNU make is the default version of make. Check the version by invoking
make -v. Other versions of make may not process the PostGIS Makefile properly.
• Proj4 reprojection library, version 4.6.0 or greater. Proj4 4.9 or above is needed to take advantage of improved geodetic.
The Proj4 library is used to provide coordinate reprojection support within PostGIS. Proj4 is available for download from
http://trac.osgeo.org/proj/ .
• GEOS geometry library, version 3.4 or greater, but GEOS 3.7+ is recommended to take full advantage of all the new functions
and features. You should have at least GEOS 3.5, without which you will be missing some major enhancements such as
ST_ClipByBox2D and ST_Subdivide. GEOS is available for download from http://trac.osgeo.org/geos/ and 3.5+ is backward-
compatible with older versions so fairly safe to upgrade.
• LibXML2, version 2.5.x or higher. LibXML2 is currently used in some imports functions (ST_GeomFromGML and ST_GeomFromKM
LibXML2 is available for download from http://xmlsoft.org/downloads.html.
• JSON-C, version 0.9 or higher. JSON-C is currently used to import GeoJSON via the function ST_GeomFromGeoJson.
JSON-C is available for download from https://github.com/json-c/json-c/releases/.
• GDAL, version 1.8 or higher (1.9 or higher is strongly recommended since some things will not work well or behavior differ-
ently with lower versions). This is required for raster support and to be able to install with CREATE EXTENSION postgis
so highly recommended for those running 9.1+. http://trac.osgeo.org/gdal/wiki/DownloadSource.

Optional

• GDAL (pseudo optional) only if you don’t want raster and don’t care about installing with CREATE EXTENSION postgis
can you leave it out. Keep in mind other extensions may have a requires postgis extension which will prevent you from
installing them unless you install postgis as an extension. So it is highly recommended you compile with GDAL support.
Also make sure to enable the drivers you want to use as described in Section 2.1.
• GTK (requires GTK+2.0, 2.8+) to compile the shp2pgsql-gui shape file loader. http://www.gtk.org/ .
• SFCGAL, version 1.1 (or higher) could be used to provide additional 2D and 3D advanced analysis functions to PostGIS cf
Section 8.10. And also allow to use SFCGAL rather than GEOS for some 2D functions provided by both backends (like
ST_Intersection or ST_Area, for instance). A PostgreSQL configuration variable postgis.backend allow end user to
control which backend he want to use if SFCGAL is installed (GEOS by default). Nota: SFCGAL 1.2 require at least CGAL
4.3 and Boost 1.54 (cf: http://oslandia.github.io/SFCGAL/installation.html) https://github.com/Oslandia/SFCGAL.
• In order to build the Chapter 12 you will also need PCRE http://www.pcre.org (which generally is already installed on nix sys-
tems). Regex::Assemble perl CPAN package is only needed if you want to rebuild the data encoded in parseaddress-stciti
h. Chapter 12 will automatically be built if it detects a PCRE library, or you pass in a valid --with-pcre-dir=/path/to/pcre
during configure.
• To enable ST_AsMVT protobuf-c library (for usage) and the protoc-c compiler (for building) are required. Also, pkg-config is
required to verify the correct minimum version of protobuf-c. See protobuf-c.
• CUnit (CUnit). This is needed for regression testing. http://cunit.sourceforge.net/
• DocBook (xsltproc) is required for building the documentation. Docbook is available from http://www.docbook.org/ .
• DBLatex (dblatex) is required for building the documentation in PDF format. DBLatex is available from http://dblatex.sourceforge.n
.
• ImageMagick (convert) is required to generate the images used in the documentation. ImageMagick is available from
http://www.imagemagick.org/ .
PostGIS 2.4.3 Manual 7 / 803

2.3 Getting the Source

Retrieve the PostGIS source archive from the downloads website http://download.osgeo.org/postgis/source/postgis-2.4.3.tar.gz
wget http://download.osgeo.org/postgis/source/postgis-2.4.3.tar.gz
tar -xvzf postgis-2.4.3.tar.gz

This will create a directory called postgis-2.4.3 in the current working directory.
Alternatively, checkout the source from the svn repository http://svn.osgeo.org/postgis/trunk/ .
svn checkout http://svn.osgeo.org/postgis/trunk/ postgis-2.4.3

Change into the newly created postgis-2.4.3 directory to continue the installation.

2.4 Compiling and Install from Source: Detailed

Note
Many OS systems now include pre-built packages for PostgreSQL/PostGIS. In many cases compilation is only neces-
sary if you want the most bleeding edge versions or you are a package maintainer.
This section includes general compilation instructions, if you are compiling for Windows etc or another OS, you may
find additional more detailed help at PostGIS User contributed compile guides and PostGIS Dev Wiki.
Pre-Built Packages for various OS are listed in PostGIS Pre-built Packages
If you are a windows user, you can get stable builds via Stackbuilder or PostGIS Windows download site We also
have very bleeding-edge windows experimental builds that are built usually once or twice a week or whenever anything
exciting happens. You can use these to experiment with the in progress releases of PostGIS

The PostGIS module is an extension to the PostgreSQL backend server. As such, PostGIS 2.4.3 requires full PostgreSQL server
headers access in order to compile. It can be built against PostgreSQL versions 9.3 or higher. Earlier versions of PostgreSQL are
not supported.
Refer to the PostgreSQL installation guides if you haven’t already installed PostgreSQL. http://www.postgresql.org .

Note
For GEOS functionality, when you install PostgresSQL you may need to explicitly link PostgreSQL against the standard
C++ library:
LDFLAGS=-lstdc++ ./configure [YOUR OPTIONS HERE]

This is a workaround for bogus C++ exceptions interaction with older development tools. If you experience weird
problems (backend unexpectedly closed or similar things) try this trick. This will require recompiling your PostgreSQL
from scratch, of course.

The following steps outline the configuration and compilation of the PostGIS source. They are written for Linux users and will
not work on Windows or Mac.

2.4.1 Configuration

As with most linux installations, the first step is to generate the Makefile that will be used to build the source code. This is done
by running the shell script
./configure
PostGIS 2.4.3 Manual 8 / 803

With no additional parameters, this command will attempt to automatically locate the required components and libraries needed
to build the PostGIS source code on your system. Although this is the most common usage of ./configure, the script accepts
several parameters for those who have the required libraries and programs in non-standard locations.
The following list shows only the most commonly used parameters. For a complete list, use the --help or --help=short parame-
ters.

--prefix=PREFIX This is the location the PostGIS libraries and SQL scripts will be installed to. By default, this location is the
same as the detected PostgreSQL installation.

Caution
This parameter is currently broken, as the package will only install into the PostgreSQL installation directory. Visit
http://trac.osgeo.org/postgis/ticket/635 to track this bug.

--with-pgconfig=FILE PostgreSQL provides a utility called pg_config to enable extensions like PostGIS to locate the Post-
greSQL installation directory. Use this parameter (--with-pgconfig=/path/to/pg_config) to manually specify a particular
PostgreSQL installation that PostGIS will build against.
--with-gdalconfig=FILE GDAL, a required library, provides functionality needed for raster support gdal-config to enable soft-
ware installations to locate the GDAL installation directory. Use this parameter (--with-gdalconfig=/path/to/gdal-config)
to manually specify a particular GDAL installation that PostGIS will build against.

--with-geosconfig=FILE GEOS, a required geometry library, provides a utility called geos-config to enable software installa-
tions to locate the GEOS installation directory. Use this parameter (--with-geosconfig=/path/to/geos-config) to manually
specify a particular GEOS installation that PostGIS will build against.
--with-xml2config=FILE LibXML is the library required for doing GeomFromKML/GML processes. It normally is found
if you have libxml installed, but if not or you want a specific version used, you’ll need to point PostGIS at a specific
xml2-config confi file to enable software installations to locate the LibXML installation directory. Use this parameter
(>--with-xml2config=/path/to/xml2-config) to manually specify a particular LibXML installation that PostGIS will build
against.
--with-projdir=DIR Proj4 is a reprojection library required by PostGIS. Use this parameter (--with-projdir=/path/to/projdir)
to manually specify a particular Proj4 installation directory that PostGIS will build against.

--with-libiconv=DIR Directory where iconv is installed.

--with-jsondir=DIR JSON-C is an MIT-licensed JSON library required by PostGIS ST_GeomFromJSON support. Use this
parameter (--with-jsondir=/path/to/jsondir) to manually specify a particular JSON-C installation directory that PostGIS
will build against.

--with-pcredir=DIR PCRE is an BSD-licensed Perl Compatible Regular Expression library required by address_standardizer
extension. Use this parameter (--with-pcredir=/path/to/pcredir) to manually specify a particular PCRE installation di-
rectory that PostGIS will build against.
--with-gui Compile the data import GUI (requires GTK+2.0). This will create shp2pgsql-gui graphical interface to shp2pgsql.

--with-raster Compile with raster support. This will build rtpostgis-2.4.3 library and rtpostgis.sql file. This may not be required
in final release as plan is to build in raster support by default.
--without-topology Disable topology support. There is no corresponding library as all logic needed for topology is in postgis-
2.4.3 library.
--with-gettext=no By default PostGIS will try to detect gettext support and compile with it, however if you run into incompatibil-
ity issues that cause breakage of loader, you can disable it entirely with this command. Refer to ticket http://trac.osgeo.org/-
postgis/ticket/748 for an example issue solved by configuring with this. NOTE: that you aren’t missing much by turning
this off. This is used for international help/label support for the GUI loader which is not yet documented and still experi-
mental.
PostGIS 2.4.3 Manual 9 / 803

--with-sfcgal=PATH By default PostGIS will not install with sfcgal support without this switch. PATH is an optional argument
that allows to specify an alternate PATH to sfcgal-config.

Note
If you obtained PostGIS from the SVN repository , the first step is really to run the script
./autogen.sh
This script will generate the configure script that in turn is used to customize the installation of PostGIS.
If you instead obtained PostGIS as a tarball, running ./autogen.sh is not necessary as configure has already been
generated.

2.4.2 Building

Once the Makefile has been generated, building PostGIS is as simple as running
make
The last line of the output should be "PostGIS was built successfully. Ready to install."
As of PostGIS v1.4.0, all the functions have comments generated from the documentation. If you wish to install these comments
into your spatial databases later, run the command which requires docbook. The postgis_comments.sql and other package
comments files raster_comments.sql, topology_comments.sql are also packaged in the tar.gz distribution in the doc folder so no
need to make comments if installing from the tar ball. Comments are also included as part of the CREATE EXTENSION install.
make comments
Introduced in PostGIS 2.0. This generates html cheat sheets suitable for quick reference or for student handouts. This requires
xsltproc to build and will generate 4 files in doc folder topology_cheatsheet.html, tiger_geocoder_cheatsheet.
html, raster_cheatsheet.html, postgis_cheatsheet.html
You can download some pre-built ones available in html and pdf from PostGIS / PostgreSQL Study Guides
make cheatsheets

2.4.3 Building PostGIS Extensions and Deploying them

The PostGIS extensions are built and installed automatically if you are using PostgreSQL 9.1+.
If you are building from source repository, you need to build the function descriptions first. These get built if you have docbook
installed. You can also manually build with the statement:
make comments
Building the comments is not necessary if you are building from a release tar ball since these are packaged pre-built with the tar
ball already.
If you are building against PostgreSQL 9.1, the extensions should automatically build as part of the make install process. You
can if needed build from the extensions folders or copy files if you need them on a different server.
cd extensions
cd postgis
make clean
make
make install
cd ..
cd postgis_topology
make clean
make
make install
cd ..
cd postgis_sfcgal
make clean
PostGIS 2.4.3 Manual 10 / 803

make
make install

cd ..
cd address_standardizer
make clean
make
make install
make installcheck

cd ..
cd postgis_tiger_geocoder
make clean
make
make install
make installcheck

The extension files will always be the same for the same version of PostGIS regardless of OS, so it is fine to copy over the
extension files from one OS to another as long as you have the PostGIS binaries already installed on your servers.
If you want to install the extensions manually on a separate server different from your development, You need to copy the
following files from the extensions folder into the PostgreSQL / share / extension folder of your PostgreSQL install
as well as the needed binaries for regular PostGIS if you don’t have them already on the server.

• These are the control files that denote information such as the version of the extension to install if not specified. postgis.
control, postgis_topology.control.
• All the files in the /sql folder of each extension. Note that these need to be copied to the root of the PostgreSQL share/extension
folder extensions/postgis/sql/*.sql, extensions/postgis_topology/sql/*.sql

Once you do that, you should see postgis, postgis_topology as available extensions in PgAdmin -> extensions.
If you are using psql, you can verify that the extensions are installed by running this query:
SELECT name, default_version,installed_version
FROM pg_available_extensions WHERE name LIKE 'postgis%' or name LIKE 'address%';

name | default_version | installed_version

------------------------------+-----------------+-------------------
address_standardizer | 2.4.3 | 2.4.3
address_standardizer_data_us | 2.4.3 | 2.4.3
postgis | 2.4.3 | 2.4.3
postgis_sfcgal | 2.4.3 |
postgis_tiger_geocoder | 2.4.3 | 2.4.3
postgis_topology | 2.4.3 |
(6 rows)

If you have the extension installed in the database you are querying, you’ll see mention in the installed_version column.
If you get no records back, it means you don’t have postgis extensions installed on the server at all. PgAdmin III 1.14+ will also
provide this information in the extensions section of the database browser tree and will even allow upgrade or uninstall by
right-clicking.
If you have the extensions available, you can install postgis extension in your database of choice by either using pgAdmin
extension interface or running these sql commands:
CREATE EXTENSION postgis;
CREATE EXTENSION postgis_sfcgal;
CREATE EXTENSION fuzzystrmatch; --needed for postgis_tiger_geocoder
--optional used by postgis_tiger_geocoder, or can be used standalone
CREATE EXTENSION address_standardizer;
CREATE EXTENSION address_standardizer_data_us;
CREATE EXTENSION postgis_tiger_geocoder;
CREATE EXTENSION postgis_topology;
PostGIS 2.4.3 Manual 11 / 803

In psql you can use to see what versions you have installed and also what schema they are installed.
\connect mygisdb
\x
\dx postgis*

List of installed extensions

-[ RECORD 1 ]-------------------------------------------------
-
Name | postgis
Version | 2.4.3
Schema | public
Description | PostGIS geometry, geography, and raster spat..
-[ RECORD 2 ]-------------------------------------------------
-
Name | postgis_tiger_geocoder
Version | 2.4.3
Schema | tiger
Description | PostGIS tiger geocoder and reverse geocoder
-[ RECORD 3 ]-------------------------------------------------
-
Name | postgis_topology
Version | 2.4.3
Schema | topology
Description | PostGIS topology spatial types and functions

Warning
Extension tables spatial_ref_sys, layer, topology can not be explicitly backed up. They can only be backed
up when the respective postgis or postgis_topology extension is backed up, which only seems to happen
when you backup the whole database. As of PostGIS 2.0.1, only srid records not packaged with PostGIS are backed
up when the database is backed up so don’t go around changing srids we package and expect your changes to be
there. Put in a ticket if you find an issue. The structures of extension tables are never backed up since they are created
with CREATE EXTENSION and assumed to be the same for a given version of an extension. These behaviors are
built into the current PostgreSQL extension model, so nothing we can do about it.

If you installed 2.4.3, without using our wonderful extension system, you can change it to be extension based by first upgrading
to the latest micro version running the upgrade scripts: postgis_upgrade_22_minor.sql,raster_upgrade_22_
minor.sql,topology_upgrade_22_minor.sql.
If you installed postgis without raster support, you’ll need to install raster support first (using the full rtpostgis.sql
Then you can run the below commands to package the functions in their respective extension.
CREATE EXTENSION postgis FROM unpackaged;
CREATE EXTENSION postgis_topology FROM unpackaged;
CREATE EXTENSION postgis_tiger_geocoder FROM unpackaged;

2.4.4 Testing

If you wish to test the PostGIS build, run

make check
The above command will run through various checks and regression tests using the generated library against an actual Post-
greSQL database.
PostGIS 2.4.3 Manual 12 / 803

Note
If you configured PostGIS using non-standard PostgreSQL, GEOS, or Proj4 locations, you may need to add their library
locations to the LD_LIBRARY_PATH environment variable.

Caution
Currently, the make check relies on the PATH and PGPORT environment variables when performing the checks - it
does not use the PostgreSQL version that may have been specified using the configuration parameter --with-pgconfig.
So make sure to modify your PATH to match the detected PostgreSQL installation during configuration or be prepared
to deal with the impending headaches.

If successful, the output of the test should be similar to the following:

CUnit - A unit testing framework for C - Version 2.1-2
http://cunit.sourceforge.net/

Suite: computational_geometry
Test: test_lw_segment_side ...passed
Test: test_lw_segment_intersects ...passed
Test: test_lwline_crossing_short_lines ...passed
Test: test_lwline_crossing_long_lines ...passed
Test: test_lwline_crossing_bugs ...passed
Test: test_lwpoint_set_ordinate ...passed
Test: test_lwpoint_get_ordinate ...passed
Test: test_point_interpolate ...passed
Test: test_lwline_clip ...passed
Test: test_lwline_clip_big ...passed
Test: test_lwmline_clip ...passed
Test: test_geohash_point ...passed
Test: test_geohash_precision ...passed
Test: test_geohash ...passed
Test: test_geohash_point_as_int ...passed
Test: test_isclosed ...passed
Test: test_lwgeom_simplify ...passed
Suite: buildarea
Test: buildarea1 ...passed
Test: buildarea2 ...passed
Test: buildarea3 ...passed
Test: buildarea4 ...passed
Test: buildarea4b ...passed
Test: buildarea5 ...passed
Test: buildarea6 ...passed
Test: buildarea7 ...passed
Suite: geometry_clean
Test: test_lwgeom_make_valid ...passed
Suite: clip_by_rectangle
Test: test_lwgeom_clip_by_rect ...passed
Suite: force_sfs
Test: test_sfs_11 ...passed
Test: test_sfs_12 ...passed
Test: test_sqlmm ...passed
Suite: geodetic
Test: test_sphere_direction ...passed
Test: test_sphere_project ...passed
Test: test_lwgeom_area_sphere ...passed
Test: test_signum ...passed
Test: test_gbox_from_spherical_coordinates ...passed
Test: test_gserialized_get_gbox_geocentric ...passed
PostGIS 2.4.3 Manual 13 / 803

Test: test_clairaut ...passed

Test: test_edge_intersection ...passed
Test: test_edge_intersects ...passed
Test: test_edge_distance_to_point ...passed
Test: test_edge_distance_to_edge ...passed
Test: test_lwgeom_distance_sphere ...passed
Test: test_lwgeom_check_geodetic ...passed
Test: test_gserialized_from_lwgeom ...passed
Test: test_spheroid_distance ...passed
Test: test_spheroid_area ...passed
Test: test_lwpoly_covers_point2d ...passed
Test: test_gbox_utils ...passed
Test: test_vector_angle ...passed
Test: test_vector_rotate ...passed
Test: test_lwgeom_segmentize_sphere ...passed
Test: test_ptarray_contains_point_sphere ...passed
Test: test_ptarray_contains_point_sphere_iowa ...passed
Suite: GEOS
Test: test_geos_noop ...passed
Test: test_geos_subdivide ...passed
Test: test_geos_linemerge ...passed
Suite: Clustering
Test: basic_test ...passed
Test: nonsequential_test ...passed
Test: basic_distance_test ...passed
Test: single_input_test ...passed
Test: empty_inputs_test ...passed
Suite: Clustering Union-Find
Test: test_unionfind_create ...passed
Test: test_unionfind_union ...passed
Test: test_unionfind_ordered_by_cluster ...passed
Suite: homogenize
Test: test_coll_point ...passed
Test: test_coll_line ...passed
Test: test_coll_poly ...passed
Test: test_coll_coll ...passed
Test: test_geom ...passed
Test: test_coll_curve ...passed
Suite: encoded_polyline_input
Test: in_encoded_polyline_test_geoms ...passed
Test: in_encoded_polyline_test_precision ...passed
Suite: geojson_input
Test: in_geojson_test_srid ...passed
Test: in_geojson_test_bbox ...passed
Test: in_geojson_test_geoms ...passed
Suite: twkb_input
Test: test_twkb_in_point ...passed
Test: test_twkb_in_linestring ...passed
Test: test_twkb_in_polygon ...passed
Test: test_twkb_in_multipoint ...passed
Test: test_twkb_in_multilinestring ...passed
Test: test_twkb_in_multipolygon ...passed
Test: test_twkb_in_collection ...passed
Test: test_twkb_in_precision ...passed
Suite: serialization/deserialization
Test: test_typmod_macros ...passed
Test: test_flags_macros ...passed
Test: test_serialized_srid ...passed
Test: test_gserialized_from_lwgeom_size ...passed
Test: test_gbox_serialized_size ...passed
Test: test_lwgeom_from_gserialized ...passed
Test: test_lwgeom_count_vertices ...passed
PostGIS 2.4.3 Manual 14 / 803

Test: test_on_gser_lwgeom_count_vertices ...passed

Test: test_geometry_type_from_string ...passed
Test: test_lwcollection_extract ...passed
Test: test_lwgeom_free ...passed
Test: test_lwgeom_flip_coordinates ...passed
Test: test_f2d ...passed
Test: test_lwgeom_clone ...passed
Test: test_lwgeom_force_clockwise ...passed
Test: test_lwgeom_calculate_gbox ...passed
Test: test_lwgeom_is_empty ...passed
Test: test_lwgeom_same ...passed
Test: test_lwline_from_lwmpoint ...passed
Test: test_lwgeom_as_curve ...passed
Test: test_lwgeom_scale ...passed
Test: test_gserialized_is_empty ...passed
Test: test_gbox_same_2d ...passed
Suite: measures
Test: test_mindistance2d_tolerance ...passed
Test: test_rect_tree_contains_point ...passed
Test: test_rect_tree_intersects_tree ...passed
Test: test_lwgeom_segmentize2d ...passed
Test: test_lwgeom_locate_along ...passed
Test: test_lw_dist2d_pt_arc ...passed
Test: test_lw_dist2d_seg_arc ...passed
Test: test_lw_dist2d_arc_arc ...passed
Test: test_lw_arc_length ...passed
Test: test_lw_dist2d_pt_ptarrayarc ...passed
Test: test_lw_dist2d_ptarray_ptarrayarc ...passed
Test: test_lwgeom_tcpa ...passed
Test: test_lwgeom_is_trajectory ...passed
Suite: effectivearea
Test: do_test_lwgeom_effectivearea_lines ...passed
Test: do_test_lwgeom_effectivearea_polys ...passed
Suite: miscellaneous
Test: test_misc_force_2d ...passed
Test: test_misc_simplify ...passed
Test: test_misc_count_vertices ...passed
Test: test_misc_area ...passed
Test: test_misc_wkb ...passed
Test: test_grid ...passed
Suite: noding
Test: test_lwgeom_node ...passed
Suite: encoded_polyline_output
Test: out_encoded_polyline_test_geoms ...passed
Test: out_encoded_polyline_test_srid ...passed
Test: out_encoded_polyline_test_precision ...passed
Suite: geojson_output
Test: out_geojson_test_precision ...passed
Test: out_geojson_test_dims ...passed
Test: out_geojson_test_srid ...passed
Test: out_geojson_test_bbox ...passed
Test: out_geojson_test_geoms ...passed
Suite: gml_output
Test: out_gml_test_precision ...passed
Test: out_gml_test_srid ...passed
Test: out_gml_test_dims ...passed
Test: out_gml_test_geodetic ...passed
Test: out_gml_test_geoms ...passed
Test: out_gml_test_geoms_prefix ...passed
Test: out_gml_test_geoms_nodims ...passed
Test: out_gml2_extent ...passed
Test: out_gml3_extent ...passed
PostGIS 2.4.3 Manual 15 / 803

Suite: kml_output
Test: out_kml_test_precision ...passed
Test: out_kml_test_dims ...passed
Test: out_kml_test_geoms ...passed
Test: out_kml_test_prefix ...passed
Suite: svg_output
Test: out_svg_test_precision ...passed
Test: out_svg_test_dims ...passed
Test: out_svg_test_relative ...passed
Test: out_svg_test_geoms ...passed
Test: out_svg_test_srid ...passed
Suite: x3d_output
Test: out_x3d3_test_precision ...passed
Test: out_x3d3_test_geoms ...passed
Test: out_x3d3_test_option ...passed
Suite: ptarray
Test: test_ptarray_append_point ...passed
Test: test_ptarray_append_ptarray ...passed
Test: test_ptarray_locate_point ...passed
Test: test_ptarray_isccw ...passed
Test: test_ptarray_signed_area ...passed
Test: test_ptarray_unstroke ...passed
Test: test_ptarray_insert_point ...passed
Test: test_ptarray_contains_point ...passed
Test: test_ptarrayarc_contains_point ...passed
Test: test_ptarray_scale ...passed
Suite: printing
Test: test_lwprint_default_format ...passed
Test: test_lwprint_format_orders ...passed
Test: test_lwprint_optional_format ...passed
Test: test_lwprint_oddball_formats ...passed
Test: test_lwprint_bad_formats ...passed
Suite: SFCGAL
Test: test_sfcgal_noop ...passed
Suite: split
Test: test_lwline_split_by_point_to ...passed
Test: test_lwgeom_split ...passed
Suite: stringbuffer
Test: test_stringbuffer_append ...passed
Test: test_stringbuffer_aprintf ...passed
Suite: surface
Test: triangle_parse ...passed
Test: tin_parse ...passed
Test: polyhedralsurface_parse ...passed
Test: surface_dimension ...passed
Suite: Internal Spatial Trees
Test: test_tree_circ_create ...passed
Test: test_tree_circ_pip ...passed
Test: test_tree_circ_pip2 ...passed
Test: test_tree_circ_distance ...passed
Test: test_tree_circ_distance_threshold ...passed
Suite: triangulate
Test: test_lwgeom_delaunay_triangulation ...passed
Suite: twkb_output
Test: test_twkb_out_point ...passed
Test: test_twkb_out_linestring ...passed
Test: test_twkb_out_polygon ...passed
Test: test_twkb_out_multipoint ...passed
Test: test_twkb_out_multilinestring ...passed
Test: test_twkb_out_multipolygon ...passed
Test: test_twkb_out_collection ...passed
Test: test_twkb_out_idlist ...passed
PostGIS 2.4.3 Manual 16 / 803

Suite: varint
Test: test_zigzag ...passed
Test: test_varint ...passed
Test: test_varint_roundtrip ...passed
Suite: wkb_input
Test: test_wkb_in_point ...passed
Test: test_wkb_in_linestring ...passed
Test: test_wkb_in_polygon ...passed
Test: test_wkb_in_multipoint ...passed
Test: test_wkb_in_multilinestring ...passed
Test: test_wkb_in_multipolygon ...passed
Test: test_wkb_in_collection ...passed
Test: test_wkb_in_circularstring ...passed
Test: test_wkb_in_compoundcurve ...passed
Test: test_wkb_in_curvpolygon ...passed
Test: test_wkb_in_multicurve ...passed
Test: test_wkb_in_multisurface ...passed
Test: test_wkb_in_malformed ...passed
Suite: wkb_output
Test: test_wkb_out_point ...passed
Test: test_wkb_out_linestring ...passed
Test: test_wkb_out_polygon ...passed
Test: test_wkb_out_multipoint ...passed
Test: test_wkb_out_multilinestring ...passed
Test: test_wkb_out_multipolygon ...passed
Test: test_wkb_out_collection ...passed
Test: test_wkb_out_circularstring ...passed
Test: test_wkb_out_compoundcurve ...passed
Test: test_wkb_out_curvpolygon ...passed
Test: test_wkb_out_multicurve ...passed
Test: test_wkb_out_multisurface ...passed
Test: test_wkb_out_polyhedralsurface ...passed
Suite: wkt_input
Test: test_wkt_in_point ...passed
Test: test_wkt_in_linestring ...passed
Test: test_wkt_in_polygon ...passed
Test: test_wkt_in_multipoint ...passed
Test: test_wkt_in_multilinestring ...passed
Test: test_wkt_in_multipolygon ...passed
Test: test_wkt_in_collection ...passed
Test: test_wkt_in_circularstring ...passed
Test: test_wkt_in_compoundcurve ...passed
Test: test_wkt_in_curvpolygon ...passed
Test: test_wkt_in_multicurve ...passed
Test: test_wkt_in_multisurface ...passed
Test: test_wkt_in_tin ...passed
Test: test_wkt_in_polyhedralsurface ...passed
Test: test_wkt_in_errlocation ...passed
Suite: wkt_output
Test: test_wkt_out_point ...passed
Test: test_wkt_out_linestring ...passed
Test: test_wkt_out_polygon ...passed
Test: test_wkt_out_multipoint ...passed
Test: test_wkt_out_multilinestring ...passed
Test: test_wkt_out_multipolygon ...passed
Test: test_wkt_out_collection ...passed
Test: test_wkt_out_circularstring ...passed
Test: test_wkt_out_compoundcurve ...passed
Test: test_wkt_out_curvpolygon ...passed
Test: test_wkt_out_multicurve ...passed
Test: test_wkt_out_multisurface ...passed
PostGIS 2.4.3 Manual 17 / 803

Run Summary: Type Total Ran Passed Failed Inactive

suites 38 38 n/a 0 0
tests 251 251 251 0 0
asserts 2468 2468 2468 0 n/a

Elapsed time = 0.298 seconds

Creating database 'postgis_reg'

Loading PostGIS into 'postgis_reg'
/projects/postgis/branches/2.2/regress/00-regress-install/share/contrib/postgis/postgis. ←-
sql
/projects/postgis/branches/2.2/regress/00-regress-install/share/contrib/postgis/ ←-
postgis_comments.sql
Loading SFCGAL into 'postgis_reg'
/projects/postgis/branches/2.2/regress/00-regress-install/share/contrib/postgis/sfcgal. ←-
sql
/projects/postgis/branches/2.2/regress/00-regress-install/share/contrib/postgis/ ←-
sfcgal_comments.sql
PostgreSQL 9.4.4, compiled by Visual C++ build 1800, 32-bit
Postgis 2.2.0dev - r13980 - 2015-08-23 06:13:07
scripts 2.2.0dev r13980
GEOS: 3.5.0-CAPI-1.9.0 r4088
PROJ: Rel. 4.9.1, 04 March 2015
SFCGAL: 1.1.0

Running tests

loader/Point .............. ok
loader/PointM .............. ok
loader/PointZ .............. ok
loader/MultiPoint .............. ok
loader/MultiPointM .............. ok
loader/MultiPointZ .............. ok
loader/Arc .............. ok
loader/ArcM .............. ok
loader/ArcZ .............. ok
loader/Polygon .............. ok
loader/PolygonM .............. ok
loader/PolygonZ .............. ok
loader/TSTPolygon ......... ok
loader/TSIPolygon ......... ok
loader/TSTIPolygon ......... ok
loader/PointWithSchema ..... ok
loader/NoTransPoint ......... ok
loader/NotReallyMultiPoint ......... ok
loader/MultiToSinglePoint ......... ok
loader/ReprojectPts ........ ok
loader/ReprojectPtsGeog ........ ok
loader/Latin1 .... ok
loader/Latin1-implicit .... ok
loader/mfile .... ok
dumper/literalsrid ....... ok
dumper/realtable ....... ok
affine .. ok
bestsrid .. ok
binary .. ok
boundary .. ok
cluster .. ok
concave_hull .. ok
ctors .. ok
dump .. ok
dumppoints .. ok
PostGIS 2.4.3 Manual 18 / 803

empty .. ok
forcecurve .. ok
geography .. ok
in_geohash .. ok
in_gml .. ok
in_kml .. ok
in_encodedpolyline .. ok
iscollection .. ok
legacy .. ok
long_xact .. ok
lwgeom_regress .. ok
measures .. ok
operators .. ok
out_geometry .. ok
out_geography .. ok
polygonize .. ok
polyhedralsurface .. ok
postgis_type_name .. ok
regress .. ok
regress_bdpoly .. ok
regress_index .. ok
regress_index_nulls .. ok
regress_management .. ok
regress_selectivity .. ok
regress_lrs .. ok
regress_ogc .. ok
regress_ogc_cover .. ok
regress_ogc_prep .. ok
regress_proj .. ok
relate .. ok
remove_repeated_points .. ok
removepoint .. ok
setpoint .. ok
simplify .. ok
simplifyvw .. ok
size .. ok
snaptogrid .. ok
split .. ok
sql-mm-serialize .. ok
sql-mm-circularstring .. ok
sql-mm-compoundcurve .. ok
sql-mm-curvepoly .. ok
sql-mm-general .. ok
sql-mm-multicurve .. ok
sql-mm-multisurface .. ok
swapordinates .. ok
summary .. ok
temporal .. ok
tickets .. ok
twkb .. ok
typmod .. ok
wkb .. ok
wkt .. ok
wmsservers .. ok
knn .. ok
hausdorff .. ok
regress_buffer_params .. ok
offsetcurve .. ok
relatematch .. ok
isvaliddetail .. ok
sharedpaths .. ok
snap .. ok
PostGIS 2.4.3 Manual 19 / 803

node .. ok
unaryunion .. ok
clean .. ok
relate_bnr .. ok
delaunaytriangles .. ok
clipbybox2d .. ok
subdivide .. ok
in_geojson .. ok
regress_sfcgal .. ok
sfcgal/empty .. ok
sfcgal/geography .. ok
sfcgal/legacy .. ok
sfcgal/measures .. ok
sfcgal/regress_ogc_prep .. ok
sfcgal/regress_ogc .. ok
sfcgal/regress .. ok
sfcgal/tickets .. ok
sfcgal/concave_hull .. ok
sfcgal/wmsservers .. ok
sfcgal/approximatemedialaxis .. ok
uninstall . /projects/postgis/branches/2.2/regress/00-regress-install/share/contrib/ ←-
postgis/uninstall_sfcgal.sql
/projects/postgis/branches/2.2/regress/00-regress-install/share/contrib/postgis/ ←-
uninstall_postgis.sql
. ok (4336)

Run tests: 118

Failed: 0

-- if you built --with-gui, you should see this too

CUnit - A unit testing framework for C - Version 2.1-2

http://cunit.sourceforge.net/

Suite: Shapefile Loader File shp2pgsql Test

Test: test_ShpLoaderCreate() ...passed
Test: test_ShpLoaderDestroy() ...passed
Suite: Shapefile Loader File pgsql2shp Test
Test: test_ShpDumperCreate() ...passed
Test: test_ShpDumperDestroy() ...passed

Run Summary: Type Total Ran Passed Failed Inactive

suites 2 2 n/a 0 0
tests 4 4 4 0 0
asserts 4 4 4 0 n/a

The postgis_tiger_geocoder and address_standardizer extensions, currenlty only support the standard Post-
greSQL installcheck. To test these use the below. Note: the make install is not necessary if you already did make install at root
of PostGIS code folder.
For address_standardizer:
cd extensions/address_standardizer
make install
make installcheck

Output should look like:

============== dropping database "contrib_regression" ==============
DROP DATABASE
============== creating database "contrib_regression" ==============
PostGIS 2.4.3 Manual 20 / 803

CREATE DATABASE
ALTER DATABASE
============== running regression test queries ==============
test test-init-extensions ... ok
test test-parseaddress ... ok
test test-standardize_address_1 ... ok
test test-standardize_address_2 ... ok

=====================
All 4 tests passed.
=====================

For tiger geocoder, make sure you have postgis and fuzzystrmatch extensions available in your PostgreSQL instance. The
address_standardizer tests will also kick in if you built postgis with address_standardizer support:
cd extensions/postgis_tiger_geocoder
make install
make installcheck

output should look like:

============== dropping database "contrib_regression" ==============
DROP DATABASE
============== creating database "contrib_regression" ==============
CREATE DATABASE
ALTER DATABASE
============== installing fuzzystrmatch ==============
CREATE EXTENSION
============== installing postgis ==============
CREATE EXTENSION
============== installing postgis_tiger_geocoder ==============
CREATE EXTENSION
============== installing address_standardizer ==============
CREATE EXTENSION
============== running regression test queries ==============
test test-normalize_address ... ok
test test-pagc_normalize_address ... ok

=====================
All 2 tests passed.
=====================

2.4.5 Installation

To install PostGIS, type

make install
This will copy the PostGIS installation files into their appropriate subdirectory specified by the --prefix configuration parameter.
In particular:

• The loader and dumper binaries are installed in [prefix]/bin.

• The SQL files, such as postgis.sql, are installed in [prefix]/share/contrib.
• The PostGIS libraries are installed in [prefix]/lib.

If you previously ran the make comments command to generate the postgis_comments.sql, raster_comments.sql
file, install the sql file by running
make comments-install
PostGIS 2.4.3 Manual 21 / 803

Note
postgis_comments.sql, raster_comments.sql, topology_comments.sql was separated from the
typical build and installation targets since with it comes the extra dependency of xsltproc.

2.5 Creating a spatial database using EXTENSIONS

If you are using PostgreSQL 9.1+ and have compiled and installed the extensions/ postgis modules, you can create a spatial
database the new way.
createdb [yourdatabase]
The core postgis extension installs PostGIS geometry, geography, raster, spatial_ref_sys and all the functions and comments with
a simple:
CREATE EXTENSION postgis;

command.
psql -d [yourdatabase] -c "CREATE EXTENSION postgis;"
Topology is packaged as a separate extension and installable with command:
psql -d [yourdatabase] -c "CREATE EXTENSION postgis_topology;"
If you plan to restore an old backup from prior versions in this new db, run:
psql -d [yourdatabase] -f legacy.sql
You can later run uninstall_legacy.sql to get rid of the deprecated functions after you are done with restoring and
cleanup.

2.6 Create a spatially-enabled database without using extensions

Note
This is generally only needed if you built-PostGIS without raster support. Since raster functions are part of the postgis
extension, extension support is not enabled if PostGIS is built without raster.

The first step in creating a PostGIS database is to create a simple PostgreSQL database.
createdb [yourdatabase]
Many of the PostGIS functions are written in the PL/pgSQL procedural language. As such, the next step to create a PostGIS
database is to enable the PL/pgSQL language in your new database. This is accomplish by the command below command. For
PostgreSQL 8.4+, this is generally already installed
createlang plpgsql [yourdatabase]
Now load the PostGIS object and function definitions into your database by loading the postgis.sql definitions file (located
in [prefix]/share/contrib as specified during the configuration step).
psql -d [yourdatabase] -f postgis.sql
For a complete set of EPSG coordinate system definition identifiers, you can also load the spatial_ref_sys.sql definitions
file and populate the spatial_ref_sys table. This will permit you to perform ST_Transform() operations on geometries.
psql -d [yourdatabase] -f spatial_ref_sys.sql
PostGIS 2.4.3 Manual 22 / 803

If you wish to add comments to the PostGIS functions, the final step is to load the postgis_comments.sql into your spatial
database. The comments can be viewed by simply typing \dd [function_name] from a psql terminal window.
psql -d [yourdatabase] -f postgis_comments.sql
Install raster support
psql -d [yourdatabase] -f rtpostgis.sql
Install raster support comments. This will provide quick help info for each raster function using psql or PgAdmin or any other
PostgreSQL tool that can show function comments
psql -d [yourdatabase] -f raster_comments.sql
Install topology support
psql -d [yourdatabase] -f topology/topology.sql
Install topology support comments. This will provide quick help info for each topology function / type using psql or PgAdmin
or any other PostgreSQL tool that can show function comments
psql -d [yourdatabase] -f topology/topology_comments.sql
If you plan to restore an old backup from prior versions in this new db, run:
psql -d [yourdatabase] -f legacy.sql

Note
There is an alternative legacy_minimal.sql you can run instead which will install barebones needed to recover
tables and work with apps like MapServer and GeoServer. If you have views that use things like distance / length etc,
you’ll need the full blown legacy.sql

You can later run uninstall_legacy.sql to get rid of the deprecated functions after you are done with restoring and
cleanup.

2.7 Installing and Using the address standardizer

The address_standardizer extension used to be a separate package that required separate download. From PostGIS 2.2
on, it is now bundled in. For more information about the address_standardize, what it does, and how to configure it for your
needs, refer to Chapter 12.
This standardizer can be used in conjunction with the PostGIS packaged tiger geocoder extension as a replacement for the
Normalize_Address discussed. To use as replacement refer to Section 2.8.3. You can also use it as a building block for your own
geocoder or use it to standardize your addresses for easier compare of addresses.
The address standardizer relies on PCRE which is usually already installed on many Nix systems, but you can download the
latest at: http://www.pcre.org. If during Section 2.4.1, PCRE is found, then the address standardizer extension will automatically
be built. If you have a custom pcre install you want to use instead, pass to configure --with-pcredir=/path/to/pcre
where /path/to/pcre is the root folder for your pcre include and lib directories.
For Windows users, the PostGIS 2.1+ bundle is packaged with the address_standardizer already so no need to compile and can
move straight to CREATE EXTENSION step.
Once you have installed, you can connect to your database and run the SQL:
CREATE EXTENSION address_standardizer;

The following test requires no rules, gaz, or lex tables

SELECT num, street, city, state, zip
FROM parse_address('1 Devonshire Place PH301, Boston, MA 02109');
PostGIS 2.4.3 Manual 23 / 803

Output should be
num | street | city | state | zip
-----+------------------------+--------+-------+-------
1 | Devonshire Place PH301 | Boston | MA | 02109

2.7.1 Installing Regex::Assemble

Perl Regex:Assemble is no longer needed for compiling address_standardizer extension since the files it generates are part of the
source tree. However if you need to edit the usps-st-city-orig.txt or usps-st-city-orig.txt usps-st-city-add
tx, you need to rebuild parseaddress-stcities.h which does require Regex:Assemble.
cpan Regexp::Assemble

or if you are on Ubuntu / Debian you might need to do

sudo perl -MCPAN -e "install Regexp::Assemble"

2.8 Installing, Upgrading Tiger Geocoder and loading data

Extras like Tiger geocoder may not be packaged in your PostGIS distribution. If you are missing the tiger geocoder extension or
want a newer version than what your install comes with, then use the share/extension/postgis_tiger_geocoder.*
files from the packages in Windows Unreleased Versions section for your version of PostgreSQL. Although these packages are for
windows, the postgis_tiger_geocoder extension files will work on any OS since the extension is an SQL/plpgsql only extension.

2.8.1 Tiger Geocoder Enabling your PostGIS database: Using Extension

If you are using PostgreSQL 9.1+ and PostGIS 2.1+, you can take advantage of the new extension model for installing tiger
geocoder. To do so:

1. First get binaries for PostGIS 2.1+ or compile and install as usual. This should install the necessary extension files as well
for tiger geocoder.
2. Connect to your database via psql or pgAdmin or some other tool and run the following SQL commands. Note that if you
are installing in a database that already has postgis, you don’t need to do the first step. If you have fuzzystrmatch
extension already installed, you don’t need to do the second step either.
CREATE EXTENSION postgis;
CREATE EXTENSION fuzzystrmatch;
CREATE EXTENSION postgis_tiger_geocoder;
--this one is optional if you want to use the rules based standardizer ( ←-
pagc_normalize_address)
CREATE EXTENSION address_standardizer;

If you already have postgis_tiger_geocoder extension installed, and just want to update to the latest run:
ALTER EXTENSION postgis UPDATE;
ALTER EXTENSION postgis_tiger_geocoder UPDATE;

If you made custom entries or changes to tiger.loader_platform and tiger.loader_variables you may
need to update these.
3. To confirm your install is working correctly, run this sql in your database:
SELECT na.address, na.streetname,na.streettypeabbrev, na.zip
FROM normalize_address('1 Devonshire Place, Boston, MA 02109') AS na;
PostGIS 2.4.3 Manual 24 / 803

Which should output

address | streetname | streettypeabbrev | zip
---------+------------+------------------+-------
1 | Devonshire | Pl | 02109

4. Create a new record in tiger.loader_platform table with the paths of your executables and server.
So for example to create a profile called debbie that follows sh convention. You would do:
INSERT INTO tiger.loader_platform(os, declare_sect, pgbin, wget, unzip_command, psql, ←-
path_sep,
loader, environ_set_command, county_process_command)
SELECT 'debbie', declare_sect, pgbin, wget, unzip_command, psql, path_sep,
loader, environ_set_command, county_process_command
FROM tiger.loader_platform
WHERE os = 'sh';

And then edit the paths in the declare_sect column to those that fit Debbie’s pg, unzip,shp2pgsql, psql, etc path locations.
If you don’t edit this loader_platform table, it will just contain common case locations of items and you’ll have to
edit the generated script after the script is generated.
5. As of PostGIS 2.4.1 the Zip code-5 digit tabulation area zcta5 load step was revised to load current zcta5 data and is part
of the Loader_Generate_Nation_Script when enabled. It is turned off by default because it takes quite a bit of time to load
(20 to 60 minutes), takes up quite a bit of disk space, and is not used that often.
To enable it, do the following:
UPDATE tiger.loader_lookuptables SET load = true WHERE table_name = 'zcta510';

If present the Geocode function can use it if a boundary filter is added to limit to just zips in that boundary. The Re-
verse_Geocode function uses it if the returned address is missing a zip, which often happens with highway reverse geocod-
ing.
6. Create a folder called gisdata on root of server or your local pc if you have a fast network connection to the server.
This folder is where the tiger files will be downloaded to and processed. If you are not happy with having the folder on
the root of the server, or simply want to change to a different folder for staging, then edit the field staging_fold in the
tiger.loader_variables table.
7. Create a folder called temp in the gisdata folder or whereever you designated the staging_fold to be. This will be
the folder where the loader extracts the downloaded tiger data.
8. Then run the Loader_Generate_Nation_Script SQL function make sure to use the name of your custom profile and copy
the script to a .sh or .bat file. So for example to build the nation load:
psql -c "SELECT Loader_Generate_Nation_Script('debbie')" -d geocoder -tA > /gisdata/ ←-
nation_script_load.sh

9. Run the generated nation load commandline scripts.

cd /gisdata
sh nation_script_load.sh

10. After you are done running the nation script, you should have three tables in your tiger_data schema and they should
be filled with data. Confirm you do by doing the following queries from psql or pgAdmin
SELECT count(*) FROM tiger_data.county_all;

count
-------
3233
(1 row)
PostGIS 2.4.3 Manual 25 / 803

SELECT count(*) FROM tiger_data.state_all;

count
-------
56
(1 row)

11. By default the tables corresponding to bg, tract, tabblock are not loaded. These tables are not used by the geocoder
but are used by folks for population statistics. If you wish to load them as part of your state loads, run the following
statement to enable them.
UPDATE tiger.loader_lookuptables SET load = true WHERE load = false AND lookup_name IN ←-
('tract', 'bg', 'tabblock');

Alternatively you can load just these tables after loading state data using the Loader_Generate_Census_Script
12. For each state you want to load data for, generate a state script Loader_Generate_Script.

Warning
DO NOT Generate the state script until you have already loaded the nation data, because the state script utilizes
county list loaded by nation script.

13.
psql -c "SELECT Loader_Generate_Script(ARRAY['MA'], 'debbie')" -d geocoder -tA > / ←-
gisdata/ma_load.sh

14. Run the generated commandline scripts.

cd /gisdata
sh ma_load.sh

15. After you are done loading all data or at a stopping point, it’s a good idea to analyze all the tiger tables to update the stats
(include inherited stats)
SELECT install_missing_indexes();
vacuum analyze verbose tiger.addr;
vacuum analyze verbose tiger.edges;
vacuum analyze verbose tiger.faces;
vacuum analyze verbose tiger.featnames;
vacuum analyze verbose tiger.place;
vacuum analyze verbose tiger.cousub;
vacuum analyze verbose tiger.county;
vacuum analyze verbose tiger.state;
vacuum analyze verbose tiger.zip_lookup_base;
vacuum analyze verbose tiger.zip_state;
vacuum analyze verbose tiger.zip_state_loc;

2.8.1.1 Converting a Tiger Geocoder Regular Install to Extension Model

If you installed the tiger geocoder without using the extension model, you can convert to the extension model as follows:

1. Follow instructions in Section 2.8.5 for the non-extension model upgrade.

2. Connect to your database with psql or pgAdmin and run the following command:
CREATE EXTENSION postgis_tiger_geocoder FROM unpackaged;
PostGIS 2.4.3 Manual 26 / 803

2.8.2 Tiger Geocoder Enabling your PostGIS database: Not Using Extensions

First install PostGIS using the prior instructions.

If you don’t have an extras folder, download http://download.osgeo.org/postgis/source/postgis-2.4.3.tar.gz
tar xvfz postgis-2.4.3.tar.gz
cd postgis-2.4.3/extras/tiger_geocoder
Edit the tiger_loader_2015.sql (or latest loader file you find, unless you want to load different year) to the paths of your
executables server etc or alternatively you can update the loader_platform table once installed. If you don’t edit this file or
the loader_platform table, it will just contain common case locations of items and you’ll have to edit the generated script
after the fact when you run the Loader_Generate_Nation_Script and Loader_Generate_Script SQL functions.
If you are installing Tiger geocoder for the first time edit either the create_geocode.bat script If you are on windows or the
create_geocode.sh if you are on Linux/Unix/Mac OSX with your PostgreSQL specific settings and run the corresponding
script from the commandline.
Verify that you now have a tiger schema in your database and that it is part of your database search_path. If it is not, add it
with a command something along the line of:
ALTER DATABASE geocoder SET search_path=public, tiger;

The normalizing address functionality works more or less without any data except for tricky addresses. Run this test and verify
things look like this:
SELECT pprint_addy(normalize_address('202 East Fremont Street, Las Vegas, Nevada 89101')) ←-
As pretty_address;
pretty_address
---------------------------------------
202 E Fremont St, Las Vegas, NV 89101

2.8.3 Using Address Standardizer Extension with Tiger geocoder

One of the many complaints of folks is the address normalizer function Normalize_Address function that normalizes an address
for prepping before geocoding. The normalizer is far from perfect and trying to patch its imperfectness takes a vast amount of
resources. As such we have integrated with another project that has a much better address standardizer engine. To use this new
address_standardizer, you compile the extension as described in Section 2.7 and install as an extension in your database.
Once you install this extension in the same database as you have installed postgis_tiger_geocoder, then the Pagc_Normalize_Ad
can be used instead of Normalize_Address. This extension is tiger agnostic, so can be used with other data sources such
as international addresses. The tiger geocoder extension does come packaged with its own custom versions of rules table (
tiger.pagc_rules) , gaz table (tiger.pagc_gaz), and lex table (tiger.pagc_lex). These you can add and update
to improve your standardizing experience for your own needs.

2.8.4 Loading Tiger Data

The instructions for loading data are available in a more detailed form in the extras/tiger_geocoder/tiger_2011/
README. This just includes the general steps.
The load process downloads data from the census website for the respective nation files, states requested, extracts the files,
and then loads each state into its own separate set of state tables. Each state table inherits from the tables defined in tiger
schema so that its sufficient to just query those tables to access all the data and drop a set of state tables at any time using the
Drop_State_Tables_Generate_Script if you need to reload a state or just don’t need a state anymore.
In order to be able to load data you’ll need the following tools:

• A tool to unzip the zip files from census website.

For Unix like systems: unzip executable which is usually already installed on most Unix like platforms.
For Windows, 7-zip which is a free compress/uncompress tool you can download from http://www.7-zip.org/
PostGIS 2.4.3 Manual 27 / 803

• shp2pgsql commandline which is installed by default when you install PostGIS.

• wget which is a web grabber tool usually installed on most Unix/Linux systems.
If you are on windows, you can get pre-compiled binaries from http://gnuwin32.sourceforge.net/packages/wget.htm

If you are upgrading from tiger_2010, you’ll need to first generate and run Drop_Nation_Tables_Generate_Script. Before you
load any state data, you need to load the nation wide data which you do with Loader_Generate_Nation_Script. Which will
generate a loader script for you. Loader_Generate_Nation_Script is a one-time step that should be done for upgrading (from
2010) and for new installs.
To load state data refer to Loader_Generate_Script to generate a data load script for your platform for the states you desire. Note
that you can install these piecemeal. You don’t have to load all the states you want all at once. You can load them as you need
them.
After the states you desire have been loaded, make sure to run the:
SELECT install_missing_indexes();

as described in Install_Missing_Indexes.
To test that things are working as they should, try to run a geocode on an address in your state using Geocode

2.8.5 Upgrading your Tiger Geocoder Install

If you have Tiger Geocoder packaged with 2.0+ already installed, you can upgrade the functions at any time even from an interim
tar ball if there are fixes you badly need. This will only work for Tiger geocoder not installed with extensions.
If you don’t have an extras folder, download http://download.osgeo.org/postgis/source/postgis-2.4.3.tar.gz
tar xvfz postgis-2.4.3.tar.gz
cd postgis-2.4.3/extras/tiger_geocoder/tiger_2011
Locate the upgrade_geocoder.bat script If you are on windows or the upgrade_geocoder.sh if you are on Linux/U-
nix/Mac OSX. Edit the file to have your postgis database credentials.
If you are upgrading from 2010 or 2011, make sure to unremark out the loader script line so you get the latest script for loading
2012 data.
Then run th corresponding script from the commandline.
Next drop all nation tables and load up the new ones. Generate a drop script with this SQL statement as detailed in Drop_Nation_Tables_G
SELECT drop_nation_tables_generate_script();

Run the generated drop SQL statements.

Generate a nation load script with this SELECT statement as detailed in Loader_Generate_Nation_Script
For windows
SELECT loader_generate_nation_script('windows');

For unix/linux
SELECT loader_generate_nation_script('sh');

Refer to Section 2.8.4 for instructions on how to run the generate script. This only needs to be done once.

Note
You can have a mix of 2010/2011 state tables and can upgrade each state separately. Before you upgrade a state to
2011, you first need to drop the 2010 tables for that state using Drop_State_Tables_Generate_Script.
PostGIS 2.4.3 Manual 28 / 803

2.9 Create a spatially-enabled database from a template

Some packaged distributions of PostGIS (in particular the Win32 installers for PostGIS >= 1.1.5) load the PostGIS functions
into a template database called template_postgis. If the template_postgis database exists in your PostgreSQL
installation then it is possible for users and/or applications to create spatially-enabled databases using a single command. Note
that in both cases, the database user must have been granted the privilege to create new databases.
From the shell:
# createdb -T template_postgis my_spatial_db

From SQL:
postgres=# CREATE DATABASE my_spatial_db TEMPLATE=template_postgis

2.10 Upgrading

Upgrading existing spatial databases can be tricky as it requires replacement or introduction of new PostGIS object definitions.
Unfortunately not all definitions can be easily replaced in a live database, so sometimes your best bet is a dump/reload process.
PostGIS provides a SOFT UPGRADE procedure for minor or bugfix releases, and a HARD UPGRADE procedure for major
releases.
Before attempting to upgrade PostGIS, it is always worth to backup your data. If you use the -Fc flag to pg_dump you will
always be able to restore the dump with a HARD UPGRADE.

2.10.1 Soft upgrade

If you installed your database using extensions, you’ll need to upgrade using the extension model as well. If you installed using
the old sql script way, then you should upgrade using the sql script way. Please refer to the appropriate.

2.10.1.1 Soft Upgrade Pre 9.1+ or without extensions

This section applies only to those who installed PostGIS not using extensions. If you have extensions and try to upgrade with
this approach you’ll get messages like:
can't drop ... because postgis extension depends on it

After compiling and installing (make install) you should find a postgis_upgrade.sql and rtpostgis_upgrade.sql
in the installation folders. For example /usr/share/postgresql/9.3/contrib/postgis_upgrade.sql. Install
the postgis_upgrade.sql. If you have raster functionality installed, you will also need to install the /usr/share/
postgresql/9.3/contrib/postgis_upgrade.sql. If you are moving from PostGIS 1.* to PostGIS 2.* or from
PostGIS 2.* prior to r7409, you need to do a HARD UPGRADE.
psql -f postgis_upgrade.sql -d your_spatial_database

The same procedure applies to raster and topology extensions, with upgrade files named rtpostgis_upgrade*.sql and
topology_upgrade*.sql respectively. If you need them:
psql -f rtpostgis_upgrade.sql -d your_spatial_database

psql -f topology_upgrade.sql -d your_spatial_database

PostGIS 2.4.3 Manual 29 / 803

Note
If you can’t find the postgis_upgrade*.sql specific for upgrading your version you are using a version too early
for a soft upgrade and need to do a HARD UPGRADE.

The PostGIS_Full_Version function should inform you about the need to run this kind of upgrade using a "procs need upgrade"
message.

2.10.1.2 Soft Upgrade 9.1+ using extensions

If you originally installed PostGIS with extensions, then you need to upgrade using extensions as well. Doing a minor upgrade
with extensions, is fairly painless.
ALTER EXTENSION postgis UPDATE TO "2.4.3";
ALTER EXTENSION postgis_topology UPDATE TO "2.4.3";

If you get an error notice something like:

No migration path defined for ... to 2.4.3

Then you’ll need to backup your database, create a fresh one as described in Section 2.5 and then restore your backup ontop of
this new database.
If you get a notice message like:
Version "2.4.3" of extension "postgis" is already installed

Then everything is already up to date and you can safely ignore it. UNLESS you’re attempting to upgrade from an SVN version
to the next (which doesn’t get a new version number); in that case you can append "next" to the version string, and next time
you’ll need to drop the "next" suffix again:
ALTER EXTENSION postgis UPDATE TO "2.4.3next";
ALTER EXTENSION postgis_topology UPDATE TO "2.4.3next";

Note
If you installed PostGIS originally without a version specified, you can often skip the reinstallation of postgis extension
before restoring since the backup just has CREATE EXTENSION postgis and thus picks up the newest latest
version during restore.

2.10.2 Hard upgrade

By HARD UPGRADE we mean full dump/reload of postgis-enabled databases. You need a HARD UPGRADE when PostGIS
objects’ internal storage changes or when SOFT UPGRADE is not possible. The Release Notes appendix reports for each version
whether you need a dump/reload (HARD UPGRADE) to upgrade.
The dump/reload process is assisted by the postgis_restore.pl script which takes care of skipping from the dump all definitions
which belong to PostGIS (including old ones), allowing you to restore your schemas and data into a database with PostGIS
installed without getting duplicate symbol errors or bringing forward deprecated objects.
Supplementary instructions for windows users are available at Windows Hard upgrade.
The Procedure is as follows:

1. Create a "custom-format" dump of the database you want to upgrade (let’s call it olddb) include binary blobs (-b) and
verbose (-v) output. The user can be the owner of the db, need not be postgres super account.
PostGIS 2.4.3 Manual 30 / 803

pg_dump -h localhost -p 5432 -U postgres -Fc -b -v -f "/somepath/olddb.backup" olddb

2. Do a fresh install of PostGIS in a new database -- we’ll refer to this database as newdb. Please refer to Section 2.6 and
Section 2.5 for instructions on how to do this.
The spatial_ref_sys entries found in your dump will be restored, but they will not override existing ones in spatial_ref_sys.
This is to ensure that fixes in the official set will be properly propagated to restored databases. If for any reason you really
want your own overrides of standard entries just don’t load the spatial_ref_sys.sql file when creating the new db.
If your database is really old or you know you’ve been using long deprecated functions in your views and functions, you
might need to load legacy.sql for all your functions and views etc. to properly come back. Only do this if _really_
needed. Consider upgrading your views and functions before dumping instead, if possible. The deprecated functions can
be later removed by loading uninstall_legacy.sql.
3. Restore your backup into your fresh newdb database using postgis_restore.pl. Unexpected errors, if any, will be printed
to the standard error stream by psql. Keep a log of those.
perl utils/postgis_restore.pl "/somepath/olddb.backup" | psql -h localhost -p 5432 -U ←-
postgres newdb 2> errors.txt

Errors may arise in the following cases:

1. Some of your views or functions make use of deprecated PostGIS objects. In order to fix this you may try loading
legacy.sql script prior to restore or you’ll have to restore to a version of PostGIS which still contains those objects
and try a migration again after porting your code. If the legacy.sql way works for you, don’t forget to fix your code to
stop using deprecated functions and drop them loading uninstall_legacy.sql.
2. Some custom records of spatial_ref_sys in dump file have an invalid SRID value. Valid SRID values are bigger than 0 and
smaller than 999000. Values in the 999000.999999 range are reserved for internal use while values > 999999 can’t be used
at all. All your custom records with invalid SRIDs will be retained, with those > 999999 moved into the reserved range,
but the spatial_ref_sys table would lose a check constraint guarding for that invariant to hold and possibly also its primary
key ( when multiple invalid SRIDS get converted to the same reserved SRID value ).
In order to fix this you should copy your custom SRS to a SRID with a valid value (maybe in the 910000..910999 range),
convert all your tables to the new srid (see UpdateGeometrySRID), delete the invalid entry from spatial_ref_sys and re-
construct the check(s) with:
ALTER TABLE spatial_ref_sys ADD CONSTRAINT spatial_ref_sys_srid_check check (srid > 0 ←-
AND srid < 999000 );

ALTER TABLE spatial_ref_sys ADD PRIMARY KEY(srid));

2.11 Common Problems during installation

There are several things to check when your installation or upgrade doesn’t go as you expected.

1. Check that you have installed PostgreSQL 9.3 or newer, and that you are compiling against the same version of the
PostgreSQL source as the version of PostgreSQL that is running. Mix-ups can occur when your (Linux) distribution has
already installed PostgreSQL, or you have otherwise installed PostgreSQL before and forgotten about it. PostGIS will only
work with PostgreSQL 9.3 or newer, and strange, unexpected error messages will result if you use an older version. To
check the version of PostgreSQL which is running, connect to the database using psql and run this query:
SELECT version();

If you are running an RPM based distribution, you can check for the existence of pre-installed packages using the rpm
command as follows: rpm -qa | grep postgresql
PostGIS 2.4.3 Manual 31 / 803

2. If your upgrade fails, make sure you are restoring into a database that already has PostGIS installed.
SELECT postgis_full_version();

Also check that configure has correctly detected the location and version of PostgreSQL, the Proj4 library and the GEOS library.

1. The output from configure is used to generate the postgis_config.h file. Check that the POSTGIS_PGSQL_VERSION,
POSTGIS_PROJ_VERSION and POSTGIS_GEOS_VERSION variables have been set correctly.

2.12 Loader/Dumper

The data loader and dumper are built and installed automatically as part of the PostGIS build. To build and install them manually:
# cd postgis-2.4.3/loader
# make
# make install

The loader is called shp2pgsql and converts ESRI Shape files into SQL suitable for loading in PostGIS/PostgreSQL. The
dumper is called pgsql2shp and converts PostGIS tables (or queries) into ESRI Shape files. For more verbose documentation,
see the online help, and the manual pages.
PostGIS 2.4.3 Manual 32 / 803

Chapter 3

PostGIS Frequently Asked Questions

1. Where can I find tutorials, guides and workshops on working with PostGIS
OpenGeo has a step by step tutorial guide workshop Introduction to PostGIS. It includes packaged data as well as intro
to working with OpenGeo Suite. It is probably the best tutorial on PostGIS.BostonGIS also has a PostGIS almost idiot’s
guide on getting started. That one is more focused on the windows user.
2. My applications and desktop tools worked with PostGIS 1.5,but they don’t work with PostGIS 2.0. How do I fix this?
A lot of deprecated functions were removed from the PostGIS code base in PostGIS 2.0. This has affected applications
in addition to third-party tools such as Geoserver, MapServer, QuantumGIS, and OpenJump to name a few. There are a
couple of ways to resolve this. For the third-party apps, you can try to upgrade to the latest versions of these which have
many of these issues fixed. For your own code, you can change your code to not use the functions removed. Most of these
functions are non ST_ aliases of ST_Union, ST_Length etc. and as a last resort, install the whole of legacy.sql or
just the portions of legacy.sql you need.The legacy.sql file is located in the same folder as postgis.sql. You can
install this file after you have installed postgis.sql and spatial_ref_sys.sql to get back all the 200 some-odd old functions
we removed.
3. When I load OpenStreetMap data with osm2pgsql, I’m getting an error failed: ERROR: operator class "gist_geometry_ops"
does not exist for access method "gist" Error occurred. This worked fine in PostGIS 1.5.
In PostGIS 2, the default geometry operator class gist_geometry_ops was changed to gist_geometry_ops_2d and the
gist_geometry_ops was completely removed. This was done because PostGIS 2 also introduced Nd spatial indexes for
3D support and the old name was deemed confusing and a misnomer.Some older applications that as part of the process
create tables and indexes, explicitly referenced the operator class name. This was unnecessary if you want the default 2D
index. So if you manage said good, change index creation from:BAD:
CREATE INDEX idx_my_table_geom ON my_table USING gist(geom gist_geometry_ops);

To GOOD:
CREATE INDEX idx_my_table_geom ON my_table USING gist(geom);

The only case where you WILL need to specify the operator class is if you want a 3D spatial index as follows:
CREATE INDEX idx_my_super3d_geom ON my_super3d USING gist(geom gist_geometry_ops_nd);

If you are unfortunate to be stuck with compiled code you can’t change that has the old gist_geometry_ops hard-coded,
then you can create the old class using the legacy_gist.sql packaged in PostGIS 2.0.2+. However if you use this
fix, you are advised to at a later point drop the index and recreate it without the operator class. This will save you grief in
the future when you need to upgrade again.
4. I’m running PostgreSQL 9.0 and I can no longer read/view geometries in OpenJump, Safe FME, and some other tools?
In PostgreSQL 9.0+, the default encoding for bytea data has been changed to hex and older JDBC drivers still assume
escape format. This has affected some applications such as Java applications using older JDBC drivers or .NET ap-
plications that use the older npgsql driver that expect the old behavior of ST_AsBinary. There are two approaches to
PostGIS 2.4.3 Manual 33 / 803

getting this to work again.You can upgrade your JDBC driver to the latest PostgreSQL 9.0 version which you can get
from http://jdbc.postgresql.org/download.htmlIf you are running a .NET app, you can use Npgsql 2.0.11 or higher which
you can download from http://pgfoundry.org/frs/?group_id=1000140 and as described on Francisco Figueiredo’s NpgSQL
2.0.11 released blog entryIf upgrading your PostgreSQL driver is not an option, then you can set the default back to the
old behavior with the following change:
ALTER DATABASE mypostgisdb SET bytea_output='escape';

5. I tried to use PgAdmin to view my geometry column and it is blank, what gives?
PgAdmin doesn’t show anything for large geometries. The best ways to verify you do have data in your geometry columns
are?
-- this should return no records if all your geom fields are filled in
SELECT somefield FROM mytable WHERE geom IS NULL;

-- To tell just how large your geometry is do a query of the form

--which will tell you the most number of points you have in any of your geometry ←-
columns
SELECT MAX(ST_NPoints(geom)) FROM sometable;

6. What kind of geometric objects can I store?

You can store Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection geome-
tries. In PostGIS 2.0 and above you can also store TINS and Polyhedral Surfaces in the basic geometry type. These are
specified in the Open GIS Well Known Text Format (with Z, M, and ZM extensions). There are three data types currently
supported. The standard OGC geometry data type which uses a planar coordinate system for measurement, the geography
data type which uses a geodetic coordinate system, with calculations on either a sphere or spheroid. The newest family
member of the PostGIS spatial type family is raster for storing and analyzing raster data. Raster has its very own FAQ.
Refer to Chapter 10 and Chapter 9 for more details.
7. I’m all confused. Which data store should I use geometry or geography?
Short Answer: geography is a newer data type that supports long range distances measurements, but most computations
on it are slower than they are on geometry. If you use geography, you don’t need to learn much about planar coordinate
systems. Geography is generally best if all you care about is measuring distances and lengths and you have data from all
over the world. Geometry data type is an older data type that has many more functions supporting it, enjoys greater support
from third party tools, and operations on it are generally faster -- sometimes as much as 10 fold faster for larger geometries.
Geometry is best if you are pretty comfortable with spatial reference systems or you are dealing with localized data where
all your data fits in a single spatial reference system (SRID), or you need to do a lot of spatial processing. Note: It is fairly
easy to do one-off conversions between the two types to gain the benefits of each. Refer to Section 14.11 to see what is
currently supported and what is not. Long Answer: Refer to our more lengthy discussion in the Section 4.2.2 and function
type matrix.
8. I have more intense questions about geography, such as how big of a geographic region can I stuff in a geography column
and still get reasonable answers. Are there limitations such as poles, everything in the field must fit in a hemisphere (like
SQL Server 2008 has), speed etc?
Your questions are too deep and complex to be adequately answered in this section. Please refer to our Section 4.2.3.
9. How do I insert a GIS object into the database?
First, you need to create a table with a column of type "geometry" or "geography" to hold your GIS data. Storing geography
type data is a little different than storing geometry. Refer to Section 4.2.1 for details on storing geography. For geometry:
Connect to your database with psql and try the following SQL:
CREATE TABLE gtest ( gid serial primary key, name varchar(20)
, geom geometry(LINESTRING) );

If the geometry column definition fails, you probably have not loaded the PostGIS functions and objects into this database
or are using a pre-2.0 version of PostGIS. See the Section 2.4.Then, you can insert a geometry into the table using a SQL
insert statement. The GIS object itself is formatted using the OpenGIS Consortium "well-known text" format:
PostGIS 2.4.3 Manual 34 / 803

INSERT INTO gtest (ID, NAME, GEOM)

VALUES (
1,
'First Geometry',
ST_GeomFromText('LINESTRING(2 3,4 5,6 5,7 8)')
);

For more information about other GIS objects, see the object reference.To view your GIS data in the table:
SELECT id, name, ST_AsText(geom) AS geom FROM gtest;

The return value should look something like this:

id | name | geom
----+----------------+-----------------------------
1 | First Geometry | LINESTRING(2 3,4 5,6 5,7 8)
(1 row)

10. How do I construct a spatial query?

The same way you construct any other database query, as an SQL combination of return values, functions, and boolean
tests.For spatial queries, there are two issues that are important to keep in mind while constructing your query: is there a
spatial index you can make use of; and, are you doing expensive calculations on a large number of geometries.In general,
you will want to use the "intersects operator" (&&) which tests whether the bounding boxes of features intersect. The
reason the && operator is useful is because if a spatial index is available to speed up the test, the && operator will make
use of this. This can make queries much much faster.You will also make use of spatial functions, such as Distance(),
ST_Intersects(), ST_Contains() and ST_Within(), among others, to narrow down the results of your search. Most spatial
queries include both an indexed test and a spatial function test. The index test serves to limit the number of return tuples
to only tuples that might meet the condition of interest. The spatial functions are then use to test the condition exactly.
SELECT id, the_geom
FROM thetable
WHERE
ST_Contains(the_geom,'POLYGON((0 0, 0 10, 10 10, 10 0, 0 0))');

11. How do I speed up spatial queries on large tables?

Fast queries on large tables is the raison d’etre of spatial databases (along with transaction support) so having a good index
is important.To build a spatial index on a table with a geometry column, use the "CREATE INDEX" function as follows:
CREATE INDEX [indexname] ON [tablename] USING GIST ( [geometrycolumn] );

The "USING GIST" option tells the server to use a GiST (Generalized Search Tree) index.

Note
GiST indexes are assumed to be lossy. Lossy indexes uses a proxy object (in the spatial case, a bounding box)
for building the index.

You should also ensure that the PostgreSQL query planner has enough information about your index to make rational
decisions about when to use it. To do this, you have to "gather statistics" on your geometry tables.For PostgreSQL
8.0.x and greater, just run the VACUUM ANALYZE command.For PostgreSQL 7.4.x and below, run the SELECT UP-
DATE_GEOMETRY_STATS() command.
12. Why aren’t PostgreSQL R-Tree indexes supported?
Early versions of PostGIS used the PostgreSQL R-Tree indexes. However, PostgreSQL R-Trees have been completely
discarded since version 0.6, and spatial indexing is provided with an R-Tree-over-GiST scheme.Our tests have shown
search speed for native R-Tree and GiST to be comparable. Native PostgreSQL R-Trees have two limitations which make
them undesirable for use with GIS features (note that these limitations are due to the current PostgreSQL native R-Tree
implementation, not the R-Tree concept in general):
PostGIS 2.4.3 Manual 35 / 803

• R-Tree indexes in PostgreSQL cannot handle features which are larger than 8K in size. GiST indexes can, using the
"lossy" trick of substituting the bounding box for the feature itself.
• R-Tree indexes in PostgreSQL are not "null safe", so building an index on a geometry column which contains null
geometries will fail.

13. Why should I use the AddGeometryColumn() function and all the other OpenGIS stuff?
If you do not want to use the OpenGIS support functions, you do not have to. Simply create tables as in older versions,
defining your geometry columns in the CREATE statement. All your geometries will have SRIDs of -1, and the OpenGIS
meta-data tables will not be filled in properly. However, this will cause most applications based on PostGIS to fail, and it
is generally suggested that you do use AddGeometryColumn() to create geometry tables.MapServer is one application
which makes use of the geometry_columns meta-data. Specifically, MapServer can use the SRID of the geometry
column to do on-the-fly reprojection of features into the correct map projection.
14. What is the best way to find all objects within a radius of another object?
To use the database most efficiently, it is best to do radius queries which combine the radius test with a bounding box test:
the bounding box test uses the spatial index, giving fast access to a subset of data which the radius test is then applied to.The
ST_DWithin(geometry, geometry, distance) function is a handy way of performing an indexed distance
search. It works by creating a search rectangle large enough to enclose the distance radius, then performing an exact
distance search on the indexed subset of results.For example, to find all objects with 100 meters of POINT(1000 1000) the
following query would work well:
SELECT * FROM geotable
WHERE ST_DWithin(geocolumn, 'POINT(1000 1000)', 100.0);

15. How do I perform a coordinate reprojection as part of a query?

To perform a reprojection, both the source and destination coordinate systems must be defined in the SPATIAL_REF_SYS
table, and the geometries being reprojected must already have an SRID set on them. Once that is done, a reprojection is
as simple as referring to the desired destination SRID. The below projects a geometry to NAD 83 long lat. The below will
only work if the srid of the_geom is not -1 (not undefined spatial ref)
SELECT ST_Transform(the_geom,4269) FROM geotable;

16. I did an ST_AsEWKT and ST_AsText on my rather large geometry and it returned blank field. What gives?
You are probably using PgAdmin or some other tool that doesn’t output large text. If your geometry is big enough, it will
appear blank in these tools. Use PSQL if you really need to see it or output it in WKT.
--To check number of geometries are really blank
SELECT count(gid) FROM geotable WHERE the_geom IS NULL;

17. When I do an ST_Intersects, it says my two geometries don’t intersect when I KNOW THEY DO. What gives?
This generally happens in two common cases. Your geometry is invalid -- check ST_IsValid or you are assuming they
intersect because ST_AsText truncates the numbers and you have lots of decimals after it is not showing you.
18. I am releasing software that uses PostGIS, does that mean my software has to be licensed using the GPL like PostGIS?
Will I have to publish all my code if I use PostGIS?
Almost certainly not. As an example, consider Oracle database running on Linux. Linux is GPL, Oracle is not: does
Oracle running on Linux have to be distributed using the GPL? No. Similarly your software can use a PostgreSQL/PostGIS
database as much as it wants and be under any license you like.The only exception would be if you made changes to the
PostGIS source code, and distributed your changed version of PostGIS. In that case you would have to share the code of
your changed PostGIS (but not the code of applications running on top of it). Even in this limited case, you would still only
have to distribute source code to people you distributed binaries to. The GPL does not require that you publish your source
code, only that you share it with people you give binaries to.The above remains true even if you use PostGIS in conjunction
with the optional CGAL-enabled functions. Portions of CGAL are GPL, but so is all of PostGIS already: using CGAL
does not make PostGIS any more GPL than it was to start with.
PostGIS 2.4.3 Manual 36 / 803

Chapter 4

Using PostGIS: Data Management and Queries

4.1 GIS Objects

The GIS objects supported by PostGIS are a superset of the "Simple Features" defined by the OpenGIS Consortium (OGC). As
of version 0.9, PostGIS supports all the objects and functions specified in the OGC "Simple Features for SQL" specification.
PostGIS extends the standard with support for 3DZ,3DM and 4D coordinates.

4.1.1 OpenGIS WKB and WKT

The OpenGIS specification defines two standard ways of expressing spatial objects: the Well-Known Text (WKT) form and the
Well-Known Binary (WKB) form. Both WKT and WKB include information about the type of the object and the coordinates
which form the object.
Examples of the text representations (WKT) of the spatial objects of the features are as follows:

• POINT(0 0)
• LINESTRING(0 0,1 1,1 2)
• POLYGON((0 0,4 0,4 4,0 4,0 0),(1 1, 2 1, 2 2, 1 2,1 1))
• MULTIPOINT((0 0),(1 2))
• MULTILINESTRING((0 0,1 1,1 2),(2 3,3 2,5 4))
• MULTIPOLYGON(((0 0,4 0,4 4,0 4,0 0),(1 1,2 1,2 2,1 2,1 1)), ((-1 -1,-1 -2,-2 -2,-2 -1,-1 -1)))
• GEOMETRYCOLLECTION(POINT(2 3),LINESTRING(2 3,3 4))

The OpenGIS specification also requires that the internal storage format of spatial objects include a spatial referencing system
identifier (SRID). The SRID is required when creating spatial objects for insertion into the database.
Input/Output of these formats are available using the following interfaces:
bytea WKB = ST_AsBinary(geometry);
text WKT = ST_AsText(geometry);
geometry = ST_GeomFromWKB(bytea WKB, SRID);
geometry = ST_GeometryFromText(text WKT, SRID);

For example, a valid insert statement to create and insert an OGC spatial object would be:
INSERT INTO geotable ( the_geom, the_name )
VALUES ( ST_GeomFromText('POINT(-126.4 45.32)', 312), 'A Place');
PostGIS 2.4.3 Manual 37 / 803

4.1.2 PostGIS EWKB, EWKT and Canonical Forms

OGC formats only support 2d geometries, and the associated SRID is *never* embedded in the input/output representations.
PostGIS extended formats are currently superset of OGC one (every valid WKB/WKT is a valid EWKB/EWKT) but this might
vary in the future, specifically if OGC comes out with a new format conflicting with our extensions. Thus you SHOULD NOT
rely on this feature!
PostGIS EWKB/EWKT add 3dm,3dz,4d coordinates support and embedded SRID information.
Examples of the text representations (EWKT) of the extended spatial objects of the features are as follows.

• POINT(0 0 0) -- XYZ
• SRID=32632;POINT(0 0) -- XY with SRID
• POINTM(0 0 0) -- XYM
• POINT(0 0 0 0) -- XYZM
• SRID=4326;MULTIPOINTM(0 0 0,1 2 1) -- XYM with SRID
• MULTILINESTRING((0 0 0,1 1 0,1 2 1),(2 3 1,3 2 1,5 4 1))
• POLYGON((0 0 0,4 0 0,4 4 0,0 4 0,0 0 0),(1 1 0,2 1 0,2 2 0,1 2 0,1 1 0))
• MULTIPOLYGON(((0 0 0,4 0 0,4 4 0,0 4 0,0 0 0),(1 1 0,2 1 0,2 2 0,1 2 0,1 1 0)),((-1 -1 0,-1 -2 0,-2 -2 0,-2 -1 0,-1 -1 0)))
• GEOMETRYCOLLECTIONM( POINTM(2 3 9), LINESTRINGM(2 3 4, 3 4 5) )
• MULTICURVE( (0 0, 5 5), CIRCULARSTRING(4 0, 4 4, 8 4) )
• POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)), ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0
0 0)), ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)), ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )
• TRIANGLE ((0 0, 0 9, 9 0, 0 0))
• TIN( ((0 0 0, 0 0 1, 0 1 0, 0 0 0)), ((0 0 0, 0 1 0, 1 1 0, 0 0 0)) )

Input/Output of these formats are available using the following interfaces:

bytea EWKB = ST_AsEWKB(geometry);
text EWKT = ST_AsEWKT(geometry);
geometry = ST_GeomFromEWKB(bytea EWKB);
geometry = ST_GeomFromEWKT(text EWKT);

For example, a valid insert statement to create and insert a PostGIS spatial object would be:
INSERT INTO geotable ( the_geom, the_name )
VALUES ( ST_GeomFromEWKT('SRID=312;POINTM(-126.4 45.32 15)'), 'A Place' )

The "canonical forms" of a PostgreSQL type are the representations you get with a simple query (without any function call) and
the one which is guaranteed to be accepted with a simple insert, update or copy. For the postgis ’geometry’ type these are:
- Output
- binary: EWKB
ascii: HEXEWKB (EWKB in hex form)
- Input
- binary: EWKB
ascii: HEXEWKB|EWKT

For example this statement reads EWKT and returns HEXEWKB in the process of canonical ascii input/output:
=# SELECT 'SRID=4;POINT(0 0)'::geometry;

geometry
----------------------------------------------------
01010000200400000000000000000000000000000000000000
(1 row)
PostGIS 2.4.3 Manual 38 / 803

4.1.3 SQL-MM Part 3

The SQL Multimedia Applications Spatial specification extends the simple features for SQL spec by defining a number of
circularly interpolated curves.
The SQL-MM definitions include 3dm, 3dz and 4d coordinates, but do not allow the embedding of SRID information.
The well-known text extensions are not yet fully supported. Examples of some simple curved geometries are shown below:

• CIRCULARSTRING(0 0, 1 1, 1 0)
CIRCULARSTRING(0 0, 4 0, 4 4, 0 4, 0 0)
The CIRCULARSTRING is the basic curve type, similar to a LINESTRING in the linear world. A single segment required
three points, the start and end points (first and third) and any other point on the arc. The exception to this is for a closed circle,
where the start and end points are the same. In this case the second point MUST be the center of the arc, ie the opposite
side of the circle. To chain arcs together, the last point of the previous arc becomes the first point of the next arc, just like in
LINESTRING. This means that a valid circular string must have an odd number of points greater than 1.
• COMPOUNDCURVE(CIRCULARSTRING(0 0, 1 1, 1 0),(1 0, 0 1))
A compound curve is a single, continuous curve that has both curved (circular) segments and linear segments. That means that
in addition to having well-formed components, the end point of every component (except the last) must be coincident with the
start point of the following component.
• CURVEPOLYGON(CIRCULARSTRING(0 0, 4 0, 4 4, 0 4, 0 0),(1 1, 3 3, 3 1, 1 1))
Example compound curve in a curve polygon: CURVEPOLYGON(COMPOUNDCURVE(CIRCULARSTRING(0 0,2 0, 2 1,
2 3, 4 3),(4 3, 4 5, 1 4, 0 0)), CIRCULARSTRING(1.7 1, 1.4 0.4, 1.6 0.4, 1.6 0.5, 1.7 1) )
A CURVEPOLYGON is just like a polygon, with an outer ring and zero or more inner rings. The difference is that a ring can
take the form of a circular string, linear string or compound string.
As of PostGIS 1.4 PostGIS supports compound curves in a curve polygon.
• MULTICURVE((0 0, 5 5),CIRCULARSTRING(4 0, 4 4, 8 4))
The MULTICURVE is a collection of curves, which can include linear strings, circular strings or compound strings.
• MULTISURFACE(CURVEPOLYGON(CIRCULARSTRING(0 0, 4 0, 4 4, 0 4, 0 0),(1 1, 3 3, 3 1, 1 1)),((10 10, 14 12, 11 10,
10 10),(11 11, 11.5 11, 11 11.5, 11 11)))
This is a collection of surfaces, which can be (linear) polygons or curve polygons.

Note
PostGIS prior to 1.4 does not support compound curves in a curve polygon, but PostGIS 1.4 and above do support the
use of Compound Curves in a Curve Polygon.

Note
All floating point comparisons within the SQL-MM implementation are performed to a specified tolerance, currently
1E-8.

4.2 PostGIS Geography Type

The geography type provides native support for spatial features represented on "geographic" coordinates (sometimes called
"geodetic" coordinates, or "lat/lon", or "lon/lat"). Geographic coordinates are spherical coordinates expressed in angular units
(degrees).
PostGIS 2.4.3 Manual 39 / 803

The basis for the PostGIS geometry type is a plane. The shortest path between two points on the plane is a straight line. That
means calculations on geometries (areas, distances, lengths, intersections, etc) can be calculated using cartesian mathematics and
straight line vectors.
The basis for the PostGIS geographic type is a sphere. The shortest path between two points on the sphere is a great circle arc.
That means that calculations on geographies (areas, distances, lengths, intersections, etc) must be calculated on the sphere, using
more complicated mathematics. For more accurate measurements, the calculations must take the actual spheroidal shape of the
world into account, and the mathematics becomes very complicated indeed.
Because the underlying mathematics is much more complicated, there are fewer functions defined for the geography type than
for the geometry type. Over time, as new algorithms are added, the capabilities of the geography type will expand.
It uses a data type called geography. None of the GEOS functions support the geography type. As a workaround one can
convert back and forth between geometry and geography types.
Prior to PostGIS 2.2, the geography type only supported WGS 84 long lat (SRID:4326). For PostGIS 2.2 and above, any long/lat
based spatial reference system defined in the spatial_ref_sys table can be used. You can even add your own custom
spheroidal spatial refence system as described in geography type is not limited to earth.
Regardless which spatial reference system you use, the units returned by the measurement (ST_Distance, ST_Length, ST_Perimeter,
ST_Area) and for input of ST_DWithin are in meters.
The geography type uses the PostgreSQL 8.3+ typmod definition format so that a table with a geography field can be added in a
single step. All the standard OGC formats except for curves are supported.

4.2.1 Geography Basics

The geography type does not support curves, TINS, or POLYHEDRALSURFACEs, but other geometry types are supported.
Standard geometry type data will autocast to geography if it is of SRID 4326. You can also use the EWKT and EWKB conven-
tions to insert data.

• POINT: Creating a table with 2d point geography when srid is not specified defaults to 4326 WGS 84 long lat:
CREATE TABLE ptgeogwgs(gid serial PRIMARY KEY, geog geography(POINT) );

POINT: Creating a table with 2d point geography in NAD83 longlat:

CREATE TABLE ptgeognad83(gid serial PRIMARY KEY, geog geography(POINT,4269) );

Creating a table with z coordinate point and explicitly specifying srid

CREATE TABLE ptzgeogwgs84(gid serial PRIMARY KEY, geog geography(POINTZ,4326) );

• LINESTRING
CREATE TABLE lgeog(gid serial PRIMARY KEY, geog geography(LINESTRING) );

• POLYGON
--polygon NAD 1927 long lat
CREATE TABLE lgeognad27(gid serial PRIMARY KEY, geog geography(POLYGON,4267) );

• MULTIPOINT

• MULTILINESTRING
• MULTIPOLYGON
• GEOMETRYCOLLECTION
PostGIS 2.4.3 Manual 40 / 803

The geography fields don’t get registered in the geometry_columns. They get registered in a view called geography_columns
which is a view against the system catalogs so is always automatically kept up to date without need for an AddGeom... like func-
tion.
Now, check the "geography_columns" view and see that your table is listed.
You can create a new table with a GEOGRAPHY column using the CREATE TABLE syntax.
CREATE TABLE global_points (
id SERIAL PRIMARY KEY,
name VARCHAR(64),
location GEOGRAPHY(POINT,4326)
);

Note that the location column has type GEOGRAPHY and that geography type supports two optional modifier: a type modifier
that restricts the kind of shapes and dimensions allowed in the column; an SRID modifier that restricts the coordinate reference
identifier to a particular number.
Allowable values for the type modifier are: POINT, LINESTRING, POLYGON, MULTIPOINT, MULTILINESTRING, MUL-
TIPOLYGON. The modifier also supports dimensionality restrictions through suffixes: Z, M and ZM. So, for example a modifier
of ’LINESTRINGM’ would only allow line strings with three dimensions in, and would treat the third dimension as a measure.
Similarly, ’POINTZM’ would expect four dimensional data.
If you do not specify an SRID, the SRID will default to 4326 WGS 84 long/lat will be used, and all calculations will proceed
using WGS84.
Once you have created your table, you can see it in the GEOGRAPHY_COLUMNS table:
-- See the contents of the metadata view
SELECT * FROM geography_columns;

You can insert data into the table the same as you would if it was using a GEOMETRY column:
-- Add some data into the test table
INSERT INTO global_points (name, location) VALUES ('Town', ST_GeogFromText('SRID=4326;POINT ←-
(-110 30)') );
INSERT INTO global_points (name, location) VALUES ('Forest', ST_GeogFromText('SRID=4326; ←-
POINT(-109 29)') );
INSERT INTO global_points (name, location) VALUES ('London', ST_GeogFromText('SRID=4326; ←-
POINT(0 49)') );

Creating an index works the same as GEOMETRY. PostGIS will note that the column type is GEOGRAPHY and create an
appropriate sphere-based index instead of the usual planar index used for GEOMETRY.
-- Index the test table with a spherical index
CREATE INDEX global_points_gix ON global_points USING GIST ( location );

Query and measurement functions use units of meters. So distance parameters should be expressed in meters, and return values
should be expected in meters (or square meters for areas).
-- Show a distance query and note, London is outside the 1000km tolerance
SELECT name FROM global_points WHERE ST_DWithin(location, ST_GeogFromText('SRID=4326; ←-
POINT(-110 29)'), 1000000);

You can see the power of GEOGRAPHY in action by calculating how close a plane flying from Seattle to London (LINESTRING(-
122.33 47.606, 0.0 51.5)) comes to Reykjavik (POINT(-21.96 64.15)).
-- Distance calculation using GEOGRAPHY (122.2km)
SELECT ST_Distance('LINESTRING(-122.33 47.606, 0.0 51.5)'::geography, 'POINT(-21.96 ←-
64.15)':: geography);

-- Distance calculation using GEOMETRY (13.3 "degrees")

SELECT ST_Distance('LINESTRING(-122.33 47.606, 0.0 51.5)'::geometry, 'POINT(-21.96 64.15) ←-
':: geometry);
PostGIS 2.4.3 Manual 41 / 803

Testing different lon/lat projects, requires PostGIS 2.2+. Any long lat spatial reference system listed in spatial_ref_sys
table is allowed.
-- NAD 83 lon/lat
SELECT 'SRID=4269;POINT(-123 34)'::geography;
geography
----------------------------------------------------
0101000020AD1000000000000000C05EC00000000000004140
(1 row)

-- NAD27 lon/lat
SELECT 'SRID=4267;POINT(-123 34)'::geography;

geography
----------------------------------------------------
0101000020AB1000000000000000C05EC00000000000004140
(1 row)

-- NAD83 UTM zone meters, yields error since its a meter based projection
SELECT 'SRID=26910;POINT(-123 34)'::geography;

ERROR: Only lon/lat coordinate systems are supported in geography.

LINE 1: SELECT 'SRID=26910;POINT(-123 34)'::geography;

The GEOGRAPHY type calculates the true shortest distance over the sphere between Reykjavik and the great circle flight path
between Seattle and London.
Great Circle mapper The GEOMETRY type calculates a meaningless cartesian distance between Reykjavik and the straight line
path from Seattle to London plotted on a flat map of the world. The nominal units of the result might be called "degrees", but the
result doesn’t correspond to any true angular difference between the points, so even calling them "degrees" is inaccurate.

4.2.2 When to use Geography Data type over Geometry data type

The geography type allows you to store data in longitude/latitude coordinates, but at a cost: there are fewer functions defined on
GEOGRAPHY than there are on GEOMETRY; those functions that are defined take more CPU time to execute.
The type you choose should be conditioned on the expected working area of the application you are building. Will your data
span the globe or a large continental area, or is it local to a state, county or municipality?

• If your data is contained in a small area, you might find that choosing an appropriate projection and using GEOMETRY is the
best solution, in terms of performance and functionality available.
• If your data is global or covers a continental region, you may find that GEOGRAPHY allows you to build a system without
having to worry about projection details. You store your data in longitude/latitude, and use the functions that have been defined
on GEOGRAPHY.
• If you don’t understand projections, and you don’t want to learn about them, and you’re prepared to accept the limitations in
functionality available in GEOGRAPHY, then it might be easier for you to use GEOGRAPHY than GEOMETRY. Simply load
your data up as longitude/latitude and go from there.

Refer to Section 14.11 for compare between what is supported for Geography vs. Geometry. For a brief listing and description
of Geography functions, refer to Section 14.4

4.2.3 Geography Advanced FAQ

1. Do you calculate on the sphere or the spheroid?

By default, all distance and area calculations are done on the spheroid. You should find that the results of calculations in
local areas match up will with local planar results in good local projections. Over larger areas, the spheroidal calculations
PostGIS 2.4.3 Manual 42 / 803

will be more accurate than any calculation done on a projected plane. All the geography functions have the option of
using a sphere calculation, by setting a final boolean parameter to ’FALSE’. This will somewhat speed up calculations,
particularly for cases where the geometries are very simple.

2. What about the date-line and the poles?

All the calculations have no conception of date-line or poles, the coordinates are spherical (longitude/latitude) so a shape
that crosses the dateline is, from a calculation point of view, no different from any other shape.
3. What is the longest arc you can process?
We use great circle arcs as the "interpolation line" between two points. That means any two points are actually joined up
two ways, depending on which direction you travel along the great circle. All our code assumes that the points are joined
by the *shorter* of the two paths along the great circle. As a consequence, shapes that have arcs of more than 180 degrees
will not be correctly modelled.
4. Why is it so slow to calculate the area of Europe / Russia / insert big geographic region here ?
Because the polygon is so darned huge! Big areas are bad for two reasons: their bounds are huge, so the index tends to pull
the feature no matter what query you run; the number of vertices is huge, and tests (distance, containment) have to traverse
the vertex list at least once and sometimes N times (with N being the number of vertices in the other candidate feature).
As with GEOMETRY, we recommend that when you have very large polygons, but are doing queries in small areas, you
"denormalize" your geometric data into smaller chunks so that the index can effectively subquery parts of the object and
so queries don’t have to pull out the whole object every time. Just because you *can* store all of Europe in one polygon
doesn’t mean you *should*.

4.3 Using OpenGIS Standards

The OpenGIS "Simple Features Specification for SQL" defines standard GIS object types, the functions required to manipulate
them, and a set of meta-data tables. In order to ensure that meta-data remain consistent, operations such as creating and removing
a spatial column are carried out through special procedures defined by OpenGIS.
There are two OpenGIS meta-data tables: SPATIAL_REF_SYS and GEOMETRY_COLUMNS. The SPATIAL_REF_SYS table
holds the numeric IDs and textual descriptions of coordinate systems used in the spatial database.

4.3.1 The SPATIAL_REF_SYS Table and Spatial Reference Systems

The spatial_ref_sys table is a PostGIS included and OGC compliant database table that lists over 3000 known spatial reference
systems and details needed to transform/reproject between them.
Although the PostGIS spatial_ref_sys table contains over 3000 of the more commonly used spatial reference system definitions
that can be handled by the proj library, it does not contain all known to man and you can even define your own custom projection
if you are familiar with proj4 constructs. Keep in mind that most spatial reference systems are regional and have no meaning
when used outside of the bounds they were intended for.
An excellent resource for finding spatial reference systems not defined in the core set is http://spatialreference.org/
Some of the more commonly used spatial reference systems are: 4326 - WGS 84 Long Lat, 4269 - NAD 83 Long Lat, 3395 -
WGS 84 World Mercator, 2163 - US National Atlas Equal Area, Spatial reference systems for each NAD 83, WGS 84 UTM
zone - UTM zones are one of the most ideal for measurement, but only cover 6-degree regions.
Various US state plane spatial reference systems (meter or feet based) - usually one or 2 exists per US state. Most of the meter
ones are in the core set, but many of the feet based ones or ESRI created ones you will need to pull from spatialreference.org.
For details on determining which UTM zone to use for your area of interest, check out the utmzone PostGIS plpgsql helper
function.
The SPATIAL_REF_SYS table definition is as follows:
PostGIS 2.4.3 Manual 43 / 803

CREATE TABLE spatial_ref_sys (

srid INTEGER NOT NULL PRIMARY KEY,
auth_name VARCHAR(256),
auth_srid INTEGER,
srtext VARCHAR(2048),
proj4text VARCHAR(2048)
)

The SPATIAL_REF_SYS columns are as follows:

SRID An integer value that uniquely identifies the Spatial Referencing System (SRS) within the database.

AUTH_NAME The name of the standard or standards body that is being cited for this reference system. For example, "EPSG"
would be a valid AUTH_NAME.
AUTH_SRID The ID of the Spatial Reference System as defined by the Authority cited in the AUTH_NAME. In the case of
EPSG, this is where the EPSG projection code would go.

SRTEXT The Well-Known Text representation of the Spatial Reference System. An example of a WKT SRS representation is:
PROJCS["NAD83 / UTM Zone 10N",
GEOGCS["NAD83",
DATUM["North_American_Datum_1983",
SPHEROID["GRS 1980",6378137,298.257222101]
],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433]
],
PROJECTION["Transverse_Mercator"],
PARAMETER["latitude_of_origin",0],
PARAMETER["central_meridian",-123],
PARAMETER["scale_factor",0.9996],
PARAMETER["false_easting",500000],
PARAMETER["false_northing",0],
UNIT["metre",1]
]

For a listing of EPSG projection codes and their corresponding WKT representations, see http://www.opengeospatial.org/.
For a discussion of WKT in general, see the OpenGIS "Coordinate Transformation Services Implementation Specification"
at http://www.opengeospatial.org/standards. For information on the European Petroleum Survey Group (EPSG) and their
database of spatial reference systems, see http://www.epsg.org.
PROJ4TEXT PostGIS uses the Proj4 library to provide coordinate transformation capabilities. The PROJ4TEXT column
contains the Proj4 coordinate definition string for a particular SRID. For example:
+proj=utm +zone=10 +ellps=clrk66 +datum=NAD27 +units=m

For more information about, see the Proj4 web site at http://trac.osgeo.org/proj/. The spatial_ref_sys.sql file
contains both SRTEXT and PROJ4TEXT definitions for all EPSG projections.

4.3.2 The GEOMETRY_COLUMNS VIEW

In versions of PostGIS prior to 2.0.0, geometry_columns was a table that could be directly edited, and sometimes got out of
synch with the actual definition of the geometry columns. In PostGIS 2.0.0, GEOMETRY_COLUMNS became a view with the
same front-facing structure as prior versions, but reading from database system catalogs Its structure is as follows:
\d geometry_columns
PostGIS 2.4.3 Manual 44 / 803

View "public.geometry_columns"
Column | Type | Modifiers
-------------------+------------------------+-----------
f_table_catalog | character varying(256) |
f_table_schema | character varying(256) |
f_table_name | character varying(256) |
f_geometry_column | character varying(256) |
coord_dimension | integer |
srid | integer |
type | character varying(30) |

The column meanings have not changed from prior versions and are:

F_TABLE_CATALOG, F_TABLE_SCHEMA, F_TABLE_NAME The fully qualified name of the feature table containing
the geometry column. Note that the terms "catalog" and "schema" are Oracle-ish. There is not PostgreSQL analogue of
"catalog" so that column is left blank -- for "schema" the PostgreSQL schema name is used (public is the default).

F_GEOMETRY_COLUMN The name of the geometry column in the feature table.

COORD_DIMENSION The spatial dimension (2, 3 or 4 dimensional) of the column.
SRID The ID of the spatial reference system used for the coordinate geometry in this table. It is a foreign key reference to the
SPATIAL_REF_SYS.

TYPE The type of the spatial object. To restrict the spatial column to a single type, use one of: POINT, LINESTRING, POLY-
GON, MULTIPOINT, MULTILINESTRING, MULTIPOLYGON, GEOMETRYCOLLECTION or corresponding XYM
versions POINTM, LINESTRINGM, POLYGONM, MULTIPOINTM, MULTILINESTRINGM, MULTIPOLYGONM,
GEOMETRYCOLLECTIONM. For heterogeneous (mixed-type) collections, you can use "GEOMETRY" as the type.

Note
This attribute is (probably) not part of the OpenGIS specification, but is required for ensuring type homogeneity.

4.3.3 Creating a Spatial Table

Creating a table with spatial data, can be done in one step. As shown in the following example which creates a roads table with
a 2D linestring geometry column in WGS84 long lat
CREATE TABLE ROADS ( ID int4
, ROAD_NAME varchar(25), geom geometry(LINESTRING,4326) );

We can add additional columns using standard ALTER TABLE command as we do in this next example where we add a 3-D
linestring.
ALTER TABLE roads ADD COLUMN geom2 geometry(LINESTRINGZ,4326);

For backwards compability, you can still create a spatial table in two stages using the management functions.

• Create a normal non-spatial table.

For example: CREATE TABLE ROADS ( ID int4, ROAD_NAME varchar(25) )
• Add a spatial column to the table using the OpenGIS "AddGeometryColumn" function. Refer to AddGeometryColumn for
more details.
The syntax is:
PostGIS 2.4.3 Manual 45 / 803

AddGeometryColumn(
<schema_name>,
<table_name>,
<column_name>,
<srid>,
<type>,
<dimension>
)

Or, using current schema:

AddGeometryColumn(
<table_name>,
<column_name>,
<srid>,
<type>,
<dimension>
)

Example1: SELECT AddGeometryColumn(’public’, ’roads’, ’geom’, 423, ’LINESTRING’, 2)

Example2: SELECT AddGeometryColumn( ’roads’, ’geom’, 423, ’LINESTRING’, 2)

Here is an example of SQL used to create a table and add a spatial column (assuming that an SRID of 128 exists already):
CREATE TABLE parks (
park_id INTEGER,
park_name VARCHAR,
park_date DATE,
park_type VARCHAR
);
SELECT AddGeometryColumn('parks', 'park_geom', 128, 'MULTIPOLYGON', 2 );

Here is another example, using the generic "geometry" type and the undefined SRID value of 0:
CREATE TABLE roads (
road_id INTEGER,
road_name VARCHAR
);
SELECT AddGeometryColumn( 'roads', 'roads_geom', 0, 'GEOMETRY', 3 );

4.3.4 Manually Registering Geometry Columns in geometry_columns

The AddGeometryColumn() approach creates a geometry column of specified type. This type and dimension are queryable from
the geometry_columns view. Starting with PostGIS 2.0, geometry_columns is no longer editable and all geometry columns
are autoregistered.
If your geometry columns were created as generic in a table or view and no constraints applied, they will not have a dimension,
type or srid in geometry_columns views, but will still be listed.
Two of the cases where this may happen, but you can’t use AddGeometryColumn, is in the case of SQL Views and bulk inserts.
For bulk insert case, you can correct the registration in the geometry_columns table by constraining the column or doing an alter
table. For views, you could expose using a CAST operation. Note in PostGIS 2.0+ if your column is typmod based, the creation
process would register it correctly, so no need to do anything. Also views that have no spatial function applied to the geometry
will register the same as the underlying table geometry column.
--Lets say you have a view created like this
CREATE VIEW public.vwmytablemercator AS
SELECT gid, ST_Transform(geom,3395) As geom, f_name
FROM public.mytable;
PostGIS 2.4.3 Manual 46 / 803

-- For it to register correctly in PostGIS 2.0+

-- You need to cast the geometry
--
DROP VIEW public.vwmytablemercator;
CREATE VIEW public.vwmytablemercator AS
SELECT gid, ST_Transform(geom,3395)::geometry(Geometry, 3395) As geom, f_name
FROM public.mytable;

-- If you know the geometry type for sure is a 2D POLYGON then you could do
DROP VIEW public.vwmytablemercator;
CREATE VIEW public.vwmytablemercator AS
SELECT gid, ST_Transform(geom,3395)::geometry(Polygon, 3395) As geom, f_name
FROM public.mytable;

--Lets say you created a derivative table by doing a bulk insert

SELECT poi.gid, poi.geom, citybounds.city_name
INTO myschema.my_special_pois
FROM poi INNER JOIN citybounds ON ST_Intersects(citybounds.geom, poi.geom);

--Create 2d index on new table

CREATE INDEX idx_myschema_myspecialpois_geom_gist
ON myschema.my_special_pois USING gist(geom);

-- If your points are 3D points or 3M points,

-- then you might want to create an nd index instead of a 2d index
-- like so
CREATE INDEX my_special_pois_geom_gist_nd
ON my_special_pois USING gist(geom gist_geometry_ops_nd);

--To manually register this new table's geometry column in geometry_columns

-- Note that this approach will work for both PostGIS 2.0+ and PostGIS 1.4+
-- For PostGIS 2.0 it will also change the underlying structure of the table to
-- to make the column typmod based.
-- For PostGIS prior to 2.0, this technique can also be used to register views
SELECT populate_geometry_columns('myschema.my_special_pois'::regclass);

--If you are using PostGIS 2.0 and for whatever reason, you
-- you need the old constraint based definition behavior
-- (such as case of inherited tables where all children do not have the same type and srid)
-- set new optional use_typmod argument to false
SELECT populate_geometry_columns('myschema.my_special_pois'::regclass, false);

Although the old-constraint based method is still supported, a constraint-based geometry column used directly in a view, will not
register correctly in geometry_columns, as will a typmod one. In this example we define a column using typmod and another
using constraints.
CREATE TABLE pois_ny(gid SERIAL PRIMARY KEY
, poi_name text, cat varchar(20)
, geom geometry(POINT,4326) );
SELECT AddGeometryColumn('pois_ny', 'geom_2160', 2160, 'POINT', 2, false);

If we run in psql
\d pois_ny;

We observe they are defined differently -- one is typmod, one is constraint

Table "public.pois_ny"
Column | Type | Modifiers
PostGIS 2.4.3 Manual 47 / 803

-----------+-----------------------+------------------------------------------------------
gid | integer | not null default nextval('pois_ny_gid_seq'::regclass)
poi_name | text |
cat | character varying(20) |
geom | geometry(Point,4326) |
geom_2160 | geometry |
Indexes:
"pois_ny_pkey" PRIMARY KEY, btree (gid)
Check constraints:
"enforce_dims_geom_2160" CHECK (st_ndims(geom_2160) = 2)
"enforce_geotype_geom_2160" CHECK (geometrytype(geom_2160) = 'POINT'::text
OR geom_2160 IS NULL)
"enforce_srid_geom_2160" CHECK (st_srid(geom_2160) = 2160)

In geometry_columns, they both register correctly

SELECT f_table_name, f_geometry_column, srid, type
FROM geometry_columns
WHERE f_table_name = 'pois_ny';

f_table_name | f_geometry_column | srid | type

-------------+-------------------+------+-------
pois_ny | geom | 4326 | POINT
pois_ny | geom_2160 | 2160 | POINT

However -- if we were to create a view like this

CREATE VIEW vw_pois_ny_parks AS
SELECT *
FROM pois_ny
WHERE cat='park';

SELECT f_table_name, f_geometry_column, srid, type

FROM geometry_columns
WHERE f_table_name = 'vw_pois_ny_parks';

The typmod based geom view column registers correctly, but the constraint based one does not.
f_table_name | f_geometry_column | srid | type
------------------+-------------------+------+----------
vw_pois_ny_parks | geom | 4326 | POINT
vw_pois_ny_parks | geom_2160 | 0 | GEOMETRY

This may change in future versions of PostGIS, but for now To force the constraint based view column to register correctly, we
need to do this:
DROP VIEW vw_pois_ny_parks;
CREATE VIEW vw_pois_ny_parks AS
SELECT gid, poi_name, cat
, geom
, geom_2160::geometry(POINT,2160) As geom_2160
FROM pois_ny
WHERE cat='park';
SELECT f_table_name, f_geometry_column, srid, type
FROM geometry_columns
WHERE f_table_name = 'vw_pois_ny_parks';

f_table_name | f_geometry_column | srid | type

------------------+-------------------+------+-------
vw_pois_ny_parks | geom | 4326 | POINT
vw_pois_ny_parks | geom_2160 | 2160 | POINT
PostGIS 2.4.3 Manual 48 / 803

4.3.5 Ensuring OpenGIS compliancy of geometries

PostGIS is compliant with the Open Geospatial Consortium’s (OGC) OpenGIS Specifications. As such, many PostGIS methods
require, or more accurately, assume that geometries that are operated on are both simple and valid. For example, it does not
make sense to calculate the area of a polygon that has a hole defined outside of the polygon, or to construct a polygon from a
non-simple boundary line.
According to the OGC Specifications, a simple geometry is one that has no anomalous geometric points, such as self intersection
or self tangency and primarily refers to 0 or 1-dimensional geometries (i.e. [MULTI]POINT, [MULTI]LINESTRING).
Geometry validity, on the other hand, primarily refers to 2-dimensional geometries (i.e. [MULTI]POLYGON) and defines the
set of assertions that characterizes a valid polygon. The description of each geometric class includes specific conditions that
further detail geometric simplicity and validity.
A POINT is inheritably simple as a 0-dimensional geometry object.
MULTIPOINTs are simple if no two coordinates (POINTs) are equal (have identical coordinate values).
A LINESTRING is simple if it does not pass through the same POINT twice (except for the endpoints, in which case it is referred
to as a linear ring and additionally considered closed).

(a) (b)
PostGIS 2.4.3 Manual 49 / 803

(c) (d)

(a) and (c) are simple LINESTRINGs, (b) and (d) are not.

A MULTILINESTRING is simple only if all of its elements are simple and the only intersection between any two elements
occurs at POINTs that are on the boundaries of both elements.

(e) (f) (g)

(e) and (f) are simple MULTILINESTRINGs, (g) is not.

By definition, a POLYGON is always simple. It is valid if no two rings in the boundary (made up of an exterior ring and interior
rings) cross. The boundary of a POLYGON may intersect at a POINT but only as a tangent (i.e. not on a line). A POLYGON may
not have cut lines or spikes and the interior rings must be contained entirely within the exterior ring.
PostGIS 2.4.3 Manual 50 / 803

(h) (i) (j)

(k) (l) (m)

(h) and (i) are valid POLYGONs, (j-m) cannot be represented as single POLYGONs, but (j) and (m) could be represented as
a valid MULTIPOLYGON.

A MULTIPOLYGON is valid if and only if all of its elements are valid and the interiors of no two elements intersect. The
boundaries of any two elements may touch, but only at a finite number of POINTs.
PostGIS 2.4.3 Manual 51 / 803

(n) (o)

(n) and (o) are not valid MULTIPOLYGONs. (p), however, is valid.

Most of the functions implemented by the GEOS library rely on the assumption that your geometries are valid as specified by
the OpenGIS Simple Feature Specification. To check simplicity or validity of geometries you can use the ST_IsSimple() and
ST_IsValid()
-- Typically, it doesn't make sense to check
-- for validity on linear features since it will always return TRUE.
-- But in this example, PostGIS extends the definition of the OGC IsValid
-- by returning false if a LineString has less than 2 *distinct* vertices.
gisdb=# SELECT
ST_IsValid('LINESTRING(0 0, 1 1)'),
ST_IsValid('LINESTRING(0 0, 0 0, 0 0)');

st_isvalid | st_isvalid
------------+-----------
t | f

By default, PostGIS does not apply this validity check on geometry input, because testing for validity needs lots of CPU time for
complex geometries, especially polygons. If you do not trust your data sources, you can manually enforce such a check to your
tables by adding a check constraint:
ALTER TABLE mytable
ADD CONSTRAINT geometry_valid_check
CHECK (ST_IsValid(the_geom));

If you encounter any strange error messages such as "GEOS Intersection() threw an error!" or "JTS Intersection() threw an error!"
when calling PostGIS functions with valid input geometries, you likely found an error in either PostGIS or one of the libraries
it uses, and you should contact the PostGIS developers. The same is true if a PostGIS function returns an invalid geometry for
valid input.

Note
Strictly compliant OGC geometries cannot have Z or M values. The ST_IsValid() function won’t consider higher dimen-
sioned geometries invalid! Invocations of AddGeometryColumn() will add a constraint checking geometry dimensions,
so it is enough to specify 2 there.
PostGIS 2.4.3 Manual 52 / 803

4.3.6 Dimensionally Extended 9 Intersection Model (DE-9IM)

It is sometimes the case that the typical spatial predicates (ST_Contains, ST_Crosses, ST_Intersects, ST_Touches, ...) are
insufficient in and of themselves to adequately provide that desired spatial filter.

For example, consider a linear dataset representing a road network. It may be the task of a GIS analyst to identify all road
segments that cross each other, not at a point, but on a line, perhaps invalidating some business rule. In this case,
ST_Crosses does not adequately provide the necessary spatial filter since, for linear features, it returns true only where
they cross at a point.
One two-step solution might be to first perform the actual intersection (ST_Intersection) of pairs of road segments that
spatially intersect (ST_Intersects), and then compare the intersection’s ST_GeometryType with ’LINESTRING’ (properly
dealing with cases that return GEOMETRYCOLLECTIONs of [MULTI]POINTs, [MULTI]LINESTRINGs, etc.).
A more elegant / faster solution may indeed be desirable.
PostGIS 2.4.3 Manual 53 / 803

A second [theoretical] example may be that of a GIS analyst trying to locate all wharfs or docks that intersect a lake’s
boundary on a line and where only one end of the wharf is up on shore. In other words, where a wharf is within, but not
completely within a lake, intersecting the boundary of a lake on a line, and where the wharf’s endpoints are both
completely within and on the boundary of the lake. The analyst may need to use a combination of spatial predicates to
isolate the sought after features:
• ST_Contains(lake, wharf) = TRUE
• ST_ContainsProperly(lake, wharf) = FALSE

• ST_GeometryType(ST_Intersection(wharf, lake)) = ’LINESTRING’

• ST_NumGeometries(ST_Multi(ST_Intersection(ST_Boundary(wharf), ST_Boundary(lake)))) = 1
... (needless to say, this could get quite complicated)

So enters the Dimensionally Extended 9 Intersection Model, or DE-9IM for short.

4.3.6.1 Theory

According to the OpenGIS Simple Features Implementation Specification for SQL, "the basic approach to comparing two ge-
ometries is to make pair-wise tests of the intersections between the Interiors, Boundaries and Exteriors of the two geometries and
to classify the relationship between the two geometries based on the entries in the resulting ’intersection’ matrix."

Boundary
The boundary of a geometry is the set of geometries of the next lower dimension. For POINTs, which have a dimension of
0, the boundary is the empty set. The boundary of a LINESTRING are the two endpoints. For POLYGONs, the boundary
is the linework that make up the exterior and interior rings.

Interior
The interior of a geometry are those points of a geometry that are left when the boundary is removed. For POINTs,
the interior is the POINT itself. The interior of a LINESTRING are the set of real points between the endpoints. For
POLYGONs, the interior is the areal surface inside the polygon.

Exterior
The exterior of a geometry is the universe, an areal surface, not on the interior or boundary of the geometry.
PostGIS 2.4.3 Manual 54 / 803

Given geometry a, where the I(a), B(a), and E(a) are the Interior, Boundary, and Exterior of a, the mathematical representation
of the matrix is:

Interior Boundary Exterior

Interior dim( I(a) ∩ I(b) ) dim( I(a) ∩ B(b) ) dim( I(a) ∩ E(b) )
Boundary dim( B(a) ∩ I(b) ) dim( B(a) ∩ B(b) ) dim( B(a) ∩ E(b) )
Exterior dim( E(a) ∩ I(b) ) dim( E(a) ∩ B(b) ) dim( E(a) ∩ E(b) )

Where dim(a) is the dimension of a as specified by ST_Dimension but has the domain of {0,1,2,T,F,*}

• 0 => point
• 1 => line
• 2 => area
• T => {0,1,2}
• F => empty set
• * => don’t care

Visually, for two overlapping polygonal geometries, this looks like:

PostGIS 2.4.3 Manual 55 / 803

Interior Boundary Exterior

Interior

dim(...) = 2 dim(...) = 1 dim(...) = 2

Boundary

dim(...) = 1 dim(...) = 0 dim(...) = 1

Exterior

dim(...) = 2 dim(...) = 1 dim(...) = 2

Read from left to right and from top to bottom, the dimensional matrix is represented, ’212101212’.
A relate matrix that would therefore represent our first example of two lines that intersect on a line would be: ’1*1***1**’
-- Identify road segments that cross on a line
SELECT a.id
FROM roads a, roads b
WHERE a.id != b.id
AND a.geom && b.geom
AND ST_Relate(a.geom, b.geom, '1*1***1**');

A relate matrix that represents the second example of wharfs partly on the lake’s shoreline would be ’102101FF2’
-- Identify wharfs partly on a lake's shoreline
SELECT a.lake_id, b.wharf_id
FROM lakes a, wharfs b
WHERE a.geom && b.geom
AND ST_Relate(a.geom, b.geom, '102101FF2');
PostGIS 2.4.3 Manual 56 / 803

For more information or reading, see:

• OpenGIS Simple Features Implementation Specification for SQL (version 1.1, section 2.1.13.2)
• Dimensionally Extended Nine-Intersection Model (DE-9IM)
• GeoTools: Point Set Theory and the DE-9IM Matrix
• Encyclopedia of GIS By Hui Xiong

4.4 Loading GIS (Vector) Data

Once you have created a spatial table, you are ready to upload GIS data to the database. Currently, there are two ways to get data
into a PostGIS/PostgreSQL database: using formatted SQL statements or using the Shape file loader/dumper.

4.4.1 Loading Data Using SQL

If you can convert your data to a text representation, then using formatted SQL might be the easiest way to get your data into
PostGIS. As with Oracle and other SQL databases, data can be bulk loaded by piping a large text file full of SQL "INSERT"
statements into the SQL terminal monitor.
A data upload file (roads.sql for example) might look like this:
BEGIN;
INSERT INTO roads (road_id, roads_geom, road_name)
VALUES (1,ST_GeomFromText('LINESTRING(191232 243118,191108 243242)',-1),'Jeff Rd');
INSERT INTO roads (road_id, roads_geom, road_name)
VALUES (2,ST_GeomFromText('LINESTRING(189141 244158,189265 244817)',-1),'Geordie Rd');
INSERT INTO roads (road_id, roads_geom, road_name)
VALUES (3,ST_GeomFromText('LINESTRING(192783 228138,192612 229814)',-1),'Paul St');
INSERT INTO roads (road_id, roads_geom, road_name)
VALUES (4,ST_GeomFromText('LINESTRING(189412 252431,189631 259122)',-1),'Graeme Ave');
INSERT INTO roads (road_id, roads_geom, road_name)
VALUES (5,ST_GeomFromText('LINESTRING(190131 224148,190871 228134)',-1),'Phil Tce');
INSERT INTO roads (road_id, roads_geom, road_name)
VALUES (6,ST_GeomFromText('LINESTRING(198231 263418,198213 268322)',-1),'Dave Cres');
COMMIT;

The data file can be piped into PostgreSQL very easily using the "psql" SQL terminal monitor:
psql -d [database] -f roads.sql

4.4.2 shp2pgsql: Using the ESRI Shapefile Loader

The shp2pgsql data loader converts ESRI Shape files into SQL suitable for insertion into a PostGIS/PostgreSQL database
either in geometry or geography format. The loader has several operating modes distinguished by command line flags:
In addition to the shp2pgsql command-line loader, there is an shp2pgsql-gui graphical interface with most of the options as
the command-line loader, but may be easier to use for one-off non-scripted loading or if you are new to PostGIS. It can also be
configured as a plugin to PgAdminIII.

(c|a|d|p) These are mutually exclusive options:

-c Creates a new table and populates it from the shapefile. This is the default mode.
-a Appends data from the Shape file into the database table. Note that to use this option to load multiple files, the files
must have the same attributes and same data types.
-d Drops the database table before creating a new table with the data in the Shape file.
PostGIS 2.4.3 Manual 57 / 803

-p Only produces the table creation SQL code, without adding any actual data. This can be used if you need to completely
separate the table creation and data loading steps.
-? Display help screen.
-D Use the PostgreSQL "dump" format for the output data. This can be combined with -a, -c and -d. It is much faster to load
than the default "insert" SQL format. Use this for very large data sets.
-s [<FROM_SRID%gt;:]<SRID> Creates and populates the geometry tables with the specified SRID. Optionally specifies that
the input shapefile uses the given FROM_SRID, in which case the geometries will be reprojected to the target SRID.
FROM_SRID cannot be specified with -D.
-k Keep identifiers’ case (column, schema and attributes). Note that attributes in Shapefile are all UPPERCASE.
-i Coerce all integers to standard 32-bit integers, do not create 64-bit bigints, even if the DBF header signature appears to warrant
it.
-I Create a GiST index on the geometry column.
-m -m a_file_name Specify a file containing a set of mappings of (long) column names to 10 character DBF column names.
The content of the file is one or more lines of two names separated by white space and no trailing or leading space. For
example:
COLUMNNAME DBFFIELD1
AVERYLONGCOLUMNNAME DBFFIELD2

-S Generate simple geometries instead of MULTI geometries. Will only succeed if all the geometries are actually single (I.E. a
MULTIPOLYGON with a single shell, or or a MULTIPOINT with a single vertex).
-t <dimensionality> Force the output geometry to have the specified dimensionality. Use the following strings to indicate the
dimensionality: 2D, 3DZ, 3DM, 4D.
If the input has fewer dimensions that specified, the output will have those dimensions filled in with zeroes. If the input
has more dimensions that specified, the unwanted dimensions will be stripped.
-w Output WKT format, instead of WKB. Note that this can introduce coordinate drifts due to loss of precision.
-e Execute each statement on its own, without using a transaction. This allows loading of the majority of good data when there
are some bad geometries that generate errors. Note that this cannot be used with the -D flag as the "dump" format always
uses a transaction.
-W <encoding> Specify encoding of the input data (dbf file). When used, all attributes of the dbf are converted from the
specified encoding to UTF8. The resulting SQL output will contain a SET CLIENT_ENCODING to UTF8 command,
so that the backend will be able to reconvert from UTF8 to whatever encoding the database is configured to use internally.
-N <policy> NULL geometries handling policy (insert*,skip,abort)
-n -n Only import DBF file. If your data has no corresponding shapefile, it will automatically switch to this mode and load just
the dbf. So setting this flag is only needed if you have a full shapefile set, and you only want the attribute data and no
geometry.
-G Use geography type instead of geometry (requires lon/lat data) in WGS84 long lat (SRID=4326)
-T <tablespace> Specify the tablespace for the new table. Indexes will still use the default tablespace unless the -X parameter
is also used. The PostgreSQL documentation has a good description on when to use custom tablespaces.
-X <tablespace> Specify the tablespace for the new table’s indexes. This applies to the primary key index, and the GIST spatial
index if -I is also used.

An example session using the loader to create an input file and uploading it might look like this:
# shp2pgsql -c -D -s 4269 -i -I shaperoads.shp myschema.roadstable > roads.sql
# psql -d roadsdb -f roads.sql

A conversion and upload can be done all in one step using UNIX pipes:
# shp2pgsql shaperoads.shp myschema.roadstable | psql -d roadsdb
PostGIS 2.4.3 Manual 58 / 803

4.5 Retrieving GIS Data

Data can be extracted from the database using either SQL or the Shape file loader/dumper. In the section on SQL we will discuss
some of the operators available to do comparisons and queries on spatial tables.

4.5.1 Using SQL to Retrieve Data

The most straightforward means of pulling data out of the database is to use a SQL select query to reduce the number of
RECORDS and COLUMNS returned and dump the resulting columns into a parsable text file:
db=# SELECT road_id, ST_AsText(road_geom) AS geom, road_name FROM roads;

road_id | geom | road_name

--------+-----------------------------------------+-----------
1 | LINESTRING(191232 243118,191108 243242) | Jeff Rd
2 | LINESTRING(189141 244158,189265 244817) | Geordie Rd
3 | LINESTRING(192783 228138,192612 229814) | Paul St
4 | LINESTRING(189412 252431,189631 259122) | Graeme Ave
5 | LINESTRING(190131 224148,190871 228134) | Phil Tce
6 | LINESTRING(198231 263418,198213 268322) | Dave Cres
7 | LINESTRING(218421 284121,224123 241231) | Chris Way
(6 rows)

However, there will be times when some kind of restriction is necessary to cut down the number of fields returned. In the case of
attribute-based restrictions, just use the same SQL syntax as normal with a non-spatial table. In the case of spatial restrictions,
the following operators are available/useful:

&& This operator tells whether the bounding box of one geometry intersects the bounding box of another.
ST_OrderingEquals This tests whether two geometries are geometrically identical. For example, if ’POLYGON((0 0,1 1,1 0,0
0))’ is the same as ’POLYGON((0 0,1 1,1 0,0 0))’ (it is).
= This operator is a little more naive, it only tests whether the bounding boxes of two geometries are the same.

Next, you can use these operators in queries. Note that when specifying geometries and boxes on the SQL command line,
you must explicitly turn the string representations into geometries by using the "ST_GeomFromText()" function. The 312 is a
fictitious spatial reference system that matches our data. So, for example:
SELECT road_id, road_name
FROM roads
WHERE ST_OrderingEquals(roads_geom , ST_GeomFromText('LINESTRING(191232 243118,191108 ←-
243242)',312) ) ;

The above query would return the single record from the "ROADS_GEOM" table in which the geometry was equal to that value.
When using the "&&" operator, you can specify either a BOX3D as the comparison feature or a GEOMETRY. When you specify
a GEOMETRY, however, its bounding box will be used for the comparison.
SELECT road_id, road_name
FROM roads
WHERE roads_geom && ST_GeomFromText('POLYGON((...))',312);

The above query will use the bounding box of the polygon for comparison purposes.
The most common spatial query will probably be a "frame-based" query, used by client software, like data browsers and web
mappers, to grab a "map frame" worth of data for display. Using a "BOX3D" object for the frame, such a query looks like this:
SELECT ST_AsText(roads_geom) AS geom
FROM roads
WHERE
roads_geom && ST_MakeEnvelope(191232, 243117,191232, 243119,312);

Note the use of the SRID 312, to specify the projection of the envelope.
PostGIS 2.4.3 Manual 59 / 803

4.5.2 Using the Dumper

The pgsql2shp table dumper connects directly to the database and converts a table (possibly defined by a query) into a shape
file. The basic syntax is:
pgsql2shp [<options>] <database> [<schema>.]<table>

pgsql2shp [<options>] <database> <query>

The commandline options are:

-f <filename> Write the output to a particular filename.

-h <host> The database host to connect to.

-p <port> The port to connect to on the database host.
-P <password> The password to use when connecting to the database.
-u <user> The username to use when connecting to the database.

-g <geometry column> In the case of tables with multiple geometry columns, the geometry column to use when writing the
shape file.
-b Use a binary cursor. This will make the operation faster, but will not work if any NON-geometry attribute in the table lacks a
cast to text.

-r Raw mode. Do not drop the gid field, or escape column names.
-d For backward compatibility: write a 3-dimensional shape file when dumping from old (pre-1.0.0) postgis databases (the
default is to write a 2-dimensional shape file in that case). Starting from postgis-1.0.0+, dimensions are fully encoded.
-m filename Remap identifiers to ten character names. The content of the file is lines of two symbols separated by a single
white space and no trailing or leading space: VERYLONGSYMBOL SHORTONE ANOTHERVERYLONGSYMBOL
SHORTER etc.

4.6 Building Indexes

Indexes are what make using a spatial database for large data sets possible. Without indexing, any search for a feature would
require a "sequential scan" of every record in the database. Indexing speeds up searching by organizing the data into a search
tree which can be quickly traversed to find a particular record. PostgreSQL supports three kinds of indexes by default: B-Tree
indexes, R-Tree indexes, and GiST indexes.

• B-Trees are used for data which can be sorted along one axis; for example, numbers, letters, dates. GIS data cannot be rationally
sorted along one axis (which is greater, (0,0) or (0,1) or (1,0)?) so B-Tree indexing is of no use for us.
• R-Trees break up data into rectangles, and sub-rectangles, and sub-sub rectangles, etc. R-Trees are used by some spatial
databases to index GIS data, but the PostgreSQL R-Tree implementation is not as robust as the GiST implementation.

• GiST (Generalized Search Trees) indexes break up data into "things to one side", "things which overlap", "things which are
inside" and can be used on a wide range of data-types, including GIS data. PostGIS uses an R-Tree index implemented on top
of GiST to index GIS data.
PostGIS 2.4.3 Manual 60 / 803

4.6.1 GiST Indexes

GiST stands for "Generalized Search Tree" and is a generic form of indexing. In addition to GIS indexing, GiST is used to speed
up searches on all kinds of irregular data structures (integer arrays, spectral data, etc) which are not amenable to normal B-Tree
indexing.
Once a GIS data table exceeds a few thousand rows, you will want to build an index to speed up spatial searches of the data
(unless all your searches are based on attributes, in which case you’ll want to build a normal index on the attribute fields).
The syntax for building a GiST index on a "geometry" column is as follows:
CREATE INDEX [indexname] ON [tablename] USING GIST ( [geometryfield] );

The above syntax will always build a 2D-index. To get the an n-dimensional index supported in PostGIS 2.0+ for the geometry
type, you can create one using this syntax
CREATE INDEX [indexname] ON [tablename] USING GIST ([geometryfield] gist_geometry_ops_nd);

Building a spatial index is a computationally intensive exercise: on tables of around 1 million rows, on a 300MHz Solaris
machine, we have found building a GiST index takes about 1 hour. After building an index, it is important to force PostgreSQL
to collect table statistics, which are used to optimize query plans:
VACUUM ANALYZE [table_name] [(column_name)];
-- This is only needed for PostgreSQL 7.4 installations and below
SELECT UPDATE_GEOMETRY_STATS([table_name], [column_name]);

GiST indexes have two advantages over R-Tree indexes in PostgreSQL. Firstly, GiST indexes are "null safe", meaning they can
index columns which include null values. Secondly, GiST indexes support the concept of "lossiness" which is important when
dealing with GIS objects larger than the PostgreSQL 8K page size. Lossiness allows PostgreSQL to store only the "important"
part of an object in an index -- in the case of GIS objects, just the bounding box. GIS objects larger than 8K will cause R-Tree
indexes to fail in the process of being built.

4.6.2 BRIN Indexes

BRIN stands for "Block Range Index" and is a generic form of indexing that has been introduced in PostgreSQL 9.5. BRIN is
a lossy kind of index, and its main usage is to provide a compromise for both read and write performance. Its primary goal is
to handle very large tables for which some of the columns have some natural correlation with their physical location within the
table. In addition to GIS indexing, BRIN is used to speed up searches on various kinds of regular or irregular data structures
(integer, arrays etc).
Once a GIS data table exceeds a few thousand rows, you will want to build an index to speed up spatial searches of the data
(unless all your searches are based on attributes, in which case you’ll want to build a normal index on the attribute fields). GiST
indexes are really performant as long as their size doesn’t exceed the amount of RAM available for the database, and as long as
you can afford the storage size, and the penalty in write workload. Otherwise, BRIN index can be considered as an alternative.
The idea of a BRIN index is to store only the bouding box englobing all the geometries contained in all the rows in a set of table
blocks, called a range. Obviously, this indexing method will only be efficient if the data is physically ordered in a way where
the resulting bouding boxes for block ranges will be mutually exclusive. The resulting index will be really small, but will be less
efficient than a GiST index in many cases.
Building a BRIN index is way less intensive than building a GiST index. It’s quite common to build a BRIN index in more than
ten time less than a GiST index would have required. As a BRIN index only store one bouding box for one to many table blocks,
it’s pretty common to consume up to a thousand time less disk space for this kind of indexes.
You can choose the number of blocks to summarize in a range. If you decrease this number, the index will be bigger but will
probably help to get better performance.
The syntax for building a BRIN index on a "geometry" column is as follows:
CREATE INDEX [indexname] ON [tablename] USING BRIN ( [geometryfield] );
PostGIS 2.4.3 Manual 61 / 803

The above syntax will always build a 2D-index. To get a 3d-dimensional index, you can create one using this syntax
CREATE INDEX [indexname] ON [tablename] USING BRIN ([geometryfield] ←-
brin_geometry_inclusion_ops_3d);

You can also get a 4d-dimensional index using the 4d operator class
CREATE INDEX [indexname] ON [tablename] USING BRIN ([geometryfield] ←-
brin_geometry_inclusion_ops_4d);

These above syntaxes will use the default number or block in a range, which is 128. To specify the number of blocks you want
to summarise in a range, you can create one using this syntax
CREATE INDEX [indexname] ON [tablename] USING BRIN ( [geometryfield] ) WITH ( ←-
pages_per_range = [number]);

Also, keep in mind that a BRIN index will only store one index value for a large number of rows. If your table stores geometries
with a mixed number of dimensions, it’s likely that the resulting index will have poor performance. You can avoid this drop of
performance by choosing the operator class whith the least number of dimensions of the stored geometries
Also the "geography" datatype is supported for BRIN indexing. The syntax for building a BRIN index on a "geography" column
is as follows:
CREATE INDEX [indexname] ON [tablename] USING BRIN ( [geographyfield] );

The above syntax will always build a 2D-index for geospatial objects on the spheroid.
Currently, just the "inclusion support" is considered here, meaning that just &&, ~ and @ operators can be used for the 2D cases
(both for "geometry" and for "geography"), and just the &&& operator can be used for the 3D geometries. There is no support for
kNN searches at the moment.
VACUUM ANALYZE [table_name] [(column_name)];
-- This is only needed for PostgreSQL 7.4 installations and below
SELECT UPDATE_GEOMETRY_STATS([table_name], [column_name]);

4.6.3 Using Indexes

Ordinarily, indexes invisibly speed up data access: once the index is built, the query planner transparently decides when to use
index information to speed up a query plan. Unfortunately, the PostgreSQL query planner does not optimize the use of GiST
indexes well, so sometimes searches which should use a spatial index instead default to a sequence scan of the whole table.
If you find your spatial indexes are not being used (or your attribute indexes, for that matter) there are a couple things you can
do:

• Firstly, make sure statistics are gathered about the number and distributions of values in a table, to provide the query plan-
ner with better information to make decisions around index usage. For PostgreSQL 7.4 installations and below this is done
by running update_geometry_stats([table_name, column_name]) (compute distribution) and VACUUM ANALYZE [ta-
ble_name] [column_name] (compute number of values). Starting with PostgreSQL 8.0 running VACUUM ANALYZE will
do both operations. You should regularly vacuum your databases anyways -- many PostgreSQL DBAs have VACUUM run as
an off-peak cron job on a regular basis.
• If vacuuming does not work, you can force the planner to use the index information by using the SET ENABLE_SEQSCAN=OFF
command. You should only use this command sparingly, and only on spatially indexed queries: generally speaking, the planner
knows better than you do about when to use normal B-Tree indexes. Once you have run your query, you should consider setting
ENABLE_SEQSCAN back on, so that other queries will utilize the planner as normal.

Note
As of version 0.6, it should not be necessary to force the planner to use the index with ENABLE_SEQSCAN.
PostGIS 2.4.3 Manual 62 / 803

• If you find the planner wrong about the cost of sequential vs index scans try reducing the value of random_page_cost in
postgresql.conf or using SET random_page_cost=#. Default value for the parameter is 4, try setting it to 1 or 2. Decrementing
the value makes the planner more inclined of using Index scans.

4.7 Complex Queries

The raison d’etre of spatial database functionality is performing queries inside the database which would ordinarily require
desktop GIS functionality. Using PostGIS effectively requires knowing what spatial functions are available, and ensuring that
appropriate indexes are in place to provide good performance. The SRID of 312 used in these examples is purely for demonstra-
tion. You should be using a REAL SRID listed in the the spatial_ref_sys table and one that matches the projection of your data.
If your data has no spatial reference system specified, you should be THINKING very thoughtfully why it doesn’t and maybe it
should.
If your reason is because you are modeling something that doesn’t have a geographic spatial reference system defined such as
the internals of a molecule or the floorplan of a not yet built amusement park then that’s fine. If the location of the amusement
park has been planned however, then it would make sense to use a suitable planar coordinate system for that location if nothing
more than to ensure the amusement part is not trespassing on already existing structures.
Even in the case where you are planning a Mars expedition to transport the human race in the event of a nuclear holocaust and
you want to map out the Mars planet for rehabitation, you can use a non-earthly coordinate system such as Mars 2000 make
one up and insert it in the spatial_ref_sys table. Though this Mars coordinate system is a non-planar one (it’s in degrees
spheroidal), you can use it with the geography type to have your length and proximity measurements in meters instead of degrees.

4.7.1 Taking Advantage of Indexes

When constructing a query it is important to remember that only the bounding-box-based operators such as && can take ad-
vantage of the GiST spatial index. Functions such as ST_Distance() cannot use the index to optimize their operation. For
example, the following query would be quite slow on a large table:
SELECT the_geom
FROM geom_table
WHERE ST_Distance(the_geom, ST_GeomFromText('POINT(100000 200000)', 312)) < 100

This query is selecting all the geometries in geom_table which are within 100 units of the point (100000, 200000). It will be
slow because it is calculating the distance between each point in the table and our specified point, ie. one ST_Distance()
calculation for each row in the table. We can avoid this by using the && operator to reduce the number of distance calculations
required:
SELECT the_geom
FROM geom_table
WHERE ST_DWithin(the_geom, ST_MakeEnvelope(90900, 190900, 100100, 200100,312), 100)

This query selects the same geometries, but it does it in a more efficient way. Assuming there is a GiST index on the_geom,
the query planner will recognize that it can use the index to reduce the number of rows before calculating the result of the
ST_distance() function. Notice that the ST_MakeEnvelope geometry which is used in the && operation is a 200 unit
square box centered on the original point - this is our "query box". The && operator uses the index to quickly reduce the result
set down to only those geometries which have bounding boxes that overlap the "query box". Assuming that our query box is
much smaller than the extents of the entire geometry table, this will drastically reduce the number of distance calculations that
need to be done.

Change in Behavior
As of PostGIS 1.3.0, most of the Geometry Relationship Functions, with the notable exceptions of ST_Disjoint and
ST_Relate, include implicit bounding box overlap operators.
PostGIS 2.4.3 Manual 63 / 803

4.7.2 Examples of Spatial SQL

The examples in this section will make use of two tables, a table of linear roads, and a table of polygonal municipality boundaries.
The table definitions for the bc_roads table is:
Column | Type | Description
------------+-------------------+-------------------
gid | integer | Unique ID
name | character varying | Road Name
the_geom | geometry | Location Geometry (Linestring)

The table definition for the bc_municipality table is:

Column | Type | Description
-----------+-------------------+-------------------
gid | integer | Unique ID
code | integer | Unique ID
name | character varying | City / Town Name
the_geom | geometry | Location Geometry (Polygon)

1. What is the total length of all roads, expressed in kilometers?

You can answer this question with a very simple piece of SQL:
SELECT sum(ST_Length(the_geom))/1000 AS km_roads FROM bc_roads;

km_roads
------------------
70842.1243039643
(1 row)

2. How large is the city of Prince George, in hectares?

This query combines an attribute condition (on the municipality name) with a spatial calculation (of the area):
SELECT
ST_Area(the_geom)/10000 AS hectares
FROM bc_municipality
WHERE name = 'PRINCE GEORGE';

hectares
------------------
32657.9103824927
(1 row)

3. What is the largest municipality in the province, by area?

This query brings a spatial measurement into the query condition. There are several ways of approaching this problem, but
the most efficient is below:
SELECT
name,
ST_Area(the_geom)/10000 AS hectares
FROM
bc_municipality
ORDER BY hectares DESC
LIMIT 1;

name | hectares
---------------+-----------------
TUMBLER RIDGE | 155020.02556131
(1 row)
PostGIS 2.4.3 Manual 64 / 803

Note that in order to answer this query we have to calculate the area of every polygon. If we were doing this a lot it would
make sense to add an area column to the table that we could separately index for performance. By ordering the results in a
descending direction, and them using the PostgreSQL "LIMIT" command we can easily pick off the largest value without
using an aggregate function like max().

4. What is the length of roads fully contained within each municipality?

This is an example of a "spatial join", because we are bringing together data from two tables (doing a join) but using a
spatial interaction condition ("contained") as the join condition rather than the usual relational approach of joining on a
common key:
SELECT
m.name,
sum(ST_Length(r.the_geom))/1000 as roads_km
FROM
bc_roads AS r,
bc_municipality AS m
WHERE
ST_Contains(m.the_geom,r.the_geom)
GROUP BY m.name
ORDER BY roads_km;

name | roads_km
----------------------------+------------------
SURREY | 1539.47553551242
VANCOUVER | 1450.33093486576
LANGLEY DISTRICT | 833.793392535662
BURNABY | 773.769091404338
PRINCE GEORGE | 694.37554369147
...

This query takes a while, because every road in the table is summarized into the final result (about 250K roads for our
particular example table). For smaller overlays (several thousand records on several hundred) the response can be very
fast.
5. Create a new table with all the roads within the city of Prince George.
This is an example of an "overlay", which takes in two tables and outputs a new table that consists of spatially clipped or
cut resultants. Unlike the "spatial join" demonstrated above, this query actually creates new geometries. An overlay is like
a turbo-charged spatial join, and is useful for more exact analysis work:
CREATE TABLE pg_roads as
SELECT
ST_Intersection(r.the_geom, m.the_geom) AS intersection_geom,
ST_Length(r.the_geom) AS rd_orig_length,
r.*
FROM
bc_roads AS r,
bc_municipality AS m
WHERE m.name = 'PRINCE GEORGE' AND ST_Intersects(r.the_geom, m.the_geom);

6. What is the length in kilometers of "Douglas St" in Victoria?

SELECT
sum(ST_Length(r.the_geom))/1000 AS kilometers
FROM
bc_roads r,
bc_municipality m
WHERE r.name = 'Douglas St' AND m.name = 'VICTORIA'
AND ST_Contains(m.the_geom, r.the_geom) ;

kilometers
------------------
PostGIS 2.4.3 Manual 65 / 803

4.89151904172838
(1 row)

7. What is the largest municipality polygon that has a hole?

SELECT gid, name, ST_Area(the_geom) AS area
FROM bc_municipality
WHERE ST_NRings(the_geom) > 1
ORDER BY area DESC LIMIT 1;

gid | name | area

-----+--------------+------------------
12 | SPALLUMCHEEN | 257374619.430216
(1 row)
PostGIS 2.4.3 Manual 66 / 803

Chapter 5

Raster Data Management, Queries, and Applica-

tions

5.1 Loading and Creating Rasters

For most use cases, you will create PostGIS rasters by loading existing raster files using the packaged raster2pgsql raster
loader.

5.1.1 Using raster2pgsql to load rasters

The raster2pgsql is a raster loader executable that loads GDAL supported raster formats into sql suitable for loading into a
PostGIS raster table. It is capable of loading folders of raster files as well as creating overviews of rasters.
Since the raster2pgsql is compiled as part of PostGIS most often (unless you compile your own GDAL library), the raster types
supported by the executable will be the same as those compiled in the GDAL dependency library. To get a list of raster types
your particular raster2pgsql supports use the -G switch. These should be the same as those provided by your PostGIS install
documented here ST_GDALDrivers if you are using the same gdal library for both.

Note
The older version of this tool was a python script. The executable has replaced the python script. If you still find the
need for the Python script Examples of the python one can be found at GDAL PostGIS Raster Driver Usage. Please
note that the raster2pgsql python script may not work with future versions of PostGIS raster and is no longer supported.

Note
When creating overviews of a specific factor from a set of rasters that are aligned, it is possible for the overviews to not
align. Visit http://trac.osgeo.org/postgis/ticket/1764 for an example where the overviews do not align.

EXAMPLE USAGE:
raster2pgsql raster_options_go_here raster_file someschema.sometable > out.sql

-? Display help screen. Help will also display if you don’t pass in any arguments.
-G Print the supported raster formats.
(c|a|d|p) These are mutually exclusive options:
PostGIS 2.4.3 Manual 67 / 803

-c Create new table and populate it with raster(s), this is the default mode
-a Append raster(s) to an existing table.
-d Drop table, create new one and populate it with raster(s)
-p Prepare mode, only create the table.
Raster processing: Applying constraints for proper registering in raster catalogs
-C Apply raster constraints -- srid, pixelsize etc. to ensure raster is properly registered in raster_columns view.
-x Disable setting the max extent constraint. Only applied if -C flag is also used.
-r Set the constraints (spatially unique and coverage tile) for regular blocking. Only applied if -C flag is also used.
Raster processing: Optional parameters used to manipulate input raster dataset
-s <SRID> Assign output raster with specified SRID. If not provided or is zero, raster’s metadata will be checked to
determine an appropriate SRID.
-b BAND Index (1-based) of band to extract from raster. For more than one band index, separate with comma (,). If
unspecified, all bands of raster will be extracted.
-t TILE_SIZE Cut raster into tiles to be inserted one per table row. TILE_SIZE is expressed as WIDTHxHEIGHT or
set to the value "auto" to allow the loader to compute an appropriate tile size using the first raster and applied to all
rasters.
-P Pad right-most and bottom-most tiles to guarantee that all tiles have the same width and height.
-R, --register Register the raster as a filesystem (out-db) raster.
Only the metadata of the raster and path location to the raster is stored in the database (not the pixels).
-l OVERVIEW_FACTOR Create overview of the raster. For more than one factor, separate with comma(,). Overview
table name follows the pattern o_overview factor_table, where overview factor is a placeholder for
numerical overview factor and table is replaced with the base table name. Created overview is stored in the
database and is not affected by -R. Note that your generated sql file will contain both the main table and overview
tables.
-N NODATA NODATA value to use on bands without a NODATA value.

Optional parameters used to manipulate database objects

-q Wrap PostgreSQL identifiers in quotes
-f COLUMN Specify name of destination raster column, default is ’rast’
-F Add a column with the name of the file
-n COLUMN Specify the name of the filename column. Implies -F.
-q Wrap PostgreSQL identifiers in quotes.
-I Create a GiST index on the raster column.
-M Vacuum analyze the raster table.
-k Skip NODATA value checks for each raster band.
-T tablespace Specify the tablespace for the new table. Note that indices (including the primary key) will still use the
default tablespace unless the -X flag is also used.
-X tablespace Specify the tablespace for the table’s new index. This applies to the primary key and the spatial index
if the -I flag is used.
-Y Use copy statements instead of insert statements.
-e Execute each statement individually, do not use a transaction.
-E ENDIAN Control endianness of generated binary output of raster; specify 0 for XDR and 1 for NDR (default); only NDR
output is supported now

-V version Specify version of output format. Default is 0. Only 0 is supported at this time.
PostGIS 2.4.3 Manual 68 / 803

An example session using the loader to create an input file and uploading it chunked in 100x100 tiles might look like this:

Note
You can leave the schema name out e.g demelevation instead of public.demelevation and the raster table
will be created in the default schema of the database or user

raster2pgsql -s 4326 -I -C -M *.tif -F -t 100x100 public.demelevation > elev.sql

psql -d gisdb -f elev.sql

A conversion and upload can be done all in one step using UNIX pipes:
raster2pgsql -s 4326 -I -C -M *.tif -F -t 100x100 public.demelevation | psql -d gisdb

Load rasters Massachusetts state plane meters aerial tiles into a schema called aerial and create a full view, 2 and 4 level
overview tables, use copy mode for inserting (no intermediary file just straight to db), and -e don’t force everything in a transaction
(good if you want to see data in tables right away without waiting). Break up the rasters into 128x128 pixel tiles and apply raster
constraints. Use copy mode instead of table insert. (-F) Include a field called filename to hold the name of the file the tiles were
cut from.
raster2pgsql -I -C -e -Y -F -s 26986 -t 128x128 -l 2,4 bostonaerials2008/*.jpg aerials. ←-
boston | psql -U postgres -d gisdb -h localhost -p 5432

--get a list of raster types supported:

raster2pgsql -G

The -G commands outputs a list something like

Available GDAL raster formats:
Virtual Raster
GeoTIFF
National Imagery Transmission Format
Raster Product Format TOC format
ECRG TOC format
Erdas Imagine Images (.img)
CEOS SAR Image
CEOS Image
JAXA PALSAR Product Reader (Level 1.1/1.5)
Ground-based SAR Applications Testbed File Format (.gff)
ELAS
Arc/Info Binary Grid
Arc/Info ASCII Grid
GRASS ASCII Grid
SDTS Raster
DTED Elevation Raster
Portable Network Graphics
JPEG JFIF
In Memory Raster
Japanese DEM (.mem)
Graphics Interchange Format (.gif)
Graphics Interchange Format (.gif)
Envisat Image Format
Maptech BSB Nautical Charts
X11 PixMap Format
MS Windows Device Independent Bitmap
SPOT DIMAP
AirSAR Polarimetric Image
RadarSat 2 XML Product
PCIDSK Database File
PostGIS 2.4.3 Manual 69 / 803

PCRaster Raster File

ILWIS Raster Map
SGI Image File Format 1.0
SRTMHGT File Format
Leveller heightfield
Terragen heightfield
USGS Astrogeology ISIS cube (Version 3)
USGS Astrogeology ISIS cube (Version 2)
NASA Planetary Data System
EarthWatch .TIL
ERMapper .ers Labelled
NOAA Polar Orbiter Level 1b Data Set
FIT Image
GRIdded Binary (.grb)
Raster Matrix Format
EUMETSAT Archive native (.nat)
Idrisi Raster A.1
Intergraph Raster
Golden Software ASCII Grid (.grd)
Golden Software Binary Grid (.grd)
Golden Software 7 Binary Grid (.grd)
COSAR Annotated Binary Matrix (TerraSAR-X)
TerraSAR-X Product
DRDC COASP SAR Processor Raster
R Object Data Store
Portable Pixmap Format (netpbm)
USGS DOQ (Old Style)
USGS DOQ (New Style)
ENVI .hdr Labelled
ESRI .hdr Labelled
Generic Binary (.hdr Labelled)
PCI .aux Labelled
Vexcel MFF Raster
Vexcel MFF2 (HKV) Raster
Fuji BAS Scanner Image
GSC Geogrid
EOSAT FAST Format
VTP .bt (Binary Terrain) 1.3 Format
Erdas .LAN/.GIS
Convair PolGASP
Image Data and Analysis
NLAPS Data Format
Erdas Imagine Raw
DIPEx
FARSITE v.4 Landscape File (.lcp)
NOAA Vertical Datum .GTX
NADCON .los/.las Datum Grid Shift
NTv2 Datum Grid Shift
ACE2
Snow Data Assimilation System
Swedish Grid RIK (.rik)
USGS Optional ASCII DEM (and CDED)
GeoSoft Grid Exchange Format
Northwood Numeric Grid Format .grd/.tab
Northwood Classified Grid Format .grc/.tab
ARC Digitized Raster Graphics
Standard Raster Product (ASRP/USRP)
Magellan topo (.blx)
SAGA GIS Binary Grid (.sdat)
Kml Super Overlay
ASCII Gridded XYZ
HF2/HFZ heightfield raster
PostGIS 2.4.3 Manual 70 / 803

OziExplorer Image File

USGS LULC Composite Theme Grid
Arc/Info Export E00 GRID
ZMap Plus Grid
NOAA NGS Geoid Height Grids

5.1.2 Creating rasters using PostGIS raster functions

On many occasions, you’ll want to create rasters and raster tables right in the database. There are a plethora of functions to do
that. The general steps to follow.

1. Create a table with a raster column to hold the new raster records which can be accomplished with:
CREATE TABLE myrasters(rid serial primary key, rast raster);

2. There are many functions to help with that goal. If you are creating rasters not as a derivative of other rasters, you will
want to start with: ST_MakeEmptyRaster, followed by ST_AddBand
You can also create rasters from geometries. To achieve that you’ll want to use ST_AsRaster perhaps accompanied with
other functions such as ST_Union or ST_MapAlgebraFct or any of the family of other map algebra functions.
There are even many more options for creating new raster tables from existing tables. For example you can create a raster
table in a different projection from an existing one using ST_Transform

3. Once you are done populating your table initially, you’ll want to create a spatial index on the raster column with something
like:
CREATE INDEX myrasters_rast_st_convexhull_idx ON myrasters USING gist( ST_ConvexHull( ←-
rast) );

Note the use of ST_ConvexHull since most raster operators are based on the convex hull of the rasters.

Note
Pre-2.0 versions of PostGIS raster were based on the envelop rather than the convex hull. For the spatial indexes
to work properly you’ll need to drop those and replace with convex hull based index.

4. Apply raster constraints using AddRasterConstraints

5.2 Raster Catalogs

There are two raster catalog views that come packaged with PostGIS. Both views utilize information embedded in the constraints
of the raster tables. As a result the catalog views are always consistent with the raster data in the tables since the constraints are
enforced.

1. raster_columns this view catalogs all the raster table columns in your database.

2. raster_overviews this view catalogs all the raster table columns in your database that serve as overviews for a finer
grained table. Tables of this type are generated when you use the -l switch during load.
PostGIS 2.4.3 Manual 71 / 803

5.2.1 Raster Columns Catalog

The raster_columns is a catalog of all raster table columns in your database that are of type raster. It is a view utilizing the
constraints on the tables so the information is always consistent even if you restore one raster table from a backup of another
database. The following columns exist in the raster_columns catalog.
If you created your tables not with the loader or forgot to specify the -C flag during load, you can enforce the constraints after
the fact using AddRasterConstraints so that the raster_columns catalog registers the common information about your raster
tiles.

• r_table_catalog The database the table is in. This will always read the current database.
• r_table_schema The database schema the raster table belongs to.
• r_table_name raster table
• r_raster_column the column in the r_table_name table that is of type raster. There is nothing in PostGIS preventing
you from having multiple raster columns per table so its possible to have a raster table listed multiple times with a different
raster column for each.
• srid The spatial reference identifier of the raster. Should be an entry in the Section 4.3.1.
• scale_x The scaling between geometric spatial coordinates and pixel. This is only available if all tiles in the raster column
have the same scale_x and this constraint is applied. Refer to ST_ScaleX for more details.
• scale_y The scaling between geometric spatial coordinates and pixel. This is only available if all tiles in the raster column
have the same scale_y and the scale_y constraint is applied. Refer to ST_ScaleY for more details.
• blocksize_x The width (number of pixels across) of each raster tile . Refer to ST_Width for more details.

• blocksize_y The width (number of pixels down) of each raster tile . Refer to ST_Height for more details.
• same_alignment A boolean that is true if all the raster tiles have the same alignment . Refer to ST_SameAlignment for
more details.
• regular_blocking If the raster column has the spatially unique and coverage tile constraints, the value with be TRUE.
Otherwise, it will be FALSE.

• num_bands The number of bands in each tile of your raster set. This is the same information as what is provided by
ST_NumBands
• pixel_types An array defining the pixel type for each band. You will have the same number of elements in this array as
you have number of bands. The pixel_types are one of the following defined in ST_BandPixelType.

• nodata_values An array of double precision numbers denoting the nodata_value for each band. You will have the
same number of elements in this array as you have number of bands. These numbers define the pixel value for each band that
should be ignored for most operations. This is similar information provided by ST_BandNoDataValue.
• out_db An array of boolean flags indicating if the raster bands data is maintained outside the database. You will have the
same number of elements in this array as you have number of bands.

• extent This is the extent of all the raster rows in your raster set. If you plan to load more data that will change the extent of the
set, you’ll want to run the DropRasterConstraints function before load and then reapply constraints with AddRasterConstraints
after load.
• spatial_index A boolean that is true if raster column has a spatial index.
PostGIS 2.4.3 Manual 72 / 803

5.2.2 Raster Overviews

raster_overviews catalogs information about raster table columns used for overviews and additional information about
them that is useful to know when utilizing overviews. Overview tables are cataloged in both raster_columns and raster_overvi
because they are rasters in their own right but also serve an additional special purpose of being a lower resolution caricature of a
higher resolution table. These are generated along-side the main raster table when you use the -l switch in raster loading or can
be generated manually using AddOverviewConstraints.
Overview tables contain the same constraints as other raster tables as well as additional informational only constraints specific to
overviews.

Note
The information in raster_overviews does not duplicate the information in raster_columns. If you need
the information about an overview table present in raster_columns you can join the raster_overviews and
raster_columns together to get the full set of information you need.

Two main reasons for overviews are:

1. Low resolution representation of the core tables commonly used for fast mapping zoom-out.
2. Computations are generally faster to do on them than their higher resolution parents because there are fewer records and
each pixel covers more territory. Though the computations are not as accurate as the high-res tables they support, they can
be sufficient in many rule-of-thumb computations.

The raster_overviews catalog contains the following columns of information.

• o_table_catalog The database the overview table is in. This will always read the current database.
• o_table_schema The database schema the overview raster table belongs to.
• o_table_name raster overview table name
• o_raster_column the raster column in the overview table.
• r_table_catalog The database the raster table that this overview services is in. This will always read the current database.
• r_table_schema The database schema the raster table that this overview services belongs to.
• r_table_name raster table that this overview services.
• r_raster_column the raster column that this overview column services.
• overview_factor - this is the pyramid level of the overview table. The higher the number the lower the resolution of
the table. raster2pgsql if given a folder of images, will compute overview of each image file and load separately. Level 1
is assumed and always the original file. Level 2 is will have each tile represent 4 of the original. So for example if you
have a folder of 5000x5000 pixel image files that you chose to chunk 125x125, for each image file your base table will have
(5000*5000)/(125*125) records = 1600, your (l=2) o_2 table will have ceiling(1600/Power(2,2)) = 400 rows, your (l=3) o_3
will have ceiling(1600/Power(2,3) ) = 200 rows. If your pixels aren’t divisible by the size of your tiles, you’ll get some scrap
tiles (tiles not completely filled). Note that each overview tile generated by raster2pgsql has the same number of pixels as its
parent, but is of a lower resolution where each pixel of it represents (Power(2,overview_factor) pixels of the original).

5.3 Building Custom Applications with PostGIS Raster

The fact that PostGIS raster provides you with SQL functions to render rasters in known image formats gives you a lot of optoins
for rendering them. For example you can use OpenOffice / LibreOffice for rendering as demonstrated in Rendering PostGIS
Raster graphics with LibreOffice Base Reports. In addition you can use a wide variety of languages as demonstrated in this
section.
PostGIS 2.4.3 Manual 73 / 803

5.3.1 PHP Example Outputting using ST_AsPNG in concert with other raster functions

In this section, we’ll demonstrate how to use the PHP PostgreSQL driver and the ST_AsGDALRaster family of functions to
output band 1,2,3 of a raster to a PHP request stream that can then be embedded in an img src html tag.
The sample query demonstrates how to combine a whole bunch of raster functions together to grab all tiles that intersect a
particular wgs 84 bounding box and then unions with ST_Union the intersecting tiles together returning all bands, transforms to
user specified projection using ST_Transform, and then outputs the results as a png using ST_AsPNG.
You would call the below using
http://mywebserver/test_raster.php?srid=2249

to get the raster image in Massachusetts state plane feet.

<?php
/** contents of test_raster.php **/
$conn_str ='dbname=mydb host=localhost port=5432 user=myuser password=mypwd';
$dbconn = pg_connect($conn_str);
header('Content-Type: image/png');
/**If a particular projection was requested use it otherwise use mass state plane meters ←-
**/
if (!empty( $_REQUEST['srid'] ) && is_numeric( $_REQUEST['srid']) ){
$input_srid = intval($_REQUEST['srid']);
}
else { $input_srid = 26986; }
/** The set bytea_output may be needed for PostgreSQL 9.0+, but not for 8.4 **/
$sql = "set bytea_output='escape';
SELECT ST_AsPNG(ST_Transform(
ST_AddBand(ST_Union(rast,1), ARRAY[ST_Union(rast,2),ST_Union(rast,3)])
,$input_srid) ) As new_rast
FROM aerials.boston
WHERE
ST_Intersects(rast, ST_Transform(ST_MakeEnvelope(-71.1217, 42.227, -71.1210, ←-
42.218,4326),26986) )";
$result = pg_query($sql);
$row = pg_fetch_row($result);
pg_free_result($result);
if ($row === false) return;
echo pg_unescape_bytea($row[0]);
?>

5.3.2 ASP.NET C# Example Outputting using ST_AsPNG in concert with other raster functions

In this section, we’ll demonstrate how to use Npgsql PostgreSQL .NET driver and the ST_AsGDALRaster family of functions
to output band 1,2,3 of a raster to a PHP request stream that can then be embedded in an img src html tag.
You will need the npgsql .NET PostgreSQL driver for this exercise which you can get the latest of from http://npgsql.projects.postgresql.o
. Just download the latest and drop into your ASP.NET bin folder and you’ll be good to go.
The sample query demonstrates how to combine a whole bunch of raster functions together to grab all tiles that intersect a
particular wgs 84 bounding box and then unions with ST_Union the intersecting tiles together returning all bands, transforms to
user specified projection using ST_Transform, and then outputs the results as a png using ST_AsPNG.
This is same example as Section 5.3.1 except implemented in C#.
You would call the below using
http://mywebserver/TestRaster.ashx?srid=2249

to get the raster image in Massachusetts state plane feet.

PostGIS 2.4.3 Manual 74 / 803

-- web.config connection string section --

<connectionStrings>
<add name="DSN"
connectionString="server=localhost;database=mydb;Port=5432;User Id=myuser;password= ←-
mypwd"/>
</connectionStrings>

// Code for TestRaster.ashx

<%@ WebHandler Language="C#" Class="TestRaster" %>
using System;
using System.Data;
using System.Web;
using Npgsql;

public class TestRaster : IHttpHandler

{
public void ProcessRequest(HttpContext context)
{

context.Response.ContentType = "image/png";
context.Response.BinaryWrite(GetResults(context));

public bool IsReusable {

get { return false; }
}

public byte[] GetResults(HttpContext context)

{
byte[] result = null;
NpgsqlCommand command;
string sql = null;
int input_srid = 26986;
try {
using (NpgsqlConnection conn = new NpgsqlConnection(System.Configuration. ←-
ConfigurationManager.ConnectionStrings["DSN"].ConnectionString)) {
conn.Open();

if (context.Request["srid"] != null)
{
input_srid = Convert.ToInt32(context.Request["srid"]);
}
sql = @"SELECT ST_AsPNG(
ST_Transform(
ST_AddBand(
ST_Union(rast,1), ARRAY[ST_Union(rast,2),ST_Union(rast,3)])
,:input_srid) ) As new_rast
FROM aerials.boston
WHERE
ST_Intersects(rast,
ST_Transform(ST_MakeEnvelope(-71.1217, 42.227, ←-
-71.1210, 42.218,4326),26986) )";
command = new NpgsqlCommand(sql, conn);
command.Parameters.Add(new NpgsqlParameter("input_srid", input_srid));

result = (byte[]) command.ExecuteScalar();

conn.Close();
}
PostGIS 2.4.3 Manual 75 / 803

}
catch (Exception ex)
{
result = null;
context.Response.Write(ex.Message.Trim());
}
return result;
}
}

5.3.3 Java console app that outputs raster query as Image file

This is a simple java console app that takes a query that returns one image and outputs to specified file.
You can download the latest PostgreSQL JDBC drivers from http://jdbc.postgresql.org/download.html
You can compile the following code using a command something like:
set env CLASSPATH .:..\postgresql-9.0-801.jdbc4.jar
javac SaveQueryImage.java
jar cfm SaveQueryImage.jar Manifest.txt *.class

And call it from the command-line with something like

java -jar SaveQueryImage.jar "SELECT ST_AsPNG(ST_AsRaster(ST_Buffer(ST_Point(1,5),10, ' ←-
quad_segs=2'),150, 150, '8BUI',100));" "test.png"

-- Manifest.txt --
Class-Path: postgresql-9.0-801.jdbc4.jar
Main-Class: SaveQueryImage

// Code for SaveQueryImage.java

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.io.*;

public class SaveQueryImage {

public static void main(String[] argv) {
System.out.println("Checking if Driver is registered with DriverManager.");

try {
//java.sql.DriverManager.registerDriver (new org.postgresql.Driver());
Class.forName("org.postgresql.Driver");
}
catch (ClassNotFoundException cnfe) {
System.out.println("Couldn't find the driver!");
cnfe.printStackTrace();
System.exit(1);
}

Connection conn = null;

try {
conn = DriverManager.getConnection("jdbc:postgresql://localhost:5432/mydb","myuser ←-
", "mypwd");
conn.setAutoCommit(false);

PreparedStatement sGetImg = conn.prepareStatement(argv[0]);

PostGIS 2.4.3 Manual 76 / 803

ResultSet rs = sGetImg.executeQuery();

FileOutputStream fout;
try
{
rs.next();
/** Output to file name requested by user **/
fout = new FileOutputStream(new File(argv[1]) );
fout.write(rs.getBytes(1));
fout.close();
}
catch(Exception e)
{
System.out.println("Can't create file");
e.printStackTrace();
}

rs.close();
sGetImg.close();
conn.close();
}
catch (SQLException se) {
System.out.println("Couldn't connect: print out a stack trace and exit.");
se.printStackTrace();
System.exit(1);
}
}
}

5.3.4 Use PLPython to dump out images via SQL

This is a plpython stored function that creates a file in the server directory for each record. Requires you have plpython installed.
Should work fine with both plpythonu and plpython3u.
CREATE OR REPLACE FUNCTION write_file (param_bytes bytea, param_filepath text)
RETURNS text
AS $$
f = open(param_filepath, 'wb+')
f.write(param_bytes)
return param_filepath
$$ LANGUAGE plpythonu;

--write out 5 images to the PostgreSQL server in varying sizes

-- note the postgresql daemon account needs to have write access to folder
-- this echos back the file names created;
SELECT write_file(ST_AsPNG(
ST_AsRaster(ST_Buffer(ST_Point(1,5),j*5, 'quad_segs=2'),150*j, 150*j, '8BUI',100)),
'C:/temp/slices'|| j || '.png')
FROM generate_series(1,5) As j;

write_file
---------------------
C:/temp/slices1.png
C:/temp/slices2.png
C:/temp/slices3.png
C:/temp/slices4.png
C:/temp/slices5.png
PostGIS 2.4.3 Manual 77 / 803

5.3.5 Outputting Rasters with PSQL

Sadly PSQL doesn’t have easy to use built-in functionality for outputting binaries. This is a bit of a hack that piggy backs on
PostgreSQL somewhat legacy large object support. To use first launch your psql commandline connected to your database.
Unlike the python approach, this approach creates the file on your local computer.
SELECT oid, lowrite(lo_open(oid, 131072), png) As num_bytes
FROM
( VALUES (lo_create(0),
ST_AsPNG( (SELECT rast FROM aerials.boston WHERE rid=1) )
) ) As v(oid,png);
-- you'll get an output something like --
oid | num_bytes
---------+-----------
2630819 | 74860

-- next note the oid and do this replacing the c:/test.png to file path location
-- on your local computer
\lo_export 2630819 'C:/temp/aerial_samp.png'

-- this deletes the file from large object storage on db

SELECT lo_unlink(2630819);
PostGIS 2.4.3 Manual 78 / 803

Chapter 6

Using PostGIS Geometry: Building Applications

6.1 Using MapServer

The Minnesota MapServer is an internet web-mapping server which conforms to the OpenGIS Web Mapping Server specification.

• The MapServer homepage is at http://mapserver.org.

• The OpenGIS Web Map Specification is at http://www.opengeospatial.org/standards/wms.

6.1.1 Basic Usage

To use PostGIS with MapServer, you will need to know about how to configure MapServer, which is beyond the scope of this
documentation. This section will cover specific PostGIS issues and configuration details.
To use PostGIS with MapServer, you will need:

• Version 0.6 or newer of PostGIS.

• Version 3.5 or newer of MapServer.

MapServer accesses PostGIS/PostgreSQL data like any other PostgreSQL client -- using the libpq interface. This means that
MapServer can be installed on any machine with network access to the PostGIS server, and use PostGIS as a source of data. The
faster the connection between the systems, the better.

1. Compile and install MapServer, with whatever options you desire, including the "--with-postgis" configuration option.
2. In your MapServer map file, add a PostGIS layer. For example:
LAYER
CONNECTIONTYPE postgis
NAME "widehighways"
# Connect to a remote spatial database
CONNECTION "user=dbuser dbname=gisdatabase host=bigserver"
PROCESSING "CLOSE_CONNECTION=DEFER"
# Get the lines from the 'geom' column of the 'roads' table
DATA "geom from roads using srid=4326 using unique gid"
STATUS ON
TYPE LINE
# Of the lines in the extents, only render the wide highways
FILTER "type = 'highway' and numlanes >= 4"
CLASS
# Make the superhighways brighter and 2 pixels wide
PostGIS 2.4.3 Manual 79 / 803

EXPRESSION ([numlanes] >= 6)

STYLE
COLOR 255 22 22
WIDTH 2
END
END
CLASS
# All the rest are darker and only 1 pixel wide
EXPRESSION ([numlanes] < 6)
STYLE
COLOR 205 92 82
END
END
END

In the example above, the PostGIS-specific directives are as follows:

CONNECTIONTYPE For PostGIS layers, this is always "postgis".
CONNECTION The database connection is governed by the a ’connection string’ which is a standard set of keys and
values like this (with the default values in <>):
user=<username> password=<password> dbname=<username> hostname=<server> port=<5432>
An empty connection string is still valid, and any of the key/value pairs can be omitted. At a minimum you will
generally supply the database name and username to connect with.
DATA The form of this parameter is "<geocolumn> from <tablename> using srid=<srid> using unique <primary key>"
where the column is the spatial column to be rendered to the map, the SRID is SRID used by the column and the
primary key is the table primary key (or any other uniquely-valued column with an index).
You can omit the "using srid" and "using unique" clauses and MapServer will automatically determine the correct
values if possible, but at the cost of running a few extra queries on the server for each map draw.
PROCESSING Putting in a CLOSE_CONNECTION=DEFER if you have multiple layers reuses existing connections
instead of closing them. This improves speed. Refer to for MapServer PostGIS Performance Tips for a more detailed
explanation.
FILTER The filter must be a valid SQL string corresponding to the logic normally following the "WHERE" keyword in
a SQL query. So, for example, to render only roads with 6 or more lanes, use a filter of "num_lanes >= 6".
3. In your spatial database, ensure you have spatial (GiST) indexes built for any the layers you will be drawing.
CREATE INDEX [indexname] ON [tablename] USING GIST ( [geometrycolumn] );

4. If you will be querying your layers using MapServer you will also need to use the "using unique" clause in your DATA
statement.
MapServer requires unique identifiers for each spatial record when doing queries, and the PostGIS module of MapServer
uses the unique value you specify in order to provide these unique identifiers. Using the table primary key is the best
practice.

6.1.2 Frequently Asked Questions

1. When I use an EXPRESSION in my map file, the condition never returns as true, even though I know the values exist in
my table.
Unlike shape files, PostGIS field names have to be referenced in EXPRESSIONS using lower case.
EXPRESSION ([numlanes] >= 6)

2. The FILTER I use for my Shape files is not working for my PostGIS table of the same data.
Unlike shape files, filters for PostGIS layers use SQL syntax (they are appended to the SQL statement the PostGIS con-
nector generates for drawing layers in MapServer).
PostGIS 2.4.3 Manual 80 / 803

FILTER "type = 'highway' and numlanes >= 4"

3. My PostGIS layer draws much slower than my Shape file layer, is this normal?
In general, the more features you are drawing into a given map, the more likely it is that PostGIS will be slower than
Shape files. For maps with relatively few features (100s), PostGIS will often be faster. For maps with high feature density
(1000s), PostGIS will always be slower. If you are finding substantial draw performance problems, it is possible that you
have not built a spatial index on your table.
postgis# CREATE INDEX geotable_gix ON geotable USING GIST ( geocolumn );
postgis# VACUUM ANALYZE;

4. My PostGIS layer draws fine, but queries are really slow. What is wrong?
For queries to be fast, you must have a unique key for your spatial table and you must have an index on that unique key.You
can specify what unique key for mapserver to use with the USING UNIQUE clause in your DATA line:
DATA "geom FROM geotable USING UNIQUE gid"

5. Can I use "geography" columns (new in PostGIS 1.5) as a source for MapServer layers?
Yes! MapServer understands geography columns as being the same as geometry columns, but always using an SRID of
4326. Just make sure to include a "using srid=4326" clause in your DATA statement. Everything else works exactly the
same as with geometry.
DATA "geog FROM geogtable USING SRID=4326 USING UNIQUE gid"

6.1.3 Advanced Usage

The USING pseudo-SQL clause is used to add some information to help mapserver understand the results of more complex
queries. More specifically, when either a view or a subselect is used as the source table (the thing to the right of "FROM" in a
DATA definition) it is more difficult for mapserver to automatically determine a unique identifier for each row and also the SRID
for the table. The USING clause can provide mapserver with these two pieces of information as follows:
DATA "geom FROM (
SELECT
table1.geom AS geom,
table1.gid AS gid,
table2.data AS data
FROM table1
LEFT JOIN table2
ON table1.id = table2.id
) AS new_table USING UNIQUE gid USING SRID=4326"

USING UNIQUE <uniqueid> MapServer requires a unique id for each row in order to identify the row when doing map
queries. Normally it identifies the primary key from the system tables. However, views and subselects don’t automatically
have an known unique column. If you want to use MapServer’s query functionality, you need to ensure your view or
subselect includes a uniquely valued column, and declare it with USING UNIQUE. For example, you could explicitly
select nee of the table’s primary key values for this purpose, or any other column which is guaranteed to be unique for the
result set.

Note
"Querying a Map" is the action of clicking on a map to ask for information about the map features in that location.
Don’t confuse "map queries" with the SQL query in a DATA definition.

USING SRID=<srid> PostGIS needs to know which spatial referencing system is being used by the geometries in order to
return the correct data back to MapServer. Normally it is possible to find this information in the "geometry_columns" table
in the PostGIS database, however, this is not possible for tables which are created on the fly such as subselects and views.
So the USING SRID= option allows the correct SRID to be specified in the DATA definition.
PostGIS 2.4.3 Manual 81 / 803

6.1.4 Examples

Lets start with a simple example and work our way up. Consider the following MapServer layer definition:
LAYER
CONNECTIONTYPE postgis
NAME "roads"
CONNECTION "user=theuser password=thepass dbname=thedb host=theserver"
DATA "geom from roads"
STATUS ON
TYPE LINE
CLASS
STYLE
COLOR 0 0 0
END
END
END

This layer will display all the road geometries in the roads table as black lines.
Now lets say we want to show only the highways until we get zoomed in to at least a 1:100000 scale - the next two layers will
achieve this effect:
LAYER
CONNECTIONTYPE postgis
CONNECTION "user=theuser password=thepass dbname=thedb host=theserver"
PROCESSING "CLOSE_CONNECTION=DEFER"
DATA "geom from roads"
MINSCALE 100000
STATUS ON
TYPE LINE
FILTER "road_type = 'highway'"
CLASS
COLOR 0 0 0
END
END
LAYER
CONNECTIONTYPE postgis
CONNECTION "user=theuser password=thepass dbname=thedb host=theserver"
PROCESSING "CLOSE_CONNECTION=DEFER"
DATA "geom from roads"
MAXSCALE 100000
STATUS ON
TYPE LINE
CLASSITEM road_type
CLASS
EXPRESSION "highway"
STYLE
WIDTH 2
COLOR 255 0 0
END
END
CLASS
STYLE
COLOR 0 0 0
END
END
END

The first layer is used when the scale is greater than 1:100000, and displays only the roads of type "highway" as black lines. The
FILTER option causes only roads of type "highway" to be displayed.
PostGIS 2.4.3 Manual 82 / 803

The second layer is used when the scale is less than 1:100000, and will display highways as double-thick red lines, and other
roads as regular black lines.
So, we have done a couple of interesting things using only MapServer functionality, but our DATA SQL statement has remained
simple. Suppose that the name of the road is stored in another table (for whatever reason) and we need to do a join to get it and
label our roads.
LAYER
CONNECTIONTYPE postgis
CONNECTION "user=theuser password=thepass dbname=thedb host=theserver"
DATA "geom FROM (SELECT roads.gid AS gid, roads.geom AS geom,
road_names.name as name FROM roads LEFT JOIN road_names ON
roads.road_name_id = road_names.road_name_id)
AS named_roads USING UNIQUE gid USING SRID=4326"
MAXSCALE 20000
STATUS ON
TYPE ANNOTATION
LABELITEM name
CLASS
LABEL
ANGLE auto
SIZE 8
COLOR 0 192 0
TYPE truetype
FONT arial
END
END
END

This annotation layer adds green labels to all the roads when the scale gets down to 1:20000 or less. It also demonstrates how to
use an SQL join in a DATA definition.

6.2 Java Clients (JDBC)

Java clients can access PostGIS "geometry" objects in the PostgreSQL database either directly as text representations or using
the JDBC extension objects bundled with PostGIS. In order to use the extension objects, the "postgis.jar" file must be in your
CLASSPATH along with the "postgresql.jar" JDBC driver package.
import java.sql.*;
import java.util.*;
import java.lang.*;
import org.postgis.*;

public class JavaGIS {

public static void main(String[] args) {

java.sql.Connection conn;

try {
/*
* Load the JDBC driver and establish a connection.
*/
Class.forName("org.postgresql.Driver");
String url = "jdbc:postgresql://localhost:5432/database";
conn = DriverManager.getConnection(url, "postgres", "");
/*
* Add the geometry types to the connection. Note that you
* must cast the connection to the pgsql-specific connection
* implementation before calling the addDataType() method.
PostGIS 2.4.3 Manual 83 / 803

*/
((org.postgresql.PGConnection)conn).addDataType("geometry",Class.forName("org.postgis. ←-
PGgeometry"));
((org.postgresql.PGConnection)conn).addDataType("box3d",Class.forName("org.postgis. ←-
PGbox3d"));
/*
* Create a statement and execute a select query.
*/
Statement s = conn.createStatement();
ResultSet r = s.executeQuery("select geom,id from geomtable");
while( r.next() ) {
/*
* Retrieve the geometry as an object then cast it to the geometry type.
* Print things out.
*/
PGgeometry geom = (PGgeometry)r.getObject(1);
int id = r.getInt(2);
System.out.println("Row " + id + ":");
System.out.println(geom.toString());
}
s.close();
conn.close();
}
catch( Exception e ) {
e.printStackTrace();
}
}
}

The "PGgeometry" object is a wrapper object which contains a specific topological geometry object (subclasses of the abstract
class "Geometry") depending on the type: Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon.
PGgeometry geom = (PGgeometry)r.getObject(1);
if( geom.getType() == Geometry.POLYGON ) {
Polygon pl = (Polygon)geom.getGeometry();
for( int r = 0; r < pl.numRings(); r++) {
LinearRing rng = pl.getRing(r);
System.out.println("Ring: " + r);
for( int p = 0; p < rng.numPoints(); p++ ) {
Point pt = rng.getPoint(p);
System.out.println("Point: " + p);
System.out.println(pt.toString());
}
}
}

The JavaDoc for the extension objects provides a reference for the various data accessor functions in the geometric objects.

6.3 C Clients (libpq)

...

6.3.1 Text Cursors

...

6.3.2 Binary Cursors

...
PostGIS 2.4.3 Manual 84 / 803

Chapter 7

Performance tips

7.1 Small tables of large geometries

7.1.1 Problem description

Current PostgreSQL versions (including 9.6) suffer from a query optimizer weakness regarding TOAST tables. TOAST tables
are a kind of "extension room" used to store large (in the sense of data size) values that do not fit into normal data pages (like long
texts, images or complex geometries with lots of vertices), see the PostgreSQL Documentation for TOAST for more information).
The problem appears if you happen to have a table with rather large geometries, but not too manyrows of them (like a table
containing the boundaries of all European countries in high resolution). Then the table itself is small, but it uses lots of TOAST
space. In our example case, the table itself had about 80 rows and used only 3 data pages, but the TOAST table used 8225 pages.
Now issue a query where you use the geometry operator && to search for a bounding box that matches only very few of those
rows. Now the query optimizer sees that the table has only 3 pages and 80 rows. It estimates that a sequential scan on such a
small table is much faster than using an index. And so it decides to ignore the GIST index. Usually, this estimation is correct.
But in our case, the && operator has to fetch every geometry from disk to compare the bounding boxes, thus reading all TOAST
pages, too.
To see whether your suffer from this issue, use the "EXPLAIN ANALYZE" postgresql command. For more information and
the technical details, you can read the thread on the postgres performance mailing list: http://archives.postgresql.org/pgsql-
performance/2005-02/msg00030.php
and newer thread on PostGIS https://lists.osgeo.org/pipermail/postgis-devel/2017-June/026209.html

7.1.2 Workarounds

The PostgreSQL people are trying to solve this issue by making the query estimation TOAST-aware. For now, here are two
workarounds:
The first workaround is to force the query planner to use the index. Send "SET enable_seqscan TO off;" to the server before
issuing the query. This basically forces the query planner to avoid sequential scans whenever possible. So it uses the GIST index
as usual. But this flag has to be set on every connection, and it causes the query planner to make misestimations in other cases,
so you should "SET enable_seqscan TO on;" after the query.
The second workaround is to make the sequential scan as fast as the query planner thinks. This can be achieved by creating an
additional column that "caches" the bbox, and matching against this. In our example, the commands are like:
SELECT AddGeometryColumn('myschema','mytable','bbox','4326','GEOMETRY','2');
UPDATE mytable SET bbox = ST_Envelope(ST_Force2D(the_geom));

Now change your query to use the && operator against bbox instead of geom_column, like:
PostGIS 2.4.3 Manual 85 / 803

SELECT geom_column
FROM mytable
WHERE bbox && ST_SetSRID('BOX3D(0 0,1 1)'::box3d,4326);

Of course, if you change or add rows to mytable, you have to keep the bbox "in sync". The most transparent way to do this would
be triggers, but you also can modify your application to keep the bbox column current or run the UPDATE query above after
every modification.

7.2 CLUSTERing on geometry indices

For tables that are mostly read-only, and where a single index is used for the majority of queries, PostgreSQL offers the CLUS-
TER command. This command physically reorders all the data rows in the same order as the index criteria, yielding two
performance advantages: First, for index range scans, the number of seeks on the data table is drastically reduced. Second, if
your working set concentrates to some small intervals on the indices, you have a more efficient caching because the data rows
are spread along fewer data pages. (Feel invited to read the CLUSTER command documentation from the PostgreSQL manual
at this point.)
However, currently PostgreSQL does not allow clustering on PostGIS GIST indices because GIST indices simply ignores NULL
values, you get an error message like:
lwgeom=# CLUSTER my_geom_index ON my_table;
ERROR: cannot cluster when index access method does not handle null values
HINT: You may be able to work around this by marking column "the_geom" NOT NULL.

As the HINT message tells you, one can work around this deficiency by adding a "not null" constraint to the table:
lwgeom=# ALTER TABLE my_table ALTER COLUMN the_geom SET not null;
ALTER TABLE

Of course, this will not work if you in fact need NULL values in your geometry column. Additionally, you must use the above
method to add the constraint, using a CHECK constraint like "ALTER TABLE blubb ADD CHECK (geometry is not null);" will
not work.

7.3 Avoiding dimension conversion

Sometimes, you happen to have 3D or 4D data in your table, but always access it using OpenGIS compliant ST_AsText() or
ST_AsBinary() functions that only output 2D geometries. They do this by internally calling the ST_Force2D() function, which
introduces a significant overhead for large geometries. To avoid this overhead, it may be feasible to pre-drop those additional
dimensions once and forever:
UPDATE mytable SET the_geom = ST_Force2D(the_geom);
VACUUM FULL ANALYZE mytable;

Note that if you added your geometry column using AddGeometryColumn() there’ll be a constraint on geometry dimension. To
bypass it you will need to drop the constraint. Remember to update the entry in the geometry_columns table and recreate the
constraint afterwards.
In case of large tables, it may be wise to divide this UPDATE into smaller portions by constraining the UPDATE to a part of the
table via a WHERE clause and your primary key or another feasible criteria, and running a simple "VACUUM;" between your
UPDATEs. This drastically reduces the need for temporary disk space. Additionally, if you have mixed dimension geometries,
restricting the UPDATE by "WHERE dimension(the_geom)>2" skips re-writing of geometries that already are in 2D.
PostGIS 2.4.3 Manual 86 / 803

7.4 Tuning your configuration

Tuning for PostGIS is much like tuning for any PostgreSQL workload. The only additional note to keep in mind is that geome-
tries and rasters are heavy so memory related optimizations generally have more of an impact on PostGIS than other types of
PostgreSQL queries.
For general details about optimizing PostgreSQL, refer to Tuning your PostgreSQL Server.
For PostgreSQL 9.4+ all these can be set at the server level without touching postgresql.conf or postgresql.auto.conf by using the
ALTER SYSTEM.. command.
ALTER SYSTEM SET work_mem = '256MB';
-- this will force, non-startup configs to take effect for new connections
SELECT pg_reload_conf();
-- show current setting value
-- use SHOW ALL to see all settings
SHOW work_mem;

In addition to these settings, PostGIS also has some custom settings which you can find listed in Section 8.2.

7.4.1 Startup

These settings are configured in postgresql.conf:

constraint_exclusion

• Default: partition
• This is generally used for table partitioning. The default for this is set to "partition" which is ideal for PostgreSQL 8.4 and
above since it will force the planner to only analyze tables for constraint consideration if they are in an inherited hierarchy and
not pay the planner penalty otherwise.

shared_buffers

• Default: ~128MB in PostgreSQL 9.6

• Set to about 25% to 40% of available RAM. On windows you may not be able to set as high.

max_worker_processes This setting is only available for PostgreSQL 9.4+. For PostgreSQL 9.6+ this setting has additional
importance in that it controls the max number of processes you can have for parallel queries.

• Default: 8
• Sets the maximum number of background processes that the system can support. This parameter can only be set at server start.

7.4.2 Runtime

work_mem (the memory used for sort operations and complex queries)

• Default: 1-4MB
• Adjust up for large dbs, complex queries, lots of RAM
• Adjust down for many concurrent users or low RAM.
• If you have lots of RAM and few developers:
SET work_mem TO '256MB';
PostGIS 2.4.3 Manual 87 / 803

maintenance_work_mem (used for VACUUM, CREATE INDEX, etc.)

• Default: 16-64MB

• Generally too low - ties up I/O, locks objects while swapping memory
• Recommend 32MB to 1GB on production servers w/lots of RAM, but depends on the # of concurrent users. If you have lots
of RAM and few developers:
SET maintenance_work_mem TO '1GB';

max_parallel_workers_per_gather This setting is only available for PostgreSQL 9.6+ and will only affect PostGIS 2.3+, since
only PostGIS 2.3+ supports parallel queries. If set to higher than 0, then some queries such as those involving relation functions
like ST_Intersects can use multiple processes and can run more than twice as fast when doing so. If you have a lot
of processors to spare, you should change the value of this to as many processors as you have. Also make sure to bump up
max_worker_processes to at least as high as this number.

• Default: 0
• Sets the maximum number of workers that can be started by a single Gather node. Parallel workers are taken from the pool
of processes established by max_worker_processes. Note that the requested number of workers may not actually be
available at run time. If this occurs, the plan will run with fewer workers than expected, which may be inefficient. Setting this
value to 0, which is the default, disables parallel query execution.
PostGIS 2.4.3 Manual 88 / 803

Chapter 8

PostGIS Reference

The functions given below are the ones which a user of PostGIS is likely to need. There are other functions which are required
support functions to the PostGIS objects which are not of use to a general user.

Note
PostGIS has begun a transition from the existing naming convention to an SQL-MM-centric convention. As a result,
most of the functions that you know and love have been renamed using the standard spatial type (ST) prefix. Previous
functions are still available, though are not listed in this document where updated functions are equivalent. The non
ST_ functions not listed in this documentation are deprecated and will be removed in a future release so STOP USING
THEM.

8.1 PostgreSQL PostGIS Geometry/Geography/Box Types

8.1.1 box2d

box2d — A box composed of x min, ymin, xmax, ymax. Often used to return the 2d enclosing box of a geometry.

Description

box2d is a spatial data type used to represent the enclosing box of a geometry or set of geometries. ST_Extent in earlier versions
prior to PostGIS 1.4 would return a box2d.

8.1.2 box3d

box3d — A box composed of x min, ymin, zmin, xmax, ymax, zmax. Often used to return the 3d extent of a geometry or
collection of geometries.

Description

box3d is a postgis spatial data type used to represent the enclosing box of a geometry or set of geometries. ST_3DExtent returns
a box3d object.

Casting Behavior

This section lists the automatic as well as explicit casts allowed for this data type
PostGIS 2.4.3 Manual 89 / 803

Cast To Behavior
box automatic
box2d automatic
geometry automatic

8.1.3 geometry

geometry — Planar spatial data type.

Description

geometry is a fundamental postgis spatial data type used to represent a feature in the Euclidean coordinate system.

Casting Behavior

This section lists the automatic as well as explicit casts allowed for this data type

Cast To Behavior
box automatic
box2d automatic
box3d automatic
bytea automatic
geography automatic
text automatic

See Also

Section 4.1

8.1.4 geometry_dump

geometry_dump — A spatial datatype with two fields - geom (holding a geometry object) and path[] (a 1-d array holding the
position of the geometry within the dumped object.)

Description

geometry_dump is a compound data type consisting of a geometry object referenced by the .geom field and path[] a 1-dimensional
integer array (starting at 1 e.g. path[1] to get first element) array that defines the navigation path within the dumped geometry to
find this element. It is used by the ST_Dump* family of functions as an output type to explode a more complex geometry into
its constituent parts and location of parts.

See Also

Section 14.6

8.1.5 geography

geography — Ellipsoidal spatial data type.

PostGIS 2.4.3 Manual 90 / 803

Description

geography is a spatial data type used to represent a feature in the round-earth coordinate system.

Casting Behavior

This section lists the automatic as well as explicit casts allowed for this data type

Cast To Behavior
geometry explicit

See Also

Section 14.4, Section 4.2

8.2 PostGIS Grand Unified Custom Variables (GUCs)

8.2.1 postgis.backend

postgis.backend — The backend to service a function where GEOS and SFCGAL overlap. Options: geos or sfcgal. Defaults to
geos.

Description

This GUC is only relevant if you compiled PostGIS with sfcgal support. By default geos backend is used for functions where
both GEOS and SFCGAL have the same named function. This variable allows you to override and make sfcgal the backend to
service the request.
Availability: 2.1.0

Examples

Sets backend just for life of connection

set postgis.backend = sfcgal;

Sets backend for new connections to database

ALTER DATABASE mygisdb SET postgis.backend = sfcgal;

See Also

Section 8.10

8.2.2 postgis.gdal_datapath

postgis.gdal_datapath — A configuration option to assign the value of GDAL’s GDAL_DATA option. If not set, the environmen-
tally set GDAL_DATA variable is used.
PostGIS 2.4.3 Manual 91 / 803

Description

A PostgreSQL GUC variable for setting the value of GDAL’s GDAL_DATA option. The postgis.gdal_datapath value
should be the complete physical path to GDAL’s data files.
This configuration option is of most use for Windows platforms where GDAL’s data files path is not hard-coded. This option
should also be set when GDAL’s data files are not located in GDAL’s expected path.

Note
This option can be set in PostgreSQL’s configuration file postgresql.conf. It can also be set by connection or transaction.

Availability: 2.2.0

Note
Additional information about GDAL_DATA is available at GDAL’s Configuration Options.

Examples

Set and reset postgis.gdal_datapath

SET postgis.gdal_datapath TO '/usr/local/share/gdal.hidden';
SET postgis.gdal_datapath TO default;

Setting on windows for a particular database

ALTER DATABASE gisdb
SET postgis.gdal_datapath = 'C:/Program Files/PostgreSQL/9.3/gdal-data';

See Also

PostGIS_GDAL_Version, ST_Transform

8.2.3 postgis.gdal_enabled_drivers

postgis.gdal_enabled_drivers — A configuration option to set the enabled GDAL drivers in the PostGIS environment. Affects
the GDAL configuration variable GDAL_SKIP.

Description

A configuration option to set the enabled GDAL drivers in the PostGIS environment. Affects the GDAL configuration variable
GDAL_SKIP. This option can be set in PostgreSQL’s configuration file: postgresql.conf. It can also be set by connection or
transaction.
The initial value of postgis.gdal_enabled_drivers may also be set by passing the environment variable POSTGIS_GDAL_EN
with the list of enabled drivers to the process starting PostgreSQL.
Enabled GDAL specified drivers can be specified by the driver’s short-name or code. Driver short-names or codes can be found
at GDAL Raster Formats. Multiple drivers can be specified by putting a space between each driver.
PostGIS 2.4.3 Manual 92 / 803

Note
There are three special codes available for postgis.gdal_enabled_drivers. The codes are case-sensitive.

• DISABLE_ALL disables all GDAL drivers. If present, DISABLE_ALL overrides all other values in
postgis.gdal_enabled_drivers.
• ENABLE_ALL enables all GDAL drivers.

• VSICURL enables GDAL’s /vsicurl/ virtual file system.

When postgis.gdal_enabled_drivers is set to DISABLE_ALL, attempts to use out-db rasters,

ST_FromGDALRaster(), ST_AsGDALRaster(), ST_AsTIFF(), ST_AsJPEG() and ST_AsPNG() will result in error mes-
sages.

Note
In the standard PostGIS installation, postgis.gdal_enabled_drivers is set to DISABLE_ALL.

Note
Additional information about GDAL_SKIP is available at GDAL’s Configuration Options.

Availability: 2.2.0

Examples

Set and reset postgis.gdal_enabled_drivers

Sets backend for all new connections to database
ALTER DATABASE mygisdb SET postgis.gdal_enabled_drivers TO 'GTiff PNG JPEG';

Sets default enabled drivers for all new connections to server. Requires super user access and PostgreSQL 9.4+. Also not that
database, session, and user settings override this.
ALTER SYSTEM SET postgis.gdal_enabled_drivers TO 'GTiff PNG JPEG';
SELECT pg_reload_conf();

SET postgis.gdal_enabled_drivers TO 'GTiff PNG JPEG';

SET postgis.gdal_enabled_drivers = default;

Enable all GDAL Drivers

SET postgis.gdal_enabled_drivers = 'ENABLE_ALL';

Disable all GDAL Drivers

SET postgis.gdal_enabled_drivers = 'DISABLE_ALL';

See Also

ST_FromGDALRaster, ST_AsGDALRaster, ST_AsTIFF, ST_AsPNG, ST_AsJPEG, postgis.enable_outdb_rasters

PostGIS 2.4.3 Manual 93 / 803

8.2.4 postgis.enable_outdb_rasters

postgis.enable_outdb_rasters — A boolean configuration option to enable access to out-db raster bands.

Description

A boolean configuration option to enable access to out-db raster bands. This option can be set in PostgreSQL’s configuration file:
postgresql.conf. It can also be set by connection or transaction.
The initial value of postgis.enable_outdb_rasters may also be set by passing the environment variable POSTGIS_ENABLE_
with a non-zero value to the process starting PostgreSQL.

Note
Even if postgis.enable_outdb_rasters is True, the GUC postgis.enable_outdb_rasters deter-
mines the accessible raster formats.

Note
In the standard PostGIS installation, postgis.enable_outdb_rasters is set to False.

Availability: 2.2.0

Examples

Set and reset postgis.enable_outdb_rasters

SET postgis.enable_outdb_rasters TO True;
SET postgis.enable_outdb_rasters = default;
SET postgis.enable_outdb_rasters = True;
SET postgis.enable_outdb_rasters = False;

See Also

postgis.gdal_enabled_drivers

8.3 Management Functions

8.3.1 AddGeometryColumn

AddGeometryColumn — Adds a geometry column to an existing table of attributes. By default uses type modifier to define
rather than constraints. Pass in false for use_typmod to get old check constraint based behavior

Synopsis

text AddGeometryColumn(varchar table_name, varchar column_name, integer srid, varchar type, integer dimension, boolean
use_typmod=true);
text AddGeometryColumn(varchar schema_name, varchar table_name, varchar column_name, integer srid, varchar type, inte-
ger dimension, boolean use_typmod=true);
text AddGeometryColumn(varchar catalog_name, varchar schema_name, varchar table_name, varchar column_name, integer
srid, varchar type, integer dimension, boolean use_typmod=true);
PostGIS 2.4.3 Manual 94 / 803

Description

Adds a geometry column to an existing table of attributes. The schema_name is the name of the table schema. The srid
must be an integer value reference to an entry in the SPATIAL_REF_SYS table. The type must be a string corresponding to the
geometry type, eg, ’POLYGON’ or ’MULTILINESTRING’ . An error is thrown if the schemaname doesn’t exist (or not visible
in the current search_path) or the specified SRID, geometry type, or dimension is invalid.

Note
Changed: 2.0.0 This function no longer updates geometry_columns since geometry_columns is a view that reads from
system catalogs. It by default also does not create constraints, but instead uses the built in type modifier behavior of
PostgreSQL. So for example building a wgs84 POINT column with this function is now equivalent to: ALTER TABLE
some_table ADD COLUMN geom geometry(Point,4326);
Changed: 2.0.0 If you require the old behavior of constraints use the default use_typmod, but set it to false.

Note
Changed: 2.0.0 Views can no longer be manually registered in geometry_columns, however views built against geome-
try typmod tables geometries and used without wrapper functions will register themselves correctly because they inherit
the typmod behavior of their parent table column. Views that use geometry functions that output other geometries will
need to be cast to typmod geometries for these view geometry columns to be registered correctly in geometry_columns.
Refer to Section 4.3.4.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Enhanced: 2.0.0 use_typmod argument introduced. Defaults to creating typmod geometry column instead of constraint-based.

Examples

-- Create schema to hold data

CREATE SCHEMA my_schema;
-- Create a new simple PostgreSQL table
CREATE TABLE my_schema.my_spatial_table (id serial);

-- Describing the table shows a simple table with a single "id" column.
postgis=# \d my_schema.my_spatial_table
Table "my_schema.my_spatial_table"
Column | Type | Modifiers
--------+---------+------------------------------------------------------------------------- ←-

id | integer | not null default nextval('my_schema.my_spatial_table_id_seq'::regclass)

-- Add a spatial column to the table

SELECT AddGeometryColumn ('my_schema','my_spatial_table','geom',4326,'POINT',2);

-- Add a point using the old constraint based behavior

SELECT AddGeometryColumn ('my_schema','my_spatial_table','geom_c',4326,'POINT',2, false);

--Add a curvepolygon using old constraint behavior

SELECT AddGeometryColumn ('my_schema','my_spatial_table','geomcp_c',4326,'CURVEPOLYGON',2, ←-
false);
PostGIS 2.4.3 Manual 95 / 803

-- Describe the table again reveals the addition of a new geometry columns.
\d my_schema.my_spatial_table
addgeometrycolumn
-------------------------------------------------------------------------
my_schema.my_spatial_table.geomcp_c SRID:4326 TYPE:CURVEPOLYGON DIMS:2
(1 row)

Table "my_schema.my_spatial_table"
Column | Type | Modifiers
----------+----------------------+-------------------------------------------------------------------

id | integer | not null default nextval('my_schema. ←-

my_spatial_table_id_seq'::regclass)
geom | geometry(Point,4326) |
geom_c | geometry |
geomcp_c | geometry |
Check constraints:
"enforce_dims_geom_c" CHECK (st_ndims(geom_c) = 2)
"enforce_dims_geomcp_c" CHECK (st_ndims(geomcp_c) = 2)
"enforce_geotype_geom_c" CHECK (geometrytype(geom_c) = 'POINT'::text OR geom_c IS NULL)
"enforce_geotype_geomcp_c" CHECK (geometrytype(geomcp_c) = 'CURVEPOLYGON'::text OR ←-
geomcp_c IS NULL)
"enforce_srid_geom_c" CHECK (st_srid(geom_c) = 4326)
"enforce_srid_geomcp_c" CHECK (st_srid(geomcp_c) = 4326)

-- geometry_columns view also registers the new columns --

SELECT f_geometry_column As col_name, type, srid, coord_dimension As ndims
FROM geometry_columns
WHERE f_table_name = 'my_spatial_table' AND f_table_schema = 'my_schema';

col_name | type | srid | ndims

----------+--------------+------+-------
geom | Point | 4326 | 2
geom_c | Point | 4326 | 2
geomcp_c | CurvePolygon | 4326 | 2

See Also

DropGeometryColumn, DropGeometryTable, Section 4.3.2, Section 4.3.4

8.3.2 DropGeometryColumn

DropGeometryColumn — Removes a geometry column from a spatial table.

Synopsis

text DropGeometryColumn(varchar table_name, varchar column_name);

text DropGeometryColumn(varchar schema_name, varchar table_name, varchar column_name);
text DropGeometryColumn(varchar catalog_name, varchar schema_name, varchar table_name, varchar column_name);

Description

Removes a geometry column from a spatial table. Note that schema_name will need to match the f_table_schema field of the
table’s row in the geometry_columns table.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.
PostGIS 2.4.3 Manual 96 / 803

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Note
Changed: 2.0.0 This function is provided for backward compatibility. Now that since geometry_columns is now a view
against the system catalogs, you can drop a geometry column like any other table column using ALTER TABLE

Examples

SELECT DropGeometryColumn ('my_schema','my_spatial_table','geom');

----RESULT output ---
dropgeometrycolumn
------------------------------------------------------
my_schema.my_spatial_table.geom effectively removed.

-- In PostGIS 2.0+ the above is also equivalent to the standard

-- the standard alter table. Both will deregister from geometry_columns
ALTER TABLE my_schema.my_spatial_table DROP column geom;

See Also

AddGeometryColumn, DropGeometryTable, Section 4.3.2

8.3.3 DropGeometryTable

DropGeometryTable — Drops a table and all its references in geometry_columns.

Synopsis

boolean DropGeometryTable(varchar table_name);

boolean DropGeometryTable(varchar schema_name, varchar table_name);
boolean DropGeometryTable(varchar catalog_name, varchar schema_name, varchar table_name);

Description

Drops a table and all its references in geometry_columns. Note: uses current_schema() on schema-aware pgsql installations if
schema is not provided.

Note
Changed: 2.0.0 This function is provided for backward compatibility. Now that since geometry_columns is now a view
against the system catalogs, you can drop a table with geometry columns like any other table using DROP TABLE
PostGIS 2.4.3 Manual 97 / 803

Examples

SELECT DropGeometryTable ('my_schema','my_spatial_table');

----RESULT output ---
my_schema.my_spatial_table dropped.

-- The above is now equivalent to --

DROP TABLE my_schema.my_spatial_table;

See Also

AddGeometryColumn, DropGeometryColumn, Section 4.3.2

8.3.4 PostGIS_Full_Version

PostGIS_Full_Version — Reports full postgis version and build configuration infos.

Synopsis

text PostGIS_Full_Version();

Description

Reports full postgis version and build configuration infos. Also informs about synchronization between libraries and scripts
suggesting upgrades as needed.

Examples

SELECT PostGIS_Full_Version();
postgis_full_version
----------------------------------------------------------------------------------
POSTGIS="2.2.0dev r12699" GEOS="3.5.0dev-CAPI-1.9.0 r3989" SFCGAL="1.0.4" PROJ="Rel. 4.8.0, ←-
6 March 2012"
GDAL="GDAL 1.11.0, released 2014/04/16" LIBXML="2.7.8" LIBJSON="0.12" RASTER
(1 row)

See Also

Section 2.10, PostGIS_GEOS_Version, PostGIS_Lib_Version, PostGIS_LibXML_Version, PostGIS_PROJ_Version, PostGIS_Version

8.3.5 PostGIS_GEOS_Version

PostGIS_GEOS_Version — Returns the version number of the GEOS library.

Synopsis

text PostGIS_GEOS_Version();

Description

Returns the version number of the GEOS library, or NULL if GEOS support is not enabled.
PostGIS 2.4.3 Manual 98 / 803

Examples

SELECT PostGIS_GEOS_Version();
postgis_geos_version
----------------------
3.1.0-CAPI-1.5.0
(1 row)

See Also

PostGIS_Full_Version, PostGIS_Lib_Version, PostGIS_LibXML_Version, PostGIS_PROJ_Version, PostGIS_Version

8.3.6 PostGIS_Liblwgeom_Version

PostGIS_Liblwgeom_Version — Returns the version number of the liblwgeom library. This should match the version of PostGIS.

Synopsis

text PostGIS_Liblwgeom_Version();

Description

Returns the version number of the liblwgeom library/

Examples

SELECT PostGIS_Liblwgeom_Version();
postgis_liblwgeom_version
--------------------------
2.3.3 r15473
(1 row)

See Also

PostGIS_Full_Version, PostGIS_Lib_Version, PostGIS_LibXML_Version, PostGIS_PROJ_Version, PostGIS_Version

8.3.7 PostGIS_LibXML_Version

PostGIS_LibXML_Version — Returns the version number of the libxml2 library.

Synopsis

text PostGIS_LibXML_Version();

Description

Returns the version number of the LibXML2 library.

Availability: 1.5
PostGIS 2.4.3 Manual 99 / 803

Examples

SELECT PostGIS_LibXML_Version();
postgis_libxml_version
----------------------
2.7.6
(1 row)

See Also

PostGIS_Full_Version, PostGIS_Lib_Version, PostGIS_PROJ_Version, PostGIS_GEOS_Version, PostGIS_Version

8.3.8 PostGIS_Lib_Build_Date

PostGIS_Lib_Build_Date — Returns build date of the PostGIS library.

Synopsis

text PostGIS_Lib_Build_Date();

Description

Returns build date of the PostGIS library.

Examples

SELECT PostGIS_Lib_Build_Date();
postgis_lib_build_date
------------------------
2008-06-21 17:53:21
(1 row)

8.3.9 PostGIS_Lib_Version

PostGIS_Lib_Version — Returns the version number of the PostGIS library.

Synopsis

text PostGIS_Lib_Version();

Description

Returns the version number of the PostGIS library.

Examples

SELECT PostGIS_Lib_Version();
postgis_lib_version
---------------------
1.3.3
(1 row)
PostGIS 2.4.3 Manual 100 / 803

See Also

PostGIS_Full_Version, PostGIS_GEOS_Version, PostGIS_LibXML_Version, PostGIS_PROJ_Version, PostGIS_Version

8.3.10 PostGIS_PROJ_Version

PostGIS_PROJ_Version — Returns the version number of the PROJ4 library.

Synopsis

text PostGIS_PROJ_Version();

Description

Returns the version number of the PROJ4 library, or NULL if PROJ4 support is not enabled.

Examples

SELECT PostGIS_PROJ_Version();
postgis_proj_version
-------------------------
Rel. 4.4.9, 29 Oct 2004
(1 row)

See Also

PostGIS_Full_Version, PostGIS_GEOS_Version, PostGIS_Lib_Version, PostGIS_LibXML_Version, PostGIS_Version

8.3.11 PostGIS_Scripts_Build_Date

PostGIS_Scripts_Build_Date — Returns build date of the PostGIS scripts.

Synopsis

text PostGIS_Scripts_Build_Date();

Description

Returns build date of the PostGIS scripts.

Availability: 1.0.0RC1

Examples

SELECT PostGIS_Scripts_Build_Date();
postgis_scripts_build_date
-------------------------
2007-08-18 09:09:26
(1 row)
PostGIS 2.4.3 Manual 101 / 803

See Also

PostGIS_Full_Version, PostGIS_GEOS_Version, PostGIS_Lib_Version, PostGIS_LibXML_Version, PostGIS_Version

8.3.12 PostGIS_Scripts_Installed

PostGIS_Scripts_Installed — Returns version of the postgis scripts installed in this database.

Synopsis

text PostGIS_Scripts_Installed();

Description

Returns version of the postgis scripts installed in this database.

Note
If the output of this function doesn’t match the output of PostGIS_Scripts_Released you probably missed to properly
upgrade an existing database. See the Upgrading section for more info.

Availability: 0.9.0

Examples

SELECT PostGIS_Scripts_Installed();
postgis_scripts_installed
-------------------------
1.5.0SVN
(1 row)

See Also

PostGIS_Full_Version, PostGIS_Scripts_Released, PostGIS_Version

8.3.13 PostGIS_Scripts_Released

PostGIS_Scripts_Released — Returns the version number of the postgis.sql script released with the installed postgis lib.

Synopsis

text PostGIS_Scripts_Released();

Description

Returns the version number of the postgis.sql script released with the installed postgis lib.

Note
Starting with version 1.1.0 this function returns the same value of PostGIS_Lib_Version. Kept for backward compatibil-
ity.

Availability: 0.9.0
PostGIS 2.4.3 Manual 102 / 803

Examples

SELECT PostGIS_Scripts_Released();
postgis_scripts_released
-------------------------
1.3.4SVN
(1 row)

See Also

PostGIS_Full_Version, PostGIS_Scripts_Installed, PostGIS_Lib_Version

8.3.14 PostGIS_Version

PostGIS_Version — Returns PostGIS version number and compile-time options.

Synopsis

text PostGIS_Version();

Description

Returns PostGIS version number and compile-time options.

Examples

SELECT PostGIS_Version();
postgis_version
---------------------------------------
1.3 USE_GEOS=1 USE_PROJ=1 USE_STATS=1
(1 row)

See Also

PostGIS_Full_Version, PostGIS_GEOS_Version, PostGIS_Lib_Version, PostGIS_LibXML_Version, PostGIS_PROJ_Version

8.3.15 Populate_Geometry_Columns

Populate_Geometry_Columns — Ensures geometry columns are defined with type modifiers or have appropriate spatial con-
straints This ensures they will be registered correctly in geometry_columns view. By default will convert all geometry
columns with no type modifier to ones with type modifiers. To get old behavior set use_typmod=false

Synopsis

text Populate_Geometry_Columns(boolean use_typmod=true);

int Populate_Geometry_Columns(oid relation_oid, boolean use_typmod=true);
PostGIS 2.4.3 Manual 103 / 803

Description

Ensures geometry columns have appropriate type modifiers or spatial constraints to ensure they are registered correctly in
geometry_columns table.
For backwards compatibility and for spatial needs such as table inheritance where each child table may have different geometry
type, the old check constraint behavior is still supported. If you need the old behavior, you need to pass in the new optional
argument as false use_typmod=false. When this is done geometry columns will be created with no type modifiers but will
have 3 constraints defined. In particular, this means that every geometry column belonging to a table has at least three constraints:

• enforce_dims_the_geom - ensures every geometry has the same dimension (see ST_NDims)
• enforce_geotype_the_geom - ensures every geometry is of the same type (see GeometryType)
• enforce_srid_the_geom - ensures every geometry is in the same projection (see ST_SRID)

If a table oid is provided, this function tries to determine the srid, dimension, and geometry type of all geometry columns in the
table, adding constraints as necessary. If successful, an appropriate row is inserted into the geometry_columns table, otherwise,
the exception is caught and an error notice is raised describing the problem.
If the oid of a view is provided, as with a table oid, this function tries to determine the srid, dimension, and type of all
the geometries in the view, inserting appropriate entries into the geometry_columns table, but nothing is done to enforce
constraints.
The parameterless variant is a simple wrapper for the parameterized variant that first truncates and repopulates the geome-
try_columns table for every spatial table and view in the database, adding spatial constraints to tables where appropriate. It
returns a summary of the number of geometry columns detected in the database and the number that were inserted into the
geometry_columns table. The parameterized version simply returns the number of rows inserted into the geometry_columns
table.
Availability: 1.4.0
Changed: 2.0.0 By default, now uses type modifiers instead of check constraints to constrain geometry types. You can still use
check constraint behavior instead by using the new use_typmod and setting it to false.
Enhanced: 2.0.0 use_typmod optional argument was introduced that allows controlling if columns are created with typmodi-
fiers or with check constraints.

Examples

CREATE TABLE public.myspatial_table(gid serial, geom geometry);

INSERT INTO myspatial_table(geom) VALUES(ST_GeomFromText('LINESTRING(1 2, 3 4)',4326) );
-- This will now use typ modifiers. For this to work, there must exist data
SELECT Populate_Geometry_Columns('public.myspatial_table'::regclass);

populate_geometry_columns
--------------------------
1

\d myspatial_table

Table "public.myspatial_table"
Column | Type | Modifiers
--------+---------------------------+---------------------------------------------------------------

gid | integer | not null default nextval('myspatial_table_gid_seq':: ←-

regclass)
geom | geometry(LineString,4326) |
PostGIS 2.4.3 Manual 104 / 803

-- This will change the geometry columns to use constraints if they are not typmod or have ←-
constraints already.
--For this to work, there must exist data
CREATE TABLE public.myspatial_table_cs(gid serial, geom geometry);
INSERT INTO myspatial_table_cs(geom) VALUES(ST_GeomFromText('LINESTRING(1 2, 3 4)',4326) );
SELECT Populate_Geometry_Columns('public.myspatial_table_cs'::regclass, false);
populate_geometry_columns
--------------------------
1
\d myspatial_table_cs

Table "public.myspatial_table_cs"
Column | Type | Modifiers
--------+----------+------------------------------------------------------------------
gid | integer | not null default nextval('myspatial_table_cs_gid_seq'::regclass)
geom | geometry |
Check constraints:
"enforce_dims_geom" CHECK (st_ndims(geom) = 2)
"enforce_geotype_geom" CHECK (geometrytype(geom) = 'LINESTRING'::text OR geom IS NULL)
"enforce_srid_geom" CHECK (st_srid(geom) = 4326)

8.3.16 UpdateGeometrySRID

UpdateGeometrySRID — Updates the SRID of all features in a geometry column, geometry_columns metadata and srid. If it
was enforced with constraints, the constraints will be updated with new srid constraint. If the old was enforced by type definition,
the type definition will be changed.

Synopsis

text UpdateGeometrySRID(varchar table_name, varchar column_name, integer srid);

text UpdateGeometrySRID(varchar schema_name, varchar table_name, varchar column_name, integer srid);
text UpdateGeometrySRID(varchar catalog_name, varchar schema_name, varchar table_name, varchar column_name, integer
srid);

Description

Updates the SRID of all features in a geometry column, updating constraints and reference in geometry_columns. Note: uses
current_schema() on schema-aware pgsql installations if schema is not provided.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

This will change the srid of the roads table to 4326 from whatever it was before
SELECT UpdateGeometrySRID('roads','geom',4326);

The prior example is equivalent to this DDL statement

ALTER TABLE roads
ALTER COLUMN geom TYPE geometry(MULTILINESTRING, 4326)
USING ST_SetSRID(geom,4326);
PostGIS 2.4.3 Manual 105 / 803

If you got the projection wrong (or brought it in as unknown) in load and you wanted to transform to web mercator all in one
shot You can do this with DDL but there is no equivalent PostGIS management function to do so in one go.
ALTER TABLE roads
ALTER COLUMN geom TYPE geometry(MULTILINESTRING, 3857) USING ST_Transform(ST_SetSRID(geom ←-
,4326),3857) ;

See Also

UpdateRasterSRID, ST_SetSRID, ST_Transform

8.4 Geometry Constructors

8.4.1 ST_BdPolyFromText

ST_BdPolyFromText — Construct a Polygon given an arbitrary collection of closed linestrings as a MultiLineString Well-Known
text representation.

Synopsis

geometry ST_BdPolyFromText(text WKT, integer srid);

Description

Construct a Polygon given an arbitrary collection of closed linestrings as a MultiLineString Well-Known text representation.

Note
Throws an error if WKT is not a MULTILINESTRING. Throws an error if output is a MULTIPOLYGON; use
ST_BdMPolyFromText in that case, or see ST_BuildArea() for a postgis-specific approach.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2
Availability: 1.1.0 - requires GEOS >= 2.1.0.

Examples

Forthcoming

See Also

ST_BuildArea, ST_BdMPolyFromText

8.4.2 ST_BdMPolyFromText

ST_BdMPolyFromText — Construct a MultiPolygon given an arbitrary collection of closed linestrings as a MultiLineString text
representation Well-Known text representation.
PostGIS 2.4.3 Manual 106 / 803

Synopsis

geometry ST_BdMPolyFromText(text WKT, integer srid);

Description

Construct a Polygon given an arbitrary collection of closed linestrings, polygons, MultiLineStrings as Well-Known text repre-
sentation.

Note
Throws an error if WKT is not a MULTILINESTRING. Forces MULTIPOLYGON output even when result is really only
composed by a single POLYGON; use ST_BdPolyFromText if you’re sure a single POLYGON will result from operation,
or see ST_BuildArea() for a postgis-specific approach.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2
Availability: 1.1.0 - requires GEOS >= 2.1.0.

Examples

Forthcoming

See Also

ST_BuildArea, ST_BdPolyFromText

8.4.3 ST_Box2dFromGeoHash

ST_Box2dFromGeoHash — Return a BOX2D from a GeoHash string.

Synopsis

box2d ST_Box2dFromGeoHash(text geohash, integer precision=full_precision_of_geohash);

Description

Return a BOX2D from a GeoHash string.

If no precision is specficified ST_Box2dFromGeoHash returns a BOX2D based on full precision of the input GeoHash string.
If precision is specified ST_Box2dFromGeoHash will use that many characters from the GeoHash to create the BOX2D.
Lower precision values results in larger BOX2Ds and larger values increase the precision.
Availability: 2.1.0
PostGIS 2.4.3 Manual 107 / 803

Examples

SELECT ST_Box2dFromGeoHash('9qqj7nmxncgyy4d0dbxqz0');

st_geomfromgeohash
--------------------------------------------------
BOX(-115.172816 36.114646,-115.172816 36.114646)

SELECT ST_Box2dFromGeoHash('9qqj7nmxncgyy4d0dbxqz0', 0);

st_box2dfromgeohash
----------------------
BOX(-180 -90,180 90)

SELECT ST_Box2dFromGeoHash('9qqj7nmxncgyy4d0dbxqz0', 10);

st_box2dfromgeohash
---------------------------------------------------------------------------
BOX(-115.17282128334 36.1146408319473,-115.172810554504 36.1146461963654)

See Also

ST_GeoHash, ST_GeomFromGeoHash, ST_PointFromGeoHash

8.4.4 ST_GeogFromText

ST_GeogFromText — Return a specified geography value from Well-Known Text representation or extended (WKT).

Synopsis

geography ST_GeogFromText(text EWKT);

Description

Returns a geography object from the well-known text or extended well-known representation. SRID 4326 is assumed if unspec-
ified. This is an alias for ST_GeographyFromText. Points are always expressed in long lat form.

Examples

--- converting lon lat coords to geography

ALTER TABLE sometable ADD COLUMN geog geography(POINT,4326);
UPDATE sometable SET geog = ST_GeogFromText('SRID=4326;POINT(' || lon || ' ' || lat || ')') ←-
;

--- specify a geography point using EPSG:4267, NAD27

SELECT ST_AsEWKT(ST_GeogFromText('SRID=4267;POINT(-77.0092 38.889588)'));

See Also

ST_AsText, ST_GeographyFromText

8.4.5 ST_GeographyFromText

ST_GeographyFromText — Return a specified geography value from Well-Known Text representation or extended (WKT).
PostGIS 2.4.3 Manual 108 / 803

Synopsis

geography ST_GeographyFromText(text EWKT);

Description

Returns a geography object from the well-known text representation. SRID 4326 is assumed if unspecified.

See Also

ST_GeogFromText, ST_AsText

8.4.6 ST_GeogFromWKB

ST_GeogFromWKB — Creates a geography instance from a Well-Known Binary geometry representation (WKB) or extended
Well Known Binary (EWKB).

Synopsis

geography ST_GeogFromWKB(bytea wkb);

Description

The ST_GeogFromWKB function, takes a well-known binary representation (WKB) of a geometry or PostGIS Extended WKB
and creates an instance of the appropriate geography type. This function plays the role of the Geometry Factory in SQL.
If SRID is not specified, it defaults to 4326 (WGS 84 long lat).

This method supports Circular Strings and Curves

Examples

--Although bytea rep contains single \, these need to be escaped when inserting into a ←-
table
SELECT ST_AsText(
ST_GeogFromWKB(E'\\001\\002\\000\\000\\000\\002\\000\\000\\000\\037\\205\\353Q ←-
\\270~\\\\\\300\\323Mb\\020X\\231C@\\020X9\\264\\310~\\\\\\300)\\\\\\217\\302\\365\\230 ←-
C@')
);
st_astext
------------------------------------------------------
LINESTRING(-113.98 39.198,-113.981 39.195)
(1 row)

See Also

ST_GeogFromText, ST_AsBinary

8.4.7 ST_GeomFromTWKB

ST_GeomFromTWKB — Creates a geometry instance from a TWKB ("Tiny Well-Known Binary") geometry representation.
PostGIS 2.4.3 Manual 109 / 803

Synopsis

geometry ST_GeomFromTWKB(bytea twkb);

Description

The ST_GeomFromTWKB function, takes a a TWKB ("Tiny Well-Known Binary") geometry representation (WKB) and creates
an instance of the appropriate geometry type.

Examples

SELECT ST_AsText(ST_GeomFromTWKB(ST_AsTWKB('LINESTRING(126 34, 127 35)'::geometry)));

st_astext
-----------------------------
LINESTRING(126 34, 127 35)
(1 row)

SELECT ST_AsEWKT(
ST_GeomFromTWKB(E'\\x620002f7f40dbce4040105')
);
st_asewkt
------------------------------------------------------
LINESTRING(-113.98 39.198,-113.981 39.195)
(1 row)

See Also

ST_AsTWKB

8.4.8 ST_GeomCollFromText

ST_GeomCollFromText — Makes a collection Geometry from collection WKT with the given SRID. If SRID is not given, it
defaults to 0.

Synopsis

geometry ST_GeomCollFromText(text WKT, integer srid);

geometry ST_GeomCollFromText(text WKT);

Description

Makes a collection Geometry from the Well-Known-Text (WKT) representation with the given SRID. If SRID is not given, it
defaults to 0.
OGC SPEC 3.2.6.2 - option SRID is from the conformance suite
Returns null if the WKT is not a GEOMETRYCOLLECTION

Note
If you are absolutely sure all your WKT geometries are collections, don’t use this function. It is slower than
ST_GeomFromText since it adds an additional validation step.
PostGIS 2.4.3 Manual 110 / 803

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2

This method implements the SQL/MM specification.

Examples

SELECT ST_GeomCollFromText('GEOMETRYCOLLECTION(POINT(1 2),LINESTRING(1 2, 3 4))');

See Also

ST_GeomFromText, ST_SRID

8.4.9 ST_GeomFromEWKB

ST_GeomFromEWKB — Return a specified ST_Geometry value from Extended Well-Known Binary representation (EWKB).

Synopsis

geometry ST_GeomFromEWKB(bytea EWKB);

Description

Constructs a PostGIS ST_Geometry object from the OGC Extended Well-Known binary (EWKT) representation.

Note
The EWKB format is not an OGC standard, but a PostGIS specific format that includes the spatial reference system
(SRID) identifier

Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

line string binary rep 0f LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932) in NAD 83 long lat
(4269).

Note
NOTE: Even though byte arrays are delimited with \ and may have ’, we need to escape both out with \ and ” if
standard_conforming_strings is off. So it does not look exactly like its AsEWKB representation.
PostGIS 2.4.3 Manual 111 / 803

SELECT ST_GeomFromEWKB(E'\\001\\002\\000\\000 \\255\\020\\000\\000\\003\\000\\000\\000\\344 ←-

J=
\\013B\\312Q\\300n\\303(\\010\\036!E@''\\277E''K
\\312Q\\300\\366{b\\235*!E@\\225|\\354.P\\312Q
\\300p\\231\\323e1!E@');

Note
In PostgreSQL 9.1+ - standard_conforming_strings is set to on by default, where as in past versions it was set to off.
You can change defaults as needed for a single query or at the database or server level. Below is how you would do it
with standard_conforming_strings = on. In this case we escape the ’ with standard ansi ’, but slashes are not escaped

set standard_conforming_strings = on;

SELECT ST_GeomFromEWKB('\001\002\000\000 \255\020\000\000\003\000\000\000\344J=\012\013B
\312Q\300n\303(\010\036!E@''\277E''K\012\312Q\300\366{b\235*!E@\225|\354.P\312Q\012\300 ←-
p\231\323e1')

See Also

ST_AsBinary, ST_AsEWKB, ST_GeomFromWKB

8.4.10 ST_GeomFromEWKT

ST_GeomFromEWKT — Return a specified ST_Geometry value from Extended Well-Known Text representation (EWKT).

Synopsis

geometry ST_GeomFromEWKT(text EWKT);

Description

Constructs a PostGIS ST_Geometry object from the OGC Extended Well-Known text (EWKT) representation.

Note
The EWKT format is not an OGC standard, but an PostGIS specific format that includes the spatial reference system
(SRID) identifier

Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 112 / 803

Examples

SELECT ST_GeomFromEWKT('SRID=4269;LINESTRING(-71.160281 42.258729,-71.160837 ←-

42.259113,-71.161144 42.25932)');
SELECT ST_GeomFromEWKT('SRID=4269;MULTILINESTRING((-71.160281 42.258729,-71.160837 ←-
42.259113,-71.161144 42.25932))');

SELECT ST_GeomFromEWKT('SRID=4269;POINT(-71.064544 42.28787)');

SELECT ST_GeomFromEWKT('SRID=4269;POLYGON((-71.1776585052917 ←-
42.3902909739571,-71.1776820268866 42.3903701743239,
-71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 ←-
42.3902909739571))');

SELECT ST_GeomFromEWKT('SRID=4269;MULTIPOLYGON(((-71.1031880899493 42.3152774590236,

-71.1031627617667 42.3152960829043,-71.102923838298 42.3149156848307,
-71.1023097974109 42.3151969047397,-71.1019285062273 42.3147384934248,
-71.102505233663 42.3144722937587,-71.10277487471 42.3141658254797,
-71.103113945163 42.3142739188902,-71.10324876416 42.31402489987,
-71.1033002961013 42.3140393340215,-71.1033488797549 42.3139495090772,
-71.103396240451 42.3138632439557,-71.1041521907712 42.3141153348029,
-71.1041411411543 42.3141545014533,-71.1041287795912 42.3142114839058,
-71.1041188134329 42.3142693656241,-71.1041112482575 42.3143272556118,
-71.1041072845732 42.3143851580048,-71.1041057218871 42.3144430686681,
-71.1041065602059 42.3145009876017,-71.1041097995362 42.3145589148055,
-71.1041166403905 42.3146168544148,-71.1041258822717 42.3146748022936,
-71.1041375307579 42.3147318674446,-71.1041492906949 42.3147711126569,
-71.1041598612795 42.314808571739,-71.1042515013869 42.3151287620809,
-71.1041173835118 42.3150739481917,-71.1040809891419 42.3151344119048,
-71.1040438678912 42.3151191367447,-71.1040194562988 42.3151832057859,
-71.1038734225584 42.3151140942995,-71.1038446938243 42.3151006300338,
-71.1038315271889 42.315094347535,-71.1037393329282 42.315054824985,
-71.1035447555574 42.3152608696313,-71.1033436658644 42.3151648370544,
-71.1032580383161 42.3152269126061,-71.103223066939 42.3152517403219,
-71.1031880899493 42.3152774590236)),
((-71.1043632495873 42.315113108546,-71.1043583974082 42.3151211109857,
-71.1043443253471 42.3150676015829,-71.1043850704575 42.3150793250568,-71.1043632495873 ←-
42.315113108546)))');

--3d circular string

SELECT ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)');

--Polyhedral Surface example

SELECT ST_GeomFromEWKT('POLYHEDRALSURFACE(
((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1))
)');

See Also

ST_AsEWKT, ST_GeomFromText, ST_GeomFromEWKT

PostGIS 2.4.3 Manual 113 / 803

8.4.11 ST_GeometryFromText

ST_GeometryFromText — Return a specified ST_Geometry value from Well-Known Text representation (WKT). This is an alias
name for ST_GeomFromText

Synopsis

geometry ST_GeometryFromText(text WKT);

geometry ST_GeometryFromText(text WKT, integer srid);

Description

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.40

See Also

ST_GeomFromText

8.4.12 ST_GeomFromGeoHash

ST_GeomFromGeoHash — Return a geometry from a GeoHash string.

Synopsis

geometry ST_GeomFromGeoHash(text geohash, integer precision=full_precision_of_geohash);

Description

Return a geometry from a GeoHash string. The geometry will be a polygon representing the GeoHash bounds.
If no precision is specified ST_GeomFromGeoHash returns a polygon based on full precision of the input GeoHash string.
If precision is specified ST_GeomFromGeoHash will use that many characters from the GeoHash to create the polygon.
Availability: 2.1.0

Examples

SELECT ST_AsText(ST_GeomFromGeoHash('9qqj7nmxncgyy4d0dbxqz0'));
st_astext
-----------------------------------------------------------------------------------------------------

POLYGON((-115.172816 36.114646,-115.172816 36.114646,-115.172816 36.114646,-115.172816 ←-

36.114646,-115.172816 36.114646))

SELECT ST_AsText(ST_GeomFromGeoHash('9qqj7nmxncgyy4d0dbxqz0', 4));

st_astext
-----------------------------------------------------------------------------------------------------

POLYGON((-115.3125 36.03515625,-115.3125 36.2109375,-114.9609375 36.2109375,-114.9609375 ←-

36.03515625,-115.3125 36.03515625))
PostGIS 2.4.3 Manual 114 / 803

SELECT ST_AsText(ST_GeomFromGeoHash('9qqj7nmxncgyy4d0dbxqz0', 10));

st_astext ←-

-----------------------------------------------------------------------------------------------------

POLYGON((-115.17282128334 36.1146408319473,-115.17282128334 ←-
36.1146461963654,-115.172810554504 36.1146461963654,-115.172810554504 ←-
36.1146408319473,-115.17282128334 36.1146408319473))

See Also

ST_GeoHash,ST_Box2dFromGeoHash, ST_PointFromGeoHash

8.4.13 ST_GeomFromGML

ST_GeomFromGML — Takes as input GML representation of geometry and outputs a PostGIS geometry object

Synopsis

geometry ST_GeomFromGML(text geomgml);

geometry ST_GeomFromGML(text geomgml, integer srid);

Description

Constructs a PostGIS ST_Geometry object from the OGC GML representation.

ST_GeomFromGML works only for GML Geometry fragments. It throws an error if you try to use it on a whole GML document.
OGC GML versions supported:

• GML 3.2.1 Namespace

• GML 3.1.1 Simple Features profile SF-2 (with GML 3.1.0 and 3.0.0 backward compatibility)
• GML 2.1.2

OGC GML standards, cf: http://www.opengeospatial.org/standards/gml:

Availability: 1.5, requires libxml2 1.6+
Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
Enhanced: 2.0.0 default srid optional parameter added.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
GML allow mixed dimensions (2D and 3D inside the same MultiGeometry for instance). As PostGIS geometries don’t,
ST_GeomFromGML convert the whole geometry to 2D if a missing Z dimension is found once.
PostGIS 2.4.3 Manual 115 / 803

GML support mixed SRS inside the same MultiGeometry. As PostGIS geometries don’t, ST_GeomFromGML, in this case,
reproject all subgeometries to the SRS root node. If no srsName attribute available for the GML root node, the function throw an
error.
ST_GeomFromGML function is not pedantic about an explicit GML namespace. You could avoid to mention it explicitly for
common usages. But you need it if you want to use XLink feature inside GML.

Note
ST_GeomFromGML function not support SQL/MM curves geometries.

Examples - A single geometry with srsName

SELECT ST_GeomFromGML('
<gml:LineString srsName="EPSG:4269">
<gml:coordinates>
-71.16028,42.258729 -71.160837,42.259112 -71.161143,42.25932
</gml:coordinates>
</gml:LineString>');

Examples - XLink usage

SELECT ST_GeomFromGML('
<gml:LineString xmlns:gml="http://www.opengis.net/gml"
xmlns:xlink="http://www.w3.org/1999/xlink"
srsName="urn:ogc:def:crs:EPSG::4269">
<gml:pointProperty>
<gml:Point gml:id="p1"><gml:pos>42.258729 -71.16028</gml:pos></gml:Point>
</gml:pointProperty>
<gml:pos>42.259112 -71.160837</gml:pos>
<gml:pointProperty>
<gml:Point xlink:type="simple" xlink:href="#p1"/>
</gml:pointProperty>
</gml:LineString>'););

Examples - Polyhedral Surface

SELECT ST_AsEWKT(ST_GeomFromGML('
<gml:PolyhedralSurface>
<gml:polygonPatches>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing><gml:posList srsDimension="3">0 0 0 0 0 1 0 1 1 0 1 0 0 0 0</gml: ←-
posList></gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing><gml:posList srsDimension="3">0 0 0 0 1 0 1 1 0 1 0 0 0 0 0</gml:posList ←-
></gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
PostGIS 2.4.3 Manual 116 / 803

<gml:LinearRing><gml:posList srsDimension="3">0 0 0 1 0 0 1 0 1 0 0 1 0 0 0</gml:posList ←-

></gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing><gml:posList srsDimension="3">1 1 0 1 1 1 1 0 1 1 0 0 1 1 0</gml:posList ←-
></gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing><gml:posList srsDimension="3">0 1 0 0 1 1 1 1 1 1 1 0 0 1 0</gml:posList ←-
></gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing><gml:posList srsDimension="3">0 0 1 1 0 1 1 1 1 0 1 1 0 0 1</gml:posList ←-
></gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
</gml:polygonPatches>
</gml:PolyhedralSurface>'));

-- result --
POLYHEDRALSURFACE(((0 0 0,0 0 1,0 1 1,0 1 0,0 0 0)),
((0 0 0,0 1 0,1 1 0,1 0 0,0 0 0)),
((0 0 0,1 0 0,1 0 1,0 0 1,0 0 0)),
((1 1 0,1 1 1,1 0 1,1 0 0,1 1 0)),
((0 1 0,0 1 1,1 1 1,1 1 0,0 1 0)),
((0 0 1,1 0 1,1 1 1,0 1 1,0 0 1)))

See Also

Section 2.4.1, ST_AsGML, ST_GMLToSQL

8.4.14 ST_GeomFromGeoJSON

ST_GeomFromGeoJSON — Takes as input a geojson representation of a geometry and outputs a PostGIS geometry object

Synopsis

geometry ST_GeomFromGeoJSON(text geomjson);

Description

Constructs a PostGIS geometry object from the GeoJSON representation.

ST_GeomFromGeoJSON works only for JSON Geometry fragments. It throws an error if you try to use it on a whole JSON
document.
Availability: 2.0.0 requires - JSON-C >= 0.9

Note
If you do not have JSON-C enabled, support you will get an error notice instead of seeing an output. To enable JSON-C,
run configure --with-jsondir=/path/to/json-c. See Section 2.4.1 for details.
PostGIS 2.4.3 Manual 117 / 803

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_AsText(ST_GeomFromGeoJSON('{"type":"Point","coordinates":[-48.23456,20.12345]}')) ←-
As wkt;
wkt
------
POINT(-48.23456 20.12345)

-- a 3D linestring
SELECT ST_AsText(ST_GeomFromGeoJSON('{"type":"LineString","coordinates ←-
":[[1,2,3],[4,5,6],[7,8,9]]}')) As wkt;

wkt
-------------------
LINESTRING(1 2,4 5,7 8)

See Also

ST_AsText, ST_AsGeoJSON, Section 2.4.1

8.4.15 ST_GeomFromKML

ST_GeomFromKML — Takes as input KML representation of geometry and outputs a PostGIS geometry object

Synopsis

geometry ST_GeomFromKML(text geomkml);

Description

Constructs a PostGIS ST_Geometry object from the OGC KML representation.

ST_GeomFromKML works only for KML Geometry fragments. It throws an error if you try to use it on a whole KML document.
OGC KML versions supported:

• KML 2.2.0 Namespace

OGC KML standards, cf: http://www.opengeospatial.org/standards/kml:

Availability: 1.5,libxml2 2.6+

This function supports 3d and will not drop the z-index.

Note
ST_GeomFromKML function not support SQL/MM curves geometries.
PostGIS 2.4.3 Manual 118 / 803

Examples - A single geometry with srsName

SELECT ST_GeomFromKML('
<LineString>
<coordinates>-71.1663,42.2614
-71.1667,42.2616</coordinates>
</LineString>');

See Also

Section 2.4.1, ST_AsKML

8.4.16 ST_GMLToSQL

ST_GMLToSQL — Return a specified ST_Geometry value from GML representation. This is an alias name for ST_GeomFromGML

Synopsis

geometry ST_GMLToSQL(text geomgml);

geometry ST_GMLToSQL(text geomgml, integer srid);

Description

This method implements the SQL/MM specification. SQL-MM 3: 5.1.50 (except for curves support).
Availability: 1.5, requires libxml2 1.6+
Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
Enhanced: 2.0.0 default srid optional parameter added.

See Also

Section 2.4.1, ST_GeomFromGML, ST_AsGML

8.4.17 ST_GeomFromText

ST_GeomFromText — Return a specified ST_Geometry value from Well-Known Text representation (WKT).

Synopsis

geometry ST_GeomFromText(text WKT);

geometry ST_GeomFromText(text WKT, integer srid);

Description

Constructs a PostGIS ST_Geometry object from the OGC Well-Known text representation.

Note
There are two variants of ST_GeomFromText function. The first takes no SRID and returns a geometry with no defined
spatial reference system (SRID=0). The second takes a SRID as the second argument and returns a geometry that
includes this SRID as part of its metadata.
PostGIS 2.4.3 Manual 119 / 803

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2 - option SRID
is from the conformance suite.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.40

This method supports Circular Strings and Curves

Warning
Changed: 2.0.0 In prior versions of PostGIS ST_GeomFromText(’GEOMETRYCOLLECTION(EMPTY)’) was allowed.
This is now illegal in PostGIS 2.0.0 to better conform with SQL/MM standards. This should now be written as
ST_GeomFromText(’GEOMETRYCOLLECTION EMPTY’)

Examples

SELECT ST_GeomFromText('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 ←-

42.25932)');
SELECT ST_GeomFromText('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 ←-
42.25932)',4269);

SELECT ST_GeomFromText('MULTILINESTRING((-71.160281 42.258729,-71.160837 ←-

42.259113,-71.161144 42.25932))');

SELECT ST_GeomFromText('POINT(-71.064544 42.28787)');

SELECT ST_GeomFromText('POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 ←-

42.3903701743239,
-71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 ←-
42.3902909739571))');

SELECT ST_GeomFromText('MULTIPOLYGON(((-71.1031880899493 42.3152774590236,

-71.1031627617667 42.3152960829043,-71.102923838298 42.3149156848307,
-71.1023097974109 42.3151969047397,-71.1019285062273 42.3147384934248,
-71.102505233663 42.3144722937587,-71.10277487471 42.3141658254797,
-71.103113945163 42.3142739188902,-71.10324876416 42.31402489987,
-71.1033002961013 42.3140393340215,-71.1033488797549 42.3139495090772,
-71.103396240451 42.3138632439557,-71.1041521907712 42.3141153348029,
-71.1041411411543 42.3141545014533,-71.1041287795912 42.3142114839058,
-71.1041188134329 42.3142693656241,-71.1041112482575 42.3143272556118,
-71.1041072845732 42.3143851580048,-71.1041057218871 42.3144430686681,
-71.1041065602059 42.3145009876017,-71.1041097995362 42.3145589148055,
-71.1041166403905 42.3146168544148,-71.1041258822717 42.3146748022936,
-71.1041375307579 42.3147318674446,-71.1041492906949 42.3147711126569,
-71.1041598612795 42.314808571739,-71.1042515013869 42.3151287620809,
-71.1041173835118 42.3150739481917,-71.1040809891419 42.3151344119048,
-71.1040438678912 42.3151191367447,-71.1040194562988 42.3151832057859,
-71.1038734225584 42.3151140942995,-71.1038446938243 42.3151006300338,
-71.1038315271889 42.315094347535,-71.1037393329282 42.315054824985,
-71.1035447555574 42.3152608696313,-71.1033436658644 42.3151648370544,
-71.1032580383161 42.3152269126061,-71.103223066939 42.3152517403219,
-71.1031880899493 42.3152774590236)),
((-71.1043632495873 42.315113108546,-71.1043583974082 42.3151211109857,
-71.1043443253471 42.3150676015829,-71.1043850704575 42.3150793250568,-71.1043632495873 ←-
42.315113108546)))',4326);

SELECT ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)');

PostGIS 2.4.3 Manual 120 / 803

See Also

ST_GeomFromEWKT, ST_GeomFromWKB, ST_SRID

8.4.18 ST_GeomFromWKB

ST_GeomFromWKB — Creates a geometry instance from a Well-Known Binary geometry representation (WKB) and optional
SRID.

Synopsis

geometry ST_GeomFromWKB(bytea geom);

geometry ST_GeomFromWKB(bytea geom, integer srid);

Description

The ST_GeomFromWKB function, takes a well-known binary representation of a geometry and a Spatial Reference System ID
(SRID) and creates an instance of the appropriate geometry type. This function plays the role of the Geometry Factory in SQL.
This is an alternate name for ST_WKBToSQL.
If SRID is not specified, it defaults to 0 (Unknown).

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.7.2 - the optional
SRID is from the conformance suite

This method implements the SQL/MM specification. SQL-MM 3: 5.1.41

This method supports Circular Strings and Curves

Examples

--Although bytea rep contains single \, these need to be escaped when inserting into a ←-
table
-- unless standard_conforming_strings is set to on.
SELECT ST_AsEWKT(
ST_GeomFromWKB(E'\\001\\002\\000\\000\\000\\002\\000\\000\\000\\037\\205\\353Q ←-
\\270~\\\\\\300\\323Mb\\020X\\231C@\\020X9\\264\\310~\\\\\\300)\\\\\\217\\302\\365\\230 ←-
C@',4326)
);
st_asewkt
------------------------------------------------------
SRID=4326;LINESTRING(-113.98 39.198,-113.981 39.195)
(1 row)

SELECT
ST_AsText(
ST_GeomFromWKB(
ST_AsEWKB('POINT(2 5)'::geometry)
)
);
st_astext
------------
POINT(2 5)
(1 row)
PostGIS 2.4.3 Manual 121 / 803

See Also

ST_WKBToSQL, ST_AsBinary, ST_GeomFromEWKB

8.4.19 ST_LineFromEncodedPolyline

ST_LineFromEncodedPolyline — Creates a LineString from an Encoded Polyline.

Synopsis

geometry ST_LineFromEncodedPolyline(text polyline, integer precision=5);

Description

Creates a LineString from an Encoded Polyline string.

See http://developers.google.com/maps/documentation/utilities/polylinealgorithm
Availability: 2.2.0

Examples

--Create a line string from a polyline

SELECT ST_AsEWKT(ST_LineFromEncodedPolyline('_p~iF~ps|U_ulLnnqC_mqNvxq`@'));
--result--
LINESTRING(-120.2 38.5,-120.95 40.7,-126.453 43.252)

See Also

ST_AsEncodedPolyline

8.4.20 ST_LineFromMultiPoint

ST_LineFromMultiPoint — Creates a LineString from a MultiPoint geometry.

Synopsis

geometry ST_LineFromMultiPoint(geometry aMultiPoint);

Description

Creates a LineString from a MultiPoint geometry.

This function supports 3d and will not drop the z-index.

Examples

--Create a 3d line string from a 3d multipoint

SELECT ST_AsEWKT(ST_LineFromMultiPoint(ST_GeomFromEWKT('MULTIPOINT(1 2 3, 4 5 6, 7 8 9)'))) ←-
;
--result--
LINESTRING(1 2 3,4 5 6,7 8 9)
PostGIS 2.4.3 Manual 122 / 803

See Also

ST_AsEWKT, ST_Collect, ST_MakeLine

8.4.21 ST_LineFromText

ST_LineFromText — Makes a Geometry from WKT representation with the given SRID. If SRID is not given, it defaults to 0.

Synopsis

geometry ST_LineFromText(text WKT);

geometry ST_LineFromText(text WKT, integer srid);

Description

Makes a Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0. If WKT passed in is not a
LINESTRING, then null is returned.

Note
OGC SPEC 3.2.6.2 - option SRID is from the conformance suite.

Note
If you know all your geometries are LINESTRINGS, its more efficient to just use ST_GeomFromText. This just calls
ST_GeomFromText and adds additional validation that it returns a linestring.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2

This method implements the SQL/MM specification. SQL-MM 3: 7.2.8

Examples

SELECT ST_LineFromText('LINESTRING(1 2, 3 4)') AS aline, ST_LineFromText('POINT(1 2)') AS ←-

null_return;
aline | null_return
------------------------------------------------
010200000002000000000000000000F ... | t

See Also

ST_GeomFromText

8.4.22 ST_LineFromWKB

ST_LineFromWKB — Makes a LINESTRING from WKB with the given SRID

PostGIS 2.4.3 Manual 123 / 803

Synopsis

geometry ST_LineFromWKB(bytea WKB);

geometry ST_LineFromWKB(bytea WKB, integer srid);

Description

The ST_LineFromWKB function, takes a well-known binary representation of geometry and a Spatial Reference System ID
(SRID) and creates an instance of the appropriate geometry type - in this case, a LINESTRING geometry. This function plays
the role of the Geometry Factory in SQL.
If an SRID is not specified, it defaults to 0. NULL is returned if the input bytea does not represent a LINESTRING.

Note
OGC SPEC 3.2.6.2 - option SRID is from the conformance suite.

Note
If you know all your geometries are LINESTRINGs, its more efficient to just use ST_GeomFromWKB. This function
just calls ST_GeomFromWKB and adds additional validation that it returns a linestring.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2

This method implements the SQL/MM specification. SQL-MM 3: 7.2.9

Examples

SELECT ST_LineFromWKB(ST_AsBinary(ST_GeomFromText('LINESTRING(1 2, 3 4)'))) AS aline,

ST_LineFromWKB(ST_AsBinary(ST_GeomFromText('POINT(1 2)'))) IS NULL AS null_return;
aline | null_return
------------------------------------------------
010200000002000000000000000000F ... | t

See Also

ST_GeomFromWKB, ST_LinestringFromWKB

8.4.23 ST_LinestringFromWKB

ST_LinestringFromWKB — Makes a geometry from WKB with the given SRID.

Synopsis

geometry ST_LinestringFromWKB(bytea WKB);

geometry ST_LinestringFromWKB(bytea WKB, integer srid);
PostGIS 2.4.3 Manual 124 / 803

Description

The ST_LinestringFromWKB function, takes a well-known binary representation of geometry and a Spatial Reference Sys-
tem ID (SRID) and creates an instance of the appropriate geometry type - in this case, a LINESTRING geometry. This function
plays the role of the Geometry Factory in SQL.
If an SRID is not specified, it defaults to 0. NULL is returned if the input bytea does not represent a LINESTRING geometry.
This an alias for ST_LineFromWKB.

Note
OGC SPEC 3.2.6.2 - optional SRID is from the conformance suite.

Note
If you know all your geometries are LINESTRINGs, it’s more efficient to just use ST_GeomFromWKB. This function
just calls ST_GeomFromWKB and adds additional validation that it returns a LINESTRING.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2

This method implements the SQL/MM specification. SQL-MM 3: 7.2.9

Examples

SELECT
ST_LineStringFromWKB(
ST_AsBinary(ST_GeomFromText('LINESTRING(1 2, 3 4)'))
) AS aline,
ST_LinestringFromWKB(
ST_AsBinary(ST_GeomFromText('POINT(1 2)'))
) IS NULL AS null_return;
aline | null_return
------------------------------------------------
010200000002000000000000000000F ... | t

See Also

ST_GeomFromWKB, ST_LineFromWKB

8.4.24 ST_MakeBox2D

ST_MakeBox2D — Creates a BOX2D defined by the given point geometries.

Synopsis

box2d ST_MakeBox2D(geometry pointLowLeft, geometry pointUpRight);

Description

Creates a BOX2D defined by the given point geometries. This is useful for doing range queries
PostGIS 2.4.3 Manual 125 / 803

Examples

--Return all features that fall reside or partly reside in a US national atlas coordinate ←-
bounding box
--It is assumed here that the geometries are stored with SRID = 2163 (US National atlas ←-
equal area)
SELECT feature_id, feature_name, the_geom
FROM features
WHERE the_geom && ST_SetSRID(ST_MakeBox2D(ST_Point(-989502.1875, 528439.5625),
ST_Point(-987121.375 ,529933.1875)),2163)

See Also

ST_MakePoint, ST_Point, ST_SetSRID, ST_SRID

8.4.25 ST_3DMakeBox

ST_3DMakeBox — Creates a BOX3D defined by the given 3d point geometries.

Synopsis

box3d ST_3DMakeBox(geometry point3DLowLeftBottom, geometry point3DUpRightTop);

Description

Creates a BOX3D defined by the given 2 3D point geometries.

This function supports 3d and will not drop the z-index.

Changed: 2.0.0 In prior versions this used to be called ST_MakeBox3D

Examples

SELECT ST_3DMakeBox(ST_MakePoint(-989502.1875, 528439.5625, 10),

ST_MakePoint(-987121.375 ,529933.1875, 10)) As abb3d

--bb3d--
--------
BOX3D(-989502.1875 528439.5625 10,-987121.375 529933.1875 10)

See Also

ST_MakePoint, ST_SetSRID, ST_SRID

8.4.26 ST_MakeLine

ST_MakeLine — Creates a Linestring from point, multipoint, or line geometries.

Synopsis

geometry ST_MakeLine(geometry set geoms);

geometry ST_MakeLine(geometry geom1, geometry geom2);
geometry ST_MakeLine(geometry[] geoms_array);
PostGIS 2.4.3 Manual 126 / 803

Description

ST_MakeLine comes in 3 forms: a spatial aggregate that takes rows of point, multipoint, or line geometries and returns a line
string, a function that takes an array of point, multipoint, or line, and a regular function that takes two point, multipoint, or line
geometries. You might want to use a subselect to order points before feeding them to the aggregate version of this function.
Inputs other than point, multipoint, or lines are ignored.
When adding line components common nodes at the beginning of lines are removed from the output. Common nodes in point
and multipoint inputs are not removed.

This function supports 3d and will not drop the z-index.

Availability: 2.3.0 - Support for multipoint input elements was introduced
Availability: 2.0.0 - Support for linestring input elements was introduced
Availability: 1.4.0 - ST_MakeLine(geomarray) was introduced. ST_MakeLine aggregate functions was enhanced to handle more
points faster.

Examples: Spatial Aggregate version

This example takes a sequence of GPS points and creates one record for each gps travel where the geometry field is a line string
composed of the gps points in the order of the travel.
-- For pre-PostgreSQL 9.0 - this usually works,
-- but the planner may on occasion choose not to respect the order of the subquery
SELECT gps.gps_track, ST_MakeLine(gps.the_geom) As newgeom
FROM (SELECT gps_track,gps_time, the_geom
FROM gps_points ORDER BY gps_track, gps_time) As gps
GROUP BY gps.gps_track;

-- If you are using PostgreSQL 9.0+

-- (you can use the new ORDER BY support for aggregates)
-- this is a guaranteed way to get a correctly ordered linestring
-- Your order by part can order by more than one column if needed
SELECT gps.gps_track, ST_MakeLine(gps.the_geom ORDER BY gps_time) As newgeom
FROM gps_points As gps
GROUP BY gps.gps_track;

Examples: Non-Spatial Aggregate version

First example is a simple one off line string composed of 2 points. The second formulates line strings from 2 points a user draws.
The third is a one-off that joins 2 3d points to create a line in 3d space.
SELECT ST_AsText(ST_MakeLine(ST_MakePoint(1,2), ST_MakePoint(3,4)));
st_astext
---------------------
LINESTRING(1 2,3 4)

SELECT userpoints.id, ST_MakeLine(startpoint, endpoint) As drawn_line

FROM userpoints ;

SELECT ST_AsEWKT(ST_MakeLine(ST_MakePoint(1,2,3), ST_MakePoint(3,4,5)));

st_asewkt
-------------------------
LINESTRING(1 2 3,3 4 5)
PostGIS 2.4.3 Manual 127 / 803

Examples: Using Array version

SELECT ST_MakeLine(ARRAY(SELECT ST_Centroid(the_geom) FROM visit_locations ORDER BY ←-

visit_time));

--Making a 3d line with 3 3-d points

SELECT ST_AsEWKT(ST_MakeLine(ARRAY[ST_MakePoint(1,2,3),
ST_MakePoint(3,4,5), ST_MakePoint(6,6,6)]));
st_asewkt
-------------------------
LINESTRING(1 2 3,3 4 5,6 6 6)

See Also

ST_AsEWKT, ST_AsText, ST_GeomFromText, ST_MakePoint

8.4.27 ST_MakeEnvelope

ST_MakeEnvelope — Creates a rectangular Polygon formed from the given minimums and maximums. Input values must be in
SRS specified by the SRID.

Synopsis

geometry ST_MakeEnvelope(double precision xmin, double precision ymin, double precision xmax, double precision ymax,
integer srid=unknown);

Description

Creates a rectangular Polygon formed from the minima and maxima. by the given shell. Input values must be in SRS specified
by the SRID. If no SRID is specified the unknown spatial reference system is assumed
Availability: 1.5
Enhanced: 2.0: Ability to specify an envelope without specifying an SRID was introduced.

Example: Building a bounding box polygon

SELECT ST_AsText(ST_MakeEnvelope(10, 10, 11, 11, 4326));

st_asewkt
-----------
POLYGON((10 10, 10 11, 11 11, 11 10, 10 10))

See Also

ST_MakePoint, ST_MakeLine, ST_MakePolygon

8.4.28 ST_MakePolygon

ST_MakePolygon — Creates a Polygon formed by the given shell. Input geometries must be closed LINESTRINGS.
PostGIS 2.4.3 Manual 128 / 803

Synopsis

geometry ST_MakePolygon(geometry linestring);

geometry ST_MakePolygon(geometry outerlinestring, geometry[] interiorlinestrings);

Description

Creates a Polygon formed by the given shell. Input geometries must be closed LINESTRINGS. Comes in 2 variants.
Variant 1: Takes one closed linestring.
Variant 2: Creates a Polygon formed by the given shell and array of holes. You can construct a geometry array using ST_Accum
or the PostgreSQL ARRAY[] and ARRAY() constructs. Input geometries must be closed LINESTRINGS.

Note
This function will not accept a MULTILINESTRING. Use ST_LineMerge or ST_Dump to generate line strings.

This function supports 3d and will not drop the z-index.

Examples: Single closed LINESTRING

--2d line
SELECT ST_MakePolygon(ST_GeomFromText('LINESTRING(75.15 29.53,77 29,77.6 29.5, 75.15 29.53) ←-
'));
--If linestring is not closed
--you can add the start point to close it
SELECT ST_MakePolygon(ST_AddPoint(foo.open_line, ST_StartPoint(foo.open_line)))
FROM (
SELECT ST_GeomFromText('LINESTRING(75.15 29.53,77 29,77.6 29.5)') As open_line) As foo;

--3d closed line

SELECT ST_MakePolygon(ST_GeomFromText('LINESTRING(75.15 29.53 1,77 29 1,77.6 29.5 1, 75.15 ←-
29.53 1)'));

st_asewkt
-----------
POLYGON((75.15 29.53 1,77 29 1,77.6 29.5 1,75.15 29.53 1))

--measured line --
SELECT ST_MakePolygon(ST_GeomFromText('LINESTRINGM(75.15 29.53 1,77 29 1,77.6 29.5 2, 75.15 ←-
29.53 2)'));

st_asewkt
----------
POLYGONM((75.15 29.53 1,77 29 1,77.6 29.5 2,75.15 29.53 2))

Examples: Outer shell with inner shells

Build a donut with an ant hole

SELECT ST_MakePolygon(
ST_ExteriorRing(ST_Buffer(foo.line,10)),
ARRAY[ST_Translate(foo.line,1,1),
ST_ExteriorRing(ST_Buffer(ST_MakePoint(20,20),1)) ]
PostGIS 2.4.3 Manual 129 / 803

)
FROM
(SELECT ST_ExteriorRing(ST_Buffer(ST_MakePoint(10,10),10,10))
As line )
As foo;

Build province boundaries with holes representing lakes in the province from a set of province polygons/multipolygons and water
linestrings. This is an example of using PostGIS ST_Accum.

Note
The CASE construct is used because feeding a null array into ST_MakePolygon results in NULL.

Note
A left join is used to guarantee we get all provinces back even if they have no lakes.

SELECT p.gid, p.province_name,

CASE WHEN
ST_Accum(w.the_geom) IS NULL THEN p.the_geom
ELSE ST_MakePolygon(ST_LineMerge(ST_Boundary(p.the_geom)), ST_Accum(w.the_geom)) END
FROM
provinces p LEFT JOIN waterlines w
ON (ST_Within(w.the_geom, p.the_geom) AND ST_IsClosed(w.the_geom))
GROUP BY p.gid, p.province_name, p.the_geom;

--Same example above but utilizing a correlated subquery

--and PostgreSQL built-in ARRAY() function that converts a row set to an array

SELECT p.gid, p.province_name, CASE WHEN

EXISTS(SELECT w.the_geom
FROM waterlines w
WHERE ST_Within(w.the_geom, p.the_geom)
AND ST_IsClosed(w.the_geom))
THEN
ST_MakePolygon(ST_LineMerge(ST_Boundary(p.the_geom)),
ARRAY(SELECT w.the_geom
FROM waterlines w
WHERE ST_Within(w.the_geom, p.the_geom)
AND ST_IsClosed(w.the_geom)))
ELSE p.the_geom END As the_geom
FROM
provinces p;

See Also

ST_Boundary, ST_Accum, ST_AddPoint, ST_GeometryType, ST_IsClosed, ST_LineMerge, ST_BuildArea

8.4.29 ST_MakePoint

ST_MakePoint — Creates a 2D,3DZ or 4D point geometry.

PostGIS 2.4.3 Manual 130 / 803

Synopsis

geometry ST_MakePoint(double precision x, double precision y);

geometry ST_MakePoint(double precision x, double precision y, double precision z);
geometry ST_MakePoint(double precision x, double precision y, double precision z, double precision m);

Description

Creates a 2D,3DZ or 4D point geometry (geometry with measure). ST_MakePoint while not being OGC compliant is generally
faster and more precise than ST_GeomFromText and ST_PointFromText. It is also easier to use if you have raw coordinates rather
than WKT.

Note
Note x is longitude and y is latitude

Note
Use ST_MakePointM if you need to make a point with x,y,m.

This function supports 3d and will not drop the z-index.

Examples

--Return point with unknown SRID

SELECT ST_MakePoint(-71.1043443253471, 42.3150676015829);

--Return point marked as WGS 84 long lat

SELECT ST_SetSRID(ST_MakePoint(-71.1043443253471, 42.3150676015829),4326);

--Return a 3D point (e.g. has altitude)

SELECT ST_MakePoint(1, 2,1.5);

--Get z of point
SELECT ST_Z(ST_MakePoint(1, 2,1.5));
result
-------
1.5

See Also

ST_GeomFromText, ST_PointFromText, ST_SetSRID, ST_MakePointM

8.4.30 ST_MakePointM

ST_MakePointM — Creates a point geometry with an x y and m coordinate.

Synopsis

geometry ST_MakePointM(float x, float y, float m);

PostGIS 2.4.3 Manual 131 / 803

Description

Creates a point with x, y and measure coordinates.

Note
Note x is longitude and y is latitude.

Examples

We use ST_AsEWKT in these examples to show the text representation instead of ST_AsText because ST_AsText does not
support returning M.
--Return EWKT representation of point with unknown SRID
SELECT ST_AsEWKT(ST_MakePointM(-71.1043443253471, 42.3150676015829, 10));

--result
st_asewkt
-----------------------------------------------
POINTM(-71.1043443253471 42.3150676015829 10)

--Return EWKT representation of point with measure marked as WGS 84 long lat
SELECT ST_AsEWKT(ST_SetSRID(ST_MakePointM(-71.1043443253471, 42.3150676015829,10),4326));

st_asewkt
---------------------------------------------------------
SRID=4326;POINTM(-71.1043443253471 42.3150676015829 10)

--Return a 3d point (e.g. has altitude)

SELECT ST_MakePoint(1, 2,1.5);

--Get m of point
SELECT ST_M(ST_MakePointM(-71.1043443253471, 42.3150676015829,10));
result
-------
10

See Also

ST_AsEWKT, ST_MakePoint, ST_SetSRID

8.4.31 ST_MLineFromText

ST_MLineFromText — Return a specified ST_MultiLineString value from WKT representation.

Synopsis

geometry ST_MLineFromText(text WKT, integer srid);

geometry ST_MLineFromText(text WKT);
PostGIS 2.4.3 Manual 132 / 803

Description

Makes a Geometry from Well-Known-Text (WKT) with the given SRID. If SRID is not given, it defaults to 0.
OGC SPEC 3.2.6.2 - option SRID is from the conformance suite
Returns null if the WKT is not a MULTILINESTRING

Note
If you are absolutely sure all your WKT geometries are points, don’t use this function. It is slower than
ST_GeomFromText since it adds an additional validation step.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2

This method implements the SQL/MM specification.SQL-MM 3: 9.4.4

Examples

SELECT ST_MLineFromText('MULTILINESTRING((1 2, 3 4), (4 5, 6 7))');

See Also

ST_GeomFromText

8.4.32 ST_MPointFromText

ST_MPointFromText — Makes a Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0.

Synopsis

geometry ST_MPointFromText(text WKT, integer srid);

geometry ST_MPointFromText(text WKT);

Description

Makes a Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0.
OGC SPEC 3.2.6.2 - option SRID is from the conformance suite
Returns null if the WKT is not a MULTIPOINT

Note
If you are absolutely sure all your WKT geometries are points, don’t use this function. It is slower than
ST_GeomFromText since it adds an additional validation step.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. 3.2.6.2

This method implements the SQL/MM specification. SQL-MM 3: 9.2.4

PostGIS 2.4.3 Manual 133 / 803

Examples

SELECT ST_MPointFromText('MULTIPOINT(1 2, 3 4)');

SELECT ST_MPointFromText('MULTIPOINT(-70.9590 42.1180, -70.9611 42.1223)', 4326);

See Also

ST_GeomFromText

8.4.33 ST_MPolyFromText

ST_MPolyFromText — Makes a MultiPolygon Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0.

Synopsis

geometry ST_MPolyFromText(text WKT, integer srid);

geometry ST_MPolyFromText(text WKT);

Description

Makes a MultiPolygon from WKT with the given SRID. If SRID is not given, it defaults to 0.
OGC SPEC 3.2.6.2 - option SRID is from the conformance suite
Throws an error if the WKT is not a MULTIPOLYGON

Note
If you are absolutely sure all your WKT geometries are multipolygons, don’t use this function. It is slower than
ST_GeomFromText since it adds an additional validation step.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2

This method implements the SQL/MM specification. SQL-MM 3: 9.6.4

Examples

SELECT ST_MPolyFromText('MULTIPOLYGON(((0 0 1,20 0 1,20 20 1,0 20 1,0 0 1),(5 5 3,5 7 3,7 7 ←-

3,7 5 3,5 5 3)))');
SELECt ST_MPolyFromText('MULTIPOLYGON(((-70.916 42.1002,-70.9468 42.0946,-70.9765 ←-
42.0872,-70.9754 42.0875,-70.9749 42.0879,-70.9752 42.0881,-70.9754 42.0891,-70.9758 ←-
42.0894,-70.9759 42.0897,-70.9759 42.0899,-70.9754 42.0902,-70.9756 42.0906,-70.9753 ←-
42.0907,-70.9753 42.0917,-70.9757 42.0924,-70.9755 42.0928,-70.9755 42.0942,-70.9751 ←-
42.0948,-70.9755 42.0953,-70.9751 42.0958,-70.9751 42.0962,-70.9759 42.0983,-70.9767 ←-
42.0987,-70.9768 42.0991,-70.9771 42.0997,-70.9771 42.1003,-70.9768 42.1005,-70.977 ←-
42.1011,-70.9766 42.1019,-70.9768 42.1026,-70.9769 42.1033,-70.9775 42.1042,-70.9773 ←-
42.1043,-70.9776 42.1043,-70.9778 42.1048,-70.9773 42.1058,-70.9774 42.1061,-70.9779 ←-
42.1065,-70.9782 42.1078,-70.9788 42.1085,-70.9798 42.1087,-70.9806 42.109,-70.9807 ←-
42.1093,-70.9806 42.1099,-70.9809 42.1109,-70.9808 42.1112,-70.9798 42.1116,-70.9792 ←-
42.1127,-70.979 42.1129,-70.9787 42.1134,-70.979 42.1139,-70.9791 42.1141,-70.9987 ←-
42.1116,-71.0022 42.1273,
-70.9408 42.1513,-70.9315 42.1165,-70.916 42.1002)))',4326);
PostGIS 2.4.3 Manual 134 / 803

See Also

ST_GeomFromText, ST_SRID

8.4.34 ST_Point

ST_Point — Returns an ST_Point with the given coordinate values. OGC alias for ST_MakePoint.

Synopsis

geometry ST_Point(float x_lon, float y_lat);

Description

Returns an ST_Point with the given coordinate values. MM compliant alias for ST_MakePoint that takes just an x and y.

This method implements the SQL/MM specification. SQL-MM 3: 6.1.2

Examples: Geometry

SELECT ST_SetSRID(ST_Point(-71.1043443253471, 42.3150676015829),4326)

Examples: Geography

SELECT CAST(ST_SetSRID(ST_Point(-71.1043443253471, 42.3150676015829),4326) As geography);

-- the :: is PostgreSQL short-hand for casting.

SELECT ST_SetSRID(ST_Point(-71.1043443253471, 42.3150676015829),4326)::geography;

--If your point coordinates are in a different spatial reference from WGS-84 long lat, then ←-
you need to transform before casting
-- This example we convert a point in Pennsylvania State Plane feet to WGS 84 and then ←-
geography
SELECT ST_Transform(ST_SetSRID(ST_Point(3637510, 3014852),2273),4326)::geography;

See Also

Section 4.2.1, ST_MakePoint, ST_SetSRID, ST_Transform

8.4.35 ST_PointFromGeoHash

ST_PointFromGeoHash — Return a point from a GeoHash string.

Synopsis

point ST_PointFromGeoHash(text geohash, integer precision=full_precision_of_geohash);

PostGIS 2.4.3 Manual 135 / 803

Description

Return a point from a GeoHash string. The point represents the center point of the GeoHash.
If no precision is specified ST_PointFromGeoHash returns a point based on full precision of the input GeoHash string.
If precision is specified ST_PointFromGeoHash will use that many characters from the GeoHash to create the point.
Availability: 2.1.0

Examples

SELECT ST_AsText(ST_PointFromGeoHash('9qqj7nmxncgyy4d0dbxqz0'));
st_astext
------------------------------
POINT(-115.172816 36.114646)

SELECT ST_AsText(ST_PointFromGeoHash('9qqj7nmxncgyy4d0dbxqz0', 4));

st_astext
-----------------------------------
POINT(-115.13671875 36.123046875)

SELECT ST_AsText(ST_PointFromGeoHash('9qqj7nmxncgyy4d0dbxqz0', 10));

st_astext
-------------------------------------------
POINT(-115.172815918922 36.1146435141563)

See Also

ST_GeoHash, ST_Box2dFromGeoHash, ST_GeomFromGeoHash

8.4.36 ST_PointFromText

ST_PointFromText — Makes a point Geometry from WKT with the given SRID. If SRID is not given, it defaults to unknown.

Synopsis

geometry ST_PointFromText(text WKT);

geometry ST_PointFromText(text WKT, integer srid);

Description

Constructs a PostGIS ST_Geometry point object from the OGC Well-Known text representation. If SRID is not given, it defaults
to unknown (currently 0). If geometry is not a WKT point representation, returns null. If completely invalid WKT, then throws
an error.

Note
There are 2 variants of ST_PointFromText function, the first takes no SRID and returns a geometry with no defined
spatial reference system. The second takes a spatial reference id as the second argument and returns an ST_Geometry
that includes this srid as part of its meta-data. The srid must be defined in the spatial_ref_sys table.
PostGIS 2.4.3 Manual 136 / 803

Note
If you are absolutely sure all your WKT geometries are points, don’t use this function. It is slower than
ST_GeomFromText since it adds an additional validation step. If you are building points from long lat coordinates
and care more about performance and accuracy than OGC compliance, use ST_MakePoint or OGC compliant alias
ST_Point.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2 - option SRID
is from the conformance suite.

This method implements the SQL/MM specification. SQL-MM 3: 6.1.8

Examples

SELECT ST_PointFromText('POINT(-71.064544 42.28787)');

SELECT ST_PointFromText('POINT(-71.064544 42.28787)', 4326);

See Also

ST_GeomFromText, ST_MakePoint, ST_Point, ST_SRID

8.4.37 ST_PointFromWKB

ST_PointFromWKB — Makes a geometry from WKB with the given SRID

Synopsis

geometry ST_GeomFromWKB(bytea geom);

geometry ST_GeomFromWKB(bytea geom, integer srid);

Description

The ST_PointFromWKB function, takes a well-known binary representation of geometry and a Spatial Reference System ID
(SRID) and creates an instance of the appropriate geometry type - in this case, a POINT geometry. This function plays the role
of the Geometry Factory in SQL.
If an SRID is not specified, it defaults to 0. NULL is returned if the input bytea does not represent a POINT geometry.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.7.2

This method implements the SQL/MM specification. SQL-MM 3: 6.1.9

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 137 / 803

Examples

SELECT
ST_AsText(
ST_PointFromWKB(
ST_AsEWKB('POINT(2 5)'::geometry)
)
);
st_astext
------------
POINT(2 5)
(1 row)

SELECT
ST_AsText(
ST_PointFromWKB(
ST_AsEWKB('LINESTRING(2 5, 2 6)'::geometry)
)
);
st_astext
-----------

(1 row)

See Also

ST_GeomFromWKB, ST_LineFromWKB

8.4.38 ST_Polygon

ST_Polygon — Returns a polygon built from the specified linestring and SRID.

Synopsis

geometry ST_Polygon(geometry aLineString, integer srid);

Description

Returns a polygon built from the specified linestring and SRID.

Note
ST_Polygon is similar to first version of ST_MakePolygon except it also sets the spatial ref sys (SRID) of the polygon.
Will not work with MULTILINESTRINGS so use LineMerge to merge multilines. Also does not create polygons with
holes. Use ST_MakePolygon for that.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 8.3.2

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 138 / 803

Examples

--a 2d polygon
SELECT ST_Polygon(ST_GeomFromText('LINESTRING(75.15 29.53,77 29,77.6 29.5, 75.15 29.53)'), ←-
4326);

--result--
POLYGON((75.15 29.53,77 29,77.6 29.5,75.15 29.53))
--a 3d polygon
SELECT ST_AsEWKT(ST_Polygon(ST_GeomFromEWKT('LINESTRING(75.15 29.53 1,77 29 1,77.6 29.5 1, ←-
75.15 29.53 1)'), 4326));

result
------
SRID=4326;POLYGON((75.15 29.53 1,77 29 1,77.6 29.5 1,75.15 29.53 1))

See Also

ST_AsEWKT, ST_AsText, ST_GeomFromEWKT, ST_GeomFromText, ST_LineMerge, ST_MakePolygon

8.4.39 ST_PolygonFromText

ST_PolygonFromText — Makes a Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0.

Synopsis

geometry ST_PolygonFromText(text WKT);

geometry ST_PolygonFromText(text WKT, integer srid);

Description

Makes a Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0. Returns null if WKT is not a polygon.
OGC SPEC 3.2.6.2 - option SRID is from the conformance suite

Note
If you are absolutely sure all your WKT geometries are polygons, don’t use this function. It is slower than
ST_GeomFromText since it adds an additional validation step.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.6.2

This method implements the SQL/MM specification. SQL-MM 3: 8.3.6

Examples

SELECT ST_PolygonFromText('POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 ←-

42.3903701743239,
-71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 ←-
42.3902909739571))');
st_polygonfromtext
------------------
PostGIS 2.4.3 Manual 139 / 803

010300000001000000050000006...

SELECT ST_PolygonFromText('POINT(1 2)') IS NULL as point_is_notpoly;

point_is_not_poly
----------
t

See Also

ST_GeomFromText

8.4.40 ST_WKBToSQL

ST_WKBToSQL — Return a specified ST_Geometry value from Well-Known Binary representation (WKB). This is an alias
name for ST_GeomFromWKB that takes no srid

Synopsis

geometry ST_WKBToSQL(bytea WKB);

Description

This method implements the SQL/MM specification. SQL-MM 3: 5.1.36

See Also

ST_GeomFromWKB

8.4.41 ST_WKTToSQL

ST_WKTToSQL — Return a specified ST_Geometry value from Well-Known Text representation (WKT). This is an alias name
for ST_GeomFromText

Synopsis

geometry ST_WKTToSQL(text WKT);

Description

This method implements the SQL/MM specification. SQL-MM 3: 5.1.34

See Also

ST_GeomFromText
PostGIS 2.4.3 Manual 140 / 803

8.5 Geometry Accessors

8.5.1 GeometryType

GeometryType — Returns the type of the geometry as a string. Eg: ’LINESTRING’, ’POLYGON’, ’MULTIPOINT’, etc.

Synopsis

text GeometryType(geometry geomA);

Description

Returns the type of the geometry as a string. Eg: ’LINESTRING’, ’POLYGON’, ’MULTIPOINT’, etc.
OGC SPEC s2.1.1.1 - Returns the name of the instantiable subtype of Geometry of which this Geometry instance is a member.
The name of the instantiable subtype of Geometry is returned as a string.

Note
This function also indicates if the geometry is measured, by returning a string of the form ’POINTM’.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method supports Circular Strings and Curves

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT GeometryType(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 ←-

29.07)'));
geometrytype
--------------
LINESTRING

SELECT ST_GeometryType(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 ←-

0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
POLYHEDRALSURFACE
PostGIS 2.4.3 Manual 141 / 803

SELECT GeometryType(geom) as result

FROM
(SELECT
ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') AS geom
) AS g;
result
--------
TIN

See Also

ST_GeometryType

8.5.2 ST_Boundary

ST_Boundary — Returns the closure of the combinatorial boundary of this Geometry.

Synopsis

geometry ST_Boundary(geometry geomA);

Description

Returns the closure of the combinatorial boundary of this Geometry. The combinatorial boundary is defined as described in
section 3.12.3.2 of the OGC SPEC. Because the result of this function is a closure, and hence topologically closed, the resulting
boundary can be represented using representational geometry primitives as discussed in the OGC SPEC, section 3.12.2.
Performed by the GEOS module

Note
Prior to 2.0.0, this function throws an exception if used with GEOMETRYCOLLECTION. From 2.0.0 up it will return
NULL instead (unsupported input).

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. OGC SPEC s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.14

This function supports 3d and will not drop the z-index.

Enhanced: 2.1.0 support for Triangle was introduced
PostGIS 2.4.3 Manual 142 / 803

Examples
PostGIS 2.4.3 Manual 143 / 803

polygon holes with boundary multilinestring

SELECT ST_Boundary(geom)
Linestring with boundary points overlaid
FROM (SELECT
'POLYGON (( 10 130, 50 190, 110 190, 140 ←-
SELECT ST_Boundary(geom)
150, 150 80, 100 10, 20 40, 10 130 ),
FROM (SELECT 'LINESTRING(100 150,50 60, ←- ( 70 40, 100 50, 120 80, 80 110, ←-
70 80, 160 170)'::geometry As geom) As f; 50 90, 70 40 ))'::geometry As geom) As f;
-- ST_AsText output -- ST_AsText output
MULTIPOINT(100 150,160 170) MULTILINESTRING((10 130,50 190,110 ←-
190,140 150,150 80,100 10,20 40,10 130),
(70 40,100 50,120 80,80 110,50 ←-
90,70 40))

SELECT ST_AsText(ST_Boundary(ST_GeomFromText('LINESTRING(1 1,0 0, -1 1)')));

st_astext
-----------
MULTIPOINT(1 1,-1 1)

SELECT ST_AsText(ST_Boundary(ST_GeomFromText('POLYGON((1 1,0 0, -1 1, 1 1))')));

st_astext
----------
LINESTRING(1 1,0 0,-1 1,1 1)

--Using a 3d polygon
SELECT ST_AsEWKT(ST_Boundary(ST_GeomFromEWKT('POLYGON((1 1 1,0 0 1, -1 1 1, 1 1 1))')));

st_asewkt
-----------------------------------
LINESTRING(1 1 1,0 0 1,-1 1 1,1 1 1)

--Using a 3d multilinestring
SELECT ST_AsEWKT(ST_Boundary(ST_GeomFromEWKT('MULTILINESTRING((1 1 1,0 0 0.5, -1 1 1),(1 1 ←-
0.5,0 0 0.5, -1 1 0.5, 1 1 0.5) )')));

st_asewkt
----------
MULTIPOINT(-1 1 1,1 1 0.75)
PostGIS 2.4.3 Manual 144 / 803

See Also

ST_AsText, ST_ExteriorRing, ST_MakePolygon

8.5.3 ST_CoordDim

ST_CoordDim — Return the coordinate dimension of the ST_Geometry value.

Synopsis

integer ST_CoordDim(geometry geomA);

Description

Return the coordinate dimension of the ST_Geometry value.

This is the MM compliant alias name for ST_NDims

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.3

This method supports Circular Strings and Curves

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT ST_CoordDim('CIRCULARSTRING(1 2 3, 1 3 4, 5 6 7, 8 9 10, 11 12 13)');

---result--
3

SELECT ST_CoordDim(ST_Point(1,2));
--result--
2

See Also

ST_NDims

8.5.4 ST_Dimension

ST_Dimension — The inherent dimension of this Geometry object, which must be less than or equal to the coordinate dimension.
PostGIS 2.4.3 Manual 145 / 803

Synopsis

integer ST_Dimension(geometry g);

Description

The inherent dimension of this Geometry object, which must be less than or equal to the coordinate dimension. OGC SPEC
s2.1.1.1 - returns 0 for POINT, 1 for LINESTRING, 2 for POLYGON, and the largest dimension of the components of a
GEOMETRYCOLLECTION. If unknown (empty geometry) null is returned.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.2

Enhanced: 2.0.0 support for Polyhedral surfaces and TINs was introduced. No longer throws an exception if given empty
geometry.

Note
Prior to 2.0.0, this function throws an exception if used with empty geometry.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT ST_Dimension('GEOMETRYCOLLECTION(LINESTRING(1 1,0 0),POINT(0 0))');

ST_Dimension
-----------
1

See Also

ST_NDims

8.5.5 ST_EndPoint

ST_EndPoint — Returns the last point of a LINESTRING or CIRCULARLINESTRING geometry as a POINT.

Synopsis

boolean ST_EndPoint(geometry g);

Description

Returns the last point of a LINESTRING geometry as a POINT or NULL if the input parameter is not a LINESTRING.

This method implements the SQL/MM specification. SQL-MM 3: 7.1.4

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 146 / 803

Note
Changed: 2.0.0 no longer works with single geometry multilinestrings. In older versions of PostGIS -- a single line
multilinestring would work happily with this function and return the start point. In 2.0.0 it just returns NULL like any other
multilinestring. The older behavior was an undocumented feature, but people who assumed they had their data stored
as LINESTRING may experience these returning NULL in 2.0 now.

Examples

postgis=# SELECT ST_AsText(ST_EndPoint('LINESTRING(1 1, 2 2, 3 3)'::geometry));

st_astext
------------
POINT(3 3)
(1 row)

postgis=# SELECT ST_EndPoint('POINT(1 1)'::geometry) IS NULL AS is_null;

is_null
----------
t
(1 row)

--3d endpoint
SELECT ST_AsEWKT(ST_EndPoint('LINESTRING(1 1 2, 1 2 3, 0 0 5)'));
st_asewkt
--------------
POINT(0 0 5)
(1 row)

See Also

ST_PointN, ST_StartPoint

8.5.6 ST_Envelope

ST_Envelope — Returns a geometry representing the double precision (float8) bounding box of the supplied geometry.

Synopsis

geometry ST_Envelope(geometry g1);

Description

Returns the float8 minimum bounding box for the supplied geometry, as a geometry. The polygon is defined by the corner
points of the bounding box ((MINX, MINY), (MINX, MAXY), (MAXX, MAXY), (MAXX, MINY), (MINX, MINY)). (PostGIS will add
a ZMIN/ZMAX coordinate as well).
Degenerate cases (vertical lines, points) will return a geometry of lower dimension than POLYGON, ie. POINT or LINESTRING.
Availability: 1.5.0 behavior changed to output double precision instead of float4

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.15

PostGIS 2.4.3 Manual 147 / 803

Examples

SELECT ST_AsText(ST_Envelope('POINT(1 3)'::geometry));

st_astext
------------
POINT(1 3)
(1 row)

SELECT ST_AsText(ST_Envelope('LINESTRING(0 0, 1 3)'::geometry));

st_astext
--------------------------------
POLYGON((0 0,0 3,1 3,1 0,0 0))
(1 row)

SELECT ST_AsText(ST_Envelope('POLYGON((0 0, 0 1, 1.0000001 1, 1.0000001 0, 0 0))'::geometry ←-

));
st_astext
--------------------------------------------------------------
POLYGON((0 0,0 1,1.00000011920929 1,1.00000011920929 0,0 0))
(1 row)
SELECT ST_AsText(ST_Envelope('POLYGON((0 0, 0 1, 1.0000000001 1, 1.0000000001 0, 0 0))':: ←-
geometry));
st_astext
--------------------------------------------------------------
POLYGON((0 0,0 1,1.00000011920929 1,1.00000011920929 0,0 0))
(1 row)

SELECT Box3D(geom), Box2D(geom), ST_AsText(ST_Envelope(geom)) As envelopewkt

FROM (SELECT 'POLYGON((0 0, 0 1000012333334.34545678, 1.0000001 1, 1.0000001 0, 0 0))':: ←-
geometry As geom) As foo;

See Also

Box2D, Box3D

8.5.7 ST_BoundingDiagonal

ST_BoundingDiagonal — Returns the diagonal of the supplied geometry’s bounding box.

Synopsis

geometry ST_BoundingDiagonal(geometry geom, boolean fits=false);

Description

Returns the diagonal of the supplied geometry’s bounding box as linestring. If the input geometry is empty, the diagonal line is
also empty, otherwise it is a 2-points linestring with minimum values of each dimension in its start point and maximum values in
its end point.
The returned linestring geometry always retains SRID and dimensionality (Z and M presence) of the input geometry.
The fits parameter specifies if the best fit is needed. If false, the diagonal of a somewhat larger bounding box can be accepted
(is faster to obtain for geometries with a lot of vertices). In any case the bounding box of the returned diagonal line always covers
the input geometry.
PostGIS 2.4.3 Manual 148 / 803

Note
In degenerate cases (a single vertex in input) the returned linestring will be topologically invalid (no interior). This does
not make the return semantically invalid.

Availability: 2.2.0

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

Examples

-- Get the minimum X in a buffer around a point

SELECT ST_X(ST_StartPoint(ST_BoundingDiagonal(
ST_Buffer(ST_MakePoint(0,0),10)
)));
st_x
------
-10

See Also

ST_StartPoint, ST_EndPoint, ST_X, ST_Y, ST_Z, ST_M, &&&

8.5.8 ST_ExteriorRing

ST_ExteriorRing — Returns a line string representing the exterior ring of the POLYGON geometry. Return NULL if the geometry
is not a polygon. Will not work with MULTIPOLYGON

Synopsis

geometry ST_ExteriorRing(geometry a_polygon);

Description

Returns a line string representing the exterior ring of the POLYGON geometry. Return NULL if the geometry is not a polygon.

Note
Only works with POLYGON geometry types

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. 2.1.5.1

This method implements the SQL/MM specification. SQL-MM 3: 8.2.3, 8.3.3

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 149 / 803

Examples

--If you have a table of polygons

SELECT gid, ST_ExteriorRing(the_geom) AS ering
FROM sometable;

--If you have a table of MULTIPOLYGONs

--and want to return a MULTILINESTRING composed of the exterior rings of each polygon
SELECT gid, ST_Collect(ST_ExteriorRing(the_geom)) AS erings
FROM (SELECT gid, (ST_Dump(the_geom)).geom As the_geom
FROM sometable) As foo
GROUP BY gid;

--3d Example
SELECT ST_AsEWKT(
ST_ExteriorRing(
ST_GeomFromEWKT('POLYGON((0 0 1, 1 1 1, 1 2 1, 1 1 1, 0 0 1))')
)
);

st_asewkt
---------
LINESTRING(0 0 1,1 1 1,1 2 1,1 1 1,0 0 1)

See Also

ST_InteriorRingN, ST_Boundary, ST_NumInteriorRings

8.5.9 ST_GeometryN

ST_GeometryN — Return the 1-based Nth geometry if the geometry is a GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINES
MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE Otherwise, return NULL.

Synopsis

geometry ST_GeometryN(geometry geomA, integer n);

Description

Return the 1-based Nth geometry if the geometry is a GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINESTRING,
MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE Otherwise, return NULL

Note
Index is 1-based as for OGC specs since version 0.8.0. Previous versions implemented this as 0-based instead.

Note
If you want to extract all geometries, of a geometry, ST_Dump is more efficient and will also work for singular geoms.
PostGIS 2.4.3 Manual 150 / 803

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Changed: 2.0.0 Prior versions would return NULL for singular geometries. This was changed to return the geometry for
ST_GeometryN(..,1) case.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 9.1.5

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Standard Examples

--Extracting a subset of points from a 3d multipoint

SELECT n, ST_AsEWKT(ST_GeometryN(the_geom, n)) As geomewkt
FROM (
VALUES (ST_GeomFromEWKT('MULTIPOINT(1 2 7, 3 4 7, 5 6 7, 8 9 10)') ),
( ST_GeomFromEWKT('MULTICURVE(CIRCULARSTRING(2.5 2.5,4.5 2.5, 3.5 3.5), (10 11, 12 11))') )
)As foo(the_geom)
CROSS JOIN generate_series(1,100) n
WHERE n <= ST_NumGeometries(the_geom);

n | geomewkt
---+-----------------------------------------
1 | POINT(1 2 7)
2 | POINT(3 4 7)
3 | POINT(5 6 7)
4 | POINT(8 9 10)
1 | CIRCULARSTRING(2.5 2.5,4.5 2.5,3.5 3.5)
2 | LINESTRING(10 11,12 11)

--Extracting all geometries (useful when you want to assign an id)

SELECT gid, n, ST_GeometryN(the_geom, n)
FROM sometable CROSS JOIN generate_series(1,100) n
WHERE n <= ST_NumGeometries(the_geom);

Polyhedral Surfaces, TIN and Triangle Examples

-- Polyhedral surface example

-- Break a Polyhedral surface into its faces
SELECT ST_AsEWKT(ST_GeometryN(p_geom,3)) As geom_ewkt
FROM (SELECT ST_GeomFromEWKT('POLYHEDRALSURFACE(
((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1))
PostGIS 2.4.3 Manual 151 / 803

)') AS p_geom ) AS a;

geom_ewkt
------------------------------------------
POLYGON((0 0 0,1 0 0,1 0 1,0 0 1,0 0 0))

-- TIN --
SELECT ST_AsEWKT(ST_GeometryN(geom,2)) as wkt
FROM
(SELECT
ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') AS geom
) AS g;
-- result --
wkt
-------------------------------------
TRIANGLE((0 0 0,0 1 0,1 1 0,0 0 0))

See Also

ST_Dump, ST_NumGeometries

8.5.10 ST_GeometryType

ST_GeometryType — Return the geometry type of the ST_Geometry value.

Synopsis

text ST_GeometryType(geometry g1);

Description

Returns the type of the geometry as a string. EG: ’ST_Linestring’, ’ST_Polygon’,’ST_MultiPolygon’ etc. This function differs
from GeometryType(geometry) in the case of the string and ST in front that is returned, as well as the fact that it will not indicate
whether the geometry is measured.
Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.4

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

PostGIS 2.4.3 Manual 152 / 803

Examples

SELECT ST_GeometryType(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 ←-

29.31,77.29 29.07)'));
--result
ST_LineString

SELECT ST_GeometryType(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 ←-

0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
ST_PolyhedralSurface

SELECT ST_GeometryType(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 ←-

0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
ST_PolyhedralSurface

SELECT ST_GeometryType(geom) as result

FROM
(SELECT
ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') AS geom
) AS g;
result
--------
ST_Tin

See Also

GeometryType

8.5.11 ST_InteriorRingN

ST_InteriorRingN — Return the Nth interior linestring ring of the polygon geometry. Return NULL if the geometry is not a
polygon or the given N is out of range.

Synopsis

geometry ST_InteriorRingN(geometry a_polygon, integer n);

PostGIS 2.4.3 Manual 153 / 803

Description

Return the Nth interior linestring ring of the polygon geometry. Return NULL if the geometry is not a polygon or the given N is
out of range. index starts at 1.

Note
This will not work for MULTIPOLYGONs. Use in conjunction with ST_Dump for MULTIPOLYGONS

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 8.2.6, 8.3.5

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_AsText(ST_InteriorRingN(the_geom, 1)) As the_geom

FROM (SELECT ST_BuildArea(
ST_Collect(ST_Buffer(ST_Point(1,2), 20,3),
ST_Buffer(ST_Point(1, 2), 10,3))) As the_geom
) as foo

See Also

ST_ExteriorRing ST_BuildArea, ST_Collect, ST_Dump, ST_NumInteriorRing, ST_NumInteriorRings

8.5.12 ST_IsPolygonCCW

ST_IsPolygonCCW — Returns true if all exterior rings are oriented counter-clockwise and all interior rings are oriented clock-
wise.

Synopsis

boolean ST_IsPolygonCCW ( geometry geom );

Description

Returns true if all polygonal components of the input geometry use a counter-clockwise orientation for their exterior ring, and a
clockwise direction for all interior rings.
Returns true if the geometry has no polygonal components.

Note
Closed linestrings are not considered polygonal components, so you would still get a true return by passing a single
closed linestring no matter its orientation.
PostGIS 2.4.3 Manual 154 / 803

Note
If a polygonal geometry does not use reversed orientation for interior rings (i.e., if one or more interior rings are oriented
in the same direction as an exterior ring) then both ST_IsPolygonCW and ST_IsPolygonCCW will return false.

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

See Also

ST_ForcePolygonCW , ST_ForcePolygonCCW , ST_IsPolygonCW

8.5.13 ST_IsPolygonCW

ST_IsPolygonCW — Returns true if all exterior rings are oriented clockwise and all interior rings are oriented counter-clockwise.

Synopsis

boolean ST_IsPolygonCW ( geometry geom );

Description

Returns true if all polygonal components of the input geometry use a clockwise orientation for their exterior ring, and a counter-
clockwise direction for all interior rings.
Returns true if the geometry has no polygonal components.

Note
Closed linestrings are not considered polygonal components, so you would still get a true return by passing a single
closed linestring no matter its orientation.

Note
If a polygonal geometry does not use reversed orientation for interior rings (i.e., if one or more interior rings are oriented
in the same direction as an exterior ring) then both ST_IsPolygonCW and ST_IsPolygonCCW will return false.

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

See Also

ST_ForcePolygonCW , ST_ForcePolygonCCW , ST_IsPolygonCW

PostGIS 2.4.3 Manual 155 / 803

8.5.14 ST_IsClosed

ST_IsClosed — Returns TRUE if the LINESTRING’s start and end points are coincident. For Polyhedral surface is closed
(volumetric).

Synopsis

boolean ST_IsClosed(geometry g);

Description

Returns TRUE if the LINESTRING’s start and end points are coincident. For Polyhedral Surfaces, it tells you if the surface is
areal (open) or volumetric (closed).

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 7.1.5, 9.3.3

Note
SQL-MM defines the result of ST_IsClosed(NULL) to be 0, while PostGIS returns NULL.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.

This function supports Polyhedral surfaces.

Line String and Point Examples

postgis=# SELECT ST_IsClosed('LINESTRING(0 0, 1 1)'::geometry);

st_isclosed
-------------
f
(1 row)

postgis=# SELECT ST_IsClosed('LINESTRING(0 0, 0 1, 1 1, 0 0)'::geometry);

st_isclosed
-------------
t
(1 row)

postgis=# SELECT ST_IsClosed('MULTILINESTRING((0 0, 0 1, 1 1, 0 0),(0 0, 1 1))'::geometry);

st_isclosed
-------------
f
(1 row)

postgis=# SELECT ST_IsClosed('POINT(0 0)'::geometry);

st_isclosed
PostGIS 2.4.3 Manual 156 / 803

-------------
t
(1 row)

postgis=# SELECT ST_IsClosed('MULTIPOINT((0 0), (1 1))'::geometry);

st_isclosed
-------------
t
(1 row)

Polyhedral Surface Examples

-- A cube --
SELECT ST_IsClosed(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 ←-
0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));

st_isclosed
-------------
t

-- Same as cube but missing a side --

SELECT ST_IsClosed(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 ←-
0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)) )'));

st_isclosed
-------------
f

See Also

ST_IsRing

8.5.15 ST_IsCollection

ST_IsCollection — Returns TRUE if the argument is a collection (MULTI*, GEOMETRYCOLLECTION, ...)

Synopsis

boolean ST_IsCollection(geometry g);

Description

Returns TRUE if the geometry type of the argument is either:

• GEOMETRYCOLLECTION
• MULTI{POINT,POLYGON,LINESTRING,CURVE,SURFACE}
PostGIS 2.4.3 Manual 157 / 803

• COMPOUNDCURVE

Note
This function analyzes the type of the geometry. This means that it will return TRUE on collections that are empty or
that contain a single element.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

postgis=# SELECT ST_IsCollection('LINESTRING(0 0, 1 1)'::geometry);

st_iscollection
-------------
f
(1 row)

postgis=# SELECT ST_IsCollection('MULTIPOINT EMPTY'::geometry);

st_iscollection
-------------
t
(1 row)

postgis=# SELECT ST_IsCollection('MULTIPOINT((0 0))'::geometry);

st_iscollection
-------------
t
(1 row)

postgis=# SELECT ST_IsCollection('MULTIPOINT((0 0), (42 42))'::geometry);

st_iscollection
-------------
t
(1 row)

postgis=# SELECT ST_IsCollection('GEOMETRYCOLLECTION(POINT(0 0))'::geometry);

st_iscollection
-------------
t
(1 row)

See Also

ST_NumGeometries

8.5.16 ST_IsEmpty

ST_IsEmpty — Returns true if this Geometry is an empty geometrycollection, polygon, point etc.

Synopsis

boolean ST_IsEmpty(geometry geomA);

PostGIS 2.4.3 Manual 158 / 803

Description

Returns true if this Geometry is an empty geometry. If true, then this Geometry represents an empty geometry collection,
polygon, point etc.

Note
SQL-MM defines the result of ST_IsEmpty(NULL) to be 0, while PostGIS returns NULL.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.7

This method supports Circular Strings and Curves

Warning
Changed: 2.0.0 In prior versions of PostGIS ST_GeomFromText(’GEOMETRYCOLLECTION(EMPTY)’) was allowed.
This is now illegal in PostGIS 2.0.0 to better conform with SQL/MM standards

Examples

SELECT ST_IsEmpty(ST_GeomFromText('GEOMETRYCOLLECTION EMPTY'));

st_isempty
------------
t
(1 row)

SELECT ST_IsEmpty(ST_GeomFromText('POLYGON EMPTY'));

st_isempty
------------
t
(1 row)

SELECT ST_IsEmpty(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))'));

st_isempty
------------
f
(1 row)

SELECT ST_IsEmpty(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))')) = false;

?column?
----------
t
(1 row)

SELECT ST_IsEmpty(ST_GeomFromText('CIRCULARSTRING EMPTY'));

st_isempty
------------
t
(1 row)
PostGIS 2.4.3 Manual 159 / 803

8.5.17 ST_IsRing

ST_IsRing — Returns TRUE if this LINESTRING is both closed and simple.

Synopsis

boolean ST_IsRing(geometry g);

Description

Returns TRUE if this LINESTRING is both ST_IsClosed (ST_StartPoint((g )) ~= ST_Endpoint((g ))) and ST_IsSimple
(does not self intersect).

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. 2.1.5.1

This method implements the SQL/MM specification. SQL-MM 3: 7.1.6

Note
SQL-MM defines the result of ST_IsRing(NULL) to be 0, while PostGIS returns NULL.

Examples

SELECT ST_IsRing(the_geom), ST_IsClosed(the_geom), ST_IsSimple(the_geom)

FROM (SELECT 'LINESTRING(0 0, 0 1, 1 1, 1 0, 0 0)'::geometry AS the_geom) AS foo;
st_isring | st_isclosed | st_issimple
-----------+-------------+-------------
t | t | t
(1 row)

SELECT ST_IsRing(the_geom), ST_IsClosed(the_geom), ST_IsSimple(the_geom)

FROM (SELECT 'LINESTRING(0 0, 0 1, 1 0, 1 1, 0 0)'::geometry AS the_geom) AS foo;
st_isring | st_isclosed | st_issimple
-----------+-------------+-------------
f | t | f
(1 row)

See Also

ST_IsClosed, ST_IsSimple, ST_StartPoint, ST_EndPoint

8.5.18 ST_IsSimple

ST_IsSimple — Returns (TRUE) if this Geometry has no anomalous geometric points, such as self intersection or self tangency.

Synopsis

boolean ST_IsSimple(geometry geomA);

PostGIS 2.4.3 Manual 160 / 803

Description

Returns true if this Geometry has no anomalous geometric points, such as self intersection or self tangency. For more information
on the OGC’s definition of geometry simplicity and validity, refer to "Ensuring OpenGIS compliancy of geometries"

Note
SQL-MM defines the result of ST_IsSimple(NULL) to be 0, while PostGIS returns NULL.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.8

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_IsSimple(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))'));

st_issimple
-------------
t
(1 row)

SELECT ST_IsSimple(ST_GeomFromText('LINESTRING(1 1,2 2,2 3.5,1 3,1 2,2 1)'));

st_issimple
-------------
f
(1 row)

See Also

ST_IsValid

8.5.19 ST_IsValid

ST_IsValid — Returns true if the ST_Geometry is well formed.

Synopsis

boolean ST_IsValid(geometry g);

boolean ST_IsValid(geometry g, integer flags);

Description

Test if an ST_Geometry value is well formed. For geometries that are invalid, the PostgreSQL NOTICE will provide details
of why it is not valid. For more information on the OGC’s definition of geometry simplicity and validity, refer to "Ensuring
OpenGIS compliancy of geometries"
PostGIS 2.4.3 Manual 161 / 803

Note
SQL-MM defines the result of ST_IsValid(NULL) to be 0, while PostGIS returns NULL.

The version accepting flags is available starting with 2.0.0 and requires GEOS >= 3.3.0. Such version does not print a NOTICE
explaining the invalidity. Allowed flags are documented in ST_IsValidDetail.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.9

Note
Neither OGC-SFS nor SQL-MM specifications include a flag argument for ST_IsValid. The flag is a PostGIS extension.

Examples

SELECT ST_IsValid(ST_GeomFromText('LINESTRING(0 0, 1 1)')) As good_line,

ST_IsValid(ST_GeomFromText('POLYGON((0 0, 1 1, 1 2, 1 1, 0 0))')) As bad_poly
--results
NOTICE: Self-intersection at or near point 0 0
good_line | bad_poly
-----------+----------
t | f

See Also

ST_IsSimple, ST_IsValidReason, ST_IsValidDetail, ST_Summary

8.5.20 ST_IsValidReason

ST_IsValidReason — Returns text stating if a geometry is valid or not and if not valid, a reason why.

Synopsis

text ST_IsValidReason(geometry geomA);

text ST_IsValidReason(geometry geomA, integer flags);

Description

Returns text stating if a geometry is valid or not an if not valid, a reason why.
Useful in combination with ST_IsValid to generate a detailed report of invalid geometries and reasons.
Allowed flags are documented in ST_IsValidDetail.
Availability: 1.4 - requires GEOS >= 3.1.0.
Availability: 2.0 - requires GEOS >= 3.3.0 for the version taking flags.
PostGIS 2.4.3 Manual 162 / 803

Examples

--First 3 Rejects from a successful quintuplet experiment

SELECT gid, ST_IsValidReason(the_geom) as validity_info
FROM
(SELECT ST_MakePolygon(ST_ExteriorRing(e.buff), ST_Accum(f.line)) As the_geom, gid
FROM (SELECT ST_Buffer(ST_MakePoint(x1*10,y1), z1) As buff, x1*10 + y1*100 + z1*1000 As gid
FROM generate_series(-4,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,8) z1
WHERE x1 > y1*0.5 AND z1 < x1*y1) As e
INNER JOIN (SELECT ST_Translate(ST_ExteriorRing(ST_Buffer(ST_MakePoint(x1*10,y1), z1)),y1 ←-
*1, z1*2) As line
FROM generate_series(-3,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,10) z1
WHERE x1 > y1*0.75 AND z1 < x1*y1) As f
ON (ST_Area(e.buff) > 78 AND ST_Contains(e.buff, f.line))
GROUP BY gid, e.buff) As quintuplet_experiment
WHERE ST_IsValid(the_geom) = false
ORDER BY gid
LIMIT 3;

gid | validity_info
------+--------------------------
5330 | Self-intersection [32 5]
5340 | Self-intersection [42 5]
5350 | Self-intersection [52 5]

--simple example
SELECT ST_IsValidReason('LINESTRING(220227 150406,2220227 150407,222020 150410)');

st_isvalidreason
------------------
Valid Geometry

See Also

ST_IsValid, ST_Summary

8.5.21 ST_IsValidDetail

ST_IsValidDetail — Returns a valid_detail (valid,reason,location) row stating if a geometry is valid or not and if not valid, a
reason why and a location where.

Synopsis

valid_detail ST_IsValidDetail(geometry geom);

valid_detail ST_IsValidDetail(geometry geom, integer flags);

Description

Returns a valid_detail row, formed by a boolean (valid) stating if a geometry is valid, a varchar (reason) stating a reason why it
is invalid and a geometry (location) pointing out where it is invalid.
PostGIS 2.4.3 Manual 163 / 803

Useful to substitute and improve the combination of ST_IsValid and ST_IsValidReason to generate a detailed report of invalid
geometries.
The ’flags’ argument is a bitfield. It can have the following values:

• 1: Consider self-intersecting rings forming holes as valid. This is also know as "the ESRI flag". Note that this is against the
OGC model.

Availability: 2.0.0 - requires GEOS >= 3.3.0.

Examples

--First 3 Rejects from a successful quintuplet experiment

SELECT gid, reason(ST_IsValidDetail(the_geom)), ST_AsText(location(ST_IsValidDetail( ←-
the_geom))) as location
FROM
(SELECT ST_MakePolygon(ST_ExteriorRing(e.buff), ST_Accum(f.line)) As the_geom, gid
FROM (SELECT ST_Buffer(ST_MakePoint(x1*10,y1), z1) As buff, x1*10 + y1*100 + z1*1000 As gid
FROM generate_series(-4,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,8) z1
WHERE x1 > y1*0.5 AND z1 < x1*y1) As e
INNER JOIN (SELECT ST_Translate(ST_ExteriorRing(ST_Buffer(ST_MakePoint(x1*10,y1), z1)),y1 ←-
*1, z1*2) As line
FROM generate_series(-3,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,10) z1
WHERE x1 > y1*0.75 AND z1 < x1*y1) As f
ON (ST_Area(e.buff) > 78 AND ST_Contains(e.buff, f.line))
GROUP BY gid, e.buff) As quintuplet_experiment
WHERE ST_IsValid(the_geom) = false
ORDER BY gid
LIMIT 3;

gid | reason | location

------+-------------------+-------------
5330 | Self-intersection | POINT(32 5)
5340 | Self-intersection | POINT(42 5)
5350 | Self-intersection | POINT(52 5)

--simple example
SELECT * FROM ST_IsValidDetail('LINESTRING(220227 150406,2220227 150407,222020 150410)');

valid | reason | location

-------+--------+----------
t | |

See Also

ST_IsValid, ST_IsValidReason

8.5.22 ST_M

ST_M — Return the M coordinate of the point, or NULL if not available. Input must be a point.
PostGIS 2.4.3 Manual 164 / 803

Synopsis

float ST_M(geometry a_point);

Description

Return the M coordinate of the point, or NULL if not available. Input must be a point.

Note
This is not (yet) part of the OGC spec, but is listed here to complete the point coordinate extractor function list.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification.

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_M(ST_GeomFromEWKT('POINT(1 2 3 4)'));

st_m
------
4
(1 row)

See Also

ST_GeomFromEWKT, ST_X, ST_Y, ST_Z

8.5.23 ST_NDims

ST_NDims — Returns coordinate dimension of the geometry as a small int. Values are: 2,3 or 4.

Synopsis

integer ST_NDims(geometry g1);

Description

Returns the coordinate dimension of the geometry. PostGIS supports 2 - (x,y) , 3 - (x,y,z) or 2D with measure - x,y,m, and 4 - 3D
with measure space x,y,z,m

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 165 / 803

Examples

SELECT ST_NDims(ST_GeomFromText('POINT(1 1)')) As d2point,

ST_NDims(ST_GeomFromEWKT('POINT(1 1 2)')) As d3point,
ST_NDims(ST_GeomFromEWKT('POINTM(1 1 0.5)')) As d2pointm;

d2point | d3point | d2pointm

---------+---------+----------
2 | 3 | 3

See Also

ST_CoordDim, ST_Dimension, ST_GeomFromEWKT

8.5.24 ST_NPoints

ST_NPoints — Return the number of points (vertexes) in a geometry.

Synopsis

integer ST_NPoints(geometry g1);

Description

Return the number of points in a geometry. Works for all geometries.

Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_NPoints(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 ←-

29.07)'));
--result
4

--Polygon in 3D space
SELECT ST_NPoints(ST_GeomFromEWKT('LINESTRING(77.29 29.07 1,77.42 29.26 0,77.27 29.31 ←-
-1,77.29 29.07 3)'))
--result
4
PostGIS 2.4.3 Manual 166 / 803

See Also

ST_NumPoints

8.5.25 ST_NRings

ST_NRings — If the geometry is a polygon or multi-polygon returns the number of rings.

Synopsis

integer ST_NRings(geometry geomA);

Description

If the geometry is a polygon or multi-polygon returns the number of rings. Unlike NumInteriorRings, it counts the outer rings as
well.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_NRings(the_geom) As Nrings, ST_NumInteriorRings(the_geom) As ninterrings

FROM (SELECT ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))') As the_geom) As foo ←-
;
nrings | ninterrings
--------+-------------
1 | 0
(1 row)

See Also

ST_NumInteriorRings

8.5.26 ST_NumGeometries

ST_NumGeometries — If geometry is a GEOMETRYCOLLECTION (or MULTI*) return the number of geometries, for single
geometries will return 1, otherwise return NULL.

Synopsis

integer ST_NumGeometries(geometry geom);

PostGIS 2.4.3 Manual 167 / 803

Description

Returns the number of Geometries. If geometry is a GEOMETRYCOLLECTION (or MULTI*) return the number of geometries,
for single geometries will return 1, otherwise return NULL.
Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Changed: 2.0.0 In prior versions this would return NULL if the geometry was not a collection/MULTI type. 2.0.0+ now returns
1 for single geometries e.g POLYGON, LINESTRING, POINT.

This method implements the SQL/MM specification. SQL-MM 3: 9.1.4

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

--Prior versions would have returned NULL for this -- in 2.0.0 this returns 1
SELECT ST_NumGeometries(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 ←-
29.31,77.29 29.07)'));
--result
1

--Geometry Collection Example - multis count as one geom in a collection

SELECT ST_NumGeometries(ST_GeomFromEWKT('GEOMETRYCOLLECTION(MULTIPOINT(-2 3 , -2 2),
LINESTRING(5 5 ,10 10),
POLYGON((-7 4.2,-7.1 5,-7.1 4.3,-7 4.2)))'));
--result
3

See Also

ST_GeometryN, ST_Multi

8.5.27 ST_NumInteriorRings

ST_NumInteriorRings — Return the number of interior rings of a polygon geometry.

Synopsis

integer ST_NumInteriorRings(geometry a_polygon);

Description

Return the number of interior rings of a polygon geometry. Return NULL if the geometry is not a polygon.

This method implements the SQL/MM specification. SQL-MM 3: 8.2.5

Changed: 2.0.0 - in prior versions it would allow passing a MULTIPOLYGON, returning the number of interior rings of first
POLYGON.
PostGIS 2.4.3 Manual 168 / 803

Examples

--If you have a regular polygon

SELECT gid, field1, field2, ST_NumInteriorRings(the_geom) AS numholes
FROM sometable;

--If you have multipolygons

--And you want to know the total number of interior rings in the MULTIPOLYGON
SELECT gid, field1, field2, SUM(ST_NumInteriorRings(the_geom)) AS numholes
FROM (SELECT gid, field1, field2, (ST_Dump(the_geom)).geom As the_geom
FROM sometable) As foo
GROUP BY gid, field1,field2;

See Also

ST_NumInteriorRing

8.5.28 ST_NumInteriorRing

ST_NumInteriorRing — Return the number of interior rings of a polygon in the geometry. Synonym for ST_NumInteriorRings.

Synopsis

integer ST_NumInteriorRing(geometry a_polygon);

See Also

ST_NumInteriorRings

8.5.29 ST_NumPatches

ST_NumPatches — Return the number of faces on a Polyhedral Surface. Will return null for non-polyhedral geometries.

Synopsis

integer ST_NumPatches(geometry g1);

Description

Return the number of faces on a Polyhedral Surface. Will return null for non-polyhedral geometries. This is an alias for
ST_NumGeometries to support MM naming. Faster to use ST_NumGeometries if you don’t care about MM convention.
Availability: 2.0.0

This function supports 3d and will not drop the z-index.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: ?

This function supports Polyhedral surfaces.

PostGIS 2.4.3 Manual 169 / 803

Examples

SELECT ST_NumPatches(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 ←-

0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
6

See Also

ST_GeomFromEWKT, ST_NumGeometries

8.5.30 ST_NumPoints

ST_NumPoints — Return the number of points in an ST_LineString or ST_CircularString value.

Synopsis

integer ST_NumPoints(geometry g1);

Description

Return the number of points in an ST_LineString or ST_CircularString value. Prior to 1.4 only works with Linestrings as the
specs state. From 1.4 forward this is an alias for ST_NPoints which returns number of vertexes for not just line strings. Consider
using ST_NPoints instead which is multi-purpose and works with many geometry types.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 7.2.4

Examples

SELECT ST_NumPoints(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 ←-

29.07)'));
--result
4

See Also

ST_NPoints

8.5.31 ST_PatchN

ST_PatchN — Return the 1-based Nth geometry (face) if the geometry is a POLYHEDRALSURFACE, POLYHEDRALSUR-
FACEM. Otherwise, return NULL.

Synopsis

geometry ST_PatchN(geometry geomA, integer n);

PostGIS 2.4.3 Manual 170 / 803

Description

>Return the 1-based Nth geometry (face) if the geometry is a POLYHEDRALSURFACE, POLYHEDRALSURFACEM. Other-
wise, return NULL. This returns the same answer as ST_GeometryN for Polyhedral Surfaces. Using ST_GemoetryN is faster.

Note
Index is 1-based.

Note
If you want to extract all geometries, of a geometry, ST_Dump is more efficient.

Availability: 2.0.0

This method implements the SQL/MM specification. SQL-MM 3: ?

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

Examples

--Extract the 2nd face of the polyhedral surface

SELECT ST_AsEWKT(ST_PatchN(geom, 2)) As geomewkt
FROM (
VALUES (ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )')) ) As ←-
foo(geom);

geomewkt
---+-----------------------------------------
POLYGON((0 0 0,0 1 0,1 1 0,1 0 0,0 0 0))

See Also

ST_AsEWKT, ST_GeomFromEWKT, ST_Dump, ST_GeometryN, ST_NumGeometries

8.5.32 ST_PointN

ST_PointN — Return the Nth point in the first LineString or circular LineString in the geometry. Negative values are counted
backwards from the end of the LineString. Returns NULL if there is no linestring in the geometry.

Synopsis

geometry ST_PointN(geometry a_linestring, integer n);

PostGIS 2.4.3 Manual 171 / 803

Description

Return the Nth point in a single linestring or circular linestring in the geometry. Negative values are counted backwards from the
end of the LineString, so that -1 is the last point. Returns NULL if there is no linestring in the geometry.

Note
Index is 1-based as for OGC specs since version 0.8.0. Backward indexing (negative index) is not in OGC Previous
versions implemented this as 0-based instead.

Note
If you want to get the nth point of each line string in a multilinestring, use in conjunction with ST_Dump

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 7.2.5, 7.3.5

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Note
Changed: 2.0.0 no longer works with single geometry multilinestrings. In older versions of PostGIS -- a single line
multilinestring would work happily with this function and return the start point. In 2.0.0 it just returns NULL like any other
multilinestring.
Changed: 2.3.0 : negative indexing available (-1 is last point)

Examples

-- Extract all POINTs from a LINESTRING

SELECT ST_AsText(
ST_PointN(
column1,
generate_series(1, ST_NPoints(column1))
))
FROM ( VALUES ('LINESTRING(0 0, 1 1, 2 2)'::geometry) ) AS foo;

st_astext
------------
POINT(0 0)
POINT(1 1)
POINT(2 2)
(3 rows)

--Example circular string

SELECT ST_AsText(ST_PointN(ST_GeomFromText('CIRCULARSTRING(1 2, 3 2, 1 2)'),2));

st_astext
----------
POINT(3 2)
PostGIS 2.4.3 Manual 172 / 803

SELECT st_astext(f)
FROM ST_GeometryFromtext('LINESTRING(0 0 0, 1 1 1, 2 2 2)') as g
,ST_PointN(g, -2) AS f -- 1 based index

st_astext
----------
"POINT Z (1 1 1)"

See Also

ST_NPoints

8.5.33 ST_Points

ST_Points — Returns a MultiPoint containing all of the coordinates of a geometry.

Synopsis

geometry ST_Points( geometry geom );

Description

Returns a MultiPoint containing all of the coordinates of a geometry. Does not remove points that are duplicated in the input
geometry, including start and end points of ring geometries. (If this behavior is undesired, duplicates may be removed using
ST_RemoveRepeatedPoints).
M and Z ordinates will be preserved if present.

This method supports Circular Strings and Curves

This function supports 3d and will not drop the z-index.

Availability: 2.3.0

Examples

SELECT ST_AsText(ST_Points('POLYGON Z ((30 10 4,10 30 5,40 40 6, 30 10))'));

--result
MULTIPOINT Z (30 10 4,10 30 5,40 40 6, 30 10 4)

See Also

ST_RemoveRepeatedPoints

8.5.34 ST_SRID

ST_SRID — Returns the spatial reference identifier for the ST_Geometry as defined in spatial_ref_sys table.
PostGIS 2.4.3 Manual 173 / 803

Synopsis

integer ST_SRID(geometry g1);

Description

Returns the spatial reference identifier for the ST_Geometry as defined in spatial_ref_sys table. Section 4.3.1

Note
spatial_ref_sys table is a table that catalogs all spatial reference systems known to PostGIS and is used for transforma-
tions from one spatial reference system to another. So verifying you have the right spatial reference system identifier is
important if you plan to ever transform your geometries.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.5

This method supports Circular Strings and Curves

Examples

SELECT ST_SRID(ST_GeomFromText('POINT(-71.1043 42.315)',4326));

--result
4326

See Also

Section 4.3.1, ST_GeomFromText, ST_SetSRID, ST_Transform

8.5.35 ST_StartPoint

ST_StartPoint — Returns the first point of a LINESTRING geometry as a POINT.

Synopsis

geometry ST_StartPoint(geometry geomA);

Description

Returns the first point of a LINESTRING or CIRCULARLINESTRING geometry as a POINT or NULL if the input parameter is
not a LINESTRING or CIRCULARLINESTRING.

This method implements the SQL/MM specification. SQL-MM 3: 7.1.3

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 174 / 803

Note
Changed: 2.0.0 no longer works with single geometry multilinestrings. In older versions of PostGIS -- a single line
multilinestring would work happily with this function and return the start point. In 2.0.0 it just returns NULL like any other
multilinestring. The older behavior was an undocumented feature, but people who assumed they had their data stored
as LINESTRING may experience these returning NULL in 2.0 now.

Examples

SELECT ST_AsText(ST_StartPoint('LINESTRING(0 1, 0 2)'::geometry));

st_astext
------------
POINT(0 1)
(1 row)

SELECT ST_StartPoint('POINT(0 1)'::geometry) IS NULL AS is_null;

is_null
----------
t
(1 row)

--3d line
SELECT ST_AsEWKT(ST_StartPoint('LINESTRING(0 1 1, 0 2 2)'::geometry));
st_asewkt
------------
POINT(0 1 1)
(1 row)

-- circular linestring --
SELECT ST_AsText(ST_StartPoint('CIRCULARSTRING(5 2,-3 1.999999, -2 1, -4 2, 5 2)'::geometry ←-
));
st_astext
------------
POINT(5 2)

See Also

ST_EndPoint, ST_PointN

8.5.36 ST_Summary

ST_Summary — Returns a text summary of the contents of the geometry.

Synopsis

text ST_Summary(geometry g);

text ST_Summary(geography g);

Description

Returns a text summary of the contents of the geometry.

Flags shown square brackets after the geometry type have the following meaning:

• M: has M ordinate
PostGIS 2.4.3 Manual 175 / 803

• Z: has Z ordinate
• B: has a cached bounding box
• G: is geodetic (geography)

• S: has spatial reference system

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
Availability: 1.2.2
Enhanced: 2.0.0 added support for geography
Enhanced: 2.1.0 S flag to denote if has a known spatial reference system
Enhanced: 2.2.0 Added support for TIN and Curves

Examples

=# SELECT ST_Summary(ST_GeomFromText('LINESTRING(0 0, 1 1)')) as geom,

ST_Summary(ST_GeogFromText('POLYGON((0 0, 1 1, 1 2, 1 1, 0 0))')) geog;
geom | geog
-----------------------------+--------------------------
LineString[B] with 2 points | Polygon[BGS] with 1 rings
| ring 0 has 5 points
:
(1 row)

=# SELECT ST_Summary(ST_GeogFromText('LINESTRING(0 0 1, 1 1 1)')) As geog_line,

ST_Summary(ST_GeomFromText('SRID=4326;POLYGON((0 0 1, 1 1 2, 1 2 3, 1 1 1, 0 0 1)) ←-
')) As geom_poly;
;
geog_line | geom_poly
-------------------------------- +--------------------------
LineString[ZBGS] with 2 points | Polygon[ZBS] with 1 rings
: ring 0 has 5 points
:
(1 row)

See Also

PostGIS_DropBBox, PostGIS_AddBBox, ST_Force3DM, ST_Force3DZ, ST_Force2D, geography

ST_IsValid, ST_IsValid, ST_IsValidReason, ST_IsValidDetail

8.5.37 ST_X

ST_X — Return the X coordinate of the point, or NULL if not available. Input must be a point.
PostGIS 2.4.3 Manual 176 / 803

Synopsis

float ST_X(geometry a_point);

Description

Return the X coordinate of the point, or NULL if not available. Input must be a point.

Note
If you want to get the max min x values of any geometry look at ST_XMin, ST_XMax functions.

This method implements the SQL/MM specification. SQL-MM 3: 6.1.3

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_X(ST_GeomFromEWKT('POINT(1 2 3 4)'));

st_x
------
1
(1 row)

SELECT ST_Y(ST_Centroid(ST_GeomFromEWKT('LINESTRING(1 2 3 4, 1 1 1 1)')));

st_y
------
1.5
(1 row)

See Also

ST_Centroid, ST_GeomFromEWKT, ST_M, ST_XMax, ST_XMin, ST_Y, ST_Z

8.5.38 ST_XMax

ST_XMax — Returns X maxima of a bounding box 2d or 3d or a geometry.

Synopsis

float ST_XMax(box3d aGeomorBox2DorBox3D);

Description

Returns X maxima of a bounding box 2d or 3d or a geometry.

PostGIS 2.4.3 Manual 177 / 803

Note
Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will
not auto-cast.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_XMax('BOX3D(1 2 3, 4 5 6)');

st_xmax
-------
4

SELECT ST_XMax(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));

st_xmax
-------
5

SELECT ST_XMax(CAST('BOX(-3 2, 3 4)' As box2d));

st_xmax
-------
3
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a ←-
BOX3D
SELECT ST_XMax('LINESTRING(1 3, 5 6)');

--ERROR: BOX3D parser - doesn't start with BOX3D(

SELECT ST_XMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 ←-

150406 3)'));
st_xmax
--------
220288.248780547

See Also

ST_XMin, ST_YMax, ST_YMin, ST_ZMax, ST_ZMin

8.5.39 ST_XMin

ST_XMin — Returns X minima of a bounding box 2d or 3d or a geometry.

Synopsis

float ST_XMin(box3d aGeomorBox2DorBox3D);

PostGIS 2.4.3 Manual 178 / 803

Description

Returns X minima of a bounding box 2d or 3d or a geometry.

Note
Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will
not auto-cast.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_XMin('BOX3D(1 2 3, 4 5 6)');

st_xmin
-------
1

SELECT ST_XMin(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));

st_xmin
-------
1

SELECT ST_XMin(CAST('BOX(-3 2, 3 4)' As box2d));

st_xmin
-------
-3
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a ←-
BOX3D
SELECT ST_XMin('LINESTRING(1 3, 5 6)');

--ERROR: BOX3D parser - doesn't start with BOX3D(

SELECT ST_XMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 ←-

150406 3)'));
st_xmin
--------
220186.995121892

See Also

ST_XMax, ST_YMax, ST_YMin, ST_ZMax, ST_ZMin

8.5.40 ST_Y

ST_Y — Return the Y coordinate of the point, or NULL if not available. Input must be a point.

Synopsis

float ST_Y(geometry a_point);

PostGIS 2.4.3 Manual 179 / 803

Description

Return the Y coordinate of the point, or NULL if not available. Input must be a point.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 6.1.4

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_Y(ST_GeomFromEWKT('POINT(1 2 3 4)'));

st_y
------
2
(1 row)

SELECT ST_Y(ST_Centroid(ST_GeomFromEWKT('LINESTRING(1 2 3 4, 1 1 1 1)')));

st_y
------
1.5
(1 row)

See Also

ST_Centroid, ST_GeomFromEWKT, ST_M, ST_X, ST_YMax, ST_YMin, ST_Z

8.5.41 ST_YMax

ST_YMax — Returns Y maxima of a bounding box 2d or 3d or a geometry.

Synopsis

float ST_YMax(box3d aGeomorBox2DorBox3D);

Description

Returns Y maxima of a bounding box 2d or 3d or a geometry.

Note
Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will
not auto-cast.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 180 / 803

Examples

SELECT ST_YMax('BOX3D(1 2 3, 4 5 6)');

st_ymax
-------
5

SELECT ST_YMax(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));

st_ymax
-------
6

SELECT ST_YMax(CAST('BOX(-3 2, 3 4)' As box2d));

st_ymax
-------
4
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a ←-
BOX3D
SELECT ST_YMax('LINESTRING(1 3, 5 6)');

--ERROR: BOX3D parser - doesn't start with BOX3D(

SELECT ST_YMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 ←-

150406 3)'));
st_ymax
--------
150506.126829327

See Also

ST_XMin, ST_XMax, ST_YMin, ST_ZMax, ST_ZMin

8.5.42 ST_YMin

ST_YMin — Returns Y minima of a bounding box 2d or 3d or a geometry.

Synopsis

float ST_YMin(box3d aGeomorBox2DorBox3D);

Description

Returns Y minima of a bounding box 2d or 3d or a geometry.

Note
Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will
not auto-cast.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 181 / 803

Examples

SELECT ST_YMin('BOX3D(1 2 3, 4 5 6)');

st_ymin
-------
2

SELECT ST_YMin(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));

st_ymin
-------
3

SELECT ST_YMin(CAST('BOX(-3 2, 3 4)' As box2d));

st_ymin
-------
2
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a ←-
BOX3D
SELECT ST_YMin('LINESTRING(1 3, 5 6)');

--ERROR: BOX3D parser - doesn't start with BOX3D(

SELECT ST_YMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 ←-

150406 3)'));
st_ymin
--------
150406

See Also

ST_GeomFromEWKT, ST_XMin, ST_XMax, ST_YMax, ST_ZMax, ST_ZMin

8.5.43 ST_Z

ST_Z — Return the Z coordinate of the point, or NULL if not available. Input must be a point.

Synopsis

float ST_Z(geometry a_point);

Description

Return the Z coordinate of the point, or NULL if not available. Input must be a point.

This method implements the SQL/MM specification.

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_Z(ST_GeomFromEWKT('POINT(1 2 3 4)'));

st_z
------
3
PostGIS 2.4.3 Manual 182 / 803

(1 row)

See Also

ST_GeomFromEWKT, ST_M, ST_X, ST_Y, ST_ZMax, ST_ZMin

8.5.44 ST_ZMax

ST_ZMax — Returns Z minima of a bounding box 2d or 3d or a geometry.

Synopsis

float ST_ZMax(box3d aGeomorBox2DorBox3D);

Description

Returns Z maxima of a bounding box 2d or 3d or a geometry.

Note
Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will
not auto-cast.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_ZMax('BOX3D(1 2 3, 4 5 6)');

st_zmax
-------
6

SELECT ST_ZMax(ST_GeomFromEWKT('LINESTRING(1 3 4, 5 6 7)'));

st_zmax
-------
7

SELECT ST_ZMax('BOX3D(-3 2 1, 3 4 1)' );

st_zmax
-------
1
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a ←-
BOX3D
SELECT ST_ZMax('LINESTRING(1 3 4, 5 6 7)');

--ERROR: BOX3D parser - doesn't start with BOX3D(

SELECT ST_ZMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 ←-

150406 3)'));
PostGIS 2.4.3 Manual 183 / 803

st_zmax
--------
3

See Also

ST_GeomFromEWKT, ST_XMin, ST_XMax, ST_YMax, ST_YMin, ST_ZMax

8.5.45 ST_Zmflag

ST_Zmflag — Returns ZM (dimension semantic) flag of the geometries as a small int. Values are: 0=2d, 1=3dm, 2=3dz, 3=4d.

Synopsis

smallint ST_Zmflag(geometry geomA);

Description

Returns ZM (dimension semantic) flag of the geometries as a small int. Values are: 0=2d, 1=3dm, 2=3dz, 3=4d.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRING(1 2, 3 4)'));

st_zmflag
-----------
0

SELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRINGM(1 2 3, 3 4 3)'));

st_zmflag
-----------
1

SELECT ST_Zmflag(ST_GeomFromEWKT('CIRCULARSTRING(1 2 3, 3 4 3, 5 6 3)'));

st_zmflag
-----------
2
SELECT ST_Zmflag(ST_GeomFromEWKT('POINT(1 2 3 4)'));
st_zmflag
-----------
3

See Also

ST_CoordDim, ST_NDims, ST_Dimension

8.5.46 ST_ZMin

ST_ZMin — Returns Z minima of a bounding box 2d or 3d or a geometry.

PostGIS 2.4.3 Manual 184 / 803

Synopsis

float ST_ZMin(box3d aGeomorBox2DorBox3D);

Description

Returns Z minima of a bounding box 2d or 3d or a geometry.

Note
Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will
not auto-cast.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_ZMin('BOX3D(1 2 3, 4 5 6)');

st_zmin
-------
3

SELECT ST_ZMin(ST_GeomFromEWKT('LINESTRING(1 3 4, 5 6 7)'));

st_zmin
-------
4

SELECT ST_ZMin('BOX3D(-3 2 1, 3 4 1)' );

st_zmin
-------
1
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a ←-
BOX3D
SELECT ST_ZMin('LINESTRING(1 3 4, 5 6 7)');

--ERROR: BOX3D parser - doesn't start with BOX3D(

SELECT ST_ZMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 ←-

150406 3)'));
st_zmin
--------
1

See Also

ST_GeomFromEWKT, ST_GeomFromText, ST_XMin, ST_XMax, ST_YMax, ST_YMin, ST_ZMax

8.6 Geometry Editors

8.6.1 ST_AddPoint

ST_AddPoint — Add a point to a LineString.

PostGIS 2.4.3 Manual 185 / 803

Synopsis

geometry ST_AddPoint(geometry linestring, geometry point);

geometry ST_AddPoint(geometry linestring, geometry point, integer position);

Description

Adds a point to a LineString before point <position> (0-based index). Third parameter can be omitted or set to -1 for appending.
Availability: 1.1.0

This function supports 3d and will not drop the z-index.

Examples

--guarantee all linestrings in a table are closed

--by adding the start point of each linestring to the end of the line string
--only for those that are not closed
UPDATE sometable
SET the_geom = ST_AddPoint(the_geom, ST_StartPoint(the_geom))
FROM sometable
WHERE ST_IsClosed(the_geom) = false;

--Adding point to a 3-d line

SELECT ST_AsEWKT(ST_AddPoint(ST_GeomFromEWKT('LINESTRING(0 0 1, 1 1 1)'), ST_MakePoint ←-
(1, 2, 3)));

--result
st_asewkt
----------
LINESTRING(0 0 1,1 1 1,1 2 3)

See Also

ST_RemovePoint, ST_SetPoint

8.6.2 ST_Affine

ST_Affine — Apply a 3d affine transformation to a geometry.

Synopsis

geometry ST_Affine(geometry geomA, float a, float b, float c, float d, float e, float f, float g, float h, float i, float xoff, float yoff,
float zoff);
geometry ST_Affine(geometry geomA, float a, float b, float d, float e, float xoff, float yoff);

Description

Applies a 3d affine transformation to the geometry to do things like translate, rotate, scale in one step.
Version 1: The call
ST_Affine(geom, a, b, c, d, e, f, g, h, i, xoff, yoff, zoff)
PostGIS 2.4.3 Manual 186 / 803

represents the transformation matrix

/ a b c xoff \
| d e f yoff |
| g h i zoff |
\ 0 0 0 1 /

and the vertices are transformed as follows:

x' = a*x + b*y + c*z + xoff
y' = d*x + e*y + f*z + yoff
z' = g*x + h*y + i*z + zoff

All of the translate / scale functions below are expressed via such an affine transformation.
Version 2: Applies a 2d affine transformation to the geometry. The call
ST_Affine(geom, a, b, d, e, xoff, yoff)

represents the transformation matrix

/ a b 0 xoff \ / a b xoff \
| d e 0 yoff | rsp. | d e yoff |
| 0 0 1 0 | \ 0 0 1 /
\ 0 0 0 1 /

and the vertices are transformed as follows:

x' = a*x + b*y + xoff
y' = d*x + e*y + yoff
z' = z

This method is a subcase of the 3D method above.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Availability: 1.1.2. Name changed from Affine to ST_Affine in 1.2.2

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples
PostGIS 2.4.3 Manual 187 / 803

--Rotate a 3d line 180 degrees about the z axis. Note this is long-hand for doing ←-
ST_Rotate();
SELECT ST_AsEWKT(ST_Affine(the_geom, cos(pi()), -sin(pi()), 0, sin(pi()), cos(pi()), 0, ←-
0, 0, 1, 0, 0, 0)) As using_affine,
ST_AsEWKT(ST_Rotate(the_geom, pi())) As using_rotate
FROM (SELECT ST_GeomFromEWKT('LINESTRING(1 2 3, 1 4 3)') As the_geom) As foo;
using_affine | using_rotate
-----------------------------+-----------------------------
LINESTRING(-1 -2 3,-1 -4 3) | LINESTRING(-1 -2 3,-1 -4 3)
(1 row)

--Rotate a 3d line 180 degrees in both the x and z axis

SELECT ST_AsEWKT(ST_Affine(the_geom, cos(pi()), -sin(pi()), 0, sin(pi()), cos(pi()), -sin( ←-
pi()), 0, sin(pi()), cos(pi()), 0, 0, 0))
FROM (SELECT ST_GeomFromEWKT('LINESTRING(1 2 3, 1 4 3)') As the_geom) As foo;
st_asewkt
-------------------------------
LINESTRING(-1 -2 -3,-1 -4 -3)
(1 row)

See Also

ST_Rotate, ST_Scale, ST_Translate, ST_TransScale

8.6.3 ST_Force2D

ST_Force2D — Force the geometries into a "2-dimensional mode".

Synopsis

geometry ST_Force2D(geometry geomA);

Description

Forces the geometries into a "2-dimensional mode" so that all output representations will only have the X and Y coordinates.
This is useful for force OGC-compliant output (since OGC only specifies 2-D geometries).
Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_2D.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_AsEWKT(ST_Force2D(ST_GeomFromEWKT('CIRCULARSTRING(1 1 2, 2 3 2, 4 5 2, 6 7 2, 5 6 ←-
2)')));
st_asewkt
-------------------------------------
PostGIS 2.4.3 Manual 188 / 803

CIRCULARSTRING(1 1,2 3,4 5,6 7,5 6)

SELECT ST_AsEWKT(ST_Force2D('POLYGON((0 0 2,0 5 2,5 0 2,0 0 2),(1 1 2,3 1 2,1 3 2,1 1 2)) ←-
'));

st_asewkt
----------------------------------------------
POLYGON((0 0,0 5,5 0,0 0),(1 1,3 1,1 3,1 1))

See Also

ST_Force3D

8.6.4 ST_Force3D

ST_Force3D — Force the geometries into XYZ mode. This is an alias for ST_Force3DZ.

Synopsis

geometry ST_Force3D(geometry geomA);

Description

Forces the geometries into XYZ mode. This is an alias for ST_Force_3DZ. If a geometry has no Z component, then a 0 Z
coordinate is tacked on.
Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_3D.

This function supports Polyhedral surfaces.

This method supports Circular Strings and Curves

This function supports 3d and will not drop the z-index.

Examples

--Nothing happens to an already 3D geometry

SELECT ST_AsEWKT(ST_Force3D(ST_GeomFromEWKT('CIRCULARSTRING(1 1 2, 2 3 2, 4 5 2, 6 7 2, ←-
5 6 2)')));
st_asewkt
-----------------------------------------------
CIRCULARSTRING(1 1 2,2 3 2,4 5 2,6 7 2,5 6 2)

SELECT ST_AsEWKT(ST_Force3D('POLYGON((0 0,0 5,5 0,0 0),(1 1,3 1,1 3,1 1))'));

st_asewkt
--------------------------------------------------------------
POLYGON((0 0 0,0 5 0,5 0 0,0 0 0),(1 1 0,3 1 0,1 3 0,1 1 0))
PostGIS 2.4.3 Manual 189 / 803

See Also

ST_AsEWKT, ST_Force2D, ST_Force3DM, ST_Force3DZ

8.6.5 ST_Force3DZ

ST_Force3DZ — Force the geometries into XYZ mode.

Synopsis

geometry ST_Force3DZ(geometry geomA);

Description

Forces the geometries into XYZ mode. This is a synonym for ST_Force3DZ. If a geometry has no Z component, then a 0 Z
coordinate is tacked on.
Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_3DZ.

This function supports Polyhedral surfaces.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

--Nothing happens to an already 3D geometry

SELECT ST_AsEWKT(ST_Force3DZ(ST_GeomFromEWKT('CIRCULARSTRING(1 1 2, 2 3 2, 4 5 2, 6 7 2, 5 ←-
6 2)')));
st_asewkt
-----------------------------------------------
CIRCULARSTRING(1 1 2,2 3 2,4 5 2,6 7 2,5 6 2)

SELECT ST_AsEWKT(ST_Force3DZ('POLYGON((0 0,0 5,5 0,0 0),(1 1,3 1,1 3,1 1))'));

st_asewkt
--------------------------------------------------------------
POLYGON((0 0 0,0 5 0,5 0 0,0 0 0),(1 1 0,3 1 0,1 3 0,1 1 0))

See Also

ST_AsEWKT, ST_Force2D, ST_Force3DM, ST_Force3D

8.6.6 ST_Force3DM

ST_Force3DM — Force the geometries into XYM mode.

PostGIS 2.4.3 Manual 190 / 803

Synopsis

geometry ST_Force3DM(geometry geomA);

Description

Forces the geometries into XYM mode. If a geometry has no M component, then a 0 M coordinate is tacked on. If it has a Z
component, then Z is removed
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_3DM.

This method supports Circular Strings and Curves

Examples

--Nothing happens to an already 3D geometry

SELECT ST_AsEWKT(ST_Force3DM(ST_GeomFromEWKT('CIRCULARSTRING(1 1 2, 2 3 2, 4 5 2, 6 7 2, 5 ←-
6 2)')));
st_asewkt
------------------------------------------------
CIRCULARSTRINGM(1 1 0,2 3 0,4 5 0,6 7 0,5 6 0)

SELECT ST_AsEWKT(ST_Force3DM('POLYGON((0 0 1,0 5 1,5 0 1,0 0 1),(1 1 1,3 1 1,1 3 1,1 1 1)) ←-
'));

st_asewkt
---------------------------------------------------------------
POLYGONM((0 0 0,0 5 0,5 0 0,0 0 0),(1 1 0,3 1 0,1 3 0,1 1 0))

See Also

ST_AsEWKT, ST_Force2D, ST_Force3DM, ST_Force3D, ST_GeomFromEWKT

8.6.7 ST_Force4D

ST_Force4D — Force the geometries into XYZM mode.

Synopsis

geometry ST_Force4D(geometry geomA);

Description

Forces the geometries into XYZM mode. 0 is tacked on for missing Z and M dimensions.
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_4D.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 191 / 803

Examples

--Nothing happens to an already 3D geometry

SELECT ST_AsEWKT(ST_Force4D(ST_GeomFromEWKT('CIRCULARSTRING(1 1 2, 2 3 2, 4 5 2, 6 7 2, 5 6 ←-
2)')));
st_asewkt
---------------------------------------------------------
CIRCULARSTRING(1 1 2 0,2 3 2 0,4 5 2 0,6 7 2 0,5 6 2 0)

SELECT ST_AsEWKT(ST_Force4D('MULTILINESTRINGM((0 0 1,0 5 2,5 0 3,0 0 4),(1 1 1,3 1 1,1 3 ←-

1,1 1 1))'));

st_asewkt
--------------------------------------------------------------------------------------
MULTILINESTRING((0 0 0 1,0 5 0 2,5 0 0 3,0 0 0 4),(1 1 0 1,3 1 0 1,1 3 0 1,1 1 0 1))

See Also

ST_AsEWKT, ST_Force2D, ST_Force3DM, ST_Force3D

8.6.8 ST_ForcePolygonCCW

ST_ForcePolygonCCW — Orients all exterior rings counter-clockwise and all interior rings clockwise.

Synopsis

geometry ST_ForcePolygonCCW ( geometry geom );

Description

Forces (Multi)Polygons to use a counter-clockwise orientation for their exterior ring, and a clockwise orientation for their interior
rings. Non-polygonal geometries are returned unchanged.

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

See Also

ST_ForcePolygonCW , ST_IsPolygonCCW , ST_IsPolygonCW

8.6.9 ST_ForceCollection

ST_ForceCollection — Convert the geometry into a GEOMETRYCOLLECTION.

Synopsis

geometry ST_ForceCollection(geometry geomA);

PostGIS 2.4.3 Manual 192 / 803

Description

Converts the geometry into a GEOMETRYCOLLECTION. This is useful for simplifying the WKB representation.
Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
Availability: 1.2.2, prior to 1.3.4 this function will crash with Curves. This is fixed in 1.3.4+
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_Collection.

This function supports Polyhedral surfaces.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_AsEWKT(ST_ForceCollection('POLYGON((0 0 1,0 5 1,5 0 1,0 0 1),(1 1 1,3 1 1,1 3 ←-

1,1 1 1))'));

st_asewkt
----------------------------------------------------------------------------------
GEOMETRYCOLLECTION(POLYGON((0 0 1,0 5 1,5 0 1,0 0 1),(1 1 1,3 1 1,1 3 1,1 1 1)))

SELECT ST_AsText(ST_ForceCollection('CIRCULARSTRING(220227 150406,2220227 150407,220227 ←-

150406)'));
st_astext
--------------------------------------------------------------------------------
GEOMETRYCOLLECTION(CIRCULARSTRING(220227 150406,2220227 150407,220227 150406))
(1 row)

-- POLYHEDRAL example --
SELECT ST_AsEWKT(ST_ForceCollection('POLYHEDRALSURFACE(((0 0 0,0 0 1,0 1 1,0 1 0,0 0 0)),
((0 0 0,0 1 0,1 1 0,1 0 0,0 0 0)),
((0 0 0,1 0 0,1 0 1,0 0 1,0 0 0)),
((1 1 0,1 1 1,1 0 1,1 0 0,1 1 0)),
((0 1 0,0 1 1,1 1 1,1 1 0,0 1 0)),
((0 0 1,1 0 1,1 1 1,0 1 1,0 0 1)))'))

st_asewkt
----------------------------------------------------------------------------------
GEOMETRYCOLLECTION(
POLYGON((0 0 0,0 0 1,0 1 1,0 1 0,0 0 0)),
POLYGON((0 0 0,0 1 0,1 1 0,1 0 0,0 0 0)),
POLYGON((0 0 0,1 0 0,1 0 1,0 0 1,0 0 0)),
POLYGON((1 1 0,1 1 1,1 0 1,1 0 0,1 1 0)),
POLYGON((0 1 0,0 1 1,1 1 1,1 1 0,0 1 0)),
POLYGON((0 0 1,1 0 1,1 1 1,0 1 1,0 0 1))
)

See Also

ST_AsEWKT, ST_Force2D, ST_Force3DM, ST_Force3D, ST_GeomFromEWKT

PostGIS 2.4.3 Manual 193 / 803

8.6.10 ST_ForcePolygonCW

ST_ForcePolygonCW — Orients all exterior rings clockwise and all interior rings counter-clockwise.

Synopsis

geometry ST_ForcePolygonCW ( geometry geom );

Description

Forces (Multi)Polygons to use a clockwise orientation for their exterior ring, and a counter-clockwise orientation for their interior
rings. Non-polygonal geometries are returned unchanged.

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

See Also

ST_ForcePolygonCCW , ST_IsPolygonCCW , ST_IsPolygonCW

8.6.11 ST_ForceSFS

ST_ForceSFS — Force the geometries to use SFS 1.1 geometry types only.

Synopsis

geometry ST_ForceSFS(geometry geomA);

geometry ST_ForceSFS(geometry geomA, text version);

Description

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This method supports Circular Strings and Curves

This function supports 3d and will not drop the z-index.

8.6.12 ST_ForceRHR

ST_ForceRHR — Force the orientation of the vertices in a polygon to follow the Right-Hand-Rule.

Synopsis

geometry ST_ForceRHR(geometry g);

PostGIS 2.4.3 Manual 194 / 803

Description

Forces the orientation of the vertices in a polygon to follow a Right-Hand-Rule, in which the area that is bounded by the polygon
is to the right of the boundary. In particular, the exterior ring is orientated in a clockwise direction and the interior rings in a
counter-clockwise direction. This function is a synonym for ST_ForcePolygonCW

Note
The above definition of the Right-Hand-Rule conflicts with definitions used in other contexts. To avoid confusion, it is
recommended to use ST_ForcePolygonCW.

Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

Examples

SELECT ST_AsEWKT(
ST_ForceRHR(
'POLYGON((0 0 2, 5 0 2, 0 5 2, 0 0 2),(1 1 2, 1 3 2, 3 1 2, 1 1 2))'
)
);
st_asewkt
--------------------------------------------------------------
POLYGON((0 0 2,0 5 2,5 0 2,0 0 2),(1 1 2,3 1 2,1 3 2,1 1 2))
(1 row)

See Also

ST_ForcePolygonCCW , ST_ForcePolygonCW , ST_IsPolygonCCW , ST_IsPolygonCW , ST_BuildArea, ST_Polygonize,

ST_Reverse

8.6.13 ST_ForceCurve

ST_ForceCurve — Upcast a geometry into its curved type, if applicable.

Synopsis

geometry ST_ForceCurve(geometry g);

Description

Turns a geometry into its curved representation, if applicable: lines become compoundcurves, multilines become multicurves
polygons become curvepolygons multipolygons become multisurfaces. If the geometry input is already a curved representation
returns back same as input.
Availability: 2.2.0

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 195 / 803

Examples

SELECT ST_AsText(
ST_ForceCurve(
'POLYGON((0 0 2, 5 0 2, 0 5 2, 0 0 2),(1 1 2, 1 3 2, 3 1 2, 1 1 2))'::geometry
)
);
st_astext
----------------------------------------------------------------------
CURVEPOLYGON Z ((0 0 2,5 0 2,0 5 2,0 0 2),(1 1 2,1 3 2,3 1 2,1 1 2))
(1 row)

See Also

ST_LineToCurve

8.6.14 ST_LineMerge

ST_LineMerge — Return a (set of) LineString(s) formed by sewing together a MULTILINESTRING.

Synopsis

geometry ST_LineMerge(geometry amultilinestring);

Description

Returns a (set of) LineString(s) formed by sewing together the constituent line work of a MULTILINESTRING.

Note
Only use with MULTILINESTRING/LINESTRINGs. If you feed a polygon or geometry collection into this function, it will
return an empty GEOMETRYCOLLECTION

Availability: 1.1.0

Note
requires GEOS >= 2.1.0

Examples

SELECT ST_AsText(ST_LineMerge(
ST_GeomFromText('MULTILINESTRING((-29 -27,-30 -29.7,-36 -31,-45 -33),(-45 -33,-46 -32))')
)
);
st_astext
-------------------------------------------------------------------------------------------------- ←

LINESTRING(-29 -27,-30 -29.7,-36 -31,-45 -33,-46 -32)

(1 row)
PostGIS 2.4.3 Manual 196 / 803

--If can't be merged - original MULTILINESTRING is returned

SELECT ST_AsText(ST_LineMerge(
ST_GeomFromText('MULTILINESTRING((-29 -27,-30 -29.7,-36 -31,-45 -33),(-45.2 -33.2,-46 -32)) ←-
')
)
);
st_astext
----------------
MULTILINESTRING((-45.2 -33.2,-46 -32),(-29 -27,-30 -29.7,-36 -31,-45 -33))

See Also

ST_Segmentize, ST_LineSubstring

8.6.15 ST_CollectionExtract

ST_CollectionExtract — Given a (multi)geometry, return a (multi)geometry consisting only of elements of the specified type.

Synopsis

geometry ST_CollectionExtract(geometry collection, integer type);

Description

Given a (multi)geometry, returns a (multi)geometry consisting only of elements of the specified type. Sub-geometries that are
not the specified type are ignored. If there are no sub-geometries of the right type, an EMPTY geometry will be returned. Only
points, lines and polygons are supported. Type numbers are 1 == POINT, 2 == LINESTRING, 3 == POLYGON.
Availability: 1.5.0

Note
Prior to 1.5.3 this function returned non-collection inputs untouched, no matter type. In 1.5.3 non-matching single
geometries result in a NULL return. In of 2.0.0 every case of missing match results in a typed EMPTY return.

Warning
When specifying 3 == POLYGON a multipolygon is returned even when the edges are shared. This results in an invalid
multipolygon for many cases such as applying this function on an ST_Split result.

Examples

-- Constants: 1 == POINT, 2 == LINESTRING, 3 == POLYGON

SELECT ST_AsText(ST_CollectionExtract(ST_GeomFromText('GEOMETRYCOLLECTION( ←-
GEOMETRYCOLLECTION(POINT(0 0)))'),1));
st_astext
---------------
MULTIPOINT(0 0)
(1 row)

SELECT ST_AsText(ST_CollectionExtract(ST_GeomFromText('GEOMETRYCOLLECTION( ←-
GEOMETRYCOLLECTION(LINESTRING(0 0, 1 1)),LINESTRING(2 2, 3 3))'),2));
PostGIS 2.4.3 Manual 197 / 803

st_astext
---------------
MULTILINESTRING((0 0, 1 1), (2 2, 3 3))
(1 row)

See Also

ST_Multi, ST_Dump, ST_CollectionHomogenize

8.6.16 ST_CollectionHomogenize

ST_CollectionHomogenize — Given a geometry collection, return the "simplest" representation of the contents.

Synopsis

geometry ST_CollectionHomogenize(geometry collection);

Description

Given a geometry collection, returns the "simplest" representation of the contents. Singletons will be returned as singletons.
Collections that are homogeneous will be returned as the appropriate multi-type.

Warning
When specifying 3 == POLYGON a multipolygon is returned even when the edges are shared. This results in an invalid
multipolygon for many cases such as applying this function on an ST_Split result.

Availability: 2.0.0

Examples

SELECT ST_AsText(ST_CollectionHomogenize('GEOMETRYCOLLECTION(POINT(0 0))'));

st_astext
------------
POINT(0 0)
(1 row)

SELECT ST_AsText(ST_CollectionHomogenize('GEOMETRYCOLLECTION(POINT(0 0),POINT(1 1))'));

st_astext
---------------------
MULTIPOINT(0 0,1 1)
(1 row)

See Also

ST_Multi, ST_CollectionExtract
PostGIS 2.4.3 Manual 198 / 803

8.6.17 ST_Multi

ST_Multi — Return the geometry as a MULTI* geometry.

Synopsis

geometry ST_Multi(geometry g1);

Description

Returns the geometry as a MULTI* geometry. If the geometry is already a MULTI*, it is returned unchanged.

Examples

SELECT ST_AsText(ST_Multi(ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,

743265 2967450,743265.625 2967416,743238 2967416))')));
st_astext
-----------------------------------------------------------------------------------------------

MULTIPOLYGON(((743238 2967416,743238 2967450,743265 2967450,743265.625 2967416,

743238 2967416)))
(1 row)

See Also

ST_AsText

8.6.18 ST_Normalize

ST_Normalize — Return the geometry in its canonical form.

Synopsis

geometry ST_Normalize(geometry geom);

Description

Returns the geometry in its normalized/canonical form. May reorder vertices in polygon rings, rings in a polygon, elements in a
multi-geometry complex.
Mostly only useful for testing purposes (comparing expected and obtained results).

Examples

SELECT ST_AsText(ST_Normalize(ST_GeomFromText(
'GEOMETRYCOLLECTION(
POINT(2 3),
MULTILINESTRING((0 0, 1 1),(2 2, 3 3)),
POLYGON(
(0 10,0 0,10 0,10 10,0 10),
(4 2,2 2,2 4,4 4,4 2),
(6 8,8 8,8 6,6 6,6 8)
PostGIS 2.4.3 Manual 199 / 803

)
)'
)));
st_astext
-----------------------------------------------------------------------------------------------------

GEOMETRYCOLLECTION(POLYGON((0 0,0 10,10 10,10 0,0 0),(6 6,8 6,8 8,6 8,6 6),(2 2,4 2,4 4,2 ←-
4,2 2)),MULTILINESTRING((2 2,3 3),(0 0,1 1)),POINT(2 3))
(1 row)

See Also

ST_Equals,

8.6.19 ST_RemovePoint

ST_RemovePoint — Remove point from a linestring.

Synopsis

geometry ST_RemovePoint(geometry linestring, integer offset);

Description

Remove a point from a linestring, given its 0-based index. Useful for turning a closed ring into an open line string
Availability: 1.1.0

This function supports 3d and will not drop the z-index.

Examples

--guarantee no LINESTRINGS are closed

--by removing the end point. The below assumes the_geom is of type LINESTRING
UPDATE sometable
SET the_geom = ST_RemovePoint(the_geom, ST_NPoints(the_geom) - 1)
FROM sometable
WHERE ST_IsClosed(the_geom) = true;

See Also

ST_AddPoint, ST_NPoints, ST_NumPoints

8.6.20 ST_Reverse

ST_Reverse — Return the geometry with vertex order reversed.

Synopsis

geometry ST_Reverse(geometry g1);

PostGIS 2.4.3 Manual 200 / 803

Description

Can be used on any geometry and reverses the order of the vertexes.
Enhanced: 2.4.0 support for curves was introduced.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

Examples

SELECT ST_AsText(the_geom) as line, ST_AsText(ST_Reverse(the_geom)) As reverseline

FROM
(SELECT ST_MakeLine(ST_MakePoint(1,2),
ST_MakePoint(1,10)) As the_geom) as foo;
--result
line | reverseline
---------------------+----------------------
LINESTRING(1 2,1 10) | LINESTRING(1 10,1 2)

8.6.21 ST_Rotate

ST_Rotate — Rotate a geometry rotRadians counter-clockwise about an origin.

Synopsis

geometry ST_Rotate(geometry geomA, float rotRadians);

geometry ST_Rotate(geometry geomA, float rotRadians, float x0, float y0);
geometry ST_Rotate(geometry geomA, float rotRadians, geometry pointOrigin);

Description

Rotates geometry rotRadians counter-clockwise about the origin. The rotation origin can be specified either as a POINT geome-
try, or as x and y coordinates. If the origin is not specified, the geometry is rotated about POINT(0 0).
Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Enhanced: 2.0.0 additional parameters for specifying the origin of rotation were added.
Availability: 1.1.2. Name changed from Rotate to ST_Rotate in 1.2.2

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 201 / 803

Examples

--Rotate 180 degrees

SELECT ST_AsEWKT(ST_Rotate('LINESTRING (50 160, 50 50, 100 50)', pi()));
st_asewkt
---------------------------------------
LINESTRING(-50 -160,-50 -50,-100 -50)
(1 row)

--Rotate 30 degrees counter-clockwise at x=50, y=160

SELECT ST_AsEWKT(ST_Rotate('LINESTRING (50 160, 50 50, 100 50)', pi()/6, 50, 160));
st_asewkt
---------------------------------------------------------------------------
LINESTRING(50 160,105 64.7372055837117,148.301270189222 89.7372055837117)
(1 row)

--Rotate 60 degrees clockwise from centroid

SELECT ST_AsEWKT(ST_Rotate(geom, -pi()/3, ST_Centroid(geom)))
FROM (SELECT 'LINESTRING (50 160, 50 50, 100 50)'::geometry AS geom) AS foo;
st_asewkt
--------------------------------------------------------------
LINESTRING(116.4225 130.6721,21.1597 75.6721,46.1597 32.3708)
(1 row)

See Also

ST_Affine, ST_RotateX, ST_RotateY, ST_RotateZ

8.6.22 ST_RotateX

ST_RotateX — Rotate a geometry rotRadians about the X axis.

Synopsis

geometry ST_RotateX(geometry geomA, float rotRadians);

Description

Rotate a geometry geomA - rotRadians about the X axis.

Note
ST_RotateX(geomA, rotRadians) is short-hand for ST_Affine(geomA, 1, 0, 0, 0,
cos(rotRadians), -sin(rotRadians), 0, sin(rotRadians), cos(rotRadians), 0,
0, 0).

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Availability: 1.1.2. Name changed from RotateX to ST_RotateX in 1.2.2

This function supports Polyhedral surfaces.

This function supports 3d and will not drop the z-index.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 202 / 803

Examples

--Rotate a line 90 degrees along x-axis

SELECT ST_AsEWKT(ST_RotateX(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), pi()/2));
st_asewkt
---------------------------
LINESTRING(1 -3 2,1 -1 1)

See Also

ST_Affine, ST_RotateY, ST_RotateZ

8.6.23 ST_RotateY

ST_RotateY — Rotate a geometry rotRadians about the Y axis.

Synopsis

geometry ST_RotateY(geometry geomA, float rotRadians);

Description

Rotate a geometry geomA - rotRadians about the y axis.

Note
ST_RotateY(geomA, rotRadians) is short-hand for ST_Affine(geomA, cos(rotRadians), 0,
sin(rotRadians), 0, 1, 0, -sin(rotRadians), 0, cos(rotRadians), 0, 0, 0).

Availability: 1.1.2. Name changed from RotateY to ST_RotateY in 1.2.2

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.

This function supports Polyhedral surfaces.

This function supports 3d and will not drop the z-index.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

--Rotate a line 90 degrees along y-axis

SELECT ST_AsEWKT(ST_RotateY(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), pi()/2));
st_asewkt
---------------------------
LINESTRING(3 2 -1,1 1 -1)

See Also

ST_Affine, ST_RotateX, ST_RotateZ

PostGIS 2.4.3 Manual 203 / 803

8.6.24 ST_RotateZ

ST_RotateZ — Rotate a geometry rotRadians about the Z axis.

Synopsis

geometry ST_RotateZ(geometry geomA, float rotRadians);

Description

Rotate a geometry geomA - rotRadians about the Z axis.

Note
This is a synonym for ST_Rotate

Note
ST_RotateZ(geomA, rotRadians) is short-hand for SELECT ST_Affine(geomA,
cos(rotRadians), -sin(rotRadians), 0, sin(rotRadians), cos(rotRadians), 0,
0, 0, 1, 0, 0, 0).

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Availability: 1.1.2. Name changed from RotateZ to ST_RotateZ in 1.2.2

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

--Rotate a line 90 degrees along z-axis

SELECT ST_AsEWKT(ST_RotateZ(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), pi()/2));
st_asewkt
---------------------------
LINESTRING(-2 1 3,-1 1 1)

--Rotate a curved circle around z-axis

SELECT ST_AsEWKT(ST_RotateZ(the_geom, pi()/2))
PostGIS 2.4.3 Manual 204 / 803

FROM (SELECT ST_LineToCurve(ST_Buffer(ST_GeomFromText('POINT(234 567)'), 3)) As the_geom) ←-

As foo;

st_asewkt
-----------------------------------------------------------------------------------------------------

CURVEPOLYGON(CIRCULARSTRING(-567 237,-564.87867965644 236.12132034356,-564 ←-

234,-569.12132034356 231.87867965644,-567 237))

See Also

ST_Affine, ST_RotateX, ST_RotateY

8.6.25 ST_Scale

ST_Scale — Scale a geometry by given factors.

Synopsis

geometry ST_Scale(geometry geomA, float XFactor, float YFactor, float ZFactor);

geometry ST_Scale(geometry geomA, float XFactor, float YFactor);
geometry ST_Scale(geometry geom, geometry factor);

Description

Scales the geometry to a new size by multiplying the ordinates with the corresponding factor parameters.
The version taking a geometry as the factor parameter allows passing a 2d, 3dm, 3dz or 4d point to set scaling factor for all
supported dimensions. Missing dimensions in the factor point are equivalent to no scaling the corresponding dimension.

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

Availability: 1.1.0.
Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Enhanced: 2.2.0 support for scaling all dimension (geometry parameter) was introduced.

This function supports Polyhedral surfaces.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports M coordinates.

PostGIS 2.4.3 Manual 205 / 803

Examples

--Version 1: scale X, Y, Z
SELECT ST_AsEWKT(ST_Scale(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), 0.5, 0.75, 0.8));
st_asewkt
--------------------------------------
LINESTRING(0.5 1.5 2.4,0.5 0.75 0.8)

--Version 2: Scale X Y
SELECT ST_AsEWKT(ST_Scale(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), 0.5, 0.75));
st_asewkt
----------------------------------
LINESTRING(0.5 1.5 3,0.5 0.75 1)

--Version 3: Scale X Y Z M
SELECT ST_AsEWKT(ST_Scale(ST_GeomFromEWKT('LINESTRING(1 2 3 4, 1 1 1 1)'),
ST_MakePoint(0.5, 0.75, 2, -1)));
st_asewkt
----------------------------------------
LINESTRING(0.5 1.5 6 -4,0.5 0.75 2 -1)

See Also

ST_Affine, ST_TransScale

8.6.26 ST_Segmentize

ST_Segmentize — Return a modified geometry/geography having no segment longer than the given distance.

Synopsis

geometry ST_Segmentize(geometry geom, float max_segment_length);

geography ST_Segmentize(geography geog, float max_segment_length);

Description

Returns a modified geometry having no segment longer than the given max_segment_length. Distance computation is
performed in 2d only. For geometry, length units are in units of spatial reference. For geography, units are in meters.
Availability: 1.2.2
Enhanced: 2.3.0 Segmentize geography now uses equal length segments
Enhanced: 2.1.0 support for geography was introduced.
Changed: 2.1.0 As a result of the introduction of geography support: The construct SELECT ST_Segmentize(’LINESTRING(1
2, 3 4)’,0.5); will result in ambiguous function error. You need to have properly typed object e.g. a geometry/-
geography column, use ST_GeomFromText, ST_GeogFromText or SELECT ST_Segmentize(’LINESTRING(1 2, 3
4)’::geometry,0.5);

Note
This will only increase segments. It will not lengthen segments shorter than max length
PostGIS 2.4.3 Manual 206 / 803

Examples

SELECT ST_AsText(ST_Segmentize(
ST_GeomFromText('MULTILINESTRING((-29 -27,-30 -29.7,-36 -31,-45 -33),(-45 -33,-46 -32))')
,5)
);
st_astext
-------------------------------------------------------------------------------------------------- ←

MULTILINESTRING((-29 -27,-30 -29.7,-34.886615700134 -30.758766735029,-36 -31,

-40.8809353009198 -32.0846522890933,-45 -33),
(-45 -33,-46 -32))
(1 row)

SELECT ST_AsText(ST_Segmentize(ST_GeomFromText('POLYGON((-29 28, -30 40, -29 28))'),10));

st_astext
-----------------------
POLYGON((-29 28,-29.8304547985374 37.9654575824488,-30 40,-29.1695452014626 ←-
30.0345424175512,-29 28))
(1 row)

See Also

ST_LineSubstring

8.6.27 ST_SetPoint

ST_SetPoint — Replace point of a linestring with a given point.

Synopsis

geometry ST_SetPoint(geometry linestring, integer zerobasedposition, geometry point);

Description

Replace point N of linestring with given point. Index is 0-based.Negative index are counted backwards, so that -1 is last point.
This is especially useful in triggers when trying to maintain relationship of joints when one vertex moves.
Availability: 1.1.0
Updated 2.3.0 : negative indexing

This function supports 3d and will not drop the z-index.

Examples

--Change first point in line string from -1 3 to -1 1

SELECT ST_AsText(ST_SetPoint('LINESTRING(-1 2,-1 3)', 0, 'POINT(-1 1)'));
st_astext
-----------------------
LINESTRING(-1 1,-1 3)

---Change last point in a line string (lets play with 3d linestring this time)
PostGIS 2.4.3 Manual 207 / 803

SELECT ST_AsEWKT(ST_SetPoint(foo.the_geom, ST_NumPoints(foo.the_geom) - 1, ST_GeomFromEWKT ←-

('POINT(-1 1 3)')))
FROM (SELECT ST_GeomFromEWKT('LINESTRING(-1 2 3,-1 3 4, 5 6 7)') As the_geom) As foo;
st_asewkt
-----------------------
LINESTRING(-1 2 3,-1 3 4,-1 1 3)

SELECT ST_AsText(ST_SetPoint(g, -3, p))

FROM ST_GEomFromText('LINESTRING(0 0, 1 1, 2 2, 3 3, 4 4)') AS g
, ST_PointN(g,1) as p;
st_astext
-----------------------
LINESTRING(0 0,1 1,0 0,3 3,4 4)

See Also

ST_AddPoint, ST_NPoints, ST_NumPoints, ST_PointN, ST_RemovePoint

8.6.28 ST_SetSRID

ST_SetSRID — Set the SRID on a geometry to a particular integer value.

Synopsis

geometry ST_SetSRID(geometry geom, integer srid);

Description

Sets the SRID on a geometry to a particular integer value. Useful in constructing bounding boxes for queries.

Note
This function does not transform the geometry coordinates in any way - it simply sets the meta data defining the spatial
reference system the geometry is assumed to be in. Use ST_Transform if you want to transform the geometry into a
new projection.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method supports Circular Strings and Curves

Examples

-- Mark a point as WGS 84 long lat --

SELECT ST_SetSRID(ST_Point(-123.365556, 48.428611),4326) As wgs84long_lat;
-- the ewkt representation (wrap with ST_AsEWKT) -
SRID=4326;POINT(-123.365556 48.428611)

-- Mark a point as WGS 84 long lat and then transform to web mercator (Spherical Mercator) --
SELECT ST_Transform(ST_SetSRID(ST_Point(-123.365556, 48.428611),4326),3785) As spere_merc;
-- the ewkt representation (wrap with ST_AsEWKT) -
SRID=3785;POINT(-13732990.8753491 6178458.96425423)
PostGIS 2.4.3 Manual 208 / 803

See Also

Section 4.3.1, ST_AsEWKT, ST_Point, ST_SRID, ST_Transform, UpdateGeometrySRID

8.6.29 ST_SnapToGrid

ST_SnapToGrid — Snap all points of the input geometry to a regular grid.

Synopsis

geometry ST_SnapToGrid(geometry geomA, float originX, float originY, float sizeX, float sizeY);
geometry ST_SnapToGrid(geometry geomA, float sizeX, float sizeY);
geometry ST_SnapToGrid(geometry geomA, float size);
geometry ST_SnapToGrid(geometry geomA, geometry pointOrigin, float sizeX, float sizeY, float sizeZ, float sizeM);

Description

Variant 1,2,3: Snap all points of the input geometry to the grid defined by its origin and cell size. Remove consecutive points
falling on the same cell, eventually returning NULL if output points are not enough to define a geometry of the given type.
Collapsed geometries in a collection are stripped from it. Useful for reducing precision.
Variant 4: Introduced 1.1.0 - Snap all points of the input geometry to the grid defined by its origin (the second argument, must
be a point) and cell sizes. Specify 0 as size for any dimension you don’t want to snap to a grid.

Note
The returned geometry might lose its simplicity (see ST_IsSimple).

Note
Before release 1.1.0 this function always returned a 2d geometry. Starting at 1.1.0 the returned geometry will have same
dimensionality as the input one with higher dimension values untouched. Use the version taking a second geometry
argument to define all grid dimensions.

Availability: 1.0.0RC1
Availability: 1.1.0 - Z and M support

This function supports 3d and will not drop the z-index.

Examples

--Snap your geometries to a precision grid of 10^-3

UPDATE mytable
SET the_geom = ST_SnapToGrid(the_geom, 0.001);

SELECT ST_AsText(ST_SnapToGrid(
ST_GeomFromText('LINESTRING(1.1115678 2.123, 4.111111 3.2374897, 4.11112 3.23748667) ←-
'),
0.001)
);
st_astext
-------------------------------------
PostGIS 2.4.3 Manual 209 / 803

LINESTRING(1.112 2.123,4.111 3.237)

--Snap a 4d geometry
SELECT ST_AsEWKT(ST_SnapToGrid(
ST_GeomFromEWKT('LINESTRING(-1.1115678 2.123 2.3456 1.11111,
4.111111 3.2374897 3.1234 1.1111, -1.11111112 2.123 2.3456 1.1111112)'),
ST_GeomFromEWKT('POINT(1.12 2.22 3.2 4.4444)'),
0.1, 0.1, 0.1, 0.01) );
st_asewkt
------------------------------------------------------------------------------
LINESTRING(-1.08 2.12 2.3 1.1144,4.12 3.22 3.1 1.1144,-1.08 2.12 2.3 1.1144)

--With a 4d geometry - the ST_SnapToGrid(geom,size) only touches x and y coords but keeps m ←-
and z the same
SELECT ST_AsEWKT(ST_SnapToGrid(ST_GeomFromEWKT('LINESTRING(-1.1115678 2.123 3 2.3456,
4.111111 3.2374897 3.1234 1.1111)'),
0.01) );
st_asewkt
---------------------------------------------------------
LINESTRING(-1.11 2.12 3 2.3456,4.11 3.24 3.1234 1.1111)

See Also

ST_Snap, ST_AsEWKT, ST_AsText, ST_GeomFromText, ST_GeomFromEWKT, ST_Simplify

8.6.30 ST_Snap

ST_Snap — Snap segments and vertices of input geometry to vertices of a reference geometry.

Synopsis

geometry ST_Snap(geometry input, geometry reference, float tolerance);

Description

Snaps the vertices and segments of a geometry another Geometry’s vertices. A snap distance tolerance is used to control where
snapping is performed. The result geometry is the input geometry with the vertices snapped. If no snapping occurs then the input
geometry is returned unchanged.
Snapping one geometry to another can improve robustness for overlay operations by eliminating nearly-coincident edges (which
cause problems during noding and intersection calculation).
Too much snapping can result in invalid topology being created, so the number and location of snapped vertices is decided using
heuristics to determine when it is safe to snap. This can result in some potential snaps being omitted, however.

Note
The returned geometry might lose its simplicity (see ST_IsSimple) and validity (see ST_IsValid).

Availability: 2.0.0 requires GEOS >= 3.3.0.

Examples
PostGIS 2.4.3 Manual 210 / 803

A multipolygon shown with a linestring (before any snapping)

PostGIS 2.4.3 Manual 211 / 803

A multipolygon snapped to linestring to tolerance: 1.25 of

A multipolygon snapped to linestring to tolerance: 1.01 of distance. The new multipolygon is shown with reference
distance. The new multipolygon is shown with reference linestring
linestring
SELECT ST_AsText(
SELECT ST_AsText(ST_Snap(poly,line, ←- ST_Snap(poly,line, ST_Distance(poly, ←-
ST_Distance(poly,line)*1.01)) AS polysnapped line)*1.25)
FROM (SELECT ) AS polysnapped
ST_GeomFromText('MULTIPOLYGON( FROM (SELECT
((26 125, 26 200, 126 200, 126 125, ←- ST_GeomFromText('MULTIPOLYGON(
26 125 ), (( 26 125, 26 200, 126 200, 126 125, ←-
( 51 150, 101 150, 76 175, 51 150 ) ←- 26 125 ),
), ( 51 150, 101 150, 76 175, 51 150 ) ←-
(( 151 100, 151 200, 176 175, 151 ←- ),
100 )))') As poly, (( 151 100, 151 200, 176 175, 151 ←-
ST_GeomFromText('LINESTRING (5 ←- 100 )))') As poly,
107, 54 84, 101 100)') As line ST_GeomFromText('LINESTRING (5 ←-
) As foo; 107, 54 84, 101 100)') As line
) As foo;
polysnapped
--------------------------------------------------------------------- ←- polysnapped
----------------------------------------------------
MULTIPOLYGON(((26 125,26 200,126 200,126 ←-
125,101 100,26 125), MULTIPOLYGON(((5 107,26 200,126 200,126 ←-
(51 150,101 150,76 175,51 150)),((151 ←- 125,101 100,54 84,5 107),
100,151 200,176 175,151 100))) (51 150,101 150,76 175,51 150)),((151 ←-
100,151 200,176 175,151 100)))
PostGIS 2.4.3 Manual 212 / 803

The linestring snapped to the original multipolygon at

The linestring snapped to the original multipolygon at
tolerance 1.01 of distance. The new linestring is shown
tolerance 1.25 of distance. The new linestring is shown
with reference multipolygon
with reference multipolygon
SELECT ST_AsText(
SELECT ST_AsText(
ST_Snap(line, poly, ST_Distance(poly, ←-
ST_Snap(line, poly, ST_Distance(poly, ←-
line)*1.01)
line)*1.25)
) AS linesnapped
) AS linesnapped
FROM (SELECT
FROM (SELECT
ST_GeomFromText('MULTIPOLYGON(
ST_GeomFromText('MULTIPOLYGON(
((26 125, 26 200, 126 200, 126 125, ←-
(( 26 125, 26 200, 126 200, 126 125, ←-
26 125),
26 125 ),
(51 150, 101 150, 76 175, 51 150 )) ←-
(51 150, 101 150, 76 175, 51 150 )) ←-
,
,
((151 100, 151 200, 176 175, 151 ←-
((151 100, 151 200, 176 175, 151 ←-
100)))') As poly,
100 )))') As poly,
ST_GeomFromText('LINESTRING (5 ←-
ST_GeomFromText('LINESTRING (5 ←-
107, 54 84, 101 100)') As line
107, 54 84, 101 100)') As line
) As foo;
) As foo;
linesnapped
linesnapped
---------------------------------------
----------------------------------------
LINESTRING(26 125,54 84,101 100)
LINESTRING(5 107,26 125,54 84,101 100)

See Also

ST_SnapToGrid

8.6.31 ST_Transform

ST_Transform — Return a new geometry with its coordinates transformed to a different spatial reference.

Synopsis

geometry ST_Transform(geometry g1, integer srid);

geometry ST_Transform(geometry geom, text to_proj);
PostGIS 2.4.3 Manual 213 / 803

geometry ST_Transform(geometry geom, text from_proj, text to_proj);

geometry ST_Transform(geometry geom, text from_proj, integer to_srid);

Description

Returns a new geometry with its coordinates transformed to a different spatial reference system. The destination spatial reference
to_srid may be identified by a valid SRID integer parameter (i.e. it must exist in the spatial_ref_sys table). Alterna-
tively, a spatial reference defined as a PROJ.4 string can be used for to_proj and/or from_proj, however these methods are
not optimized. If the destination spatial reference system is expressed with a PROJ.4 string instead of an SRID, the SRID of the
output geometry will be set to zero. With the exception of functions with from_proj, input geometries must have a defined
SRID.
ST_Transform is often confused with ST_SetSRID(). ST_Transform actually changes the coordinates of a geometry from one
spatial reference system to another, while ST_SetSRID() simply changes the SRID identifier of the geometry.

Note
Requires PostGIS be compiled with Proj support. Use PostGIS_Full_Version to confirm you have proj support compiled
in.

Note
If using more than one transformation, it is useful to have a functional index on the commonly used transformations to
take advantage of index usage.

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.

Enhanced: 2.3.0 support for direct PROJ.4 text was introduced.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.6

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

Change Massachusetts state plane US feet geometry to WGS 84 long lat

SELECT ST_AsText(ST_Transform(ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,
743265 2967450,743265.625 2967416,743238 2967416))',2249),4326)) As wgs_geom;

wgs_geom
---------------------------
POLYGON((-71.1776848522251 42.3902896512902,-71.1776843766326 42.3903829478009,
-71.1775844305465 42.3903826677917,-71.1775825927231 42.3902893647987,-71.177684
8522251 42.3902896512902));
(1 row)
PostGIS 2.4.3 Manual 214 / 803

--3D Circular String example

SELECT ST_AsEWKT(ST_Transform(ST_GeomFromEWKT('SRID=2249;CIRCULARSTRING(743238 2967416 ←-
1,743238 2967450 2,743265 2967450 3,743265.625 2967416 3,743238 2967416 4)'),4326));

st_asewkt
--------------------------------------------------------------------------------------
SRID=4326;CIRCULARSTRING(-71.1776848522251 42.3902896512902 1,-71.1776843766326 ←-
42.3903829478009 2,
-71.1775844305465 42.3903826677917 3,
-71.1775825927231 42.3902893647987 3,-71.1776848522251 42.3902896512902 4)

Example of creating a partial functional index. For tables where you are not sure all the geometries will be filled in, its best to use
a partial index that leaves out null geometries which will both conserve space and make your index smaller and more efficient.
CREATE INDEX idx_the_geom_26986_parcels
ON parcels
USING gist
(ST_Transform(the_geom, 26986))
WHERE the_geom IS NOT NULL;

Examples of using PROJ.4 text to transform with custom spatial references.

-- Find intersection of two polygons near the North pole, using a custom Gnomic projection
-- See http://boundlessgeo.com/2012/02/flattening-the-peel/
WITH data AS (
SELECT
ST_GeomFromText('POLYGON((170 50,170 72,-130 72,-130 50,170 50))', 4326) AS p1,
ST_GeomFromText('POLYGON((-170 68,-170 90,-141 90,-141 68,-170 68))', 4326) AS p2,
'+proj=gnom +ellps=WGS84 +lat_0=70 +lon_0=-160 +no_defs'::text AS gnom
)
SELECT ST_AsText(
ST_Transform(
ST_Intersection(ST_Transform(p1, gnom), ST_Transform(p2, gnom)),
gnom, 4326))
FROM data;
st_astext
--------------------------------------------------------------------------------
POLYGON((-170 74.053793645338,-141 73.4268621378904,-141 68,-170 68,-170 74.053793645338) ←-
)

Configuring transformation behaviour

Sometimes coordinate transformation involving a grid-shift can fail, for example if PROJ.4 has not been built with grid-shift files
or the coordinate does not lie within the range for which the grid shift is defined. By default, PostGIS will throw an error if a grid
shift file is not present, but this behaviour can be configured on a per-SRID basis either by testing different to_proj values of
PROJ.4 text, or altering the proj4text value within the spatial_ref_sys table.
For example, the proj4text parameter +datum=NAD87 is a shorthand form for the following +nadgrids parameter:
+nadgrids=@conus,@alaska,@ntv2_0.gsb,@ntv1_can.dat

The @ prefix means no error is reported if the files are not present, but if the end of the list is reached with no file having been
appropriate (ie. found and overlapping) then an error is issued.
If, conversely, you wanted to ensure that at least the standard files were present, but that if all files were scanned without a hit a
null transformation is applied you could use:
+nadgrids=@conus,@alaska,@ntv2_0.gsb,@ntv1_can.dat,null
PostGIS 2.4.3 Manual 215 / 803

The null grid shift file is a valid grid shift file covering the whole world and applying no shift. So for a complete example, if you
wanted to alter PostGIS so that transformations to SRID 4267 that didn’t lie within the correct range did not throw an ERROR,
you would use the following:
UPDATE spatial_ref_sys SET proj4text = '+proj=longlat +ellps=clrk66 +nadgrids=@conus, ←-
@alaska,@ntv2_0.gsb,@ntv1_can.dat,null +no_defs' WHERE srid = 4267;

See Also

PostGIS_Full_Version, ST_AsText, ST_SetSRID, UpdateGeometrySRID

8.6.32 ST_Translate

ST_Translate — Translate a geometry by given offsets.

Synopsis

geometry ST_Translate(geometry g1, float deltax, float deltay);

geometry ST_Translate(geometry g1, float deltax, float deltay, float deltaz);

Description

Returns a new geometry whose coordinates are translated delta x,delta y,delta z units. Units are based on the units defined in
spatial reference (SRID) for this geometry.

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

Availability: 1.2.2

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

Move a point 1 degree longitude

SELECT ST_AsText(ST_Translate(ST_GeomFromText('POINT(-71.01 42.37)',4326),1,0)) As ←-
wgs_transgeomtxt;

wgs_transgeomtxt
---------------------
POINT(-70.01 42.37)

Move a linestring 1 degree longitude and 1/2 degree latitude

SELECT ST_AsText(ST_Translate(ST_GeomFromText('LINESTRING(-71.01 42.37,-71.11 42.38)',4326) ←-
,1,0.5)) As wgs_transgeomtxt;
wgs_transgeomtxt
---------------------------------------
LINESTRING(-70.01 42.87,-70.11 42.88)
PostGIS 2.4.3 Manual 216 / 803

Move a 3d point
SELECT ST_AsEWKT(ST_Translate(CAST('POINT(0 0 0)' As geometry), 5, 12,3));
st_asewkt
---------
POINT(5 12 3)

Move a curve and a point

SELECT ST_AsText(ST_Translate(ST_Collect('CURVEPOLYGON(CIRCULARSTRING(4 3,3.12 0.878,1 ←-
0,-1.121 5.1213,6 7, 8 9,4 3))','POINT(1 3)'),1,2));
st_astext
-----------------------------------------------------------------------------------------------------

GEOMETRYCOLLECTION(CURVEPOLYGON(CIRCULARSTRING(5 5,4.12 2.878,2 2,-0.121 7.1213,7 9,9 11,5 ←-

5)),POINT(2 5))

See Also

ST_Affine, ST_AsText, ST_GeomFromText

8.6.33 ST_TransScale

ST_TransScale — Translate a geometry by given factors and offsets.

Synopsis

geometry ST_TransScale(geometry geomA, float deltaX, float deltaY, float XFactor, float YFactor);

Description

Translates the geometry using the deltaX and deltaY args, then scales it using the XFactor, YFactor args, working in 2D only.

Note
ST_TransScale(geomA, deltaX, deltaY, XFactor, YFactor) is short-hand for
ST_Affine(geomA, XFactor, 0, 0, 0, YFactor, 0, 0, 0, 1, deltaX*XFactor,
deltaY*YFactor, 0).

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

Availability: 1.1.0.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 217 / 803

Examples

SELECT ST_AsEWKT(ST_TransScale(ST_GeomFromEWKT('LINESTRING(1 2 3, 1 1 1)'), 0.5, 1, 1, 2));

st_asewkt
-----------------------------
LINESTRING(1.5 6 3,1.5 4 1)

--Buffer a point to get an approximation of a circle, convert to curve and then translate ←-
1,2 and scale it 3,4
SELECT ST_AsText(ST_Transscale(ST_LineToCurve(ST_Buffer('POINT(234 567)', 3)),1,2,3,4));
st_astext
-----------------------------------------------------------------------------------------------------

CURVEPOLYGON(CIRCULARSTRING(714 2276,711.363961030679 2267.51471862576,705 ←-

2264,698.636038969321 2284.48528137424,714 2276))

See Also

ST_Affine, ST_Translate

8.7 Geometry Outputs

8.7.1 ST_AsBinary

ST_AsBinary — Return the Well-Known Binary (WKB) representation of the geometry/geography without SRID meta data.

Synopsis

bytea ST_AsBinary(geometry g1);

bytea ST_AsBinary(geometry g1, text NDR_or_XDR);
bytea ST_AsBinary(geography g1);
bytea ST_AsBinary(geography g1, text NDR_or_XDR);

Description

Returns the Well-Known Binary representation of the geometry. There are 2 variants of the function. The first variant takes no
endian encoding parameter and defaults to server machine endian. The second variant takes a second argument denoting the
encoding - using little-endian (’NDR’) or big-endian (’XDR’) encoding.
This is useful in binary cursors to pull data out of the database without converting it to a string representation.

Note
The WKB spec does not include the SRID. To get the WKB with SRID format use ST_AsEWKB

Note
ST_AsBinary is the reverse of ST_GeomFromWKB for geometry. Use ST_GeomFromWKB to convert to a postgis
geometry from ST_AsBinary representation.
PostGIS 2.4.3 Manual 218 / 803

Note
The default behavior in PostgreSQL 9.0 has been changed to output bytea in hex encoding. ST_AsBinary is the reverse
of ST_GeomFromWKB for geometry. If your GUI tools require the old behavior, then SET bytea_output=’escape’ in your
database.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Enhanced: 2.0.0 support for higher coordinate dimensions was introduced.
Enhanced: 2.0.0 support for specifying endian with geography was introduced.
Availability: 1.5.0 geography support was introduced.
Changed: 2.0.0 Inputs to this function can not be unknown -- must be geometry. Constructs such as ST_AsBinary(’POINT(1
2)’) are no longer valid and you will get an n st_asbinary(unknown) is not unique error. Code like that
needs to be changed to ST_AsBinary(’POINT(1 2)’::geometry);. If that is not possible, then install legacy.sql.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.37

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_AsBinary(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));

st_asbinary
--------------------------------
\001\003\000\000\000\001\000\000\000\005
\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000
\000\000\000\360?\000\000\000\000\000\000
\360?\000\000\000\000\000\000\360?\000\000
\000\000\000\000\360?\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000
(1 row)

SELECT ST_AsBinary(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326), 'XDR');

st_asbinary
--------------------------------
\000\000\000\000\003\000\000\000\001\000\000\000\005\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000
\000?\360\000\000\000\000\000\000?\360\000\000\000\000\000\000?\360\000\000
\000\000\000\000?\360\000\000\000\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000
(1 row)
PostGIS 2.4.3 Manual 219 / 803

See Also

ST_GeomFromWKB, ST_AsEWKB, ST_AsTWKB, ST_AsText,

8.7.2 ST_AsEncodedPolyline

ST_AsEncodedPolyline — Returns an Encoded Polyline from a LineString geometry.

Synopsis

text ST_AsEncodedPolyline(geometry geom, integer precision=5);

Description

Returns the geometry as an Encoded Polyline. This is a format very useful if you are using google maps
Availability: 2.2.0

Examples

Basic
SELECT ST_AsEncodedPolyline(GeomFromEWKT('SRID=4326;LINESTRING(-120.2 38.5,-120.95 ←-
40.7,-126.453 43.252)'));
--result--
|_p~iF~ps|U_ulLnnqC_mqNvxq`@

Use in conjunction with geography linestring and geography segmentize, and put on google maps
-- the SQL for Boston to San Francisco, segments every 100 KM
SELECT ST_AsEncodedPolyline(
ST_Segmentize(
ST_GeogFromText('LINESTRING(-71.0519 42.4935,-122.4483 37.64)'),
100000)::geometry) As encodedFlightPath;

javascript will look something like this where $ variable you replace with query result
<script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?libraries= ←-
geometry"></script>
<script type="text/javascript">
flightPath = new google.maps.Polyline({
path: google.maps.geometry.encoding.decodePath("$encodedFlightPath"),
map: map,
strokeColor: '#0000CC',
strokeOpacity: 1.0,
strokeWeight: 4
});
</script>

See Also

ST_LineFromEncodedPolyline, ST_Segmentize

8.7.3 ST_AsEWKB

ST_AsEWKB — Return the Well-Known Binary (WKB) representation of the geometry with SRID meta data.
PostGIS 2.4.3 Manual 220 / 803

Synopsis

bytea ST_AsEWKB(geometry g1);

bytea ST_AsEWKB(geometry g1, text NDR_or_XDR);

Description

Returns the Well-Known Binary representation of the geometry with SRID metadata. There are 2 variants of the function.
The first variant takes no endian encoding parameter and defaults to little endian. The second variant takes a second argument
denoting the encoding - using little-endian (’NDR’) or big-endian (’XDR’) encoding.
This is useful in binary cursors to pull data out of the database without converting it to a string representation.

Note
The WKB spec does not include the SRID. To get the OGC WKB format use ST_AsBinary

Note
ST_AsEWKB is the reverse of ST_GeomFromEWKB. Use ST_GeomFromEWKB to convert to a postgis geometry from
ST_AsEWKB representation.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT ST_AsEWKB(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));

st_asewkb
--------------------------------
\001\003\000\000 \346\020\000\000\001\000
\000\000\005\000\000\000\000
\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000
\000\000\360?\000\000\000\000\000\000\360?
\000\000\000\000\000\000\360?\000\000\000\000\000
\000\360?\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000
(1 row)
PostGIS 2.4.3 Manual 221 / 803

SELECT ST_AsEWKB(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326), 'XDR');

st_asewkb
--------------------------------
\000 \000\000\003\000\000\020\346\000\000\000\001\000\000\000\005\000\000\000\000\
000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000?
\360\000\000\000\000\000\000?\360\000\000\000\000\000\000?\360\000\000\000\000
\000\000?\360\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000
\000\000\000\000\000\000\000\000\000\000\000\000\000

See Also

ST_AsBinary, ST_AsEWKT, ST_AsText, ST_GeomFromEWKT, ST_SRID

8.7.4 ST_AsEWKT

ST_AsEWKT — Return the Well-Known Text (WKT) representation of the geometry with SRID meta data.

Synopsis

text ST_AsEWKT(geometry g1);

text ST_AsEWKT(geography g1);

Description

Returns the Well-Known Text representation of the geometry prefixed with the SRID.

Note
The WKT spec does not include the SRID. To get the OGC WKT format use ST_AsText

WKT format does not maintain precision so to prevent floating truncation, use ST_AsBinary or ST_AsEWKB format for
transport.

Note
ST_AsEWKT is the reverse of ST_GeomFromEWKT. Use ST_GeomFromEWKT to convert to a postgis geometry from
ST_AsEWKT representation.

Enhanced: 2.0.0 support for Geography, Polyhedral surfaces, Triangles and TIN was introduced.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 222 / 803

Examples

SELECT ST_AsEWKT('0103000020E61000000100000005000000000000
000000000000000000000000000000000000000000000000000000
F03F000000000000F03F000000000000F03F000000000000F03
F000000000000000000000000000000000000000000000000'::geometry);

st_asewkt
--------------------------------
SRID=4326;POLYGON((0 0,0 1,1 1,1 0,0 0))
(1 row)

SELECT ST_AsEWKT('0108000080030000000000000060 ←-
E30A4100000000785C0241000000000000F03F0000000018
E20A4100000000485F024100000000000000400000000018
E20A4100000000305C02410000000000000840')

--st_asewkt---
CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)

See Also

ST_AsBinary, ST_AsEWKB, ST_AsText, ST_GeomFromEWKT

8.7.5 ST_AsGeoJSON

ST_AsGeoJSON — Return the geometry as a GeoJSON element.

Synopsis

text ST_AsGeoJSON(geometry geom, integer maxdecimaldigits=15, integer options=0);

text ST_AsGeoJSON(geography geog, integer maxdecimaldigits=15, integer options=0);
text ST_AsGeoJSON(integer gj_version, geometry geom, integer maxdecimaldigits=15, integer options=0);
text ST_AsGeoJSON(integer gj_version, geography geog, integer maxdecimaldigits=15, integer options=0);

Description

Return the geometry as a Geometry Javascript Object Notation (GeoJSON) element. (Cf GeoJSON specifications 1.0). 2D and
3D Geometries are both supported. GeoJSON only support SFS 1.1 geometry type (no curve support for example).
The gj_version parameter is the major version of the GeoJSON spec. If specified, must be 1. This represents the spec version of
GeoJSON.
The third argument may be used to reduce the maximum number of decimal places used in output (defaults to 15).
The last ’options’ argument could be used to add Bbox or Crs in GeoJSON output:

• 0: means no option (default value)

• 1: GeoJSON Bbox
• 2: GeoJSON Short CRS (e.g EPSG:4326)

• 4: GeoJSON Long CRS (e.g urn:ogc:def:crs:EPSG::4326)

PostGIS 2.4.3 Manual 223 / 803

Version 1: ST_AsGeoJSON(geom) / precision=15 version=1 options=0

Version 2: ST_AsGeoJSON(geom, precision) / version=1 options=0
Version 3: ST_AsGeoJSON(geom, precision, options) / version=1
Version 4: ST_AsGeoJSON(gj_version, geom) / precision=15 options=0
Version 5: ST_AsGeoJSON(gj_version, geom, precision) /options=0
Version 6: ST_AsGeoJSON(gj_version, geom, precision,options)
Availability: 1.3.4
Availability: 1.5.0 geography support was introduced.
Changed: 2.0.0 support default args and named args.

This function supports 3d and will not drop the z-index.

Examples

GeoJSON format is generally more efficient than other formats for use in ajax mapping. One popular javascript client that
supports this is Open Layers. Example of its use is OpenLayers GeoJSON Example
SELECT ST_AsGeoJSON(the_geom) from fe_edges limit 1;
st_asgeojson
-----------------------------------------------------------------------------------------------------

{"type":"MultiLineString","coordinates":[[[-89.734634999999997,31.492072000000000],
[-89.734955999999997,31.492237999999997]]]}
(1 row)
--3d point
SELECT ST_AsGeoJSON('LINESTRING(1 2 3, 4 5 6)');

st_asgeojson
-----------------------------------------------------------------------------------------
{"type":"LineString","coordinates":[[1,2,3],[4,5,6]]}

8.7.6 ST_AsGML

ST_AsGML — Return the geometry as a GML version 2 or 3 element.

Synopsis

text ST_AsGML(geometry geom, integer maxdecimaldigits=15, integer options=0);

text ST_AsGML(geography geog, integer maxdecimaldigits=15, integer options=0);
text ST_AsGML(integer version, geometry geom, integer maxdecimaldigits=15, integer options=0, text nprefix=null, text id=null);
text ST_AsGML(integer version, geography geog, integer maxdecimaldigits=15, integer options=0, text nprefix=null, text
id=null);

Description

Return the geometry as a Geography Markup Language (GML) element. The version parameter, if specified, may be either 2 or
3. If no version parameter is specified then the default is assumed to be 2. The precision argument may be used to reduce the
maximum number of decimal places (maxdecimaldigits) used in output (defaults to 15).
GML 2 refer to 2.1.2 version, GML 3 to 3.1.1 version
The ’options’ argument is a bitfield. It could be used to define CRS output type in GML output, and to declare data as lat/lon:
PostGIS 2.4.3 Manual 224 / 803

• 0: GML Short CRS (e.g EPSG:4326), default value

• 1: GML Long CRS (e.g urn:ogc:def:crs:EPSG::4326)
• 2: For GML 3 only, remove srsDimension attribute from output.
• 4: For GML 3 only, use <LineString> rather than <Curve> tag for lines.
• 16: Declare that datas are lat/lon (e.g srid=4326). Default is to assume that data are planars. This option is useful for GML
3.1.1 output only, related to axis order. So if you set it, it will swap the coordinates so order is lat lon instead of database lon
lat.
• 32: Output the box of the geometry (envelope).

The ’namespace prefix’ argument may be used to specify a custom namespace prefix or no prefix (if empty). If null or omitted
’gml’ prefix is used
Availability: 1.3.2
Availability: 1.5.0 geography support was introduced.
Enhanced: 2.0.0 prefix support was introduced. Option 4 for GML3 was introduced to allow using LineString instead of Curve
tag for lines. GML3 Support for Polyhedral surfaces and TINS was introduced. Option 32 was introduced to output the box.
Changed: 2.0.0 use default named args
Enhanced: 2.1.0 id support was introduced, for GML 3.

Note
Only version 3+ of ST_AsGML supports Polyhedral Surfaces and TINS.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples: Version 2

SELECT ST_AsGML(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));

st_asgml
--------
<gml:Polygon srsName="EPSG:4326"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates ←-
>0,0 0,1 1,1 1,0 0,0</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml: ←-
Polygon>

Examples: Version 3

-- Flip coordinates and output extended EPSG (16 | 1)--

SELECT ST_AsGML(3, ST_GeomFromText('POINT(5.234234233242 6.34534534534)',4326), 5, 17);
st_asgml
--------
<gml:Point srsName="urn:ogc:def:crs:EPSG::4326"><gml:pos>6.34535 5.23423</gml:pos></gml ←-
:Point>
PostGIS 2.4.3 Manual 225 / 803

-- Output the envelope (32) --

SELECT ST_AsGML(3, ST_GeomFromText('LINESTRING(1 2, 3 4, 10 20)',4326), 5, 32);
st_asgml
--------
<gml:Envelope srsName="EPSG:4326">
<gml:lowerCorner>1 2</gml:lowerCorner>
<gml:upperCorner>10 20</gml:upperCorner>
</gml:Envelope>

-- Output the envelope (32) , reverse (lat lon instead of lon lat) (16), long srs (1)= 32 | ←-
16 | 1 = 49 --
SELECT ST_AsGML(3, ST_GeomFromText('LINESTRING(1 2, 3 4, 10 20)',4326), 5, 49);
st_asgml
--------
<gml:Envelope srsName="urn:ogc:def:crs:EPSG::4326">
<gml:lowerCorner>2 1</gml:lowerCorner>
<gml:upperCorner>20 10</gml:upperCorner>
</gml:Envelope>

-- Polyhedral Example --
SELECT ST_AsGML(3, ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0) ←-
),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
st_asgml
--------
<gml:PolyhedralSurface>
<gml:polygonPatches>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing>
<gml:posList srsDimension="3">0 0 0 0 0 1 0 1 1 0 1 0 0 0 0</gml:posList>
</gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing>
<gml:posList srsDimension="3">0 0 0 0 1 0 1 1 0 1 0 0 0 0 0</gml:posList>
</gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing>
<gml:posList srsDimension="3">0 0 0 1 0 0 1 0 1 0 0 1 0 0 0</gml:posList>
</gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing>
<gml:posList srsDimension="3">1 1 0 1 1 1 1 0 1 1 0 0 1 1 0</gml:posList>
</gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing>
<gml:posList srsDimension="3">0 1 0 0 1 1 1 1 1 1 1 0 0 1 0</gml:posList>
PostGIS 2.4.3 Manual 226 / 803

</gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing>
<gml:posList srsDimension="3">0 0 1 1 0 1 1 1 1 0 1 1 0 0 1</gml:posList>
</gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
</gml:polygonPatches>
</gml:PolyhedralSurface>

See Also

ST_GeomFromGML

8.7.7 ST_AsHEXEWKB

ST_AsHEXEWKB — Returns a Geometry in HEXEWKB format (as text) using either little-endian (NDR) or big-endian (XDR)
encoding.

Synopsis

text ST_AsHEXEWKB(geometry g1, text NDRorXDR);

text ST_AsHEXEWKB(geometry g1);

Description

Returns a Geometry in HEXEWKB format (as text) using either little-endian (NDR) or big-endian (XDR) encoding. If no
encoding is specified, then NDR is used.

Note
Availability: 1.2.2

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_AsHEXEWKB(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));

which gives same answer as

SELECT ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326)::text;

st_ashexewkb
--------
0103000020E6100000010000000500
00000000000000000000000000000000
PostGIS 2.4.3 Manual 227 / 803

00000000000000000000000000000000F03F
000000000000F03F000000000000F03F000000000000F03
F000000000000000000000000000000000000000000000000

8.7.8 ST_AsKML

ST_AsKML — Return the geometry as a KML element. Several variants. Default version=2, default precision=15

Synopsis

text ST_AsKML(geometry geom, integer maxdecimaldigits=15);

text ST_AsKML(geography geog, integer maxdecimaldigits=15);
text ST_AsKML(integer version, geometry geom, integer maxdecimaldigits=15, text nprefix=NULL);
text ST_AsKML(integer version, geography geog, integer maxdecimaldigits=15, text nprefix=NULL);

Description

Return the geometry as a Keyhole Markup Language (KML) element. There are several variants of this function. maximum
number of decimal places used in output (defaults to 15), version default to 2 and default namespace is no prefix.
Version 1: ST_AsKML(geom_or_geog, maxdecimaldigits) / version=2 / maxdecimaldigits=15
Version 2: ST_AsKML(version, geom_or_geog, maxdecimaldigits, nprefix) maxdecimaldigits=15 / nprefix=NULL

Note
Requires PostGIS be compiled with Proj support. Use PostGIS_Full_Version to confirm you have proj support compiled
in.

Note
Availability: 1.2.2 - later variants that include version param came in 1.3.2

Note
Enhanced: 2.0.0 - Add prefix namespace. Default is no prefix

Note
Changed: 2.0.0 - uses default args and supports named args

Note
AsKML output will not work with geometries that do not have an SRID

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 228 / 803

Examples

SELECT ST_AsKML(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));

st_askml
--------
<Polygon><outerBoundaryIs><LinearRing><coordinates>0,0 0,1 1,1 1,0 0,0</coordinates></ ←-
LinearRing></outerBoundaryIs></Polygon>

--3d linestring
SELECT ST_AsKML('SRID=4326;LINESTRING(1 2 3, 4 5 6)');
<LineString><coordinates>1,2,3 4,5,6</coordinates></LineString>

See Also

ST_AsSVG, ST_AsGML

8.7.9 ST_AsLatLonText

ST_AsLatLonText — Return the Degrees, Minutes, Seconds representation of the given point.

Synopsis

text ST_AsLatLonText(geometry pt, text format=”);

Description

Returns the Degrees, Minutes, Seconds representation of the point.

Note
It is assumed the point is in a lat/lon projection. The X (lon) and Y (lat) coordinates are normalized in the output to the
"normal" range (-180 to +180 for lon, -90 to +90 for lat).

The text parameter is a format string containing the format for the resulting text, similar to a date format string. Valid tokens
are "D" for degrees, "M" for minutes, "S" for seconds, and "C" for cardinal direction (NSEW). DMS tokens may be repeated to
indicate desired width and precision ("SSS.SSSS" means " 1.0023").
"M", "S", and "C" are optional. If "C" is omitted, degrees are shown with a "-" sign if south or west. If "S" is omitted, minutes
will be shown as decimal with as many digits of precision as you specify. If "M" is also omitted, degrees are shown as decimal
with as many digits precision as you specify.
If the format string is omitted (or zero-length) a default format will be used.
Availability: 2.0

Examples

Default format.
SELECT (ST_AsLatLonText('POINT (-3.2342342 -2.32498)'));
st_aslatlontext
----------------------------
2\textdegree{}19'29.928"S 3\textdegree{}14'3.243"W
PostGIS 2.4.3 Manual 229 / 803

Providing a format (same as the default).

SELECT (ST_AsLatLonText('POINT (-3.2342342 -2.32498)', 'D\textdegree{}M''S.SSS"C'));
st_aslatlontext
----------------------------
2\textdegree{}19'29.928"S 3\textdegree{}14'3.243"W

Characters other than D, M, S, C and . are just passed through.

SELECT (ST_AsLatLonText('POINT (-3.2342342 -2.32498)', 'D degrees, M minutes, S seconds to ←-
the C'));
st_aslatlontext
--------------------------------------------------------------------------------------
2 degrees, 19 minutes, 30 seconds to the S 3 degrees, 14 minutes, 3 seconds to the W

Signed degrees instead of cardinal directions.

SELECT (ST_AsLatLonText('POINT (-3.2342342 -2.32498)', 'D\textdegree{}M''S.SSS"'));
st_aslatlontext
----------------------------
-2\textdegree{}19'29.928" -3\textdegree{}14'3.243"

Decimal degrees.
SELECT (ST_AsLatLonText('POINT (-3.2342342 -2.32498)', 'D.DDDD degrees C'));
st_aslatlontext
-----------------------------------
2.3250 degrees S 3.2342 degrees W

Excessively large values are normalized.

SELECT (ST_AsLatLonText('POINT (-302.2342342 -792.32498)'));
st_aslatlontext
-------------------------------
72\textdegree{}19'29.928"S 57\textdegree{}45'56.757"E

8.7.10 ST_AsSVG

ST_AsSVG — Returns a Geometry in SVG path data given a geometry or geography object.

Synopsis

text ST_AsSVG(geometry geom, integer rel=0, integer maxdecimaldigits=15);

text ST_AsSVG(geography geog, integer rel=0, integer maxdecimaldigits=15);

Description

Return the geometry as Scalar Vector Graphics (SVG) path data. Use 1 as second argument to have the path data implemented
in terms of relative moves, the default (or 0) uses absolute moves. Third argument may be used to reduce the maximum number
of decimal digits used in output (defaults to 15). Point geometries will be rendered as cx/cy when ’rel’ arg is 0, x/y when ’rel’ is
1. Multipoint geometries are delimited by commas (","), GeometryCollection geometries are delimited by semicolons (";").

Note
Availability: 1.2.2. Availability: 1.4.0 Changed in PostGIS 1.4.0 to include L command in absolute path to conform to
http://www.w3.org/TR/SVG/paths.html#PathDataBNF

Changed: 2.0.0 to use default args and support named args

PostGIS 2.4.3 Manual 230 / 803

Examples

SELECT ST_AsSVG(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));

st_assvg
--------
M 0 0 L 0 -1 1 -1 1 0 Z

8.7.11 ST_AsText

ST_AsText — Return the Well-Known Text (WKT) representation of the geometry/geography without SRID metadata.

Synopsis

text ST_AsText(geometry g1);

text ST_AsText(geography g1);

Description

Returns the Well-Known Text representation of the geometry/geography.

Note
The WKT spec does not include the SRID. To get the SRID as part of the data, use the non-standard PostGIS
ST_AsEWKT

WKT format does not maintain precision so to prevent floating truncation, use ST_AsBinary or ST_AsEWKB format for
transport.

Note
ST_AsText is the reverse of ST_GeomFromText. Use ST_GeomFromText to convert to a postgis geometry from
ST_AsText representation.

Availability: 1.5 - support for geography was introduced.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.1

This method implements the SQL/MM specification. SQL-MM 3: 5.1.25

This method supports Circular Strings and Curves

Examples

SELECT ST_AsText('01030000000100000005000000000000000000
000000000000000000000000000000000000000000000000
F03F000000000000F03F000000000000F03F000000000000F03
F000000000000000000000000000000000000000000000000');
PostGIS 2.4.3 Manual 231 / 803

st_astext
--------------------------------
POLYGON((0 0,0 1,1 1,1 0,0 0))
(1 row)

See Also

ST_AsBinary, ST_AsEWKB, ST_AsEWKT, ST_GeomFromText

8.7.12 ST_AsTWKB

ST_AsTWKB — Returns the geometry as TWKB, aka "Tiny Well-Known Binary"

Synopsis

bytea ST_AsTWKB(geometry g1, integer decimaldigits_xy=0, integer decimaldigits_z=0, integer decimaldigits_m=0, boolean
include_sizes=false, boolean include_bounding boxes=false);
bytea ST_AsTWKB(geometry[] geometries, bigint[] unique_ids, integer decimaldigits_xy=0, integer decimaldigits_z=0, integer
decimaldigits_m=0, boolean include_sizes=false, boolean include_bounding_boxes=false);

Description

Returns the geometry in TWKB (Tiny Well-Known Binary) format. TWKB is a compressed binary format with a focus on
minimizing the size of the output.
The decimal digits parameters control how much precision is stored in the output. By default, values are rounded to the nearest
unit before encoding. If you want to transfer more precision, increase the number. For example, a value of 1 implies that the first
digit to the right of the decimal point will be preserved.
The sizes and bounding boxes parameters control whether optional information about the encoded length of the object and the
bounds of the object are included in the output. By default they are not. Do not turn them on unless your client software has a
use for them, as they just use up space (and saving space is the point of TWKB).
The array-input form of the function is used to convert a collection of geometries and unique identifiers into a TWKB collection
that preserves the identifiers. This is useful for clients that expect to unpack a collection and then access further information
about the objects inside. You can create the arrays using the array_agg function. The other parameters operate the same as for
the simple form of the function.

Note
The format specification is available online at https://github.com/TWKB/Specification, and code for building a JavaScript
client can be found at https://github.com/TWKB/twkb.js.

Enhanced: 2.4.0 memory and speed improvements.

Availability: 2.2.0

Examples

SELECT ST_AsTWKB('LINESTRING(1 1,5 5)'::geometry);

st_astwkb
--------------------------------------------
\x02000202020808
PostGIS 2.4.3 Manual 232 / 803

To create an aggregate TWKB object including identifiers aggregate the desired geometries and objects first, using "array_agg()",
then call the appropriate TWKB function.
SELECT ST_AsTWKB(array_agg(geom), array_agg(gid)) FROM mytable;
st_astwkb
--------------------------------------------
\x040402020400000202

See Also

ST_GeomFromTWKB, ST_AsBinary, ST_AsEWKB, ST_AsEWKT, ST_GeomFromText

8.7.13 ST_AsX3D

ST_AsX3D — Returns a Geometry in X3D xml node element format: ISO-IEC-19776-1.2-X3DEncodings-XML

Synopsis

text ST_AsX3D(geometry g1, integer maxdecimaldigits=15, integer options=0);

Description

Returns a geometry as an X3D xml formatted node element http://www.web3d.org/standards/number/19776-1. If maxdecimaldigits

(precision) is not specified then defaults to 15.

Note
There are various options for translating PostGIS geometries to X3D since X3D geometry types don’t map directly
to PostGIS geometry types and some newer X3D types that might be better mappings we have avoided since most
rendering tools don’t currently support them. These are the mappings we have settled on. Feel free to post a bug ticket
if you have thoughts on the idea or ways we can allow people to denote their preferred mappings.
Below is how we currently map PostGIS 2D/3D types to X3D types

The ’options’ argument is a bitfield. For PostGIS 2.2+, this is used to denote whether to represent coordinates with X3D
GeoCoordinates Geospatial node and also whether to flip the x/y axis. By default, ST_AsX3D outputs in database form (long,lat
or X,Y), but X3D default of lat/lon, y/x may be preferred.

• 0: X/Y in database order (e.g. long/lat = X,Y is standard database order), default value, and non-spatial coordinates (just
regular old Coordinate tag).
• 1: Flip X and Y. If used in conjunction with the GeoCoordinate option switch, then output will be default "latitude_first" and
coordinates will be flipped as well.
• 2: Output coordinates in GeoSpatial GeoCoordinates. This option will throw an error if geometries are not in WGS 84 long
lat (srid: 4326). This is currently the only GeoCoordinate type supported. Refer to X3D specs specifying a spatial reference
system.. Default output will be GeoCoordinate geoSystem=’"GD" "WE" "longitude_first"’. If you prefer
the X3D default of GeoCoordinate geoSystem=’"GD" "WE" "latitude_first"’ use (2 + 1) = 3

PostGIS Type 2D X3D Type 3D X3D Type

not yet implemented - will be
LINESTRING LineSet
PolyLine2D
not yet implemented - will be
MULTILINESTRING IndexedLineSet
PolyLine2D
MULTIPOINT Polypoint2D PointSet
PostGIS 2.4.3 Manual 233 / 803

PostGIS Type 2D X3D Type 3D X3D Type

outputs the space delimited outputs the space delimited
POINT
coordinates coordinates
(MULTI) POLYGON, IndexedFaceSet (inner rings currently
Invalid X3D markup
POLYHEDRALSURFACE output as another faceset)
TIN TriangleSet2D (Not Yet Implemented) IndexedTriangleSet

Note
2D geometry support not yet complete. Inner rings currently just drawn as separate polygons. We are working on
these.

Lots of advancements happening in 3D space particularly with X3D Integration with HTML5
There is also a nice open source X3D viewer you can use to view rendered geometries. Free Wrl http://freewrl.sourceforge.net/
binaries available for Mac, Linux, and Windows. Use the FreeWRL_Launcher packaged to view the geometries.
Also check out PostGIS minimalist X3D viewer that utilizes this function and x3dDom html/js open source toolkit.
Availability: 2.0.0: ISO-IEC-19776-1.2-X3DEncodings-XML
Enhanced: 2.2.0: Support for GeoCoordinates and axis (x/y, long/lat) flipping. Look at options for details.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Example: Create a fully functional X3D document - This will generate a cube that is viewable in FreeWrl and other X3D
viewers.

SELECT '<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE X3D PUBLIC "ISO//Web3D//DTD X3D 3.0//EN" "http://www.web3d.org/specifications/x3d ←-
-3.0.dtd">
<X3D>
<Scene>
<Transform>
<Shape>
<Appearance>
<Material emissiveColor=''0 0 1''/>
</Appearance> ' ||
ST_AsX3D( ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )')) ||
'</Shape>
</Transform>
</Scene>
</X3D>' As x3ddoc;

x3ddoc
--------
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE X3D PUBLIC "ISO//Web3D//DTD X3D 3.0//EN" "http://www.web3d.org/specifications/x3d ←-
-3.0.dtd">
<X3D>
PostGIS 2.4.3 Manual 234 / 803

<Scene>
<Transform>
<Shape>
<Appearance>
<Material emissiveColor='0 0 1'/>
</Appearance>
<IndexedFaceSet coordIndex='0 1 2 3 -1 4 5 6 7 -1 8 9 10 11 -1 12 13 14 15 -1 16 17 ←-
18 19 -1 20 21 22 23'>
<Coordinate point='0 0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 1 0 0 ←-
1 0 1 0 0 1 1 1 0 1 1 1 1 0 1 1 0 0 0 1 0 0 1 1 1 1 1 1 1 0 0 0 1 1 0 1 1 1 ←-
1 0 1 1' />
</IndexedFaceSet>
</Shape>
</Transform>
</Scene>
</X3D>

Example: An Octagon elevated 3 Units and decimal precision of 6

SELECT ST_AsX3D(
ST_Translate(
ST_Force_3d(
ST_Buffer(ST_Point(10,10),5, 'quad_segs=2')), 0,0,
3)
,6) As x3dfrag;

x3dfrag
--------
<IndexedFaceSet coordIndex="0 1 2 3 4 5 6 7">
<Coordinate point="15 10 3 13.535534 6.464466 3 10 5 3 6.464466 6.464466 3 5 10 3 ←-
6.464466 13.535534 3 10 15 3 13.535534 13.535534 3 " />
</IndexedFaceSet>

Example: TIN

SELECT ST_AsX3D(ST_GeomFromEWKT('TIN (((

0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)')) As x3dfrag;

x3dfrag
--------
<IndexedTriangleSet index='0 1 2 3 4 5'><Coordinate point='0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 1 ←-
1 0'/></IndexedTriangleSet>

Example: Closed multilinestring (the boundary of a polygon with holes)

PostGIS 2.4.3 Manual 235 / 803

SELECT ST_AsX3D(
ST_GeomFromEWKT('MULTILINESTRING((20 0 10,16 -12 10,0 -16 10,-12 -12 10,-20 0 ←-
10,-12 16 10,0 24 10,16 16 10,20 0 10),
(12 0 10,8 8 10,0 12 10,-8 8 10,-8 0 10,-8 -4 10,0 -8 10,8 -4 10,12 0 10))')
) As x3dfrag;

x3dfrag
--------
<IndexedLineSet coordIndex='0 1 2 3 4 5 6 7 0 -1 8 9 10 11 12 13 14 15 8'>
<Coordinate point='20 0 10 16 -12 10 0 -16 10 -12 -12 10 -20 0 10 -12 16 10 0 24 10 16 ←-
16 10 12 0 10 8 8 10 0 12 10 -8 8 10 -8 0 10 -8 -4 10 0 -8 10 8 -4 10 ' />
</IndexedLineSet>

8.7.14 ST_GeoHash

ST_GeoHash — Return a GeoHash representation of the geometry.

Synopsis

text ST_GeoHash(geometry geom, integer maxchars=full_precision_of_point);

Description

Return a GeoHash representation (http://en.wikipedia.org/wiki/Geohash) of the geometry. A GeoHash encodes a point into a text
form that is sortable and searchable based on prefixing. A shorter GeoHash is a less precise representation of a point. It can also
be thought of as a box, that contains the actual point.
If no maxchars is specified ST_GeoHash returns a GeoHash based on full precision of the input geometry type. Points return
a GeoHash with 20 characters of precision (about enough to hold the full double precision of the input). Other types return a
GeoHash with a variable amount of precision, based on the size of the feature. Larger features are represented with less precision,
smaller features with more precision. The idea is that the box implied by the GeoHash will always contain the input feature.
If maxchars is specified ST_GeoHash returns a GeoHash with at most that many characters so a possibly lower precision
representation of the input geometry. For non-points, the starting point of the calculation is the center of the bounding box of the
geometry.
Availability: 1.4.0

Note
ST_GeoHash will not work with geometries that are not in geographic (lon/lat) coordinates.

This method supports Circular Strings and Curves

Examples

SELECT ST_GeoHash(ST_SetSRID(ST_MakePoint(-126,48),4326));

st_geohash
----------------------
c0w3hf1s70w3hf1s70w3

SELECT ST_GeoHash(ST_SetSRID(ST_MakePoint(-126,48),4326),5);
PostGIS 2.4.3 Manual 236 / 803

st_geohash
------------
c0w3h

See Also

ST_GeomFromGeoHash

8.7.15 ST_AsGeobuf

ST_AsGeobuf — Return a Geobuf representation of a set of rows.

Synopsis

bytea ST_AsGeobuf(anyelement set row);

bytea ST_AsGeobuf(anyelement row, text geom_name);

Description

Return a Geobuf representation (https://github.com/mapbox/geobuf) of a set of rows corresponding to a FeatureCollection. Every

input geometry is analyzed to determine maximum precision for optimal storage. Note that Geobuf in its current form cannot be
streamed so the full output will be assembled in memory.
row row data with at least a geometry column.
geom_name is the name of the geometry column in the row data. If NULL it will default to the first found geometry column.
Availability: 2.4.0

Examples

SELECT encode(ST_AsGeobuf(q, 'geom'), 'base64')

FROM (SELECT ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))') AS geom) AS q;
st_asgeobuf
----------------------------------
GAAiEAoOCgwIBBoIAAAAAgIAAAE=

8.7.16 ST_AsMVTGeom

ST_AsMVTGeom — Transform a geometry into the coordinate space of a Mapbox Vector Tile.

Synopsis

geometry ST_AsMVTGeom(geometry geom, box2d bounds, integer extent=4096, integer buffer=256, boolean clip_geom=true);
PostGIS 2.4.3 Manual 237 / 803

Description

Transform a geometry into the coordinate space of a Mapbox Vector Tile of a set of rows corresponding to a Layer. Makes best
effort to keep and even correct validity and might collapse geometry into a lower dimension in the process.
geom is the geometry to transform.
bounds is the geometric bounds of the tile contents without buffer.
extent is the tile extent in tile coordinate space as defined by the specification. If NULL it will default to 4096.
buffer is the buffer distance in tile coordinate space to optionally clip geometries. If NULL it will default to 256.
clip_geom is a boolean to control if geometries should be clipped or encoded as is. If NULL it will default to true.
Availability: 2.4.0

Examples

SELECT ST_AsText(ST_AsMVTGeom(
ST_GeomFromText('POLYGON ((0 0, 10 0, 10 5, 0 -5, 0 0))'),
ST_MakeBox2D(ST_Point(0, 0), ST_Point(4096, 4096)),
4096, 0, false));
st_astext
--------------------------------------------------------------------
MULTIPOLYGON(((5 4096,10 4096,10 4091,5 4096)),((5 4096,0 4096,0 4101,5 4096)))

8.7.17 ST_AsMVT

ST_AsMVT — Return a Mapbox Vector Tile representation of a set of rows.

Synopsis

bytea ST_AsMVT(anyelement set row);

bytea ST_AsMVT(anyelement row, text name);
bytea ST_AsMVT(anyelement row, text name, integer extent);
bytea ST_AsMVT(anyelement row, text name, integer extent, text geom_name);

Description

Return a Mapbox Vector Tile representation of a set of rows corresponding to a Layer. Multiple calls can be concatenated
to a tile with multiple Layers. Geometry is assumed to be in tile coordinate space and valid as per specification. Typically
ST_AsMVTGeom can be used to transform geometry into tile coordinate space. Other row data will be encoded as attributes.
The Mapbox Vector Tile format can store features with a different set of attributes per feature. To make use of this feature supply
a JSONB column in the row data containing Json objects one level deep. The keys and values in the object will be parsed into
feature attributes.

Important
Do not call with a GEOMETRYCOLLECTION as an element in the row. However you can use ST_AsMVTGeom to prep
a geometry collection for inclusion.
PostGIS 2.4.3 Manual 238 / 803

row row data with at least a geometry column.

name is the name of the Layer. If NULL it will use the string "default".
extent is the tile extent in screen space as defined by the specification. If NULL it will default to 4096.
geom_name is the name of the geometry column in the row data. If NULL it will default to the first found geometry column.
Availability: 2.4.0

Examples

SELECT ST_AsMVT(q, 'test', 4096, 'geom') FROM (SELECT 1 AS c1,

ST_AsMVTGeom(ST_GeomFromText('POLYGON ((35 10, 45 45, 15 40, 10 20, 35 10), (20 30, 35 ←-
35, 30 20, 20 30))'),
ST_MakeBox2D(ST_Point(0, 0), ST_Point(4096, 4096)), 4096, 0, false) AS geom) AS q;
st_asmvt
--------------------------------------------------------------------
\ ←-
x1a320a0474657374121d12020000180322150946ec3f1a14453b0a09280f091413121e09091e0f1a026331220228012

See Also

ST_AsMVTGeom

8.8 Operators

8.8.1 &&

&& — Returns TRUE if A’s 2D bounding box intersects B’s 2D bounding box.

Synopsis

boolean &&( geometry A , geometry B );

boolean &&( geography A , geography B );

Description

The && operator returns TRUE if the 2D bounding box of geometry A intersects the 2D bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.

Availability: 1.5.0 support for geography was introduced.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

PostGIS 2.4.3 Manual 239 / 803

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 && tbl2.column2 AS overlaps

FROM ( VALUES
(1, 'LINESTRING(0 0, 3 3)'::geometry),
(2, 'LINESTRING(0 1, 0 5)'::geometry)) AS tbl1,
( VALUES
(3, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl2;

column1 | column1 | overlaps

---------+---------+----------
1 | 3 | t
2 | 3 | f
(2 rows)

See Also

|&>, &>, &<|, &<, ~, @

8.8.2 &&(geometry,box2df)

&&(geometry,box2df) — Returns TRUE if a geometry’s (cached) 2D bounding box intersects a 2D float precision bounding box
(BOX2DF).

Synopsis

boolean &&( geometry A , box2df B );

Description

The && operator returns TRUE if the cached 2D bounding box of geometry A intersects the 2D bounding box B, using float
precision. This means that if B is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box
(BOX2DF)

Note
This operand is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_MakePoint(1,1) && ST_MakeBox2D(ST_MakePoint(0,0), ST_MakePoint(2,2)) AS overlaps;

overlaps
----------
t
(1 row)
PostGIS 2.4.3 Manual 240 / 803

See Also

&&(box2df,geometry), &&(box2df,box2df), ~(geometry,box2df), ~(box2df,geometry), ~(box2df,box2df), @(geometry,box2df),

@(box2df,geometry), @(box2df,box2df)

8.8.3 &&(box2df,geometry)

&&(box2df,geometry) — Returns TRUE if a 2D float precision bounding box (BOX2DF) intersects a geometry’s (cached) 2D
bounding box.

Synopsis

boolean &&( box2df A , geometry B );

Description

The && operator returns TRUE if the 2D bounding box A intersects the cached 2D bounding box of geometry B, using float
precision. This means that if A is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box
(BOX2DF)

Note
This operand is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_MakeBox2D(ST_MakePoint(0,0), ST_MakePoint(2,2)) && ST_MakePoint(1,1) AS overlaps;

overlaps
----------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,box2df), ~(geometry,box2df), ~(box2df,geometry), ~(box2df,box2df), @(geometry,box2df),

@(box2df,geometry), @(box2df,box2df)

8.8.4 &&(box2df,box2df)

&&(box2df,box2df) — Returns TRUE if two 2D float precision bounding boxes (BOX2DF) intersect each other.
PostGIS 2.4.3 Manual 241 / 803

Synopsis

boolean &&( box2df A , box2df B );

Description

The && operator returns TRUE if two 2D bounding boxes A and B intersect each other, using float precision. This means that if
A (or B) is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box (BOX2DF)

Note
This operator is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_MakeBox2D(ST_MakePoint(0,0), ST_MakePoint(2,2)) && ST_MakeBox2D(ST_MakePoint(1,1) ←-

, ST_MakePoint(3,3)) AS overlaps;

overlaps
----------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,geometry), ~(geometry,box2df), ~(box2df,geometry), ~(box2df,box2df), @(geometry,box2df),

@(box2df,geometry), @(box2df,box2df)

8.8.5 &&&

&&& — Returns TRUE if A’s n-D bounding box intersects B’s n-D bounding box.

Synopsis

boolean &&&( geometry A , geometry B );

Description

The &&& operator returns TRUE if the n-D bounding box of geometry A intersects the n-D bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.
PostGIS 2.4.3 Manual 242 / 803

Availability: 2.0.0

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Examples: 3D LineStrings

SELECT tbl1.column1, tbl2.column1, tbl1.column2 &&& tbl2.column2 AS overlaps_3d,

tbl1.column2 && tbl2.column2 AS overlaps_2d
FROM ( VALUES
(1, 'LINESTRING Z(0 0 1, 3 3 2)'::geometry),
(2, 'LINESTRING Z(1 2 0, 0 5 -1)'::geometry)) AS tbl1,
( VALUES
(3, 'LINESTRING Z(1 2 1, 4 6 1)'::geometry)) AS tbl2;

column1 | column1 | overlaps_3d | overlaps_2d

---------+---------+-------------+-------------
1 | 3 | t | t
2 | 3 | f | t

Examples: 3M LineStrings

SELECT tbl1.column1, tbl2.column1, tbl1.column2 &&& tbl2.column2 AS overlaps_3zm,

tbl1.column2 && tbl2.column2 AS overlaps_2d
FROM ( VALUES
(1, 'LINESTRING M(0 0 1, 3 3 2)'::geometry),
(2, 'LINESTRING M(1 2 0, 0 5 -1)'::geometry)) AS tbl1,
( VALUES
(3, 'LINESTRING M(1 2 1, 4 6 1)'::geometry)) AS tbl2;

column1 | column1 | overlaps_3zm | overlaps_2d

---------+---------+-------------+-------------
1 | 3 | t | t
2 | 3 | f | t

See Also

&&

8.8.6 &&&(geometry,gidx)

&&&(geometry,gidx) — Returns TRUE if a geometry’s (cached) n-D bounding box intersects a n-D float precision bounding
box (GIDX).

Synopsis

boolean &&&( geometry A , gidx B );

PostGIS 2.4.3 Manual 243 / 803

Description

The &&& operator returns TRUE if the cached n-D bounding box of geometry A intersects the n-D bounding box B, using float
precision. This means that if B is a (double precision) box3d, it will be internally converted to a float precision 3D bounding box
(GIDX)

Note
This operator is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_MakePoint(1,1,1) &&& ST_3DMakeBox(ST_MakePoint(0,0,0), ST_MakePoint(2,2,2)) AS ←-

overlaps;

overlaps
----------
t
(1 row)

See Also

&&&(gidx,geometry), &&&(gidx,gidx)

8.8.7 &&&(gidx,geometry)

&&&(gidx,geometry) — Returns TRUE if a n-D float precision bounding box (GIDX) intersects a geometry’s (cached) n-D
bounding box.

Synopsis

boolean &&&( gidx A , geometry B );

Description

The &&& operator returns TRUE if the n-D bounding box A intersects the cached n-D bounding box of geometry B, using float
precision. This means that if A is a (double precision) box3d, it will be internally converted to a float precision 3D bounding box
(GIDX)
PostGIS 2.4.3 Manual 244 / 803

Note
This operator is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_3DMakeBox(ST_MakePoint(0,0,0), ST_MakePoint(2,2,2)) &&& ST_MakePoint(1,1,1) AS ←-

overlaps;

overlaps
----------
t
(1 row)

See Also

&&&(geometry,gidx), &&&(gidx,gidx)

8.8.8 &&&(gidx,gidx)

&&&(gidx,gidx) — Returns TRUE if two n-D float precision bounding boxes (GIDX) intersect each other.

Synopsis

boolean &&&( gidx A , gidx B );

Description

The &&& operator returns TRUE if two n-D bounding boxes A and B intersect each other, using float precision. This means that
if A (or B) is a (double precision) box3d, it will be internally converted to a float precision 3D bounding box (GIDX)

Note
This operator is intended to be used internally by BRIN indexes, more than by users.
PostGIS 2.4.3 Manual 245 / 803

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_3DMakeBox(ST_MakePoint(0,0,0), ST_MakePoint(2,2,2)) &&& ST_3DMakeBox(ST_MakePoint ←-

(1,1,1), ST_MakePoint(3,3,3)) AS overlaps;

overlaps
----------
t
(1 row)

See Also

&&&(geometry,gidx), &&&(gidx,geometry)

8.8.9 &<

&< — Returns TRUE if A’s bounding box overlaps or is to the left of B’s.

Synopsis

boolean &<( geometry A , geometry B );

Description

The &< operator returns TRUE if the bounding box of geometry A overlaps or is to the left of the bounding box of geometry B,
or more accurately, overlaps or is NOT to the right of the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 &< tbl2.column2 AS overleft

FROM
( VALUES
(1, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING(0 0, 3 3)'::geometry),
PostGIS 2.4.3 Manual 246 / 803

(3, 'LINESTRING(0 1, 0 5)'::geometry),

(4, 'LINESTRING(6 0, 6 1)'::geometry)) AS tbl2;

column1 | column1 | overleft

---------+---------+----------
1 | 2 | f
1 | 3 | f
1 | 4 | t
(3 rows)

See Also

&&, |&>, &>, &<|

8.8.10 &<|

&<| — Returns TRUE if A’s bounding box overlaps or is below B’s.

Synopsis

boolean &<|( geometry A , geometry B );

Description

The &<| operator returns TRUE if the bounding box of geometry A overlaps or is below of the bounding box of geometry B, or
more accurately, overlaps or is NOT above the bounding box of geometry B.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 &<| tbl2.column2 AS overbelow

FROM
( VALUES
(1, 'LINESTRING(6 0, 6 4)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING(0 0, 3 3)'::geometry),
(3, 'LINESTRING(0 1, 0 5)'::geometry),
(4, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl2;

column1 | column1 | overbelow

---------+---------+-----------
1 | 2 | f
1 | 3 | t
1 | 4 | t
(3 rows)
PostGIS 2.4.3 Manual 247 / 803

See Also

&&, |&>, &>, &<

8.8.11 &>

&> — Returns TRUE if A’ bounding box overlaps or is to the right of B’s.

Synopsis

boolean &>( geometry A , geometry B );

Description

The &> operator returns TRUE if the bounding box of geometry A overlaps or is to the right of the bounding box of geometry B,
or more accurately, overlaps or is NOT to the left of the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 &> tbl2.column2 AS overright

FROM
( VALUES
(1, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING(0 0, 3 3)'::geometry),
(3, 'LINESTRING(0 1, 0 5)'::geometry),
(4, 'LINESTRING(6 0, 6 1)'::geometry)) AS tbl2;

column1 | column1 | overright

---------+---------+-----------
1 | 2 | t
1 | 3 | t
1 | 4 | f
(3 rows)

See Also

&&, |&>, &<|, &<

8.8.12 <<

<< — Returns TRUE if A’s bounding box is strictly to the left of B’s.

Synopsis

boolean <<( geometry A , geometry B );

PostGIS 2.4.3 Manual 248 / 803

Description

The << operator returns TRUE if the bounding box of geometry A is strictly to the left of the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 << tbl2.column2 AS left

FROM
( VALUES
(1, 'LINESTRING (1 2, 1 5)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING (0 0, 4 3)'::geometry),
(3, 'LINESTRING (6 0, 6 5)'::geometry),
(4, 'LINESTRING (2 2, 5 6)'::geometry)) AS tbl2;

column1 | column1 | left

---------+---------+------
1 | 2 | f
1 | 3 | t
1 | 4 | t
(3 rows)

See Also

>>, |>>, <<|

8.8.13 <<|

<<| — Returns TRUE if A’s bounding box is strictly below B’s.

Synopsis

boolean <<|( geometry A , geometry B );

Description

The <<| operator returns TRUE if the bounding box of geometry A is strictly below the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.
PostGIS 2.4.3 Manual 249 / 803

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 <<| tbl2.column2 AS below

FROM
( VALUES
(1, 'LINESTRING (0 0, 4 3)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING (1 4, 1 7)'::geometry),
(3, 'LINESTRING (6 1, 6 5)'::geometry),
(4, 'LINESTRING (2 3, 5 6)'::geometry)) AS tbl2;

column1 | column1 | below

---------+---------+-------
1 | 2 | t
1 | 3 | f
1 | 4 | f
(3 rows)

See Also

<<, >>, |>>

8.8.14 =

= — Returns TRUE if the coordinates and coordinate order geometry/geography A are the same as the coordinates and coordinate
order of geometry/geography B.

Synopsis

boolean =( geometry A , geometry B );

boolean =( geography A , geography B );

Description

The = operator returns TRUE if the coordinates and coordinate order geometry/geography A are the same as the coordinates and
coordinate order of geometry/geography B. PostgreSQL uses the =, <, and > operators defined for geometries to perform internal
orderings and comparison of geometries (ie. in a GROUP BY or ORDER BY clause).

Note
Only geometry/geography that are exactly equal in all respects, with the same coordinates, in the same order, are
considered equal by this operator. For "spatial equality", that ignores things like coordinate order, and can detect
features that cover the same spatial area with different representations, use ST_OrderingEquals or ST_Equals

Caution
This operand will NOT make use of any indexes that may be available on the geometries. For an index assisted exact
equality test, combine = with &&.

Changed: 2.4.0, in prior versions this was bounding box equality not a geometric equality. If you need bounding box equality,
use ~= instead.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

PostGIS 2.4.3 Manual 250 / 803

Examples

SELECT 'LINESTRING(0 0, 0 1, 1 0)'::geometry = 'LINESTRING(1 1, 0 0)'::geometry;

?column?
----------
f
(1 row)

SELECT ST_AsText(column1)
FROM ( VALUES
('LINESTRING(0 0, 1 1)'::geometry),
('LINESTRING(1 1, 0 0)'::geometry)) AS foo;
st_astext
---------------------
LINESTRING(0 0,1 1)
LINESTRING(1 1,0 0)
(2 rows)

-- Note: the GROUP BY uses the "=" to compare for geometry equivalency.
SELECT ST_AsText(column1)
FROM ( VALUES
('LINESTRING(0 0, 1 1)'::geometry),
('LINESTRING(1 1, 0 0)'::geometry)) AS foo
GROUP BY column1;
st_astext
---------------------
LINESTRING(0 0,1 1)
LINESTRING(1 1,0 0)
(2 rows)

-- In versions prior to 2.0, this used to return true --

SELECT ST_GeomFromText('POINT(1707296.37 4820536.77)') =
ST_GeomFromText('POINT(1707296.27 4820536.87)') As pt_intersect;

--pt_intersect --
f

See Also

ST_Equals, ST_OrderingEquals, ~=

8.8.15 >>

>> — Returns TRUE if A’s bounding box is strictly to the right of B’s.

Synopsis

boolean >>( geometry A , geometry B );

Description

The >> operator returns TRUE if the bounding box of geometry A is strictly to the right of the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.
PostGIS 2.4.3 Manual 251 / 803

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 >> tbl2.column2 AS right

FROM
( VALUES
(1, 'LINESTRING (2 3, 5 6)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING (1 4, 1 7)'::geometry),
(3, 'LINESTRING (6 1, 6 5)'::geometry),
(4, 'LINESTRING (0 0, 4 3)'::geometry)) AS tbl2;

column1 | column1 | right

---------+---------+-------
1 | 2 | t
1 | 3 | f
1 | 4 | f
(3 rows)

See Also

<<, |>>, <<|

8.8.16 @

@ — Returns TRUE if A’s bounding box is contained by B’s.

Synopsis

boolean @( geometry A , geometry B );

Description

The @ operator returns TRUE if the bounding box of geometry A is completely contained by the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 @ tbl2.column2 AS contained

FROM
( VALUES
(1, 'LINESTRING (1 1, 3 3)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING (0 0, 4 4)'::geometry),
(3, 'LINESTRING (2 2, 4 4)'::geometry),
(4, 'LINESTRING (1 1, 3 3)'::geometry)) AS tbl2;

column1 | column1 | contained

---------+---------+-----------
1 | 2 | t
1 | 3 | f
1 | 4 | t
(3 rows)
PostGIS 2.4.3 Manual 252 / 803

See Also

~, &&

8.8.17 @(geometry,box2df)

@(geometry,box2df) — Returns TRUE if a geometry’s 2D bounding box is contained into a 2D float precision bounding box
(BOX2DF).

Synopsis

boolean @( geometry A , box2df B );

Description

The @ operator returns TRUE if the A geometry’s 2D bounding box is contained the 2D bounding box B, using float precision.
This means that if B is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box (BOX2DF)

Note
This operand is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_Buffer(ST_GeomFromText('POINT(2 2)'), 1) @ ST_MakeBox2D(ST_MakePoint(0,0), ←-

ST_MakePoint(5,5)) AS is_contained;

is_contained
--------------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,geometry), &&(box2df,box2df), ~(geometry,box2df), ~(box2df,geometry), ~(box2df,box2df),

@(box2df,geometry), @(box2df,box2df)

8.8.18 @(box2df,geometry)

@(box2df,geometry) — Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into a geometry’s 2D
bounding box.
PostGIS 2.4.3 Manual 253 / 803

Synopsis

boolean @( box2df A , geometry B );

Description

The @ operator returns TRUE if the 2D bounding box A is contained into the B geometry’s 2D bounding box, using float precision.
This means that if B is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box (BOX2DF)

Note
This operand is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_MakeBox2D(ST_MakePoint(2,2), ST_MakePoint(3,3)) @ ST_Buffer(ST_GeomFromText(' ←-

POINT(1 1)'), 10) AS is_contained;

is_contained
--------------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,geometry), &&(box2df,box2df), ~(geometry,box2df), ~(box2df,geometry), ~(box2df,box2df),

@(geometry,box2df), @(box2df,box2df)

8.8.19 @(box2df,box2df)

@(box2df,box2df) — Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into another 2D float precision
bounding box.

Synopsis

boolean @( box2df A , box2df B );

Description

The @ operator returns TRUE if the 2D bounding box A is contained into the 2D bounding box B, using float precision. This means
that if A (or B) is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box (BOX2DF)
PostGIS 2.4.3 Manual 254 / 803

Note
This operand is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_MakeBox2D(ST_MakePoint(2,2), ST_MakePoint(3,3)) @ ST_MakeBox2D(ST_MakePoint(0,0), ←-

ST_MakePoint(5,5)) AS is_contained;

is_contained
--------------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,geometry), &&(box2df,box2df), ~(geometry,box2df), ~(box2df,geometry), ~(box2df,box2df),

@(geometry,box2df), @(box2df,geometry)

8.8.20 |&>

|&> — Returns TRUE if A’s bounding box overlaps or is above B’s.

Synopsis

boolean |&>( geometry A , geometry B );

Description

The |&> operator returns TRUE if the bounding box of geometry A overlaps or is above the bounding box of geometry B, or
more accurately, overlaps or is NOT below the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples
PostGIS 2.4.3 Manual 255 / 803

SELECT tbl1.column1, tbl2.column1, tbl1.column2 |&> tbl2.column2 AS overabove

FROM
( VALUES
(1, 'LINESTRING(6 0, 6 4)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING(0 0, 3 3)'::geometry),
(3, 'LINESTRING(0 1, 0 5)'::geometry),
(4, 'LINESTRING(1 2, 4 6)'::geometry)) AS tbl2;

column1 | column1 | overabove

---------+---------+-----------
1 | 2 | t
1 | 3 | f
1 | 4 | f
(3 rows)

See Also

&&, &>, &<|, &<

8.8.21 |>>

|>> — Returns TRUE if A’s bounding box is strictly above B’s.

Synopsis

boolean |>>( geometry A , geometry B );

Description

The |>> operator returns TRUE if the bounding box of geometry A is strictly above the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 |>> tbl2.column2 AS above

FROM
( VALUES
(1, 'LINESTRING (1 4, 1 7)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING (0 0, 4 2)'::geometry),
(3, 'LINESTRING (6 1, 6 5)'::geometry),
(4, 'LINESTRING (2 3, 5 6)'::geometry)) AS tbl2;

column1 | column1 | above

---------+---------+-------
1 | 2 | t
1 | 3 | f
1 | 4 | f
(3 rows)
PostGIS 2.4.3 Manual 256 / 803

See Also

<<, >>, <<|

8.8.22 ~

~ — Returns TRUE if A’s bounding box contains B’s.

Synopsis

boolean ~( geometry A , geometry B );

Description

The ~ operator returns TRUE if the bounding box of geometry A completely contains the bounding box of geometry B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT tbl1.column1, tbl2.column1, tbl1.column2 ~ tbl2.column2 AS contains

FROM
( VALUES
(1, 'LINESTRING (0 0, 3 3)'::geometry)) AS tbl1,
( VALUES
(2, 'LINESTRING (0 0, 4 4)'::geometry),
(3, 'LINESTRING (1 1, 2 2)'::geometry),
(4, 'LINESTRING (0 0, 3 3)'::geometry)) AS tbl2;

column1 | column1 | contains

---------+---------+----------
1 | 2 | f
1 | 3 | t
1 | 4 | t
(3 rows)

See Also

@, &&

8.8.23 ~(geometry,box2df)

~(geometry,box2df) — Returns TRUE if a geometry’s 2D bonding box contains a 2D float precision bounding box (GIDX).

Synopsis

boolean ~( geometry A , box2df B );

PostGIS 2.4.3 Manual 257 / 803

Description

The ~ operator returns TRUE if the 2D bounding box of a geometry A contains the 2D bounding box B, using float precision.
This means that if B is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box (BOX2DF)

Note
This operand is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_Buffer(ST_GeomFromText('POINT(1 1)'), 10) ~ ST_MakeBox2D(ST_MakePoint(0,0), ←-

ST_MakePoint(2,2)) AS contains;

contains
----------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,geometry), &&(box2df,box2df), ~(box2df,geometry), ~(box2df,box2df), @(geometry,box2df),

@(box2df,geometry), @(box2df,box2df)

8.8.24 ~(box2df,geometry)

~(box2df,geometry) — Returns TRUE if a 2D float precision bounding box (BOX2DF) contains a geometry’s 2D bonding box.

Synopsis

boolean ~( box2df A , geometry B );

Description

The ~ operator returns TRUE if the 2D bounding box A contains the B geometry’s bounding box, using float precision. This
means that if A is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box (BOX2DF)

Note
This operand is intended to be used internally by BRIN indexes, more than by users.
PostGIS 2.4.3 Manual 258 / 803

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

Examples

SELECT ST_MakeBox2D(ST_MakePoint(0,0), ST_MakePoint(5,5)) ~ ST_Buffer(ST_GeomFromText(' ←-

POINT(2 2)'), 1) AS contains;

contains
----------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,geometry), &&(box2df,box2df), ~(geometry,box2df), ~(box2df,box2df), @(geometry,box2df),

@(box2df,geometry), @(box2df,box2df)

8.8.25 ~(box2df,box2df)

~(box2df,box2df) — Returns TRUE if a 2D float precision bounding box (BOX2DF) contains another 2D float precision bounding
box (BOX2DF).

Synopsis

boolean ~( box2df A , box2df B );

Description

The ~ operator returns TRUE if the 2D bounding box A contains the 2D bounding box B, using float precision. This means that
if A is a (double precision) box2d, it will be internally converted to a float precision 2D bounding box (BOX2DF)

Note
This operand is intended to be used internally by BRIN indexes, more than by users.

Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

PostGIS 2.4.3 Manual 259 / 803

Examples

SELECT ST_MakeBox2D(ST_MakePoint(0,0), ST_MakePoint(5,5)) ~ ST_MakeBox2D(ST_MakePoint(2,2), ←-

ST_MakePoint(3,3)) AS contains;

contains
----------
t
(1 row)

See Also

&&(geometry,box2df), &&(box2df,geometry), &&(box2df,box2df), ~(geometry,box2df), ~(box2df,geometry), @(geometry,box2df),

@(box2df,geometry), @(box2df,box2df)

8.8.26 ~=

~= — Returns TRUE if A’s bounding box is the same as B’s.

Synopsis

boolean ~=( geometry A , geometry B );

Description

The ~= operator returns TRUE if the bounding box of geometry/geography A is the same as the bounding box of geometry/geog-
raphy B.

Note
This operand will make use of any indexes that may be available on the geometries.

Availability: 1.5.0 changed behavior

This function supports Polyhedral surfaces.

Warning
This operator has changed behavior in PostGIS 1.5 from testing for actual geometric equality to only checking for
bounding box equality. To complicate things it also depends on if you have done a hard or soft upgrade which behavior
your database has. To find out which behavior your database has you can run the query below. To check for true
equality use ST_OrderingEquals or ST_Equals.

Examples

select 'LINESTRING(0 0, 1 1)'::geometry ~= 'LINESTRING(0 1, 1 0)'::geometry as equality;

equality |
-----------------+
t |
PostGIS 2.4.3 Manual 260 / 803

See Also

ST_Equals, ST_OrderingEquals, =

8.8.27 <->

<-> — Returns the 2D distance between A and B.

Synopsis

double precision <->( geometry A , geometry B );

double precision <->( geography A , geography B );

Description

The <-> operator returns the 2D distance between two geometries. Used in the "ORDER BY" clause provides index-assisted
nearest-neighbor result sets. For PostgreSQL below 9.5 only gives centroid distance of bounding boxes and for PostgreSQL 9.5+,
does true KNN distance search giving true distance between geometries, and distance sphere for geographies.

Note
This operand will make use of 2D GiST indexes that may be available on the geometries. It is different from other
operators that use spatial indexes in that the spatial index is only used when the operator is in the ORDER BY clause.

Note
Index only kicks in if one of the geometries is a constant (not in a subquery/cte). e.g. ’SRID=3005;POINT(1011102
450541)’::geometry instead of a.geom

Refer to OpenGeo workshop: Nearest-Neighbour Searching for real live example.

Enhanced: 2.2.0 -- True KNN ("K nearest neighbor") behavior for geometry and geography for PostgreSQL 9.5+. Note for
geography KNN is based on sphere rather than spheroid. For PostgreSQL 9.4 and below, geography support is new but only
supports centroid box.
Changed: 2.2.0 -- For PostgreSQL 9.5 users, old Hybrid syntax may be slower, so you’ll want to get rid of that hack if you are
running your code only on PostGIS 2.2+ 9.5+. See examples below.
Availability: 2.0.0 -- Weak KNN provides nearest neighbors based on geometry centroid distances instead of true distances.
Exact results for points, inexact for all other types. Available for PostgreSQL 9.1+

Examples

SELECT ST_Distance(geom, 'SRID=3005;POINT(1011102 450541)'::geometry) as d,edabbr, vaabbr

FROM va2005
ORDER BY d limit 10;

d | edabbr | vaabbr
------------------+--------+--------
0 | ALQ | 128
5541.57712511724 | ALQ | 129A
5579.67450712005 | ALQ | 001
6083.4207708641 | ALQ | 131
7691.2205404848 | ALQ | 003
PostGIS 2.4.3 Manual 261 / 803

7900.75451037313 | ALQ | 122

8694.20710669982 | ALQ | 129B
9564.24289057111 | ALQ | 130
12089.665931705 | ALQ | 127
18472.5531479404 | ALQ | 002
(10 rows)

Then the KNN raw answer:

SELECT st_distance(geom, 'SRID=3005;POINT(1011102 450541)'::geometry) as d,edabbr, vaabbr
FROM va2005
ORDER BY geom <-> 'SRID=3005;POINT(1011102 450541)'::geometry limit 10;

d | edabbr | vaabbr
------------------+--------+--------
0 | ALQ | 128
5541.57712511724 | ALQ | 129A
5579.67450712005 | ALQ | 001
6083.4207708641 | ALQ | 131
7691.2205404848 | ALQ | 003
7900.75451037313 | ALQ | 122
8694.20710669982 | ALQ | 129B
9564.24289057111 | ALQ | 130
12089.665931705 | ALQ | 127
18472.5531479404 | ALQ | 002
(10 rows)

If you run "EXPLAIN ANALYZE" on the two queries you would see a performance improvement for the second.
For users running with PostgreSQL < 9.5, use a hybrid query to find the true nearest neighbors. First a CTE query using the
index-assisted KNN, then an exact query to get correct ordering:
WITH index_query AS (
SELECT ST_Distance(geom, 'SRID=3005;POINT(1011102 450541)'::geometry) as d,edabbr, vaabbr
FROM va2005
ORDER BY geom <-> 'SRID=3005;POINT(1011102 450541)'::geometry LIMIT 100)
SELECT *
FROM index_query
ORDER BY d limit 10;

d | edabbr | vaabbr
------------------+--------+--------
0 | ALQ | 128
5541.57712511724 | ALQ | 129A
5579.67450712005 | ALQ | 001
6083.4207708641 | ALQ | 131
7691.2205404848 | ALQ | 003
7900.75451037313 | ALQ | 122
8694.20710669982 | ALQ | 129B
9564.24289057111 | ALQ | 130
12089.665931705 | ALQ | 127
18472.5531479404 | ALQ | 002
(10 rows)

See Also

ST_DWithin, ST_Distance, <#>

PostGIS 2.4.3 Manual 262 / 803

8.8.28 |=|

|=| — Returns the distance between A and B trajectories at their closest point of approach.

Synopsis

double precision |=|( geometry A , geometry B );

Description

The |=| operator returns the 3D distance between two trajectories (See ST_IsValidTrajectory). This is the same as ST_DistanceCPA
but as an operator it can be used for doing nearest neightbor searches using an N-dimensional index (requires PostgreSQL 9.5.0
or higher).

Note
This operand will make use of ND GiST indexes that may be available on the geometries. It is different from other
operators that use spatial indexes in that the spatial index is only used when the operator is in the ORDER BY clause.

Note
Index only kicks in if one of the geometries is a constant (not in a subquery/cte). e.g. ’SRID=3005;LINESTRINGM(0 0
0,0 0 1)’::geometry instead of a.geom

Availability: 2.2.0. Index-supported only available for PostgreSQL 9.5+

Examples

-- Save a literal query trajectory in a psql variable...

\set qt 'ST_AddMeasure(ST_MakeLine(ST_MakePointM(-350,300,0),ST_MakePointM(-410,490,0)) ←-
,10,20)'
-- Run the query !
SELECT track_id, dist FROM (
SELECT track_id, ST_DistanceCPA(tr,:qt) dist
FROM trajectories
ORDER BY tr |=| :qt
LIMIT 5
) foo;
track_id dist
----------+-------------------
395 | 0.576496831518066
380 | 5.06797130410151
390 | 7.72262293958322
385 | 9.8004461358071
405 | 10.9534397988433
(5 rows)

See Also

ST_DistanceCPA, ST_ClosestPointOfApproach, ST_IsValidTrajectory

PostGIS 2.4.3 Manual 263 / 803

8.8.29 <#>

<#> — Returns the 2D distance between A and B bounding boxes.

Synopsis

double precision <#>( geometry A , geometry B );

Description

The <#> operator returns distance between two floating point bounding boxes, possibly reading them from a spatial index
(PostgreSQL 9.1+ required). Useful for doing nearest neighbor approximate distance ordering.

Note
This operand will make use of any indexes that may be available on the geometries. It is different from other operators
that use spatial indexes in that the spatial index is only used when the operator is in the ORDER BY clause.

Note
Index only kicks in if one of the geometries is a constant e.g. ORDER BY (ST_GeomFromText(’POINT(1 2)’) <#> geom)
instead of g1.geom <#>.

Availability: 2.0.0 -- KNN only available for PostgreSQL 9.1+

Examples

SELECT *
FROM (
SELECT b.tlid, b.mtfcc,
b.geom <#> ST_GeomFromText('LINESTRING(746149 2948672,745954 2948576,
745787 2948499,745740 2948468,745712 2948438,
745690 2948384,745677 2948319)',2249) As b_dist,
ST_Distance(b.geom, ST_GeomFromText('LINESTRING(746149 2948672,745954 2948576,
745787 2948499,745740 2948468,745712 2948438,
745690 2948384,745677 2948319)',2249)) As act_dist
FROM bos_roads As b
ORDER BY b_dist, b.tlid
LIMIT 100) As foo
ORDER BY act_dist, tlid LIMIT 10;

tlid | mtfcc | b_dist | act_dist

-----------+-------+------------------+------------------
85732027 | S1400 | 0 | 0
85732029 | S1400 | 0 | 0
85732031 | S1400 | 0 | 0
85734335 | S1400 | 0 | 0
85736037 | S1400 | 0 | 0
624683742 | S1400 | 0 | 128.528874268666
85719343 | S1400 | 260.839270432962 | 260.839270432962
85741826 | S1400 | 164.759294123275 | 260.839270432962
85732032 | S1400 | 277.75 | 311.830282365264
85735592 | S1400 | 222.25 | 311.830282365264
(10 rows)
PostGIS 2.4.3 Manual 264 / 803

See Also

ST_DWithin, ST_Distance, <->

8.8.30 <<->>

<<->> — Returns the n-D distance between the centroids of A and B bounding boxes.

Synopsis

double precision <<->>( geometry A , geometry B );

Description

The <<->> operator returns the n-D (euclidean) distance between the centroids of the bounding boxes of two geometries. Useful
for doing nearest neighbor approximate distance ordering.

Note
This operand will make use of n-D GiST indexes that may be available on the geometries. It is different from other
operators that use spatial indexes in that the spatial index is only used when the operator is in the ORDER BY clause.

Note
Index only kicks in if one of the geometries is a constant (not in a subquery/cte). e.g. ’SRID=3005;POINT(1011102
450541)’::geometry instead of a.geom

Availability: 2.2.0 -- KNN only available for PostgreSQL 9.1+

See Also

<<#>>, <->

8.8.31 <<#>>

<<#>> — Returns the n-D distance between A and B bounding boxes.

Synopsis

double precision <<#>>( geometry A , geometry B );

Description

The <<#>> operator returns distance between two floating point bounding boxes, possibly reading them from a spatial index
(PostgreSQL 9.1+ required). Useful for doing nearest neighbor approximate distance ordering.

Note
This operand will make use of any indexes that may be available on the geometries. It is different from other operators
that use spatial indexes in that the spatial index is only used when the operator is in the ORDER BY clause.
PostGIS 2.4.3 Manual 265 / 803

Note
Index only kicks in if one of the geometries is a constant e.g. ORDER BY (ST_GeomFromText(’POINT(1 2)’) <<#>>
geom) instead of g1.geom <<#>>.

Availability: 2.2.0 -- KNN only available for PostgreSQL 9.1+

See Also

<<->>, <#>

8.9 Spatial Relationships and Measurements

8.9.1 ST_3DClosestPoint

ST_3DClosestPoint — Returns the 3-dimensional point on g1 that is closest to g2. This is the first point of the 3D shortest line.

Synopsis

geometry ST_3DClosestPoint(geometry g1, geometry g2);

Description

Returns the 3-dimensional point on g1 that is closest to g2. This is the first point of the 3D shortest line. The 3D length of the
3D shortest line is the 3D distance.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

Availability: 2.0.0
Changed: 2.2.0 - if 2 2D geometries are input, a 2D point is returned (instead of old behavior assuming 0 for missing Z). In case
of 2D and 3D, Z is no longer assumed to be 0 for missing Z.

Examples

linestring and point -- both 3d and 2d closest point

SELECT ST_AsEWKT(ST_3DClosestPoint(line,pt)) AS cp3d_line_pt,
ST_AsEWKT(ST_ClosestPoint(line,pt)) As cp2d_line_pt
FROM (SELECT 'POINT(100 100 30)'::geometry As pt,
'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 1000)':: ←-
geometry As line
) As foo;

cp3d_line_pt | ←-
cp2d_line_pt
-----------------------------------------------------------+--------------------------------------

POINT(54.6993798867619 128.935022917228 11.5475869506606) | POINT(73.0769230769231 ←-

115.384615384615)
PostGIS 2.4.3 Manual 266 / 803

linestring and multipoint -- both 3d and 2d closest point

SELECT ST_AsEWKT(ST_3DClosestPoint(line,pt)) AS cp3d_line_pt,
ST_AsEWKT(ST_ClosestPoint(line,pt)) As cp2d_line_pt
FROM (SELECT 'MULTIPOINT(100 100 30, 50 74 1000)'::geometry As pt,
'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 900)':: ←-
geometry As line
) As foo;

cp3d_line_pt | cp2d_line_pt
-----------------------------------------------------------+--------------
POINT(54.6993798867619 128.935022917228 11.5475869506606) | POINT(50 75)

Multilinestring and polygon both 3d and 2d closest point

SELECT ST_AsEWKT(ST_3DClosestPoint(poly, mline)) As cp3d,
ST_AsEWKT(ST_ClosestPoint(poly, mline)) As cp2d
FROM (SELECT ST_GeomFromEWKT('POLYGON((175 150 5, 20 40 5, 35 45 5, 50 60 5, ←-
100 100 5, 175 150 5))') As poly,
ST_GeomFromEWKT('MULTILINESTRING((175 155 2, 20 40 20, 50 60 -2, 125 ←-
100 1, 175 155 1),
(1 10 2, 5 20 1))') As mline ) As foo;
cp3d | cp2d
-------------------------------------------+--------------
POINT(39.993580415989 54.1889925532825 5) | POINT(20 40)

See Also

ST_AsEWKT, ST_ClosestPoint, ST_3DDistance, ST_3DShortestLine

8.9.2 ST_3DDistance

ST_3DDistance — For geometry type Returns the 3-dimensional cartesian minimum distance (based on spatial ref) between two
geometries in projected units.

Synopsis

float ST_3DDistance(geometry g1, geometry g2);

Description

For geometry type returns the 3-dimensional minimum cartesian distance between two geometries in projected units (spatial ref
units).

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This method implements the SQL/MM specification. SQL-MM ?

This method is also provided by SFCGAL backend.

Availability: 2.0.0
Changed: 2.2.0 - In case of 2D and 3D, Z is no longer assumed to be 0 for missing Z.
PostGIS 2.4.3 Manual 267 / 803

Examples

-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (3D point ←-
and line compared 2D point and line)
-- Note: currently no vertical datum support so Z is not transformed and assumed to be same ←-
units as final.
SELECT ST_3DDistance(
ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 4)'),2163),
ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 ←-
20)'),2163)
) As dist_3d,
ST_Distance(
ST_Transform(ST_GeomFromText('POINT(-72.1235 42.3521)',4326),2163),
ST_Transform(ST_GeomFromText('LINESTRING(-72.1260 42.45, -72.123 42.1546)', 4326) ←-
,2163)
) As dist_2d;

dist_3d | dist_2d
------------------+-----------------
127.295059324629 | 126.66425605671

-- Multilinestring and polygon both 3d and 2d distance

-- Same example as 3D closest point example
SELECT ST_3DDistance(poly, mline) As dist3d,
ST_Distance(poly, mline) As dist2d
FROM (SELECT ST_GeomFromEWKT('POLYGON((175 150 5, 20 40 5, 35 45 5, 50 60 5, 100 ←-
100 5, 175 150 5))') As poly,
ST_GeomFromEWKT('MULTILINESTRING((175 155 2, 20 40 20, 50 60 -2, 125 100 1, ←-
175 155 1),
(1 10 2, 5 20 1))') As mline ) As foo;
dist3d | dist2d
-------------------+--------
0.716635696066337 | 0

See Also

ST_Distance, ST_3DClosestPoint, ST_3DDWithin, ST_3DMaxDistance, ST_3DShortestLine, ST_Transform

8.9.3 ST_3DDWithin

ST_3DDWithin — For 3d (z) geometry type Returns true if two geometries 3d distance is within number of units.

Synopsis

boolean ST_3DDWithin(geometry g1, geometry g2, double precision distance_of_srid);

Description

For geometry type returns true if the 3d distance between two objects is within distance_of_srid specified projected units (spatial
ref units).

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

PostGIS 2.4.3 Manual 268 / 803

This method implements the SQL/MM specification. SQL-MM ?

Availability: 2.0.0

Examples

-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (3D point ←-
and line compared 2D point and line)
-- Note: currently no vertical datum support so Z is not transformed and assumed to be same ←-
units as final.
SELECT ST_3DDWithin(
ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 4)'),2163),
ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 ←-
20)'),2163),
126.8
) As within_dist_3d,
ST_DWithin(
ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 4)'),2163),
ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 ←-
20)'),2163),
126.8
) As within_dist_2d;

within_dist_3d | within_dist_2d
----------------+----------------
f | t

See Also

ST_3DDistance, ST_Distance, ST_DWithin, ST_3DMaxDistance, ST_Transform

8.9.4 ST_3DDFullyWithin

ST_3DDFullyWithin — Returns true if all of the 3D geometries are within the specified distance of one another.

Synopsis

boolean ST_3DDFullyWithin(geometry g1, geometry g2, double precision distance);

Description

Returns true if the 3D geometries are fully within the specified distance of one another. The distance is specified in units defined
by the spatial reference system of the geometries. For this function to make sense, the source geometries must both be of the
same coordinate projection, having the same SRID.

Note
This function call will automatically include a bounding box comparison that will make use of any indexes that are
available on the geometries.

Availability: 2.0.0

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

PostGIS 2.4.3 Manual 269 / 803

Examples

-- This compares the difference between fully within and distance within as well
-- as the distance fully within for the 2D footprint of the line/point vs. the 3d fully ←-
within
SELECT ST_3DDFullyWithin(geom_a, geom_b, 10) as D3DFullyWithin10, ST_3DDWithin(geom_a, ←-
geom_b, 10) as D3DWithin10,
ST_DFullyWithin(geom_a, geom_b, 20) as D2DFullyWithin20,
ST_3DDFullyWithin(geom_a, geom_b, 20) as D3DFullyWithin20 from
(select ST_GeomFromEWKT('POINT(1 1 2)') as geom_a,
ST_GeomFromEWKT('LINESTRING(1 5 2, 2 7 20, 1 9 100, 14 12 3)') as geom_b) t1;
d3dfullywithin10 | d3dwithin10 | d2dfullywithin20 | d3dfullywithin20
------------------+-------------+------------------+------------------
f | t | t | f

See Also

ST_3DMaxDistance, ST_3DDWithin, ST_DWithin, ST_DFullyWithin

8.9.5 ST_3DIntersects

ST_3DIntersects — Returns TRUE if the Geometries "spatially intersect" in 3d - only for points, linestrings, polygons, polyhedral
surface (area). With SFCGAL backend enabled also supports TINS

Synopsis

boolean ST_3DIntersects( geometry geomA , geometry geomB );

Description

Overlaps, Touches, Within all imply spatial intersection. If any of the aforementioned returns true, then the geometries also
spatially intersect. Disjoint implies false for spatial intersection.
Availability: 2.0.0

Note
This function call will automatically include a bounding box comparison that will make use of any indexes that are
available on the geometries.

Note
In order to take advantage of support for TINS, you need to enable the SFCGAL backend. This can be done at session
time with: set postgis.backend = sfcgal; or at the database or system level. Database level can be done
with ALTER DATABASE gisdb SET postgis.backend = sfcgal;.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 270 / 803

This method is also provided by SFCGAL backend.

This method implements the SQL/MM specification. SQL-MM 3: ?

Geometry Examples

SELECT ST_3DIntersects(pt, line), ST_Intersects(pt,line)

FROM (SELECT 'POINT(0 0 2)'::geometry As pt,
'LINESTRING (0 0 1, 0 2 3 )'::geometry As line) As foo;
st_3dintersects | st_intersects
-----------------+---------------
f | t
(1 row)

TIN Examples

set postgis.backend = sfcgal;

SELECT ST_3DIntersects('TIN(((0 0,1 0,0 1,0 0)))'::geometry, 'POINT(.1 .1)'::geometry);
st_3dintersects
-----------------
t

See Also

ST_Intersects

8.9.6 ST_3DLongestLine

ST_3DLongestLine — Returns the 3-dimensional longest line between two geometries

Synopsis

geometry ST_3DLongestLine(geometry g1, geometry g2);

Description

Returns the 3-dimensional longest line between two geometries. The function will only return the first longest line if more than
one. The line returned will always start in g1 and end in g2. The 3D length of the line this function returns will always be the
same as ST_3DMaxDistance returns for g1 and g2.
Availability: 2.0.0
Changed: 2.2.0 - if 2 2D geometries are input, a 2D point is returned (instead of old behavior assuming 0 for missing Z). In case
of 2D and 3D, Z is no longer assumed to be 0 for missing Z.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

Examples
PostGIS 2.4.3 Manual 271 / 803

linestring and point -- both 3d and 2d longest line

SELECT ST_AsEWKT(ST_3DLongestLine(line,pt)) AS lol3d_line_pt,
ST_AsEWKT(ST_LongestLine(line,pt)) As lol2d_line_pt
FROM (SELECT 'POINT(100 100 30)'::geometry As pt,
'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 1000)':: ←-
geometry As line
) As foo;

lol3d_line_pt | lol2d_line_pt
-----------------------------------+----------------------------
LINESTRING(50 75 1000,100 100 30) | LINESTRING(98 190,100 100)

linestring and multipoint -- both 3d and 2d longest line

SELECT ST_AsEWKT(ST_3DLongestLine(line,pt)) AS lol3d_line_pt,
ST_AsEWKT(ST_LongestLine(line,pt)) As lol2d_line_pt
FROM (SELECT 'MULTIPOINT(100 100 30, 50 74 1000)'::geometry As pt,
'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 900)':: ←-
geometry As line
) As foo;

lol3d_line_pt | lol2d_line_pt
---------------------------------+--------------------------
LINESTRING(98 190 1,50 74 1000) | LINESTRING(98 190,50 74)

Multilinestring and polygon both 3d and 2d longest line

SELECT ST_AsEWKT(ST_3DLongestLine(poly, mline)) As lol3d,
ST_AsEWKT(ST_LongestLine(poly, mline)) As lol2d
FROM (SELECT ST_GeomFromEWKT('POLYGON((175 150 5, 20 40 5, 35 45 5, 50 60 5, ←-
100 100 5, 175 150 5))') As poly,
ST_GeomFromEWKT('MULTILINESTRING((175 155 2, 20 40 20, 50 60 -2, 125 ←-
100 1, 175 155 1),
(1 10 2, 5 20 1))') As mline ) As foo;
lol3d | lol2d
------------------------------+--------------------------
LINESTRING(175 150 5,1 10 2) | LINESTRING(175 150,1 10)

See Also

ST_3DClosestPoint, ST_3DDistance, ST_LongestLine, ST_3DShortestLine, ST_3DMaxDistance

8.9.7 ST_3DMaxDistance

ST_3DMaxDistance — For geometry type Returns the 3-dimensional cartesian maximum distance (based on spatial ref) between
two geometries in projected units.

Synopsis

float ST_3DMaxDistance(geometry g1, geometry g2);

PostGIS 2.4.3 Manual 272 / 803

Description

For geometry type returns the 3-dimensional maximum cartesian distance between two geometries in projected units (spatial ref
units).

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

Availability: 2.0.0
Changed: 2.2.0 - In case of 2D and 3D, Z is no longer assumed to be 0 for missing Z.

Examples

-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (3D point ←-
and line compared 2D point and line)
-- Note: currently no vertical datum support so Z is not transformed and assumed to be same ←-
units as final.
SELECT ST_3DMaxDistance(
ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 10000)'),2163),
ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 ←-
20)'),2163)
) As dist_3d,
ST_MaxDistance(
ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 10000)'),2163),
ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 ←-
20)'),2163)
) As dist_2d;

dist_3d | dist_2d
------------------+------------------
24383.7467488441 | 22247.8472107251

See Also

ST_Distance, ST_3DDWithin, ST_3DMaxDistance, ST_Transform

8.9.8 ST_3DShortestLine

ST_3DShortestLine — Returns the 3-dimensional shortest line between two geometries

Synopsis

geometry ST_3DShortestLine(geometry g1, geometry g2);

Description

Returns the 3-dimensional shortest line between two geometries. The function will only return the first shortest line if more than
one, that the function finds. If g1 and g2 intersects in just one point the function will return a line with both start and end in that
intersection-point. If g1 and g2 are intersecting with more than one point the function will return a line with start and end in the
same point but it can be any of the intersecting points. The line returned will always start in g1 and end in g2. The 3D length of
the line this function returns will always be the same as ST_3DDistance returns for g1 and g2.
Availability: 2.0.0
PostGIS 2.4.3 Manual 273 / 803

Changed: 2.2.0 - if 2 2D geometries are input, a 2D point is returned (instead of old behavior assuming 0 for missing Z). In case
of 2D and 3D, Z is no longer assumed to be 0 for missing Z.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

Examples

linestring and point -- both 3d and 2d shortest line

SELECT ST_AsEWKT(ST_3DShortestLine(line,pt)) AS shl3d_line_pt,
ST_AsEWKT(ST_ShortestLine(line,pt)) As shl2d_line_pt
FROM (SELECT 'POINT(100 100 30)'::geometry As pt,
'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 1000)':: ←-
geometry As line
) As foo;

shl3d_line_pt | ←-
shl2d_line_pt
----------------------------------------------------------------------------+---------------------

LINESTRING(54.6993798867619 128.935022917228 11.5475869506606,100 100 30) | ←-

LINESTRING(73.0769230769231 115.384615384615,100 100)
linestring and multipoint -- both 3d and 2d shortest line
SELECT ST_AsEWKT(ST_3DShortestLine(line,pt)) AS shl3d_line_pt,
ST_AsEWKT(ST_ShortestLine(line,pt)) As shl2d_line_pt
FROM (SELECT 'MULTIPOINT(100 100 30, 50 74 1000)'::geometry As pt,
'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 900)':: ←-
geometry As line
) As foo;

shl3d_line_pt | ←-
shl2d_line_pt
---------------------------------------------------------------------------+----------------------

LINESTRING(54.6993798867619 128.935022917228 11.5475869506606,100 100 30) | LINESTRING ←-

(50 75,50 74)
Multilinestring and polygon both 3d and 2d shortest line
SELECT ST_AsEWKT(ST_3DShortestLine(poly, mline)) As shl3d,
ST_AsEWKT(ST_ShortestLine(poly, mline)) As shl2d
FROM (SELECT ST_GeomFromEWKT('POLYGON((175 150 5, 20 40 5, 35 45 5, 50 60 5, ←-
100 100 5, 175 150 5))') As poly,
ST_GeomFromEWKT('MULTILINESTRING((175 155 2, 20 40 20, 50 60 -2, 125 ←-
100 1, 175 155 1),
(1 10 2, 5 20 1))') As mline ) As foo;
shl3d ←-
| shl2d
--------------------------------------------------------------------------------------------------

LINESTRING(39.993580415989 54.1889925532825 5,40.4078575708294 53.6052383805529 ←-

5.03423778139177) | LINESTRING(20 40,20 40)
PostGIS 2.4.3 Manual 274 / 803

See Also

ST_3DClosestPoint, ST_3DDistance, ST_LongestLine, ST_ShortestLine, ST_3DMaxDistance

8.9.9 ST_Area

ST_Area — Returns the area of the surface if it is a Polygon or MultiPolygon. For geometry, a 2D Cartesian area is determined
with units specified by the SRID. For geography, area is determined on a curved surface with units in square meters.

Synopsis

float ST_Area(geometry g1);

float ST_Area(geography geog, boolean use_spheroid=true);

Description

Returns the area of the geometry if it is a Polygon or MultiPolygon. Return the area measurement of an ST_Surface or
ST_MultiSurface value. For geometry, a 2D Cartesian area is determined with units specified by the SRID. For geography,
by default area is determined on a spheroid with units in square meters. To measure around the faster but less accurate sphere,
use ST_Area(geog,false).
Enhanced: 2.0.0 - support for 2D polyhedral surfaces was introduced.
Enhanced: 2.2.0 - measurement on spheroid performed with GeographicLib for improved accuracy and robustness. Requires
Proj >= 4.9.0 to take advantage of the new feature.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 8.1.2, 9.5.3

This function supports Polyhedral surfaces.

Note
For polyhedral surfaces, only supports 2D polyhedral surfaces (not 2.5D). For 2.5D, may give a non-zero answer, but
only for the faces that sit completely in XY plane.

This method is also provided by SFCGAL backend.

Examples

Return area in square feet for a plot of Massachusetts land and multiply by conversion to get square meters. Note this is in square
feet because EPSG:2249 is Massachusetts State Plane Feet
SELECT ST_Area(the_geom) As sqft, ST_Area(the_geom)*POWER(0.3048,2) As sqm
FROM (SELECT
ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,
743265 2967450,743265.625 2967416,743238 2967416))',2249) ) As foo(the_geom);
sqft | sqm
---------+-------------
928.625 | 86.27208552
PostGIS 2.4.3 Manual 275 / 803

Return area square feet and transform to Massachusetts state plane meters (EPSG:26986) to get square meters. Note this is in
square feet because 2249 is Massachusetts State Plane Feet and transformed area is in square meters since EPSG:26986 is state
plane Massachusetts meters

SELECT ST_Area(the_geom) As sqft, ST_Area(ST_Transform(the_geom,26986)) As sqm

FROM (SELECT
ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,
743265 2967450,743265.625 2967416,743238 2967416))',2249) ) As foo(the_geom);
sqft | sqm
---------+------------------
928.625 | 86.2724304199219

Return area square feet and square meters using geography data type. Note that we transform to our geometry to geography
(before you can do that make sure your geometry is in WGS 84 long lat 4326). Geography always measures in meters. This is
just for demonstration to compare. Normally your table will be stored in geography data type already.

SELECT ST_Area(the_geog)/POWER(0.3048,2) As sqft_spheroid, ST_Area(the_geog,false)/POWER ←-

(0.3048,2) As sqft_sphere, ST_Area(the_geog) As sqm_spheroid
FROM (SELECT
geography(
ST_Transform(
ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,743265 2967450,743265.625 ←-
2967416,743238 2967416))',
2249
) ,4326
)
)
) As foo(the_geog);
sqft_spheroid | sqft_sphere | sqm_spheroid
------------------+------------------+------------------
928.684403538925 | 927.049336105925 | 86.2776042893529

--if your data is in geography already

SELECT ST_Area(the_geog)/POWER(0.3048,2) As sqft, ST_Area(the_geog) As sqm
FROM somegeogtable;

See Also

ST_GeomFromText, ST_GeographyFromText, ST_SetSRID, ST_Transform

8.9.10 ST_Azimuth

ST_Azimuth — Returns the north-based azimuth as the angle in radians measured clockwise from the vertical on pointA to
pointB.

Synopsis

float ST_Azimuth(geometry pointA, geometry pointB);

float ST_Azimuth(geography pointA, geography pointB);

Description

Returns the azimuth in radians of the segment defined by the given point geometries, or NULL if the two points are coincident.
The azimuth is angle is referenced from north, and is positive clockwise: North = 0; East = π/2; South = π; West = 3π/2.
PostGIS 2.4.3 Manual 276 / 803

For the geography type, the forward azimuth is solved as part of the inverse geodesic problem.
The azimuth is mathematical concept defined as the angle between a reference plane and a point, with angular units in radians.
Units can be converted to degrees using a built-in PostgreSQL function degrees(), as shown in the example.
Availability: 1.1.0
Enhanced: 2.0.0 support for geography was introduced.
Enhanced: 2.2.0 measurement on spheroid performed with GeographicLib for improved accuracy and robustness. Requires Proj
>= 4.9.0 to take advantage of the new feature.
Azimuth is especially useful in conjunction with ST_Translate for shifting an object along its perpendicular axis. See up-
gis_lineshift Plpgsqlfunctions PostGIS wiki section for example of this.

Examples

Geometry Azimuth in degrees

SELECT degrees(ST_Azimuth(ST_Point(25, 45), ST_Point(75, 100))) AS degA_B,
degrees(ST_Azimuth(ST_Point(75, 100), ST_Point(25, 45))) AS degB_A;

dega_b | degb_a
------------------+------------------
42.2736890060937 | 222.273689006094

Green: the start Point(25,45) with its vertical. Yellow: Green: the start Point(75,100) with its vertical. Yellow:
degA_B as the path to travel (azimuth). degB_A as the path to travel (azimuth).

See Also

ST_Point, ST_Translate, ST_Project, PostgreSQL Math Functions

8.9.11 ST_Centroid

ST_Centroid — Returns the geometric center of a geometry.

PostGIS 2.4.3 Manual 277 / 803

Synopsis

geometry ST_Centroid(geometry g1);

geography ST_Centroid(geography g1, boolean use_spheroid=true);

Description

Computes the geometric center of a geometry, or equivalently, the center of mass of the geometry as a POINT. For [MULTI]POINTs,
this is computed as the arithmetic mean of the input coordinates. For [MULTI]LINESTRINGs, this is computed as the weighted
length of each line segment. For [MULTI]POLYGONs, "weight" is thought in terms of area. If an empty geometry is sup-
plied, an empty GEOMETRYCOLLECTION is returned. If NULL is supplied, NULL is returned. If CIRCULARSTRING or
COMPOUNDCURVE are supplied, they are converted to linestring wtih CurveToLine first, then same than for LINESTRING
New in 2.3.0 : support CIRCULARSTRING and COMPOUNDCURVE (using CurveToLine)
Availability: 2.4.0 support for geography was introduced.
The centroid is equal to the centroid of the set of component Geometries of highest dimension (since the lower-dimension
geometries contribute zero "weight" to the centroid).

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 8.1.4, 9.5.5

Examples

In each of the following illustrations, the green dot represents the centroid of the source geometry.

Centroid of a MULTIPOINT Centroid of a LINESTRING

PostGIS 2.4.3 Manual 278 / 803

Centroid of a POLYGON Centroid of a GEOMETRYCOLLECTION

SELECT ST_AsText(ST_Centroid('MULTIPOINT ( -1 0, -1 2, -1 3, -1 4, -1 7, 0 1, 0 3, 1 1, 2 ←-
0, 6 0, 7 8, 9 8, 10 6 )'));
st_astext
------------------------------------------
POINT(2.30769230769231 3.30769230769231)
(1 row)

SELECT ST_AsText(ST_centroid(g))
FROM ST_GeomFromText('CIRCULARSTRING(0 2, -1 1,0 0, 0.5 0, 1 0, 2 1, 1 2, 0.5 2, 0 2)') ←-
AS g ;
------------------------------------------
POINT(0.5 1)

SELECT ST_AsText(ST_centroid(g))
FROM ST_GeomFromText('COMPOUNDCURVE(CIRCULARSTRING(0 2, -1 1,0 0),(0 0, 0.5 0, 1 0), ←-
CIRCULARSTRING( 1 0, 2 1, 1 2),(1 2, 0.5 2, 0 2))' ) AS g;
------------------------------------------
POINT(0.5 1)

See Also

ST_PointOnSurface

8.9.12 ST_ClosestPoint

ST_ClosestPoint — Returns the 2-dimensional point on g1 that is closest to g2. This is the first point of the shortest line.

Synopsis

geometry ST_ClosestPoint(geometry g1, geometry g2);

PostGIS 2.4.3 Manual 279 / 803

Description

Returns the 2-dimensional point on g1 that is closest to g2. This is the first point of the shortest line.

Note
If you have a 3D Geometry, you may prefer to use ST_3DClosestPoint.

Availability: 1.5.0

Examples

Closest between point and linestring is the point itself, but

closest point between a linestring and point is the point on
line string that is closest. closest point on polygon A to polygon B
SELECT ST_AsText(ST_ClosestPoint(pt,line) ←- SELECT ST_AsText(
) AS cp_pt_line, ST_ClosestPoint(
ST_AsText(ST_ClosestPoint(line,pt ←-
ST_GeomFromText(' ←-
)) As cp_line_pt
POLYGON((175 150, 20 40, 50 60, 125 100, 175 150
FROM (SELECT 'POINT(100 100)'::geometry ←-
ST_Buffer( ←-
As pt,
ST_GeomFromText('POINT(110 170)'), 20)
'LINESTRING (20 80, 98 ←-
)
190, 110 180, 50 75 )'::geometry As line
) As ptwkt;
) As foo;
ptwkt
------------------------------------------ ←-
cp_pt_line | ←-
cp_line_pt
POINT(140.752120669087
----------------+------------------------------------------ ←- 125.695053378061)

POINT(100 100) | POINT(73.0769230769231 ←-

115.384615384615)
PostGIS 2.4.3 Manual 280 / 803

See Also

ST_3DClosestPoint,ST_Distance, ST_LongestLine, ST_ShortestLine, ST_MaxDistance

8.9.13 ST_ClusterDBSCAN

ST_ClusterDBSCAN — Windowing function that returns integer id for the cluster each input geometry is in based on 2D
implementation of Density-based spatial clustering of applications with noise (DBSCAN) algorithm.

Synopsis

integer ST_ClusterDBSCAN(geometry winset geom, float8 eps, integer minpoints);

Description

Returns cluster number for each input geometry, based on a 2D implementation of the Density-based spatial clustering of appli-
cations with noise (DBSCAN) algorithm. Unlike ST_ClusterKMeans, it does not require the number of clusters to be specified,
but instead uses the desired distance (eps) and density(minpoints) parameters to construct each cluster.
An input geometry will be added to a cluster if it is either:

• A "core" geometry, that is within eps distance (Cartesian) of at least minpoints input geometries (including itself) or

• A "border" geometry, that is within eps distance of a core geometry.

Note that border geometries may be within eps distance of core geometries in more than one cluster; in this case, either
assignment would be correct, and the border geometry will be arbitrarily asssigned to one of the available clusters. In these
cases, it is possible for a correct cluster to be generated with fewer than minpoints geometries. When assignment of a border
geometry is ambiguous, repeated calls to ST_ClusterDBSCAN will produce identical results if an ORDER BY clause is included
in the window definition, but cluster assignments may differ from other implementations of the same algorithm.

Note
Input geometries that do not meet the criteria to join any other cluster will be assigned a cluster number of NULL.

Availability: 2.3.0 - requires GEOS

Examples

Assigning a cluster number to each polygon within 50 meters of each other. Require at least 2 polygons per cluster
PostGIS 2.4.3 Manual 281 / 803

name | ←-
bucket
-------------------------------------+-------- ←-

Manulife Tower | ←-
0
Park Lane Seaport I | ←-
0
Park Lane Seaport II | ←-
0
Renaissance Boston Waterfront Hotel | ←-
0
Seaport Boston Hotel | ←-
0
Seaport Hotel & World Trade Center | ←-
0
Waterside Place | ←-
0
World Trade Center East | ←-
0
100 Northern Avenue | ←-
1
100 Pier 4 | ←-
1
The Institute of Contemporary Art | ←-
1
within 50 meters at least 2 per cluster. singletons have 101 Seaport | ←-
2
NULL for cid
District Hall | ←-
SELECT name, ST_ClusterDBSCAN(geom, eps ←- 2
:= 50, minpoints := 2) over () AS cid One Marina Park Drive | ←-
FROM boston_polys 2
WHERE name > '' AND building > '' Twenty Two Liberty | ←-
AND ST_DWithin(geom, 2
ST_Transform( Vertex | ←-
ST_GeomFromText('POINT ←- 2
(-71.04054 42.35141)', 4326), 26986), Vertex | ←-
500); 2
Watermark Seaport | ←-
2
Blue Hills Bank Pavilion | ←-
NULL
World Trade Center West | ←-
NULL
(20 rows)

Combining parcels with the same cluster number into a single geometry. This uses named argument calling
SELECT cid, ST_Collect(geom) AS cluster_geom, array_agg(parcel_id) AS ids_in_cluster FROM (
SELECT parcel_id, ST_ClusterDBSCAN(geom, eps := 0.5, minpoints := 5) over () AS cid, ←-
geom
FROM parcels) sq
GROUP BY cid;

See Also

ST_DWithin, ST_ClusterKMeans, ST_ClusterIntersecting, ST_ClusterWithin

PostGIS 2.4.3 Manual 282 / 803

8.9.14 ST_ClusterIntersecting

ST_ClusterIntersecting — Aggregate. Returns an array with the connected components of a set of geometries

Synopsis

geometry[] ST_ClusterIntersecting(geometry set g);

Description

ST_ClusterIntersecting is an aggregate function that returns an array of GeometryCollections, where each GeometryCollection
represents an interconnected set of geometries.
Availability: 2.2.0 - requires GEOS

Examples

WITH testdata AS
(SELECT unnest(ARRAY['LINESTRING (0 0, 1 1)'::geometry,
'LINESTRING (5 5, 4 4)'::geometry,
'LINESTRING (6 6, 7 7)'::geometry,
'LINESTRING (0 0, -1 -1)'::geometry,
'POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0))'::geometry]) AS geom)

SELECT ST_AsText(unnest(ST_ClusterIntersecting(geom))) FROM testdata;

--result

st_astext
---------
GEOMETRYCOLLECTION(LINESTRING(0 0,1 1),LINESTRING(5 5,4 4),LINESTRING(0 0,-1 -1),POLYGON((0 ←-
0,4 0,4 4,0 4,0 0)))
GEOMETRYCOLLECTION(LINESTRING(6 6,7 7))

See Also

ST_ClusterDBSCAN, ST_ClusterKMeans, ST_ClusterWithin

8.9.15 ST_ClusterKMeans

ST_ClusterKMeans — Windowing function that returns integer id for the cluster each input geometry is in.

Synopsis

integer ST_ClusterKMeans(geometry winset geom, integer number_of_clusters);

Description

Returns 2D distance based k-means cluster number for each input geometry. The distance used for clustering is the distance
between the centroids of the geometries.
Availability: 2.3.0 - requires GEOS
PostGIS 2.4.3 Manual 283 / 803

Examples

Generate dummy set of parcels for examples

CREATE TABLE parcels AS
SELECT lpad((row_number() over())::text,3,'0') As parcel_id, geom,
('{residential, commercial}'::text[])[1 + mod(row_number()OVER(),2)] As type
FROM
ST_Subdivide(ST_Buffer('LINESTRING(40 100, 98 100, 100 150, 60 90)'::geometry,
40, 'endcap=square'),12) As geom;

Original Parcels

-- Partitioning parcel clusters by type

SELECT ST_ClusterKMeans(geom,3) over (PARTITION BY type) AS cid, parcel_id, type
FROM parcels;
-- result
cid | parcel_id | type
-----+-----------+-------------
1 | 005 | commercial
1 | 003 | commercial
2 | 007 | commercial
0 | 001 | commercial
1 | 004 | residential
0 | 002 | residential
2 | 006 | residential
(7 rows)

See Also

ST_ClusterDBSCAN, ST_ClusterIntersecting, ST_ClusterWithin, ST_Subdivide

8.9.16 ST_ClusterWithin

ST_ClusterWithin — Aggregate. Returns an array of GeometryCollections, where each GeometryCollection represents a set of
geometries separated by no more than the specified distance.
PostGIS 2.4.3 Manual 284 / 803

Synopsis

geometry[] ST_ClusterWithin(geometry set g, float8 distance);

Description

ST_ClusterWithin is an aggregate function that returns an array of GeometryCollections, where each GeometryCollection repre-
sents a set of geometries separated by no more than the specified distance. (Distances are Cartesian distances in the units of the
SRID.)
Availability: 2.2.0 - requires GEOS

Examples

WITH testdata AS
(SELECT unnest(ARRAY['LINESTRING (0 0, 1 1)'::geometry,
'LINESTRING (5 5, 4 4)'::geometry,
'LINESTRING (6 6, 7 7)'::geometry,
'LINESTRING (0 0, -1 -1)'::geometry,
'POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0))'::geometry]) AS geom)

SELECT ST_AsText(unnest(ST_ClusterWithin(geom, 1.4))) FROM testdata;

--result

st_astext
---------
GEOMETRYCOLLECTION(LINESTRING(0 0,1 1),LINESTRING(5 5,4 4),LINESTRING(0 0,-1 -1),POLYGON((0 ←-
0,4 0,4 4,0 4,0 0)))
GEOMETRYCOLLECTION(LINESTRING(6 6,7 7))

See Also

ST_ClusterDBSCAN, ST_ClusterKMeans, ST_ClusterIntersecting

8.9.17 ST_Contains

ST_Contains — Returns true if and only if no points of B lie in the exterior of A, and at least one point of the interior of B lies
in the interior of A.

Synopsis

boolean ST_Contains(geometry geomA, geometry geomB);

Description

Geometry A contains Geometry B if and only if no points of B lie in the exterior of A, and at least one point of the interior of B
lies in the interior of A. An important subtlety of this definition is that A does not contain its boundary, but A does contain itself.
Contrast that to ST_ContainsProperly where geometry A does not Contain Properly itself.
Returns TRUE if geometry B is completely inside geometry A. For this function to make sense, the source geometries must both
be of the same coordinate projection, having the same SRID. ST_Contains is the inverse of ST_Within. So ST_Contains(A,B)
implies ST_Within(B,A) except in the case of invalid geometries where the result is always false regardless or not defined.
Performed by the GEOS module
PostGIS 2.4.3 Manual 285 / 803

Enhanced: 2.3.0 Enhancement to PIP short-circuit extended to support MultiPoints with few points. Prior versions only supported
point in polygon.

Important
Do not call with a GEOMETRYCOLLECTION as an argument

Important
Do not use this function with invalid geometries. You will get unexpected results.

This function call will automatically include a bounding box comparison that will make use of any indexes that are available on
the geometries. To avoid index use, use the function _ST_Contains.
NOTE: this is the "allowable" version that returns a boolean, not an integer.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 // s2.1.13.3 -
same as within(geometry B, geometry A)

This method implements the SQL/MM specification. SQL-MM 3: 5.1.31

There are certain subtleties to ST_Contains and ST_Within that are not intuitively obvious. For details check out Subtleties of
OGC Covers, Contains, Within

Examples

The ST_Contains predicate returns TRUE in all the following illustrations.

LINESTRING / MULTIPOINT POLYGON / POINT

PostGIS 2.4.3 Manual 286 / 803

POLYGON / LINESTRING POLYGON / POLYGON

The ST_Contains predicate returns FALSE in all the following illustrations.

POLYGON / MULTIPOINT POLYGON / LINESTRING

-- A circle within a circle

SELECT ST_Contains(smallc, bigc) As smallcontainsbig,
ST_Contains(bigc,smallc) As bigcontainssmall,
ST_Contains(bigc, ST_Union(smallc, bigc)) as bigcontainsunion,
ST_Equals(bigc, ST_Union(smallc, bigc)) as bigisunion,
ST_Covers(bigc, ST_ExteriorRing(bigc)) As bigcoversexterior,
ST_Contains(bigc, ST_ExteriorRing(bigc)) As bigcontainsexterior
FROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,
ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;

-- Result
PostGIS 2.4.3 Manual 287 / 803

smallcontainsbig | bigcontainssmall | bigcontainsunion | bigisunion | bigcoversexterior | ←-

bigcontainsexterior
------------------+------------------+------------------+------------+-------------------+-----------

f | t | t | t | t | f

-- Example demonstrating difference between contains and contains properly

SELECT ST_GeometryType(geomA) As geomtype, ST_Contains(geomA,geomA) AS acontainsa, ←-
ST_ContainsProperly(geomA, geomA) AS acontainspropa,
ST_Contains(geomA, ST_Boundary(geomA)) As acontainsba, ST_ContainsProperly(geomA, ←-
ST_Boundary(geomA)) As acontainspropba
FROM (VALUES ( ST_Buffer(ST_Point(1,1), 5,1) ),
( ST_MakeLine(ST_Point(1,1), ST_Point(-1,-1) ) ),
( ST_Point(1,1) )
) As foo(geomA);

geomtype | acontainsa | acontainspropa | acontainsba | acontainspropba

--------------+------------+----------------+-------------+-----------------
ST_Polygon | t | f | f | f
ST_LineString | t | f | f | f
ST_Point | t | t | f | f

See Also

ST_Boundary, ST_ContainsProperly, ST_Covers, ST_CoveredBy, ST_Equals, ST_Within

8.9.18 ST_ContainsProperly

ST_ContainsProperly — Returns true if B intersects the interior of A but not the boundary (or exterior). A does not contain
properly itself, but does contain itself.

Synopsis

boolean ST_ContainsProperly(geometry geomA, geometry geomB);

Description

Returns true if B intersects the interior of A but not the boundary (or exterior).
A does not contain properly itself, but does contain itself.
Every point of the other geometry is a point of this geometry’s interior. The DE-9IM Intersection Matrix for the two geometries
matches [T**FF*FF*] used in ST_Relate

Note
From JTS docs slightly reworded: The advantage to using this predicate over ST_Contains and ST_Intersects is that it
can be computed efficiently, with no need to compute topology at individual points.
An example use case for this predicate is computing the intersections of a set of geometries with a large polygonal
geometry. Since intersection is a fairly slow operation, it can be more efficient to use containsProperly to filter out test
geometries which lie wholly inside the area. In these cases the intersection is known a priori to be exactly the original
test geometry.

Availability: 1.4.0 - requires GEOS >= 3.1.0.

PostGIS 2.4.3 Manual 288 / 803

Important
Do not call with a GEOMETRYCOLLECTION as an argument

Important
Do not use this function with invalid geometries. You will get unexpected results.

This function call will automatically include a bounding box comparison that will make use of any indexes that are available on
the geometries. To avoid index use, use the function _ST_ContainsProperly.

Examples

--a circle within a circle

SELECT ST_ContainsProperly(smallc, bigc) As smallcontainspropbig,
ST_ContainsProperly(bigc,smallc) As bigcontainspropsmall,
ST_ContainsProperly(bigc, ST_Union(smallc, bigc)) as bigcontainspropunion,
ST_Equals(bigc, ST_Union(smallc, bigc)) as bigisunion,
ST_Covers(bigc, ST_ExteriorRing(bigc)) As bigcoversexterior,
ST_ContainsProperly(bigc, ST_ExteriorRing(bigc)) As bigcontainsexterior
FROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,
ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;
--Result
smallcontainspropbig | bigcontainspropsmall | bigcontainspropunion | bigisunion | ←-
bigcoversexterior | bigcontainsexterior
------------------+------------------+------------------+------------+-------------------+-----------

f | t | f | t | t ←-
| f

--example demonstrating difference between contains and contains properly

SELECT ST_GeometryType(geomA) As geomtype, ST_Contains(geomA,geomA) AS acontainsa, ←-
ST_ContainsProperly(geomA, geomA) AS acontainspropa,
ST_Contains(geomA, ST_Boundary(geomA)) As acontainsba, ST_ContainsProperly(geomA, ←-
ST_Boundary(geomA)) As acontainspropba
FROM (VALUES ( ST_Buffer(ST_Point(1,1), 5,1) ),
( ST_MakeLine(ST_Point(1,1), ST_Point(-1,-1) ) ),
( ST_Point(1,1) )
) As foo(geomA);

geomtype | acontainsa | acontainspropa | acontainsba | acontainspropba

--------------+------------+----------------+-------------+-----------------
ST_Polygon | t | f | f | f
ST_LineString | t | f | f | f
ST_Point | t | t | f | f

See Also

ST_GeometryType, ST_Boundary, ST_Contains, ST_Covers, ST_CoveredBy, ST_Equals, ST_Relate, ST_Within

8.9.19 ST_Covers

ST_Covers — Returns 1 (TRUE) if no point in Geometry B is outside Geometry A

PostGIS 2.4.3 Manual 289 / 803

Synopsis

boolean ST_Covers(geometry geomA, geometry geomB);

boolean ST_Covers(geography geogpolyA, geography geogpointB);

Description

Returns 1 (TRUE) if no point in Geometry/Geography B is outside Geometry/Geography A

Performed by the GEOS module

Important
Do not call with a GEOMETRYCOLLECTION as an argument

Important
Do not use this function with invalid geometries. You will get unexpected results.

This function call will automatically include a bounding box comparison that will make use of any indexes that are available on
the geometries. To avoid index use, use the function _ST_Covers.
Enhanced: 2.4.0 Support for polygon in polygon and line in polygon added for geography type
Enhanced: 2.3.0 Enhancement to PIP short-circuit for geometry extended to support MultiPoints with few points. Prior versions
only supported point in polygon.
Availability: 1.5 - support for geography was introduced.
Availability: 1.2.2 - requires GEOS >= 3.0
NOTE: this is the "allowable" version that returns a boolean, not an integer.
Not an OGC standard, but Oracle has it too.
There are certain subtleties to ST_Contains and ST_Within that are not intuitively obvious. For details check out Subtleties of
OGC Covers, Contains, Within

Examples

Geometry example
--a circle covering a circle
SELECT ST_Covers(smallc,smallc) As smallinsmall,
ST_Covers(smallc, bigc) As smallcoversbig,
ST_Covers(bigc, ST_ExteriorRing(bigc)) As bigcoversexterior,
ST_Contains(bigc, ST_ExteriorRing(bigc)) As bigcontainsexterior
FROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,
ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;
--Result
smallinsmall | smallcoversbig | bigcoversexterior | bigcontainsexterior
--------------+----------------+-------------------+---------------------
t | f | t | f
(1 row)

Geeography Example
PostGIS 2.4.3 Manual 290 / 803

-- a point with a 300 meter buffer compared to a point, a point and its 10 meter buffer
SELECT ST_Covers(geog_poly, geog_pt) As poly_covers_pt,
ST_Covers(ST_Buffer(geog_pt,10), geog_pt) As buff_10m_covers_cent
FROM (SELECT ST_Buffer(ST_GeogFromText('SRID=4326;POINT(-99.327 31.4821)'), 300) As ←-
geog_poly,
ST_GeogFromText('SRID=4326;POINT(-99.33 31.483)') As geog_pt ) As foo;

poly_covers_pt | buff_10m_covers_cent
----------------+------------------
f | t

See Also

ST_Contains, ST_CoveredBy, ST_Within

8.9.20 ST_CoveredBy

ST_CoveredBy — Returns 1 (TRUE) if no point in Geometry/Geography A is outside Geometry/Geography B

Synopsis

boolean ST_CoveredBy(geometry geomA, geometry geomB);

boolean ST_CoveredBy(geography geogA, geography geogB);

Description

Returns 1 (TRUE) if no point in Geometry/Geography A is outside Geometry/Geography B

Performed by the GEOS module

Important
Do not call with a GEOMETRYCOLLECTION as an argument

Important
Do not use this function with invalid geometries. You will get unexpected results.

Availability: 1.2.2 - requires GEOS >= 3.0

This function call will automatically include a bounding box comparison that will make use of any indexes that are available on
the geometries. To avoid index use, use the function _ST_CoveredBy.
NOTE: this is the "allowable" version that returns a boolean, not an integer.
Not an OGC standard, but Oracle has it too.
There are certain subtleties to ST_Contains and ST_Within that are not intuitively obvious. For details check out Subtleties of
OGC Covers, Contains, Within
PostGIS 2.4.3 Manual 291 / 803

Examples

--a circle coveredby a circle

SELECT ST_CoveredBy(smallc,smallc) As smallinsmall,
ST_CoveredBy(smallc, bigc) As smallcoveredbybig,
ST_CoveredBy(ST_ExteriorRing(bigc), bigc) As exteriorcoveredbybig,
ST_Within(ST_ExteriorRing(bigc),bigc) As exeriorwithinbig
FROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,
ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;
--Result
smallinsmall | smallcoveredbybig | exteriorcoveredbybig | exeriorwithinbig
--------------+-------------------+----------------------+------------------
t | t | t | f
(1 row)

See Also

ST_Contains, ST_Covers, ST_ExteriorRing, ST_Within

8.9.21 ST_Crosses

ST_Crosses — Returns TRUE if the supplied geometries have some, but not all, interior points in common.

Synopsis

boolean ST_Crosses(geometry g1, geometry g2);

Description

ST_Crosses takes two geometry objects and returns TRUE if their intersection "spatially cross", that is, the geometries have
some, but not all interior points in common. The intersection of the interiors of the geometries must not be the empty set and
must have a dimensionality less than the maximum dimension of the two input geometries. Additionally, the intersection of the
two geometries must not equal either of the source geometries. Otherwise, it returns FALSE.
In mathematical terms, this is expressed as:

The DE-9IM Intersection Matrix for the two geometries is:

• T*T****** (for Point/Line, Point/Area, and Line/Area situations)

• T*****T** (for Line/Point, Area/Point, and Area/Line situations)
• 0******** (for Line/Line situations)

For any other combination of dimensions this predicate returns false.

The OpenGIS Simple Features Specification defines this predicate only for Point/Line, Point/Area, Line/Line, and Line/Area
situations. JTS / GEOS extends the definition to apply to Line/Point, Area/Point and Area/Line situations as well. This makes
the relation symmetric.

Important
Do not call with a GEOMETRYCOLLECTION as an argument
PostGIS 2.4.3 Manual 292 / 803

Note
This function call will automatically include a bounding box comparison that will make use of any indexes that are
available on the geometries.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.13.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.29

Examples

The following illustrations all return TRUE.

MULTIPOINT / LINESTRING MULTIPOINT / POLYGON

PostGIS 2.4.3 Manual 293 / 803

LINESTRING / POLYGON LINESTRING / LINESTRING

Consider a situation where a user has two tables: a table of roads and a table of highways.

CREATE TABLE roads ( CREATE TABLE highways (

id serial NOT NULL, id serial NOT NULL,
the_geom geometry, the_gem geometry,
CONSTRAINT roads_pkey PRIMARY KEY ( ←- CONSTRAINT roads_pkey PRIMARY KEY ( ←-
road_id) road_id)
); );

To determine a list of roads that cross a highway, use a query similiar to:
SELECT roads.id
FROM roads, highways
WHERE ST_Crosses(roads.the_geom, highways.the_geom);

8.9.22 ST_LineCrossingDirection

ST_LineCrossingDirection — Given 2 linestrings, returns a number between -3 and 3 denoting what kind of crossing behavior.
0 is no crossing.

Synopsis

integer ST_LineCrossingDirection(geometry linestringA, geometry linestringB);

Description

Given 2 linestrings, returns a number between -3 and 3 denoting what kind of crossing behavior. 0 is no crossing. This is only
supported for LINESTRING
Definition of integer constants is as follows:
PostGIS 2.4.3 Manual 294 / 803

• 0: LINE NO CROSS
• -1: LINE CROSS LEFT
• 1: LINE CROSS RIGHT

• -2: LINE MULTICROSS END LEFT

• 2: LINE MULTICROSS END RIGHT
• -3: LINE MULTICROSS END SAME FIRST LEFT

• 3: LINE MULTICROSS END SAME FIRST RIGHT

Availability: 1.4

Examples

Line 1 (green), Line 2 ball is start point, triangle are end Line 1 (green), Line 2 (blue) ball is start point, triangle are
points. Query below. end points. Query below.
SELECT ST_LineCrossingDirection(foo.line1 ←- SELECT ST_LineCrossingDirection(foo.line1 ←-
, foo.line2) As l1_cross_l2 , , foo.line2) As l1_cross_l2 ,
ST_LineCrossingDirection(foo. ←- ST_LineCrossingDirection(foo. ←-
line2, foo.line1) As l2_cross_l1 line2, foo.line1) As l2_cross_l1
FROM ( FROM (
SELECT SELECT
ST_GeomFromText('LINESTRING(25 169,89 ←- ST_GeomFromText('LINESTRING(25 169,89 ←-
114,40 70,86 43)') As line1, 114,40 70,86 43)') As line1,
ST_GeomFromText('LINESTRING(171 154,20 ←- ST_GeomFromText('LINESTRING (171 154, ←-
140,71 74,161 53)') As line2 20 140, 71 74, 2.99 90.16)') As line2
) As foo; ) As foo;

l1_cross_l2 | l2_cross_l1 l1_cross_l2 | l2_cross_l1

-------------+------------- -------------+-------------
3 | -3 2 | -2
PostGIS 2.4.3 Manual 295 / 803

Line 1 (green), Line 2 (blue) ball is start point, triangle are

end points. Query below. Line 1 (green), Line 2 (blue) ball is start point, triangle are
end points. Query below.
SELECT
ST_LineCrossingDirection(foo. ←- SELECT ST_LineCrossingDirection(foo.line1 ←-
line1, foo.line2) As l1_cross_l2 , , foo.line2) As l1_cross_l2 ,
ST_LineCrossingDirection(foo. ←- ST_LineCrossingDirection(foo. ←-
line2, foo.line1) As l2_cross_l1 line2, foo.line1) As l2_cross_l1
FROM ( FROM (SELECT
SELECT ST_GeomFromText('LINESTRING(25 ←-
ST_GeomFromText('LINESTRING(25 169,89 ←- 169,89 114,40 70,86 43)') As line1,
114,40 70,86 43)') As line1, ST_GeomFromText('LINESTRING(2.99 ←-
ST_GeomFromText('LINESTRING (20 140, 71 ←- 90.16,71 74,20 140,171 154)') As line2
74, 161 53)') As line2 ) As foo;
) As foo;
l1_cross_l2 | l2_cross_l1
l1_cross_l2 | l2_cross_l1 -------------+-------------
-------------+------------- -2 | 2
-1 | 1

SELECT s1.gid, s2.gid, ST_LineCrossingDirection(s1.the_geom, s2.the_geom)

FROM streets s1 CROSS JOIN streets s2 ON (s1.gid != s2.gid AND s1.the_geom && s2.the_geom ←-
)
WHERE ST_CrossingDirection(s1.the_geom, s2.the_geom) > 0;

See Also

ST_Crosses

8.9.23 ST_Disjoint

ST_Disjoint — Returns TRUE if the Geometries do not "spatially intersect" - if they do not share any space together.

Synopsis

boolean ST_Disjoint( geometry A , geometry B );

PostGIS 2.4.3 Manual 296 / 803

Description

Overlaps, Touches, Within all imply geometries are not spatially disjoint. If any of the aforementioned returns true, then the
geometries are not spatially disjoint. Disjoint implies false for spatial intersection.

Important
Do not call with a GEOMETRYCOLLECTION as an argument

Performed by the GEOS module

Note
This function call does not use indexes

Note
NOTE: this is the "allowable" version that returns a boolean, not an integer.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 //s2.1.13.3 -
a.Relate(b, ’FF*FF****’)

This method implements the SQL/MM specification. SQL-MM 3: 5.1.26

Examples

SELECT ST_Disjoint('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )'::geometry);

st_disjoint
---------------
t
(1 row)
SELECT ST_Disjoint('POINT(0 0)'::geometry, 'LINESTRING ( 0 0, 0 2 )'::geometry);
st_disjoint
---------------
f
(1 row)

See Also

ST_IntersectsST_Intersects

8.9.24 ST_Distance

ST_Distance — For geometry type Returns the 2D Cartesian distance between two geometries in projected units (based on spatial
ref). For geography type defaults to return minimum geodesic distance between two geographies in meters.
PostGIS 2.4.3 Manual 297 / 803

Synopsis

float ST_Distance(geometry g1, geometry g2);

float ST_Distance(geography gg1, geography gg2);
float ST_Distance(geography gg1, geography gg2, boolean use_spheroid);

Description

For geometry type returns the minimum 2D Cartesian distance between two geometries in projected units (spatial ref units). For
geography type defaults to return the minimum geodesic distance between two geographies in meters. If use_spheroid is false, a
faster sphere calculation is used instead of a spheroid.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.23

This method supports Circular Strings and Curves

This method is also provided by SFCGAL backend.

Availability: 1.5.0 geography support was introduced in 1.5. Speed improvements for planar to better handle large or many vertex
geometries
Enhanced: 2.1.0 improved speed for geography. See Making Geography faster for details.
Enhanced: 2.1.0 - support for curved geometries was introduced.
Enhanced: 2.2.0 - measurement on spheroid performed with GeographicLib for improved accuracy and robustness. Requires
Proj >= 4.9.0 to take advantage of the new feature.

Basic Geometry Examples

--Geometry example - units in planar degrees 4326 is WGS 84 long lat unit=degrees
SELECT ST_Distance(
ST_GeomFromText('POINT(-72.1235 42.3521)',4326),
ST_GeomFromText('LINESTRING(-72.1260 42.45, -72.123 42.1546)', 4326)
);
st_distance
-----------------
0.00150567726382282

-- Geometry example - units in meters (SRID: 26986 Massachusetts state plane meters) (most ←-
accurate for Massachusetts)
SELECT ST_Distance(
ST_Transform(ST_GeomFromText('POINT(-72.1235 42.3521)',4326),26986),
ST_Transform(ST_GeomFromText('LINESTRING(-72.1260 42.45, -72.123 42.1546)', 4326) ←-
,26986)
);
st_distance
-----------------
123.797937878454

-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (least ←-
accurate)
SELECT ST_Distance(
ST_Transform(ST_GeomFromText('POINT(-72.1235 42.3521)',4326),2163),
ST_Transform(ST_GeomFromText('LINESTRING(-72.1260 42.45, -72.123 42.1546)', 4326) ←-
,2163)
PostGIS 2.4.3 Manual 298 / 803

);

st_distance
------------------
126.664256056812

Geography Examples

-- same as geometry example but note units in meters - use sphere for slightly faster less ←-
accurate
SELECT ST_Distance(gg1, gg2) As spheroid_dist, ST_Distance(gg1, gg2, false) As sphere_dist
FROM (SELECT
ST_GeogFromText('SRID=4326;POINT(-72.1235 42.3521)') As gg1,
ST_GeogFromText('SRID=4326;LINESTRING(-72.1260 42.45, -72.123 42.1546)') As gg2
) As foo ;

spheroid_dist | sphere_dist
------------------+------------------
123.802076746848 | 123.475736916397

See Also

ST_3DDistance, ST_DWithin, ST_DistanceSphere, ST_DistanceSpheroid, ST_MaxDistance, ST_HausdorffDistance, ST_FrechetDistan

ST_Transform

8.9.25 ST_MinimumClearance

ST_MinimumClearance — Returns the minimum clearance of a geometry, a measure of a geometry’s robustness.

Synopsis

float ST_MinimumClearance(geometry g);

Description

It is not uncommon to have a geometry that, while meeting the criteria for validity according to ST_IsValid (polygons) or
ST_IsSimple (lines), would become invalid if one of the vertices moved by a slight distance, as can happen during conversion
to text-based formats (such as WKT, KML, GML GeoJSON), or binary formats that do not use double-precision floating point
coordinates (MapInfo TAB).
A geometry’s "minimum clearance" is the smallest distance by which a vertex of the geometry could be moved to produce an
invalid geometry. It can be thought of as a quantitative measure of a geometry’s robustness, where increasing values of minimum
clearance indicate increasing robustness.
If a geometry has a minimum clearance of e, it can be said that:

• No two distinct vertices in the geometry are separated by less than e.

• No vertex is closer than e to a line segement of which it is not an endpoint.

If no minimum clearance exists for a geometry (for example, a single point, or a multipoint whose points are identical), then
ST_MinimumClearance will return Infinity.
Availability: 2.3.0 - requires GEOS >= 3.6.0
PostGIS 2.4.3 Manual 299 / 803

Examples

SELECT ST_MinimumClearance('POLYGON ((0 0, 1 0, 1 1, 0.5 3.2e-4, 0 0))');

st_minimumclearance
---------------------
0.00032

See Also

ST_MinimumClearanceLine

8.9.26 ST_MinimumClearanceLine

ST_MinimumClearanceLine — Returns the two-point LineString spanning a geometry’s minimum clearance.

Synopsis

Geometry ST_MinimumClearanceLine(geometry g);

Description

Returns the two-point LineString spanning a geometry’s minimum clearance. If the geometry does not have a minimum clear-
ance, LINESTRING EMPTY will be returned.
Availability: 2.3.0 - requires GEOS >= 3.6.0

Examples

SELECT ST_AsText(ST_MinimumClearanceLine('POLYGON ((0 0, 1 0, 1 1, 0.5 3.2e-4, 0 0))'));

st_astext
-------------------------------
LINESTRING(0.5 0.00032,0.5 0)

See Also

ST_MinimumClearance

8.9.27 ST_HausdorffDistance

ST_HausdorffDistance — Returns the Hausdorff distance between two geometries. Basically a measure of how similar or
dissimilar 2 geometries are. Units are in the units of the spatial reference system of the geometries.

Synopsis

float ST_HausdorffDistance(geometry g1, geometry g2);

float ST_HausdorffDistance(geometry g1, geometry g2, float densifyFrac);
PostGIS 2.4.3 Manual 300 / 803

Description

Implements algorithm for computing a distance metric which can be thought of as the "Discrete Hausdorff Distance". This is the
Hausdorff distance restricted to discrete points for one of the geometries. Wikipedia article on Hausdorff distance Martin Davis
note on how Hausdorff Distance calculation was used to prove correctness of the CascadePolygonUnion approach.
When densifyFrac is specified, this function performs a segment densification before computing the discrete hausdorff distance.
The densifyFrac parameter sets the fraction by which to densify each segment. Each segment will be split into a number of
equal-length subsegments, whose fraction of the total length is closest to the given fraction.

Note
The current implementation supports only vertices as the discrete locations. This could be extended to allow an arbitrary
density of points to be used.

Note
This algorithm is NOT equivalent to the standard Hausdorff distance. However, it computes an approximation that is
correct for a large subset of useful cases. One important part of this subset is Linestrings that are roughly parallel to
each other, and roughly equal in length. This is a useful metric for line matching.

Availability: 1.5.0 - requires GEOS >= 3.2.0

Examples

For each building, find the parcel that best represents it. First we require the parcel intersect with the geometry. DISTINCT ON
guarantees we get each building listed only once, the ORDER BY .. ST_HausdorffDistance gives us a preference of parcel that
is most similar to the building.
SELECT DISTINCT ON(buildings.gid) buildings.gid, parcels.parcel_id
FROM buildings INNER JOIN parcels ON ST_Intersects(buildings.geom,parcels.geom)
ORDER BY buildings.gid, ST_HausdorffDistance(buildings.geom, parcels.geom);

postgis=# SELECT ST_HausdorffDistance(

'LINESTRING (0 0, 2 0)'::geometry,
'MULTIPOINT (0 1, 1 0, 2 1)'::geometry);
st_hausdorffdistance
----------------------
1
(1 row)

postgis=# SELECT st_hausdorffdistance('LINESTRING (130 0, 0 0, 0 150)'::geometry, ' ←-

LINESTRING (10 10, 10 150, 130 10)'::geometry, 0.5);
st_hausdorffdistance
----------------------
70
(1 row)

See Also

ST_FrechetDistance
PostGIS 2.4.3 Manual 301 / 803

8.9.28 ST_FrechetDistance

ST_FrechetDistance — Returns the Fréchet distance between two geometries. This is a measure of similarity between curves
that takes into account the location and ordering of the points along the curves. Units are in the units of the spatial reference
system of the geometries.

Synopsis

float ST_FrechetDistance(geometry g1, geometry g2, float densifyFrac = -1);

Description

Implements algorithm for computing the Fréchet distance restricted to discrete points for both geometries, based on Computing
Discrete Fréchet Distance. The Fréchet distance is a measure of similarity between curves that takes into account the location
and ordering of the points along the curves. Therefore it is often better than the Hausdorff distance.
When the optional densifyFrac is specified, this function performs a segment densification before computing the discrete Fréchet
distance. The densifyFrac parameter sets the fraction by which to densify each segment. Each segment will be split into a number
of equal-length subsegments, whose fraction of the total length is closest to the given fraction.

Note
The current implementation supports only vertices as the discrete locations. This could be extended to allow an arbitrary
density of points to be used.

Note
The smaller densifyFrac we specify, the more acurate Fréchet distance we get. But, the computation time and the
memory usage increase with the square of the number of subsegments.

Availability: 2.4.0 - requires GEOS >= 3.7.0

Examples

postgres=# SELECT st_frechetdistance('LINESTRING (0 0, 100 0)'::geometry, 'LINESTRING (0 0, ←-

50 50, 100 0)'::geometry);
st_frechetdistance
--------------------
70.7106781186548
(1 row)

SELECT st_frechetdistance('LINESTRING (0 0, 100 0)'::geometry, 'LINESTRING (0 0, 50 50, 100 ←-

0)'::geometry, 0.5);
st_frechetdistance
--------------------
50
(1 row)

See Also

ST_HausdorffDistance
PostGIS 2.4.3 Manual 302 / 803

8.9.29 ST_MaxDistance

ST_MaxDistance — Returns the 2-dimensional largest distance between two geometries in projected units.

Synopsis

float ST_MaxDistance(geometry g1, geometry g2);

Description

Note
Returns the 2-dimensional maximum distance between two geometries in projected units. If g1 and g2 is the same
geometry the function will return the distance between the two vertices most far from each other in that geometry.

Availability: 1.5.0

Examples

Basic furthest distance the point is to any part of the line

postgis=# SELECT ST_MaxDistance('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )'::geometry ←-
);
st_maxdistance
-----------------
2
(1 row)

postgis=# SELECT ST_MaxDistance('POINT(0 0)'::geometry, 'LINESTRING ( 2 2, 2 2 )'::geometry ←-

);
st_maxdistance
------------------
2.82842712474619
(1 row)

See Also

ST_Distance, ST_LongestLine, ST_DFullyWithin

8.9.30 ST_DistanceSphere

ST_DistanceSphere — Returns minimum distance in meters between two lon/lat geometries. Uses a spherical earth and ra-
dius derived from the spheroid defined by the SRID. Faster than ST_DistanceSpheroid ST_DistanceSpheroid, but less accurate.
PostGIS versions prior to 1.5 only implemented for points.

Synopsis

float ST_DistanceSphere(geometry geomlonlatA, geometry geomlonlatB);

PostGIS 2.4.3 Manual 303 / 803

Description

Returns minimum distance in meters between two lon/lat points. Uses a spherical earth and radius derived from the spheroid
defined by the SRID. Faster than ST_DistanceSpheroid, but less accurate. PostGIS Versions prior to 1.5 only implemented for
points.
Availability: 1.5 - support for other geometry types besides points was introduced. Prior versions only work with points.
Changed: 2.2.0 In prior versions this used to be called ST_Distance_Sphere

Examples

SELECT round(CAST(ST_DistanceSphere(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38) ←-

',4326)) As numeric),2) As dist_meters,
round(CAST(ST_Distance(ST_Transform(ST_Centroid(the_geom),32611),
ST_Transform(ST_GeomFromText('POINT(-118 38)', 4326),32611)) As numeric),2) As ←-
dist_utm11_meters,
round(CAST(ST_Distance(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38)', 4326)) As ←-
numeric),5) As dist_degrees,
round(CAST(ST_Distance(ST_Transform(the_geom,32611),
ST_Transform(ST_GeomFromText('POINT(-118 38)', 4326),32611)) As numeric),2) As ←-
min_dist_line_point_meters
FROM
(SELECT ST_GeomFromText('LINESTRING(-118.584 38.374,-118.583 38.5)', 4326) As the_geom) ←-
as foo;
dist_meters | dist_utm11_meters | dist_degrees | min_dist_line_point_meters
-------------+-------------------+--------------+----------------------------
70424.47 | 70438.00 | 0.72900 | 65871.18

See Also

ST_Distance, ST_DistanceSpheroid

8.9.31 ST_DistanceSpheroid

ST_DistanceSpheroid — Returns the minimum distance between two lon/lat geometries given a particular spheroid. PostGIS
versions prior to 1.5 only support points.

Synopsis

float ST_DistanceSpheroid(geometry geomlonlatA, geometry geomlonlatB, spheroid measurement_spheroid);

Description

Returns minimum distance in meters between two lon/lat geometries given a particular spheroid. See the explanation of spheroids
given for ST_LengthSpheroid. PostGIS version prior to 1.5 only support points.

Note
This function currently does not look at the SRID of a geometry and will always assume its represented in the coordi-
nates of the passed in spheroid. Prior versions of this function only support points.

Availability: 1.5 - support for other geometry types besides points was introduced. Prior versions only work with points.
Changed: 2.2.0 In prior versions this used to be called ST_Distance_Spheroid
PostGIS 2.4.3 Manual 304 / 803

Examples

SELECT round(CAST(
ST_DistanceSpheroid(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38)',4326), ' ←-
SPHEROID["WGS 84",6378137,298.257223563]')
As numeric),2) As dist_meters_spheroid,
round(CAST(ST_DistanceSphere(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38) ←-
',4326)) As numeric),2) As dist_meters_sphere,
round(CAST(ST_Distance(ST_Transform(ST_Centroid(the_geom),32611),
ST_Transform(ST_GeomFromText('POINT(-118 38)', 4326),32611)) As numeric),2) As ←-
dist_utm11_meters
FROM
(SELECT ST_GeomFromText('LINESTRING(-118.584 38.374,-118.583 38.5)', 4326) As the_geom) ←-
as foo;
dist_meters_spheroid | dist_meters_sphere | dist_utm11_meters
----------------------+--------------------+-------------------
70454.92 | 70424.47 | 70438.00

See Also

ST_Distance, ST_DistanceSphere

8.9.32 ST_DFullyWithin

ST_DFullyWithin — Returns true if all of the geometries are within the specified distance of one another

Synopsis

boolean ST_DFullyWithin(geometry g1, geometry g2, double precision distance);

Description

Returns true if the geometries is fully within the specified distance of one another. The distance is specified in units defined by
the spatial reference system of the geometries. For this function to make sense, the source geometries must both be of the same
coordinate projection, having the same SRID.

Note
This function call will automatically include a bounding box comparison that will make use of any indexes that are
available on the geometries.

Availability: 1.5.0

Examples

postgis=# SELECT ST_DFullyWithin(geom_a, geom_b, 10) as DFullyWithin10, ST_DWithin(geom_a, ←-

geom_b, 10) as DWithin10, ST_DFullyWithin(geom_a, geom_b, 20) as DFullyWithin20 from
(select ST_GeomFromText('POINT(1 1)') as geom_a,ST_GeomFromText('LINESTRING(1 5, 2 7, 1 ←-
9, 14 12)') as geom_b) t1;

-----------------
DFullyWithin10 | DWithin10 | DFullyWithin20 |
---------------+----------+---------------+
f | t | t |
PostGIS 2.4.3 Manual 305 / 803

See Also

ST_MaxDistance, ST_DWithin

8.9.33 ST_DWithin

ST_DWithin — Returns true if the geometries are within the specified distance of one another. For geometry units are in those
of spatial reference and For geography units are in meters and measurement is defaulted to use_spheroid=true (measure around
spheroid), for faster check, use_spheroid=false to measure along sphere.

Synopsis

boolean ST_DWithin(geometry g1, geometry g2, double precision distance_of_srid);

boolean ST_DWithin(geography gg1, geography gg2, double precision distance_meters);
boolean ST_DWithin(geography gg1, geography gg2, double precision distance_meters, boolean use_spheroid);

Description

Returns true if the geometries are within the specified distance of one another.
For Geometries: The distance is specified in units defined by the spatial reference system of the geometries. For this function to
make sense, the source geometries must both be of the same coordinate projection, having the same SRID.
For geography units are in meters and measurement is defaulted to use_spheroid=true, for faster check, use_spheroid=false to
measure along sphere.

Note
This function call will automatically include a bounding box comparison that will make use of any indexes that are
available on the geometries.

Note
Prior to 1.3, ST_Expand was commonly used in conjunction with && and ST_Distance to achieve the same effect and
in pre-1.3.4 this function was basically short-hand for that construct. From 1.3.4, ST_DWithin uses a more short-circuit
distance function which should make it more efficient than prior versions for larger buffer regions.

Note
Use ST_3DDWithin if you have 3D geometries.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.
Availability: 1.5.0 support for geography was introduced
Enhanced: 2.1.0 improved speed for geography. See Making Geography faster for details.
Enhanced: 2.1.0 support for curved geometries was introduced.
PostGIS 2.4.3 Manual 306 / 803

Examples

--Find the nearest hospital to each school

--that is within 3000 units of the school.
-- We do an ST_DWithin search to utilize indexes to limit our search list
-- that the non-indexable ST_Distance needs to process
--If the units of the spatial reference is meters then units would be meters
SELECT DISTINCT ON (s.gid) s.gid, s.school_name, s.the_geom, h.hospital_name
FROM schools s
LEFT JOIN hospitals h ON ST_DWithin(s.the_geom, h.the_geom, 3000)
ORDER BY s.gid, ST_Distance(s.the_geom, h.the_geom);

--The schools with no close hospitals

--Find all schools with no hospital within 3000 units
--away from the school. Units is in units of spatial ref (e.g. meters, feet, degrees)
SELECT s.gid, s.school_name
FROM schools s
LEFT JOIN hospitals h ON ST_DWithin(s.the_geom, h.the_geom, 3000)
WHERE h.gid IS NULL;

See Also

ST_Distance, ST_Expand

8.9.34 ST_Equals

ST_Equals — Returns true if the given geometries represent the same geometry. Directionality is ignored.

Synopsis

boolean ST_Equals(geometry A, geometry B);

Description

Returns TRUE if the given Geometries are "spatially equal". Use this for a ’better’ answer than ’=’. Note by spatially equal we
mean ST_Within(A,B) = true and ST_Within(B,A) = true and also mean ordering of points can be different but represent the same
geometry structure. To verify the order of points is consistent, use ST_OrderingEquals (it must be noted ST_OrderingEquals is
a little more stringent than simply verifying order of points are the same).

Important
This function will return false if either geometry is invalid except in the case where they are binary equal.

Important
Do not call with a GEOMETRYCOLLECTION as an argument.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2

This method implements the SQL/MM specification. SQL-MM 3: 5.1.24

Changed: 2.2.0 Returns true even for invalid geometries if they are binary equal
PostGIS 2.4.3 Manual 307 / 803

Examples

SELECT ST_Equals(ST_GeomFromText('LINESTRING(0 0, 10 10)'),

ST_GeomFromText('LINESTRING(0 0, 5 5, 10 10)'));
st_equals
-----------
t
(1 row)

SELECT ST_Equals(ST_Reverse(ST_GeomFromText('LINESTRING(0 0, 10 10)')),

ST_GeomFromText('LINESTRING(0 0, 5 5, 10 10)'));
st_equals
-----------
t
(1 row)

See Also

ST_IsValid, ST_OrderingEquals, ST_Reverse, ST_Within

8.9.35 ST_GeometricMedian

ST_GeometricMedian — Returns the geometric median of a MultiPoint.

Synopsis

geometry ST_GeometricMedian ( geometry g , float8 tolerance , int max_iter , boolean fail_if_not_converged );

Description

Computes the approximate geometric median of a MultiPoint geometry using the Weiszfeld algorithm. The geometric median
provides a centrality measure that is less sensitive to outlier points than the centroid. The algorithm will iterate until the distance
change between successive iterations is less than the supplied tolerance parameter. If this condition has not been met after
max_iterations iterations, the function will produce an error and exit, unless fail_if_not_converged is set to false.
If a tolerance value is not provided, a default tolerance value will be calculated based on the extent of the input geometry.
Availability: 2.3.0

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 308 / 803

Examples

Comparison of the centroid (turquoise point) and geometric median (red point) of a four-point MultiPoint (yellow points).

WITH test AS (
SELECT 'MULTIPOINT((0 0), (1 1), (2 2), (200 200))'::geometry geom)
SELECT
ST_AsText(ST_Centroid(geom)) centroid,
ST_AsText(ST_GeometricMedian(geom)) median
FROM test;
centroid | median
--------------------+----------------------------------------
POINT(50.75 50.75) | POINT(1.9761550281255 1.9761550281255)
(1 row)

See Also

ST_Centroid

8.9.36 ST_HasArc

ST_HasArc — Returns true if a geometry or geometry collection contains a circular string

Synopsis

boolean ST_HasArc(geometry geomA);

Description

Returns true if a geometry or geometry collection contains a circular string

Availability: 1.2.3?

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

PostGIS 2.4.3 Manual 309 / 803

Examples

SELECT ST_HasArc(ST_Collect('LINESTRING(1 2, 3 4, 5 6)', 'CIRCULARSTRING(1 1, 2 3, 4 5, 6 ←-

7, 5 6)'));
st_hasarc
--------
t

See Also

ST_CurveToLine, ST_LineToCurve

8.9.37 ST_Intersects

ST_Intersects — Returns TRUE if the Geometries/Geography "spatially intersect in 2D" - (share any portion of space) and
FALSE if they don’t (they are Disjoint). For geography -- tolerance is 0.00001 meters (so any points that close are considered to
intersect)

Synopsis

boolean ST_Intersects( geometry geomA , geometry geomB );

boolean ST_Intersects( geography geogA , geography geogB );

Description

If a geometry or geography shares any portion of space then they intersect. For geography -- tolerance is 0.00001 meters (so any
points that are close are considered to intersect)
Overlaps, Touches, Within all imply spatial intersection. If any of the aforementioned returns true, then the geometries also
spatially intersect. Disjoint implies false for spatial intersection.

Important
Do not call with a GEOMETRYCOLLECTION as an argument for geometry version. The geography version supports
GEOMETRYCOLLECTION since its a thin wrapper around distance implementation.

Enhanced: 2.3.0 Enhancement to PIP short-circuit extended to support MultiPoints with few points. Prior versions only supported
point in polygon.
Performed by the GEOS module (for geometry), geography is native
Availability: 1.5 support for geography was introduced.

Note
This function call will automatically include a bounding box comparison that will make use of any indexes that are
available on the geometries.

Note
For geography, this function has a distance tolerance of about 0.00001 meters and uses the sphere rather than spheroid
calculation.
PostGIS 2.4.3 Manual 310 / 803

Note
NOTE: this is the "allowable" version that returns a boolean, not an integer.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 //s2.1.13.3 -
ST_Intersects(g1, g2 ) --> Not (ST_Disjoint(g1, g2 ))

This method implements the SQL/MM specification. SQL-MM 3: 5.1.27

This method is also provided by SFCGAL backend.

Geometry Examples

SELECT ST_Intersects('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )'::geometry);

st_intersects
---------------
f
(1 row)
SELECT ST_Intersects('POINT(0 0)'::geometry, 'LINESTRING ( 0 0, 0 2 )'::geometry);
st_intersects
---------------
t
(1 row)

Geography Examples

SELECT ST_Intersects(
ST_GeographyFromText('SRID=4326;LINESTRING(-43.23456 72.4567,-43.23456 72.4568)'),
ST_GeographyFromText('SRID=4326;POINT(-43.23456 72.4567772)')
);

st_intersects
---------------
t

See Also

ST_3DIntersects, ST_Disjoint

8.9.38 ST_Length

ST_Length — Returns the 2D length of the geometry if it is a LineString or MultiLineString. geometry are in units of spatial
reference and geography are in meters (default spheroid)

Synopsis

float ST_Length(geometry a_2dlinestring);

float ST_Length(geography geog, boolean use_spheroid=true);
PostGIS 2.4.3 Manual 311 / 803

Description

For geometry: Returns the 2D Cartesian length of the geometry if it is a LineString, MultiLineString, ST_Curve, ST_MultiCurve.
0 is returned for areal geometries. For areal geometries use ST_Perimeter. For geometry types, units for length measures are
specified by the spatial reference system of the geometry.
For geography types, the calculations are performed using the inverse geodesic problem, where length units are in meters. If
PostGIS is compiled with PROJ version 4.8.0 or later, the spheroid is specified by the SRID, otherwise it is exclusive to WGS84.
If use_spheroid=false, then calculations will approximate a sphere instead of a spheroid.
Currently for geometry this is an alias for ST_Length2D, but this may change to support higher dimensions.

Warning
Changed: 2.0.0 Breaking change -- in prior versions applying this to a MULTI/POLYGON of type geography would give
you the perimeter of the POLYGON/MULTIPOLYGON. In 2.0.0 this was changed to return 0 to be in line with geometry
behavior. Please use ST_Perimeter if you want the perimeter of a polygon

Note
For geography measurement defaults spheroid measurement. To use the faster less accurate sphere use
ST_Length(gg,false);

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.5.1

This method implements the SQL/MM specification. SQL-MM 3: 7.1.2, 9.3.4

Availability: 1.5.0 geography support was introduced in 1.5.

This method is also provided by SFCGAL backend.

Geometry Examples

Return length in feet for line string. Note this is in feet because EPSG:2249 is Massachusetts State Plane Feet
SELECT ST_Length(ST_GeomFromText('LINESTRING(743238 2967416,743238 2967450,743265 2967450,
743265.625 2967416,743238 2967416)',2249));
st_length
---------
122.630744000095

--Transforming WGS 84 LineString to Massachusetts state plane meters

SELECT ST_Length(
ST_Transform(
ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45, -72.1240 42.45666, -72.123 ←-
42.1546)'),
26986
)
);
st_length
---------
34309.4563576191
PostGIS 2.4.3 Manual 312 / 803

Geography Examples

Return length of WGS 84 geography line

-- default calculation is using a sphere rather than spheroid
SELECT ST_Length(the_geog) As length_spheroid, ST_Length(the_geog,false) As length_sphere
FROM (SELECT ST_GeographyFromText(
'SRID=4326;LINESTRING(-72.1260 42.45, -72.1240 42.45666, -72.123 42.1546)') As the_geog)
As foo;
length_spheroid | length_sphere
------------------+------------------
34310.5703627288 | 34346.2060960742

See Also

ST_GeographyFromText, ST_GeomFromEWKT, ST_LengthSpheroid, ST_Perimeter, ST_Transform

8.9.39 ST_Length2D

ST_Length2D — Returns the 2-dimensional length of the geometry if it is a linestring or multi-linestring. This is an alias for
ST_Length

Synopsis

float ST_Length2D(geometry a_2dlinestring);

Description

Returns the 2-dimensional length of the geometry if it is a linestring or multi-linestring. This is an alias for ST_Length

See Also

ST_Length, ST_3DLength

8.9.40 ST_3DLength

ST_3DLength — Returns the 3-dimensional or 2-dimensional length of the geometry if it is a linestring or multi-linestring.

Synopsis

float ST_3DLength(geometry a_3dlinestring);

Description

Returns the 3-dimensional or 2-dimensional length of the geometry if it is a linestring or multi-linestring. For 2-d lines it will
just return the 2-d length (same as ST_Length and ST_Length2D)

This function supports 3d and will not drop the z-index.

Changed: 2.0.0 In prior versions this used to be called ST_Length3D
PostGIS 2.4.3 Manual 313 / 803

Examples

Return length in feet for a 3D cable. Note this is in feet because EPSG:2249 is Massachusetts State Plane Feet
SELECT ST_3DLength(ST_GeomFromText('LINESTRING(743238 2967416 1,743238 2967450 1,743265 ←-
2967450 3,
743265.625 2967416 3,743238 2967416 3)',2249));
ST_3DLength
-----------
122.704716741457

See Also

ST_Length, ST_Length2D

8.9.41 ST_LengthSpheroid

ST_LengthSpheroid — Calculates the 2D or 3D length/perimeter of a geometry on an ellipsoid. This is useful if the coordinates
of the geometry are in longitude/latitude and a length is desired without reprojection.

Synopsis

float ST_LengthSpheroid(geometry a_geometry, spheroid a_spheroid);

Description

Calculates the length/perimeter of a geometry on an ellipsoid. This is useful if the coordinates of the geometry are in longi-
tude/latitude and a length is desired without reprojection. The ellipsoid is a separate database type and can be constructed as
follows:
SPHEROID[<NAME>,<SEMI-MAJOR AXIS>,<INVERSE FLATTENING>]

SPHEROID["GRS_1980",6378137,298.257222101]

Availability: 1.2.2
Changed: 2.2.0 In prior versions this used to be called ST_Length_Spheroid and used to have a ST_3DLength_Spheroid alias

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_LengthSpheroid( geometry_column,

'SPHEROID["GRS_1980",6378137,298.257222101]' )
FROM geometry_table;

SELECT ST_LengthSpheroid( the_geom, sph_m ) As tot_len,

ST_LengthSpheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,
ST_LengthSpheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2
FROM (SELECT ST_GeomFromText('MULTILINESTRING((-118.584 38.374,-118.583 38.5),
(-71.05957 42.3589 , -71.061 43))') As the_geom,
CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;
tot_len | len_line1 | len_line2
------------------+------------------+------------------
PostGIS 2.4.3 Manual 314 / 803

85204.5207562955 | 13986.8725229309 | 71217.6482333646

--3D
SELECT ST_LengthSpheroid( the_geom, sph_m ) As tot_len,
ST_LengthSpheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,
ST_LengthSpheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2
FROM (SELECT ST_GeomFromEWKT('MULTILINESTRING((-118.584 38.374 20,-118.583 38.5 30) ←-
,
(-71.05957 42.3589 75, -71.061 43 90))') As the_geom,
CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;

tot_len | len_line1 | len_line2

------------------+-----------------+------------------
85204.5259107402 | 13986.876097711 | 71217.6498130292

See Also

ST_GeometryN, ST_Length

8.9.42 ST_Length2D_Spheroid

ST_Length2D_Spheroid — Calculates the 2D length/perimeter of a geometry on an ellipsoid. This is useful if the coordinates of
the geometry are in longitude/latitude and a length is desired without reprojection.

Synopsis

float ST_Length2D_Spheroid(geometry a_geometry, spheroid a_spheroid);

Description

Calculates the 2D length/perimeter of a geometry on an ellipsoid. This is useful if the coordinates of the geometry are in
longitude/latitude and a length is desired without reprojection. The ellipsoid is a separate database type and can be constructed
as follows:
SPHEROID[<NAME>,<SEMI-MAJOR AXIS>,<INVERSE FLATTENING>]

SPHEROID["GRS_1980",6378137,298.257222101]

Note
This is much like ST_LengthSpheroid except it will ignore the Z ordinate in calculations.

Examples

SELECT ST_Length2D_Spheroid( geometry_column,

'SPHEROID["GRS_1980",6378137,298.257222101]' )
FROM geometry_table;

SELECT ST_Length2D_Spheroid( the_geom, sph_m ) As tot_len,

ST_Length2D_Spheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,
ST_Length2D_Spheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2
PostGIS 2.4.3 Manual 315 / 803

FROM (SELECT ST_GeomFromText('MULTILINESTRING((-118.584 38.374,-118.583 38.5),

(-71.05957 42.3589 , -71.061 43))') As the_geom,
CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;
tot_len | len_line1 | len_line2
------------------+------------------+------------------
85204.5207562955 | 13986.8725229309 | 71217.6482333646

--3D Observe same answer

SELECT ST_Length2D_Spheroid( the_geom, sph_m ) As tot_len,
ST_Length2D_Spheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,
ST_Length2D_Spheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2
FROM (SELECT ST_GeomFromEWKT('MULTILINESTRING((-118.584 38.374 20,-118.583 38.5 30) ←-
,
(-71.05957 42.3589 75, -71.061 43 90))') As the_geom,
CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;

tot_len | len_line1 | len_line2

------------------+------------------+------------------
85204.5207562955 | 13986.8725229309 | 71217.6482333646

See Also

ST_GeometryN, ST_LengthSpheroid

8.9.43 ST_LongestLine

ST_LongestLine — Returns the 2-dimensional longest line points of two geometries. The function will only return the first
longest line if more than one, that the function finds. The line returned will always start in g1 and end in g2. The length of the
line this function returns will always be the same as st_maxdistance returns for g1 and g2.

Synopsis

geometry ST_LongestLine(geometry g1, geometry g2);

Description

Returns the 2-dimensional longest line between the points of two geometries.
Availability: 1.5.0

Examples
PostGIS 2.4.3 Manual 316 / 803

longest line between polygon and polygon

Longest line between point and line SELECT ST_AsText(
ST_LongestLine(
SELECT ST_AsText( ST_GeomFromText('POLYGON ←-
ST_LongestLine('POINT(100 100)':: ←- ((175 150, 20 40,
geometry, 50 60, 125 100, ←-
'LINESTRING (20 80, 98 ←- 175 150))'),
190, 110 180, 50 75 )'::geometry) ST_Buffer(ST_GeomFromText ←-
) As lline; ('POINT(110 170)'), 20)
)
) As llinewkt;
lline
----------------- lline
LINESTRING(100 100,98 190) -----------------
LINESTRING(20 40,121.111404660392 ←-
186.629392246051)
PostGIS 2.4.3 Manual 317 / 803

longest straight distance to travel from one part of an elegant city to the other Note the max distance = to the length of the
line.
SELECT ST_AsText(ST_LongestLine(c.the_geom, c.the_geom)) As llinewkt,
ST_MaxDistance(c.the_geom,c.the_geom) As max_dist,
ST_Length(ST_LongestLine(c.the_geom, c.the_geom)) As lenll
FROM (SELECT ST_BuildArea(ST_Collect(the_geom)) As the_geom
FROM (SELECT ST_Translate(ST_SnapToGrid(ST_Buffer(ST_Point(50 ,generate_series ←-
(50,190, 50)
),40, 'quad_segs=2'),1), x, 0) As the_geom
FROM generate_series(1,100,50) As x) AS foo
) As c;

llinewkt | max_dist | lenll

---------------------------+------------------+------------------
LINESTRING(23 22,129 178) | 188.605408193933 | 188.605408193933

See Also

ST_MaxDistance, ST_ShortestLine, ST_LongestLine

8.9.44 ST_OrderingEquals

ST_OrderingEquals — Returns true if the given geometries represent the same geometry and points are in the same directional
order.

Synopsis

boolean ST_OrderingEquals(geometry A, geometry B);

Description

ST_OrderingEquals compares two geometries and returns t (TRUE) if the geometries are equal and the coordinates are in the
same order; otherwise it returns f (FALSE).
PostGIS 2.4.3 Manual 318 / 803

Note
This function is implemented as per the ArcSDE SQL specification rather than SQL-MM.
http://edndoc.esri.com/arcsde/9.1/sql_api/sqlapi3.htm#ST_OrderingEquals

This method implements the SQL/MM specification. SQL-MM 3: 5.1.43

Examples

SELECT ST_OrderingEquals(ST_GeomFromText('LINESTRING(0 0, 10 10)'),

ST_GeomFromText('LINESTRING(0 0, 5 5, 10 10)'));
st_orderingequals
-----------
f
(1 row)

SELECT ST_OrderingEquals(ST_GeomFromText('LINESTRING(0 0, 10 10)'),

ST_GeomFromText('LINESTRING(0 0, 0 0, 10 10)'));
st_orderingequals
-----------
t
(1 row)

SELECT ST_OrderingEquals(ST_Reverse(ST_GeomFromText('LINESTRING(0 0, 10 10)')),

ST_GeomFromText('LINESTRING(0 0, 0 0, 10 10)'));
st_orderingequals
-----------
f
(1 row)

See Also

ST_Equals, ST_Reverse

8.9.45 ST_Overlaps

ST_Overlaps — Returns TRUE if the Geometries share space, are of the same dimension, but are not completely contained by
each other.

Synopsis

boolean ST_Overlaps(geometry A, geometry B);

Description

Returns TRUE if the Geometries "spatially overlap". By that we mean they intersect, but one does not completely contain another.
Performed by the GEOS module

Note
Do not call with a GeometryCollection as an argument
PostGIS 2.4.3 Manual 319 / 803

This function call will automatically include a bounding box comparison that will make use of any indexes that are available on
the geometries. To avoid index use, use the function _ST_Overlaps.
NOTE: this is the "allowable" version that returns a boolean, not an integer.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 // s2.1.13.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.32

Examples

The following illustrations all return TRUE.

MULTIPOINT / MULTIPOINT LINESTRING / LINESTRING POLYGON / POLYGON

--a point on a line is contained by the line and is of a lower dimension, and therefore ←-
does not overlap the line
nor crosses

SELECT ST_Overlaps(a,b) As a_overlap_b,

ST_Crosses(a,b) As a_crosses_b,
ST_Intersects(a, b) As a_intersects_b, ST_Contains(b,a) As b_contains_a
FROM (SELECT ST_GeomFromText('POINT(1 0.5)') As a, ST_GeomFromText('LINESTRING(1 0, 1 1, 3 ←-
5)') As b)
As foo

a_overlap_b | a_crosses_b | a_intersects_b | b_contains_a

------------+-------------+----------------+--------------
f | f | t | t

--a line that is partly contained by circle, but not fully is defined as intersecting and ←-
crossing,
-- but since of different dimension it does not overlap
SELECT ST_Overlaps(a,b) As a_overlap_b, ST_Crosses(a,b) As a_crosses_b,
ST_Intersects(a, b) As a_intersects_b,
ST_Contains(a,b) As a_contains_b
FROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 0.5)'), 3) As a, ST_GeomFromText(' ←-
LINESTRING(1 0, 1 1, 3 5)') As b)
As foo;

a_overlap_b | a_crosses_b | a_intersects_b | a_contains_b

-------------+-------------+----------------+--------------
PostGIS 2.4.3 Manual 320 / 803

f | t | t | f

-- a 2-dimensional bent hot dog (aka buffered line string) that intersects a circle,
-- but is not fully contained by the circle is defined as overlapping since they are of ←-
the same dimension,
-- but it does not cross, because the intersection of the 2 is of the same dimension
-- as the maximum dimension of the 2

SELECT ST_Overlaps(a,b) As a_overlap_b, ST_Crosses(a,b) As a_crosses_b, ST_Intersects(a, b) ←-

As a_intersects_b,
ST_Contains(b,a) As b_contains_a,
ST_Dimension(a) As dim_a, ST_Dimension(b) as dim_b, ST_Dimension(ST_Intersection(a,b)) As ←-
dima_intersection_b
FROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 0.5)'), 3) As a,
ST_Buffer(ST_GeomFromText('LINESTRING(1 0, 1 1, 3 5)'),0.5) As b)
As foo;

a_overlap_b | a_crosses_b | a_intersects_b | b_contains_a | dim_a | dim_b | ←-

dima_intersection_b
-------------+-------------+----------------+--------------+-------+-------+--------------------- ←-

t | f | t | f | 2 | 2 | 2

See Also

ST_Contains, ST_Crosses, ST_Dimension, ST_Intersects

8.9.46 ST_Perimeter

ST_Perimeter — Return the length measurement of the boundary of an ST_Surface or ST_MultiSurface geometry or geography.
(Polygon, MultiPolygon). geometry measurement is in units of spatial reference and geography is in meters.

Synopsis

float ST_Perimeter(geometry g1);

float ST_Perimeter(geography geog, boolean use_spheroid=true);

Description

Returns the 2D perimeter of the geometry/geography if it is a ST_Surface, ST_MultiSurface (Polygon, MultiPolygon). 0 is

returned for non-areal geometries. For linear geometries use ST_Length. For geometry types, units for perimeter measures are
specified by the spatial reference system of the geometry.
For geography types, the calculations are performed using the inverse geodesic problem, where perimeter units are in meters. If
PostGIS is compiled with PROJ version 4.8.0 or later, the spheroid is specified by the SRID, otherwise it is exclusive to WGS84.
If use_spheroid=false, then calculations will approximate a sphere instead of a spheroid.
Currently this is an alias for ST_Perimeter2D, but this may change to support higher dimensions.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.5.1

This method implements the SQL/MM specification. SQL-MM 3: 8.1.3, 9.5.4

Availability 2.0.0: Support for geography was introduced
PostGIS 2.4.3 Manual 321 / 803

Examples: Geometry

Return perimeter in feet for Polygon and MultiPolygon. Note this is in feet because EPSG:2249 is Massachusetts State Plane
Feet
SELECT ST_Perimeter(ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,743265 2967450,
743265.625 2967416,743238 2967416))', 2249));
st_perimeter
---------
122.630744000095
(1 row)

SELECT ST_Perimeter(ST_GeomFromText('MULTIPOLYGON(((763104.471273676 2949418.44119003,

763104.477769673 2949418.42538203,
763104.189609677 2949418.22343004,763104.471273676 2949418.44119003)),
((763104.471273676 2949418.44119003,763095.804579742 2949436.33850239,
763086.132105649 2949451.46730207,763078.452329651 2949462.11549407,
763075.354136904 2949466.17407812,763064.362142565 2949477.64291974,
763059.953961626 2949481.28983009,762994.637609571 2949532.04103014,
762990.568508415 2949535.06640477,762986.710889563 2949539.61421415,
763117.237897679 2949709.50493431,763235.236617789 2949617.95619822,
763287.718121842 2949562.20592617,763111.553321674 2949423.91664605,
763104.471273676 2949418.44119003)))', 2249));
st_perimeter
---------
845.227713366825
(1 row)

Examples: Geography

Return perimeter in meters and feet for Polygon and MultiPolygon. Note this is geography (WGS 84 long lat)
SELECT ST_Perimeter(geog) As per_meters, ST_Perimeter(geog)/0.3048 As per_ft
FROM ST_GeogFromText('POLYGON((-71.1776848522251 42.3902896512902,-71.1776843766326 ←-
42.3903829478009,
-71.1775844305465 42.3903826677917,-71.1775825927231 42.3902893647987,-71.1776848522251 ←-
42.3902896512902))') As geog;

per_meters | per_ft
-----------------+------------------
37.3790462565251 | 122.634666195949

-- MultiPolygon example --
SELECT ST_Perimeter(geog) As per_meters, ST_Perimeter(geog,false) As per_sphere_meters, ←-
ST_Perimeter(geog)/0.3048 As per_ft
FROM ST_GeogFromText('MULTIPOLYGON(((-71.1044543107478 42.340674480411,-71.1044542869917 ←-
42.3406744369506,
-71.1044553562977 42.340673886454,-71.1044543107478 42.340674480411)),
((-71.1044543107478 42.340674480411,-71.1044860600303 42.3407237015564,-71.1045215770124 ←-
42.3407653385914,
-71.1045498002983 42.3407946553165,-71.1045611902745 42.3408058316308,-71.1046016507427 ←-
42.340837442371,
-71.104617893173 42.3408475056957,-71.1048586153981 42.3409875993595,-71.1048736143677 ←-
42.3409959528211,
-71.1048878050242 42.3410084812078,-71.1044020965803 42.3414730072048,
-71.1039672113619 42.3412202916693,-71.1037740497748 42.3410666421308,
-71.1044280218456 42.3406894151355,-71.1044543107478 42.340674480411)))') As geog;

per_meters | per_sphere_meters | per_ft

------------------+-------------------+------------------
PostGIS 2.4.3 Manual 322 / 803

257.634283683311 | 257.412311446337 | 845.256836231335

See Also

ST_GeogFromText, ST_GeomFromText, ST_Length

8.9.47 ST_Perimeter2D

ST_Perimeter2D — Returns the 2-dimensional perimeter of the geometry, if it is a polygon or multi-polygon. This is currently
an alias for ST_Perimeter.

Synopsis

float ST_Perimeter2D(geometry geomA);

Description

Returns the 2-dimensional perimeter of the geometry, if it is a polygon or multi-polygon.

Note
This is currently an alias for ST_Perimeter. In future versions ST_Perimeter may return the highest dimension perimeter
for a geometry. This is still under consideration

See Also

ST_Perimeter

8.9.48 ST_3DPerimeter

ST_3DPerimeter — Returns the 3-dimensional perimeter of the geometry, if it is a polygon or multi-polygon.

Synopsis

float ST_3DPerimeter(geometry geomA);

Description

Returns the 3-dimensional perimeter of the geometry, if it is a polygon or multi-polygon. If the geometry is 2-dimensional, then
the 2-dimensional perimeter is returned.

This function supports 3d and will not drop the z-index.

Changed: 2.0.0 In prior versions this used to be called ST_Perimeter3D
PostGIS 2.4.3 Manual 323 / 803

Examples

Perimeter of a slightly elevated polygon in the air in Massachusetts state plane feet
SELECT ST_3DPerimeter(the_geom), ST_Perimeter2d(the_geom), ST_Perimeter(the_geom) FROM
(SELECT ST_GeomFromEWKT('SRID=2249;POLYGON((743238 2967416 2,743238 2967450 1,
743265.625 2967416 1,743238 2967416 2))') As the_geom) As foo;

ST_3DPerimeter | st_perimeter2d | st_perimeter

------------------+------------------+------------------
105.465793597674 | 105.432997272188 | 105.432997272188

See Also

ST_GeomFromEWKT, ST_Perimeter, ST_Perimeter2D

8.9.49 ST_PointOnSurface

ST_PointOnSurface — Returns a POINT guaranteed to lie on the surface.

Synopsis

geometry ST_PointOnSurface(geometry g1);

Description

Returns a POINT guaranteed to intersect a surface.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s3.2.14.2 // s3.2.18.2

This method implements the SQL/MM specification. SQL-MM 3: 8.1.5, 9.5.6. According to the specs, ST_PointOnSurface
works for surface geometries (POLYGONs, MULTIPOLYGONS, CURVED POLYGONS). So PostGIS seems to be extending
what the spec allows here. Most databases Oracle,DB II, ESRI SDE seem to only support this function for surfaces. SQL Server
2008 like PostGIS supports for all common geometries.

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_AsText(ST_PointOnSurface('POINT(0 5)'::geometry));

st_astext
------------
POINT(0 5)
(1 row)

SELECT ST_AsText(ST_PointOnSurface('LINESTRING(0 5, 0 10)'::geometry));

st_astext
------------
POINT(0 5)
(1 row)

SELECT ST_AsText(ST_PointOnSurface('POLYGON((0 0, 0 5, 5 5, 5 0, 0 0))'::geometry));

PostGIS 2.4.3 Manual 324 / 803

st_astext
----------------
POINT(2.5 2.5)
(1 row)

SELECT ST_AsEWKT(ST_PointOnSurface(ST_GeomFromEWKT('LINESTRING(0 5 1, 0 0 1, 0 10 2)')));

st_asewkt
----------------
POINT(0 0 1)
(1 row)

See Also

ST_Centroid, ST_PointInsideCircle

8.9.50 ST_Project

ST_Project — Returns a POINT projected from a start point using a distance in meters and bearing (azimuth) in radians.

Synopsis

geography ST_Project(geography g1, float distance, float azimuth);

Description

Returns a POINT projected along a geodesic from a start point using an azimuth (bearing) measured in radians and distance
measured in meters. This is also called a direct geodesic problem.
The azimuth is sometimes called the heading or the bearing in navigation. It is measured relative to true north (azimuth zero).
East is azimuth 90 (π/2), south is azimuth 180 (π), west is azimuth 270 (3π/2).
The distance is given in meters.
Availability: 2.0.0
Enhanced: 2.4.0 Allow negative distance and non-normalized azimuth.

Example: Using degrees - projected point 100,000 meters and bearing 45 degrees

SELECT ST_AsText(ST_Project('POINT(0 0)'::geography, 100000, radians(45.0)));

st_astext
--------------------------------------------
POINT(0.635231029125537 0.639472334729198)
(1 row)

See Also

ST_Azimuth, ST_Distance, PostgreSQL Math Functions

8.9.51 ST_Relate

ST_Relate — Returns true if this Geometry is spatially related to anotherGeometry, by testing for intersections between the
Interior, Boundary and Exterior of the two geometries as specified by the values in the intersectionMatrixPattern. If no intersec-
tionMatrixPattern is passed in, then returns the maximum intersectionMatrixPattern that relates the 2 geometries.
PostGIS 2.4.3 Manual 325 / 803

Synopsis

boolean ST_Relate(geometry geomA, geometry geomB, text intersectionMatrixPattern);

text ST_Relate(geometry geomA, geometry geomB);
text ST_Relate(geometry geomA, geometry geomB, integer BoundaryNodeRule);

Description

Version 1: Takes geomA, geomB, intersectionMatrix and Returns 1 (TRUE) if this Geometry is spatially related to anotherGe-
ometry, by testing for intersections between the Interior, Boundary and Exterior of the two geometries as specified by the values
in the DE-9IM matrix pattern.
This is especially useful for testing compound checks of intersection, crosses, etc in one step.
Do not call with a GeometryCollection as an argument

Note
This is the "allowable" version that returns a boolean, not an integer. This is defined in OGC spec

Note
This DOES NOT automagically include an index call. The reason for that is some relationships are anti e.g. Disjoint. If
you are using a relationship pattern that requires intersection, then include the && index call.

Version 2: Takes geomA and geomB and returns the Section 4.3.6
Version 3: same as version 2, but allows to specify a boundary node rule (1:OGC/MOD2, 2:Endpoint, 3:MultivalentEndpoint,
4:MonovalentEndpoint)

Note
Do not call with a GeometryCollection as an argument

not in OGC spec, but implied. see s2.1.13.2

Performed by the GEOS module

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 // s2.1.13.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.25

Enhanced: 2.0.0 - added support for specifying boundary node rule (requires GEOS >= 3.0).

Examples

--Find all compounds that intersect and not touch a poly (interior intersects)
SELECT l.* , b.name As poly_name
FROM polys As b
INNER JOIN compounds As l
ON (p.the_geom && b.the_geom
AND ST_Relate(l.the_geom, b.the_geom,'T********'));
PostGIS 2.4.3 Manual 326 / 803

SELECT ST_Relate(ST_GeometryFromText('POINT(1 2)'), ST_Buffer(ST_GeometryFromText('POINT(1 ←-

2)'),2));
st_relate
-----------
0FFFFF212

SELECT ST_Relate(ST_GeometryFromText('LINESTRING(1 2, 3 4)'), ST_GeometryFromText(' ←-

LINESTRING(5 6, 7 8)'));
st_relate
-----------
FF1FF0102

SELECT ST_Relate(ST_GeometryFromText('POINT(1 2)'), ST_Buffer(ST_GeometryFromText('POINT(1 ←-

2)'),2), '0FFFFF212');
st_relate
-----------
t

SELECT ST_Relate(ST_GeometryFromText('POINT(1 2)'), ST_Buffer(ST_GeometryFromText('POINT(1 ←-

2)'),2), '*FF*FF212');
st_relate
-----------
t

See Also

ST_Crosses, Section 4.3.6, ST_Disjoint, ST_Intersects, ST_Touches

8.9.52 ST_RelateMatch

ST_RelateMatch — Returns true if intersectionMattrixPattern1 implies intersectionMatrixPattern2

Synopsis

boolean ST_RelateMatch(text intersectionMatrix, text intersectionMatrixPattern);

Description

Takes intersectionMatrix and intersectionMatrixPattern and Returns true if the intersectionMatrix satisfies the intersectionMa-
trixPattern. For more information refer to Section 4.3.6.
Availability: 2.0.0 - requires GEOS >= 3.3.0.

Examples

SELECT ST_RelateMatch('101202FFF', 'TTTTTTFFF') ;

-- result --
t
--example of common intersection matrix patterns and example matrices
-- comparing relationships of involving one invalid geometry and ( a line and polygon that ←-
intersect at interior and boundary)
SELECT mat.name, pat.name, ST_RelateMatch(mat.val, pat.val) As satisfied
FROM
( VALUES ('Equality', 'T1FF1FFF1'),
('Overlaps', 'T*T***T**'),
PostGIS 2.4.3 Manual 327 / 803

('Within', 'T*F**F***'),
('Disjoint', 'FF*FF****') As pat(name,val)
CROSS JOIN
( VALUES ('Self intersections (invalid)', '111111111'),
('IE2_BI1_BB0_BE1_EI1_EE2', 'FF2101102'),
('IB1_IE1_BB0_BE0_EI2_EI1_EE2', 'F11F00212')
) As mat(name,val);

See Also

Section 4.3.6, ST_Relate

8.9.53 ST_ShortestLine

ST_ShortestLine — Returns the 2-dimensional shortest line between two geometries

Synopsis

geometry ST_ShortestLine(geometry g1, geometry g2);

Description

Returns the 2-dimensional shortest line between two geometries. The function will only return the first shortest line if more than
one, that the function finds. If g1 and g2 intersects in just one point the function will return a line with both start and end in that
intersection-point. If g1 and g2 are intersecting with more than one point the function will return a line with start and end in the
same point but it can be any of the intersecting points. The line returned will always start in g1 and end in g2. The length of the
line this function returns will always be the same as ST_Distance returns for g1 and g2.
Availability: 1.5.0

Examples
PostGIS 2.4.3 Manual 328 / 803

Shortest line between point and linestring

shortest line between polygon and polygon
SELECT ST_AsText(
SELECT ST_AsText(
ST_ShortestLine('POINT(100 100) ←-
ST_ShortestLine(
'::geometry,
ST_GeomFromText(' ←-
'LINESTRING (20 80, 98 ←-
POLYGON((175 150, 20 40, 50 60, 125
190, 110 180, 50 75 )'::geometry)
ST_Buffer( ←-
) As sline;
ST_GeomFromText('POINT(110 170)'), 2
)
) As slinewkt;
sline
-----------------
LINESTRING(140.752120669087 ←-
LINESTRING(100 100,73.0769230769231 ←-
125.695053378061,121.111404660392 15
115.384615384615)

See Also

ST_ClosestPoint, ST_Distance, ST_LongestLine, ST_MaxDistance

8.9.54 ST_Touches

ST_Touches — Returns TRUE if the geometries have at least one point in common, but their interiors do not intersect.

Synopsis

boolean ST_Touches(geometry g1, geometry g2);

Description

Returns TRUE if the only points in common between g1 and g2 lie in the union of the boundaries of g1 and g2. The
ST_Touches relation applies to all Area/Area, Line/Line, Line/Area, Point/Area and Point/Line pairs of relationships, but
not to the Point/Point pair.
In mathematical terms, this predicate is expressed as:
PostGIS 2.4.3 Manual 329 / 803

The allowable DE-9IM Intersection Matrices for the two geometries are:

• FT*******
• F**T*****
• F***T****

Important
Do not call with a GEOMETRYCOLLECTION as an argument

Note
This function call will automatically include a bounding box comparison that will make use of any indexes that are
available on the geometries. To avoid using an index, use _ST_Touches instead.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 // s2.1.13.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.28

Examples

The ST_Touches predicate returns TRUE in all the following illustrations.

POLYGON / POLYGON POLYGON / POLYGON POLYGON / LINESTRING

PostGIS 2.4.3 Manual 330 / 803

LINESTRING / LINESTRING LINESTRING / LINESTRING POLYGON / POINT

SELECT ST_Touches('LINESTRING(0 0, 1 1, 0 2)'::geometry, 'POINT(1 1)'::geometry);

st_touches
------------
f
(1 row)

SELECT ST_Touches('LINESTRING(0 0, 1 1, 0 2)'::geometry, 'POINT(0 2)'::geometry);

st_touches
------------
t
(1 row)

8.9.55 ST_Within

ST_Within — Returns true if the geometry A is completely inside geometry B

Synopsis

boolean ST_Within(geometry A, geometry B);

Description

Returns TRUE if geometry A is completely inside geometry B. For this function to make sense, the source geometries must both
be of the same coordinate projection, having the same SRID. It is a given that if ST_Within(A,B) is true and ST_Within(B,A) is
true, then the two geometries are considered spatially equal.
Performed by the GEOS module
Enhanced: 2.3.0 Enhancement to PIP short-circuit for geometry extended to support MultiPoints with few points. Prior versions
only supported point in polygon.

Important
Do not call with a GEOMETRYCOLLECTION as an argument
PostGIS 2.4.3 Manual 331 / 803

Important
Do not use this function with invalid geometries. You will get unexpected results.

This function call will automatically include a bounding box comparison that will make use of any indexes that are available on
the geometries. To avoid index use, use the function _ST_Within.
NOTE: this is the "allowable" version that returns a boolean, not an integer.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.2 // s2.1.13.3 -
a.Relate(b, ’T*F**F***’)

This method implements the SQL/MM specification. SQL-MM 3: 5.1.30

Examples

--a circle within a circle

SELECT ST_Within(smallc,smallc) As smallinsmall,
ST_Within(smallc, bigc) As smallinbig,
ST_Within(bigc,smallc) As biginsmall,
ST_Within(ST_Union(smallc, bigc), bigc) as unioninbig,
ST_Within(bigc, ST_Union(smallc, bigc)) as biginunion,
ST_Equals(bigc, ST_Union(smallc, bigc)) as bigisunion
FROM
(
SELECT ST_Buffer(ST_GeomFromText('POINT(50 50)'), 20) As smallc,
ST_Buffer(ST_GeomFromText('POINT(50 50)'), 40) As bigc) As foo;
--Result
smallinsmall | smallinbig | biginsmall | unioninbig | biginunion | bigisunion
--------------+------------+------------+------------+------------+------------
t | t | f | t | t | t
(1 row)

See Also

ST_Contains, ST_Equals, ST_IsValid

PostGIS 2.4.3 Manual 332 / 803

8.10 SFCGAL Functions

8.10.1 postgis_sfcgal_version

postgis_sfcgal_version — Returns the version of SFCGAL in use

Synopsis

text postgis_sfcgal_version(void);

Description

Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

8.10.2 ST_Extrude

ST_Extrude — Extrude a surface to a related volume

Synopsis

geometry ST_Extrude(geometry geom, float x, float y, float z);

Description

Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 333 / 803

Examples

3D images were generated using PostGIS ST_AsX3D and rendering in HTML using X3Dom HTML Javascript rendering library.

SELECT ST_Buffer(ST_GeomFromText('POINT ←-
(100 90)'),
50, 'quad_segs=2'),0,0,30); ST_Extrude(ST_Buffer(ST_GeomFromText(' ←-
POINT(100 90)'),
50, 'quad_segs=2'),0,0,30);

Hexagon extruded 30 units along Z produces a

PolyhedralSurfaceZ
Original octagon formed from buffering point

SELECT ST_GeomFromText('LINESTRING(50 50, ←-

100 90, 95 150)')

SELECT ST_Extrude(
ST_GeomFromText('LINESTRING(50 50, 100 ←-
90, 95 150)'),0,0,10));

LineString Extruded along Z produces a

PolyhedralSurfaceZ

Original linestring
PostGIS 2.4.3 Manual 334 / 803

See Also

ST_AsX3D

8.10.3 ST_StraightSkeleton

ST_StraightSkeleton — Compute a straight skeleton from a geometry

Synopsis

geometry ST_StraightSkeleton(geometry geom);

Description

Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT ST_StraightSkeleton(ST_GeomFromText('POLYGON (( 190 190, 10 190, 10 10, 190 10, 190 ←-

20, 160 30, 60 30, 60 130, 190 140, 190 190 ))'));

Straight Skeleton of polygon

Original polygon
PostGIS 2.4.3 Manual 335 / 803

8.10.4 ST_ApproximateMedialAxis

ST_ApproximateMedialAxis — Compute the approximate medial axis of an areal geometry.

Synopsis

geometry ST_ApproximateMedialAxis(geometry geom);

Description

Return an approximate medial axis for the areal input based on its straight skeleton. Uses an SFCGAL specific API when built
against a capable version (1.2.0+). Otherwise the function is just a wrapper around ST_StraightSkeleton (slower case).
Availability: 2.2.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT ST_ApproximateMedialAxis(ST_GeomFromText('POLYGON (( 190 190, 10 190, 10 10, 190 10, ←-

190 20, 160 30, 60 30, 60 130, 190 140, 190 190 ))'));

A polygon and its approximate medial axis

PostGIS 2.4.3 Manual 336 / 803

See Also

ST_StraightSkeleton

8.10.5 ST_IsPlanar

ST_IsPlanar — Check if a surface is or not planar

Synopsis

boolean ST_IsPlanar(geometry geom);

Description

Availability: 2.2.0: This was documented in 2.1.0 but got accidentally left out in 2.1 release.

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

8.10.6 ST_Orientation

ST_Orientation — Determine surface orientation

Synopsis

integer ST_Orientation(geometry geom);

Description

The function only applies to polygons. It returns -1 if the polygon is counterclockwise oriented and 1 if the polygon is clockwise
oriented.
Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

8.10.7 ST_ForceLHR

ST_ForceLHR — Force LHR orientation

Synopsis

geometry ST_ForceLHR(geometry geom);

PostGIS 2.4.3 Manual 337 / 803

Description

Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

8.10.8 ST_MinkowskiSum

ST_MinkowskiSum — Performs Minkowski sum

Synopsis

geometry ST_MinkowskiSum(geometry geom1, geometry geom2);

Description

This function performs a 2D minkowski sum of a point, line or polygon with a polygon.
A minkowski sum of two geometries A and B is the set of all points that are the sum of any point in A and B. Minkowski sums
are often used in motion planning and computer-aided design. More details on Wikipedia Minkowski addition.
The first parameter can be any 2D geometry (point, linestring, polygon). If a 3D geometry is passed, it will be converted to 2D
by forcing Z to 0, leading to possible cases of invalidity. The second parameter must be a 2D polygon.
Implementation utilizes CGAL 2D Minkowskisum.
Availability: 2.1.0

This method needs SFCGAL backend.

Examples

Minkowski Sum of Linestring and circle polygon where Linestring cuts thru the circle
PostGIS 2.4.3 Manual 338 / 803

Before Summing After summing

SELECT ST_MinkowskiSum(line, circle))

FROM (SELECT
ST_MakeLine(ST_MakePoint(10, 10),ST_MakePoint(100, 100)) As line,
ST_Buffer(ST_GeomFromText('POINT(50 50)'), 30) As circle) As foo;

-- wkt --
MULTIPOLYGON(((30 59.9999999999999,30.5764415879031 54.1472903395161,32.2836140246614 ←-
48.5194970290472,35.0559116309237 43.3328930094119,38.7867965644036 ←-
38.7867965644035,43.332893009412 35.0559116309236,48.5194970290474 ←-
32.2836140246614,54.1472903395162 30.5764415879031,60.0000000000001 30,65.8527096604839 ←-
30.5764415879031,71.4805029709527 32.2836140246614,76.6671069905881 ←-
35.0559116309237,81.2132034355964 38.7867965644036,171.213203435596 ←-
128.786796564404,174.944088369076 133.332893009412,177.716385975339 ←-
138.519497029047,179.423558412097 144.147290339516,180 150,179.423558412097 ←-
155.852709660484,177.716385975339 161.480502970953,174.944088369076 ←-
166.667106990588,171.213203435596 171.213203435596,166.667106990588 174.944088369076,
161.480502970953 177.716385975339,155.852709660484 179.423558412097,150 ←-
180,144.147290339516 179.423558412097,138.519497029047 177.716385975339,133.332893009412 ←-
174.944088369076,128.786796564403 171.213203435596,38.7867965644035 ←-
81.2132034355963,35.0559116309236 76.667106990588,32.2836140246614 ←-
71.4805029709526,30.5764415879031 65.8527096604838,30 59.9999999999999)))

Minkowski Sum of a polygon and multipoint

PostGIS 2.4.3 Manual 339 / 803

After summing: polygon is duplicated and translated to

Before Summing
position of points

SELECT ST_MinkowskiSum(mp, poly)

FROM (SELECT 'MULTIPOINT(25 50,70 25)'::geometry As mp,
'POLYGON((130 150, 20 40, 50 60, 125 100, 130 150))'::geometry As poly
) As foo

-- wkt --
MULTIPOLYGON(
((70 115,100 135,175 175,225 225,70 115)),
((120 65,150 85,225 125,275 175,120 65))
)

8.10.9 ST_3DIntersection

ST_3DIntersection — Perform 3D intersection

Synopsis

geometry ST_3DIntersection(geometry geom1, geometry geom2);

Description

Return a geometry that is the shared portion between geom1 and geom2.
Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 340 / 803

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

3D images were generated using PostGIS ST_AsX3D and rendering in HTML using X3Dom HTML Javascript rendering library.

SELECT ST_3DIntersection(geom1,geom2)
SELECT ST_Extrude(ST_Buffer( ←- FROM ( SELECT ST_Extrude(ST_Buffer( ←-
ST_GeomFromText('POINT(100 90)'), ST_GeomFromText('POINT(100 90)'),
50, 'quad_segs=2'),0,0,30) AS geom1, 50, 'quad_segs=2'),0,0,30) AS geom1,
ST_Extrude(ST_Buffer( ←- ST_Extrude(ST_Buffer( ←-
ST_GeomFromText('POINT(80 80)'), ST_GeomFromText('POINT(80 80)'),
50, 'quad_segs=1'),0,0,30) AS geom2; 50, 'quad_segs=1'),0,0,30) AS geom2 ) As ←-
t;

Original 3D geometries overlaid. geom2 is shown

semi-transparent
Intersection of geom1 and geom2

3D linestrings and polygons

SELECT ST_AsText(ST_3DIntersection(linestring, polygon)) As wkt
FROM ST_GeomFromText('LINESTRING Z (2 2 6,1.5 1.5 7,1 1 8,0.5 0.5 8,0 0 10)') AS ←-
linestring
CROSS JOIN ST_GeomFromText('POLYGON((0 0 8, 0 1 8, 1 1 8, 1 0 8, 0 0 8))') AS polygon;

wkt
--------------------------------
LINESTRING Z (1 1 8,0.5 0.5 8)

Cube (closed Polyhedral Surface) and Polygon Z

SELECT ST_AsText(ST_3DIntersection(
ST_GeomFromText('POLYHEDRALSURFACE Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'),
'POLYGON Z ((0 0 0, 0 0 0.5, 0 0.5 0.5, 0 0.5 0, 0 0 0))'::geometry))

TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),((0 0.5 0,0 0 0,0 0.5 0.5,0 0.5 0)))

Intersection of 2 solids that result in volumetric intersection is also a solid (ST_Dimension returns 3)
PostGIS 2.4.3 Manual 341 / 803

SELECT ST_AsText(ST_3DIntersection( ST_Extrude(ST_Buffer('POINT(10 20)'::geometry,10,1) ←-

,0,0,30),
ST_Extrude(ST_Buffer('POINT(10 20)'::geometry,10,1),2,0,10) ));

POLYHEDRALSURFACE Z (((13.3333333333333 13.3333333333333 10,20 20 0,20 20 ←-

10,13.3333333333333 13.3333333333333 10)),
((20 20 10,16.6666666666667 23.3333333333333 10,13.3333333333333 13.3333333333333 10,20 ←-
20 10)),
((20 20 0,16.6666666666667 23.3333333333333 10,20 20 10,20 20 0)),
((13.3333333333333 13.3333333333333 10,10 10 0,20 20 0,13.3333333333333 13.3333333333333 ←-
10)),
((16.6666666666667 23.3333333333333 10,12 28 10,13.3333333333333 13.3333333333333 ←-
10,16.6666666666667 23.3333333333333 10)),
((20 20 0,9.99999999999995 30 0,16.6666666666667 23.3333333333333 10,20 20 0)),
((10 10 0,9.99999999999995 30 0,20 20 0,10 10 0)),((13.3333333333333 13.3333333333333 ←-
10,12 12 10,10 10 0,13.3333333333333 13.3333333333333 10)),
((12 28 10,12 12 10,13.3333333333333 13.3333333333333 10,12 28 10)),
((16.6666666666667 23.3333333333333 10,9.99999999999995 30 0,12 28 10,16.6666666666667 ←-
23.3333333333333 10)),
((10 10 0,0 20 0,9.99999999999995 30 0,10 10 0)),
((12 12 10,11 11 10,10 10 0,12 12 10)),((12 28 10,11 11 10,12 12 10,12 28 10)),
((9.99999999999995 30 0,11 29 10,12 28 10,9.99999999999995 30 0)),((0 20 0,2 20 ←-
10,9.99999999999995 30 0,0 20 0)),
((10 10 0,2 20 10,0 20 0,10 10 0)),((11 11 10,2 20 10,10 10 0,11 11 10)),((12 28 10,11 29 ←-
10,11 11 10,12 28 10)),
((9.99999999999995 30 0,2 20 10,11 29 10,9.99999999999995 30 0)),((11 11 10,11 29 10,2 20 ←-
10,11 11 10)))

8.10.10 ST_3DDifference

ST_3DDifference — Perform 3D difference

Synopsis

geometry ST_3DDifference(geometry geom1, geometry geom2);

Description

Returns that part of geom1 that is not part of geom2.

Availability: 2.2.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

3D images were generated using PostGIS ST_AsX3D and rendering in HTML using X3Dom HTML Javascript rendering library.
PostGIS 2.4.3 Manual 342 / 803

SELECT ST_3DDifference(geom1,geom2)
FROM ( SELECT ST_Extrude(ST_Buffer( ←-
SELECT ST_Extrude(ST_Buffer( ←- ST_GeomFromText('POINT(100 90)'),
ST_GeomFromText('POINT(100 90)'), 50, 'quad_segs=2'),0,0,30) AS geom1,
50, 'quad_segs=2'),0,0,30) AS geom1, ST_Extrude(ST_Buffer( ←-
ST_Extrude(ST_Buffer( ←- ST_GeomFromText('POINT(80 80)'),
ST_GeomFromText('POINT(80 80)'), 50, 'quad_segs=1'),0,0,30) AS geom2 ) As ←-
50, 'quad_segs=1'),0,0,30) AS geom2; t;

Original 3D geometries overlaid. geom2 is the part that

will be removed.
What’s left after removing geom2

See Also

ST_Extrude, ST_AsX3D, ST_3DIntersection ST_3DUnion

8.10.11 ST_3DUnion

ST_3DUnion — Perform 3D union

Synopsis

geometry ST_3DUnion(geometry geom1, geometry geom2);

Description

Availability: 2.2.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 343 / 803

Examples

3D images were generated using PostGIS ST_AsX3D and rendering in HTML using X3Dom HTML Javascript rendering library.

SELECT ST_3DUnion(geom1,geom2)
SELECT ST_Extrude(ST_Buffer( ←- FROM ( SELECT ST_Extrude(ST_Buffer( ←-
ST_GeomFromText('POINT(100 90)'), ST_GeomFromText('POINT(100 90)'),
50, 'quad_segs=2'),0,0,30) AS geom1, 50, 'quad_segs=2'),0,0,30) AS geom1,
ST_Extrude(ST_Buffer( ←- ST_Extrude(ST_Buffer( ←-
ST_GeomFromText('POINT(80 80)'), ST_GeomFromText('POINT(80 80)'),
50, 'quad_segs=1'),0,0,30) AS geom2; 50, 'quad_segs=1'),0,0,30) AS geom2 ) As ←-
t;

Original 3D geometries overlaid. geom2 is the one with

transparency.
Union of geom1 and geom2

See Also

ST_Extrude, ST_AsX3D, ST_3DIntersection ST_3DDifference

8.10.12 ST_3DArea

ST_3DArea — Computes area of 3D surface geometries. Will return 0 for solids.

Synopsis

floatST_3DArea(geometry geom1);

Description

Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 344 / 803

Examples

Note: By default a PolyhedralSurface built from WKT is a surface geometry, not solid. It therefore has surface area. Once
converted to a solid, no area.
SELECT ST_3DArea(geom) As cube_surface_area,
ST_3DArea(ST_MakeSolid(geom)) As solid_surface_area
FROM (SELECT 'POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'::geometry) As f(geom);

cube_surface_area | solid_surface_area
-------------------+--------------------
6 | 0

See Also

ST_Area, ST_MakeSolid, ST_IsSolid, ST_Area

8.10.13 ST_Tesselate

ST_Tesselate — Perform surface Tesselation of a polygon or polyhedralsurface and returns as a TIN or collection of TINS

Synopsis

geometry ST_Tesselate(geometry geom);

Description

Takes as input a surface such a MULTI(POLYGON) or POLYHEDRALSURFACE and returns a TIN representation via the
process of tesselation using triangles.
Availability: 2.1.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples
PostGIS 2.4.3 Manual 345 / 803

SELECT ST_Tesselate(ST_GeomFromText(' ←-
POLYHEDRALSURFACE Z( ((0 0 0, 0
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 ←-
0)), ((0 0 0, 1 0 0, 1 0 1, 0
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 ←-
0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 ←-
SELECT ST_GeomFromText('POLYHEDRALSURFACE ←- 0)), ((0 0 1, 1 0 1, 1 1 1, 0
Z( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
ST_AsText output:
((0 0 0, 0 1 0, 1 1 0, 1 ←-
0 0, 0 0 0)), ((0 0 0, 1 0TIN
0, Z1 (((0
0 1, 00 0,0
0 1,0 01,0
0 0)),
1 1,0 0 0)),((0 1 ←-
((1 1 0, 1 1 1, 1 0 1, 1 ←- 0,0 0 0,0 1 1,0 1 0)),
0 0, 1 1 0)), ((0 0 0,0 1 0,1 1 0,0 0 0)),
((0 1 0, 0 1 1, 1 1 1, 1 ←- ((1 0 0,0 0 0,1 1 0,1 0 0)),((0 0 ←-
1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1,1 1)) 0)');
0,1 0 1,0 0 1)),
((0 0 1,0 0 0,1 0 0,0 0 1)),
((1 1 0,1 1 1,1 0 1,1 1 0)),((1 0 ←-
0,1 1 0,1 0 1,1 0 0)),
((0 1 0,0 1 1,1 1 1,0 1 0)),((1 1 ←-
0,0 1 0,1 1 1,1 1 0)),
((0 1 1,1 0 1,1 1 1,0 1 1)),((0 1 ←-
1,0 0 1,1 0 1,0 1 1)))

Original Cube

Tesselated Cube with triangles colored

PostGIS 2.4.3 Manual 346 / 803

SELECT
ST_Tesselate('POLYGON (( 10 190, ←-
10 70, 80 70, 80 130, 50 160, 1

SELECT 'POLYGON (( 10 190, 10 70, 80 70, ←- ST_AsText output

80 130, 50 160, 120 160, 120 190, 10 190 ))'::geometry;
TIN(((80 130,50 160,80 70,80 130)),((50 ←-
160,10 190,10 70,50 160)),
((80 70,50 160,10 70,80 70)) ←-
,((120 160,120 190,50 160,120 1
((120 190,10 190,50 160,120 190)))

Original polygon

Tesselated Polygon

8.10.14 ST_Volume

ST_Volume — Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return 0.

Synopsis

float ST_Volume(geometry geom1);

Description

Availability: 2.2.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 347 / 803

Example

When closed surfaces are created with WKT, they are treated as areal rather than solid. To make them solid, you need to use
ST_MakeSolid. Areal geometries have no volume. Here is an example to demonstrate.
SELECT ST_Volume(geom) As cube_surface_vol,
ST_Volume(ST_MakeSolid(geom)) As solid_surface_vol
FROM (SELECT 'POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'::geometry) As f(geom);

cube_surface_vol | solid_surface_vol
------------------+-------------------
0 | 1

See Also

ST_3DArea, ST_MakeSolid, ST_IsSolid

8.10.15 ST_MakeSolid

ST_MakeSolid — Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input geometry must be a
closed Polyhedral Surface or a closed TIN.

Synopsis

geometryST_MakeSolid(geometry geom1);

Description

Availability: 2.2.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

8.10.16 ST_IsSolid

ST_IsSolid — Test if the geometry is a solid. No validity check is performed.

Synopsis

booleanST_IsSolid(geometry geom1);
PostGIS 2.4.3 Manual 348 / 803

Description

Availability: 2.2.0

This method needs SFCGAL backend.

This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

8.11 Geometry Processing

8.11.1 ST_Buffer

ST_Buffer — (T) Returns a geometry covering all points within a given distance from the input geometry.

Synopsis

geometry ST_Buffer(geometry g1, float radius_of_buffer);

geometry ST_Buffer(geometry g1, float radius_of_buffer, integer num_seg_quarter_circle);
geometry ST_Buffer(geometry g1, float radius_of_buffer, text buffer_style_parameters);
geography ST_Buffer(geography g1, float radius_of_buffer_in_meters);
geography ST_Buffer(geography g1, float radius_of_buffer, integer num_seg_quarter_circle);
geography ST_Buffer(geography g1, float radius_of_buffer, text buffer_style_parameters);

Description

Returns a geometry/geography that represents all points whose distance from this Geometry/geography is less than or equal to
distance.
Geometry: Calculations are in the Spatial Reference System of the geometry. Introduced in 1.5 support for different end cap and
mitre settings to control shape.

Note
Negative radii: For polygons, a negative radius can be used, which will shrink the polygon rather than expanding it.

Note
Geography: For geography this is really a thin wrapper around the geometry implementation. It first determines the
best SRID that fits the bounding box of the geography object (favoring UTM, Lambert Azimuthal Equal Area (LAEA)
north/south pole, and falling back on mercator in worst case scenario) and then buffers in that planar spatial ref and
retransforms back to WGS84 geography.

For geography this may not behave as expected if object is sufficiently large that it falls between two UTM zones or crosses
the dateline
PostGIS 2.4.3 Manual 349 / 803

Availability: 1.5 - ST_Buffer was enhanced to support different endcaps and join types. These are useful for example to convert
road linestrings into polygon roads with flat or square edges instead of rounded edges. Thin wrapper for geography was added. -
requires GEOS >= 3.2 to take advantage of advanced geometry functionality.
The optional third parameter (currently only applies to geometry) can either specify number of segments used to approximate a
quarter circle (integer case, defaults to 8) or a list of blank-separated key=value pairs (string case) to tweak operations as follows:

• ’quad_segs=#’ : number of segments used to approximate a quarter circle (defaults to 8).

• ’endcap=round|flat|square’ : endcap style (defaults to "round", needs GEOS-3.2 or higher for a different value). ’butt’ is also
accepted as a synonym for ’flat’.

• ’join=round|mitre|bevel’ : join style (defaults to "round", needs GEOS-3.2 or higher for a different value). ’miter’ is also
accepted as a synonym for ’mitre’.
• ’mitre_limit=#.#’ : mitre ratio limit (only affects mitered join style). ’miter_limit’ is also accepted as a synonym for ’mitre_limit’.

Units of radius are measured in units of the spatial reference system.

The inputs can be POINTS, MULTIPOINTS, LINESTRINGS, MULTILINESTRINGS, POLYGONS, MULTIPOLYGONS, and
GeometryCollections.

Note
This function ignores the third dimension (z) and will always give a 2-d buffer even when presented with a 3d-geometry.

Performed by the GEOS module.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.17

Note
People often make the mistake of using this function to try to do radius searches. Creating a buffer to a radius search
is slow and pointless. Use ST_DWithin instead.

Examples
PostGIS 2.4.3 Manual 350 / 803

quad_segs=8 (default) quad_segs=2 (lame)

SELECT ST_Buffer( SELECT ST_Buffer(
ST_GeomFromText('POINT(100 90)'), ST_GeomFromText('POINT(100 90)'),
50, 'quad_segs=8'); 50, 'quad_segs=2');

endcap=round join=round (default) endcap=square

SELECT ST_Buffer( SELECT ST_Buffer(
ST_GeomFromText( ST_GeomFromText(
'LINESTRING(50 50,150 150,150 50)' 'LINESTRING(50 50,150 150,150 50)'
), 10, 'endcap=round join=round'); ), 10, 'endcap=square join=round');
PostGIS 2.4.3 Manual 351 / 803

join=bevel join=mitre mitre_limit=5.0 (default mitre limit)

SELECT ST_Buffer( SELECT ST_Buffer(
ST_GeomFromText( ST_GeomFromText(
'LINESTRING(50 50,150 150,150 50)' 'LINESTRING(50 50,150 150,150 50)'
), 10, 'join=bevel'); ), 10, 'join=mitre mitre_limit=5.0');

--A buffered point approximates a circle

-- A buffered point forcing approximation of (see diagram)
-- 2 points per quarter circle is poly with 8 sides (see diagram)
SELECT ST_NPoints(ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50)) As ←-
promisingcircle_pcount,
ST_NPoints(ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50, 2)) As lamecircle_pcount;

promisingcircle_pcount | lamecircle_pcount
------------------------+-------------------
33 | 9

--A lighter but lamer circle

-- only 2 points per quarter circle is an octagon
--Below is a 100 meter octagon
-- Note coordinates are in NAD 83 long lat which we transform
to Mass state plane meter and then buffer to get measurements in meters;
SELECT ST_AsText(ST_Buffer(
ST_Transform(
ST_SetSRID(ST_MakePoint(-71.063526, 42.35785),4269), 26986)
,100,2)) As octagon;
----------------------
POLYGON((236057.59057465 900908.759918696,236028.301252769 900838.049240578,235
957.59057465 900808.759918696,235886.879896532 900838.049240578,235857.59057465
900908.759918696,235886.879896532 900979.470596815,235957.59057465 901008.759918
696,236028.301252769 900979.470596815,236057.59057465 900908.759918696))

See Also

ST_Collect, ST_DWithin, ST_SetSRID, ST_Transform, ST_Union

PostGIS 2.4.3 Manual 352 / 803

8.11.2 ST_BuildArea

ST_BuildArea — Creates an areal geometry formed by the constituent linework of given geometry

Synopsis

geometry ST_BuildArea(geometry A);

Description

Creates an areal geometry formed by the constituent linework of given geometry. The return type can be a Polygon or Multi-
Polygon, depending on input. If the input lineworks do not form polygons NULL is returned. The inputs can be LINESTRINGS,
MULTILINESTRINGS, POLYGONS, MULTIPOLYGONS, and GeometryCollections.
This function will assume all inner geometries represent holes

Note
Input linework must be correctly noded for this function to work properly

Availability: 1.1.0 - requires GEOS >= 2.1.0.

Examples

This will create a donut

SELECT ST_BuildArea(ST_Collect(smallc,bigc))
FROM (SELECT
ST_Buffer(
ST_GeomFromText('POINT(100 90)'), 25) As smallc,
ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As bigc) As foo;
PostGIS 2.4.3 Manual 353 / 803

This will create a gaping hole inside the circle with prongs sticking out
SELECT ST_BuildArea(ST_Collect(line,circle))
FROM (SELECT
ST_Buffer(
ST_MakeLine(ST_MakePoint(10, 10),ST_MakePoint(190, 190)),
5) As line,
ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As circle) As foo;

--this creates the same gaping hole

--but using linestrings instead of polygons
SELECT ST_BuildArea(
ST_Collect(ST_ExteriorRing(line),ST_ExteriorRing(circle))
)
FROM (SELECT ST_Buffer(
ST_MakeLine(ST_MakePoint(10, 10),ST_MakePoint(190, 190))
,5) As line,
ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As circle) As foo;

See Also

ST_Node, ST_MakePolygon, ST_BdPolyFromText, ST_BdMPolyFromTextwrappers to this function with standard OGC inter-
face

8.11.3 ST_ClipByBox2D

ST_ClipByBox2D — Returns the portion of a geometry falling within a rectangle.

Synopsis

geometry ST_ClipByBox2D(geometry geom, box2d box);

PostGIS 2.4.3 Manual 354 / 803

Description

Clips a geometry by a 2D box in a fast but possibly dirty way. The output geometry is not guaranteed to be valid (self-intersections
for a polygon may be introduced). Topologically invalid input geometries do not result in exceptions being thrown.
Performed by the GEOS module.

Note
Requires GEOS 3.5.0+

Availability: 2.2.0 - requires GEOS >= 3.5.0.

Examples

-- Rely on implicit cast from geometry to box2d for the second parameter
SELECT ST_ClipByBox2D(the_geom, ST_MakeEnvelope(0,0,10,10)) FROM mytab;

See Also

ST_Intersection, ST_MakeBox2D, ST_MakeEnvelope

8.11.4 ST_Collect

ST_Collect — Return a specified ST_Geometry value from a collection of other geometries.

Synopsis

geometry ST_Collect(geometry set g1field);

geometry ST_Collect(geometry g1, geometry g2);
geometry ST_Collect(geometry[] g1_array);

Description

Output type can be a MULTI* or a GEOMETRYCOLLECTION. Comes in 2 variants. Variant 1 collects 2 geometries. Variant
2 is an aggregate function that takes a set of geometries and collects them into a single ST_Geometry.
Aggregate version: This function returns a GEOMETRYCOLLECTION or a MULTI object from a set of geometries. The
ST_Collect() function is an "aggregate" function in the terminology of PostgreSQL. That means that it operates on rows of
data, in the same way the SUM() and AVG() functions do. For example, "SELECT ST_Collect(GEOM) FROM GEOMTABLE
GROUP BY ATTRCOLUMN" will return a separate GEOMETRYCOLLECTION for each distinct value of ATTRCOLUMN.
Non-Aggregate version: This function returns a geometry being a collection of two input geometries. Output type can be a
MULTI* or a GEOMETRYCOLLECTION.

Note
ST_Collect and ST_Union are often interchangeable except that ST_Collect will always return a GeometryCollection
or MULTI geometry and ST_Union may return single geometries when it dissolves boundaries. ST_Union will also
split linestrings at node intersections, whereas ST_Collect will never split linestrings and in turn just return as MUL-
TILINESTRING. To prevent ST_Collect from returning a Geometry Collection when collecting MULTI geometries, one
can use the below trick that utilizes ST_Dump to expand the MULTIs out to singles and then regroup them.
PostGIS 2.4.3 Manual 355 / 803

Availability: 1.4.0 - ST_Collect(geomarray) was introduced. ST_Collect was enhanced to handle more geometries faster.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves This method supports Circular Strings and Curves, but will never return
a MULTICURVE or MULTI as one would expect and PostGIS does not currently support those.

Examples

Aggregate example
SELECT stusps, ST_Collect(f.the_geom) as singlegeom
FROM (SELECT stusps, (ST_Dump(the_geom)).geom As the_geom
FROM
somestatetable ) As f
GROUP BY stusps

Non-Aggregate example
SELECT ST_AsText(ST_Collect(ST_GeomFromText('POINT(1 2)'),
ST_GeomFromText('POINT(-2 3)') ));

st_astext
----------
MULTIPOINT(1 2,-2 3)

--Collect 2 d points
SELECT ST_AsText(ST_Collect(ST_GeomFromText('POINT(1 2)'),
ST_GeomFromText('POINT(1 2)') ) );

st_astext
----------
MULTIPOINT(1 2,1 2)

--Collect 3d points
SELECT ST_AsEWKT(ST_Collect(ST_GeomFromEWKT('POINT(1 2 3)'),
ST_GeomFromEWKT('POINT(1 2 4)') ) );

st_asewkt
-------------------------
MULTIPOINT(1 2 3,1 2 4)

--Example with curves

SELECT ST_AsText(ST_Collect(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 ←-
150505,220227 150406)'),
ST_GeomFromText('CIRCULARSTRING(220227 150406,2220227 150407,220227 150406)')));
st_astext
------------------------------------------------------------------------------------
GEOMETRYCOLLECTION(CIRCULARSTRING(220268 150415,220227 150505,220227 150406),
CIRCULARSTRING(220227 150406,2220227 150407,220227 150406))

--New ST_Collect array construct

SELECT ST_Collect(ARRAY(SELECT the_geom FROM sometable));

SELECT ST_AsText(ST_Collect(ARRAY[ST_GeomFromText('LINESTRING(1 2, 3 4)'),

ST_GeomFromText('LINESTRING(3 4, 4 5)')])) As wktcollect;

--wkt collect --
MULTILINESTRING((1 2,3 4),(3 4,4 5))
PostGIS 2.4.3 Manual 356 / 803

See Also

ST_Dump, ST_Union

8.11.5 ST_ConcaveHull

ST_ConcaveHull — The concave hull of a geometry represents a possibly concave geometry that encloses all geometries within
the set. You can think of it as shrink wrapping.

Synopsis

geometry ST_ConcaveHull(geometry geomA, float target_percent, boolean allow_holes=false);

Description

The concave hull of a geometry represents a possibly concave geometry that encloses all geometries within the set. Defaults to
false for allowing polygons with holes. The result is never higher than a single polygon.
The target_percent is the target percent of area of convex hull the PostGIS solution will try to approach before giving up or
exiting. One can think of the concave hull as the geometry you get by vacuum sealing a set of geometries. The target_percent
of 1 will give you the same answer as the convex hull. A target_percent between 0 and 0.99 will give you something that should
have a smaller area than the convex hull. This is different from a convex hull which is more like wrapping a rubber band around
the set of geometries.
It is usually used with MULTI and Geometry Collections. Although it is not an aggregate - you can use it in conjunction with
ST_Collect or ST_Union to get the concave hull of a set of points/linestring/polygons ST_ConcaveHull(ST_Collect(somepointfield),
0.80).
It is much slower to compute than convex hull but encloses the geometry better and is also useful for image recognition.
Performed by the GEOS module

Note
Note - If you are using with points, linestrings, or geometry collections use ST_Collect. If you are using with polygons,
use ST_Union since it may fail with invalid geometries.

Note
Note - The smaller you make the target percent, the longer it takes to process the concave hull and more likely to run
into topological exceptions. Also the more floating points and number of points you accrue. First try a 0.99 which does
a first hop, is usually very fast, sometimes as fast as computing the convex hull, and usually gives much better than
99% of shrink since it almost always overshoots. Second hope of 0.98 it slower, others get slower usually quadratically.
To reduce precision and float points, use ST_SimplifyPreserveTopology or ST_SnapToGrid after ST_ConcaveHull.
ST_SnapToGrid is a bit faster, but could result in invalid geometries where as ST_SimplifyPreserveTopology almost
always preserves the validity of the geometry.

More real world examples and brief explanation of the technique are shown http://www.bostongis.com/postgis_concavehull.snippet
Also check out Simon Greener’s article on demonstrating ConcaveHull introduced in Oracle 11G R2. http://www.spatialdbadvisor.com/-
oracle_spatial_tips_tricks/172/concave-hull-geometries-in-oracle-11gr2. The solution we get at 0.75 target percent of convex hull
is similar to the shape Simon gets with Oracle SDO_CONCAVEHULL_BOUNDARY.
Availability: 2.0.0
PostGIS 2.4.3 Manual 357 / 803

Examples

--Get estimate of infected area based on point observations

SELECT d.disease_type,
ST_ConcaveHull(ST_Collect(d.pnt_geom), 0.99) As geom
FROM disease_obs As d
GROUP BY d.disease_type;

ST_ConcaveHull of 2 polygons encased in target 100%

-- geometries overlaid with concavehull at target 90% of
shrink concave hull
convex hull area
-- geometries overlaid with concavehull
-- geometries overlaid with concavehull ←-
-- at target 100% shrink (this is the ←-
at target 90% shrink
same as convex hull - since no shrink) SELECT
SELECT
ST_ConcaveHull(
ST_ConcaveHull(
ST_Union(ST_GeomFromText ←-
ST_Union(ST_GeomFromText ←-
('POLYGON((175 150, 20 40,
('POLYGON((175 150, 20 40,
50 60, 125 100, ←-
50 60, 125 100, ←-
175 150))'),
175 150))'),
ST_Buffer(ST_GeomFromText ←-
ST_Buffer(ST_GeomFromText ←-
('POINT(110 170)'), 20)
('POINT(110 170)'), 20)
), 0.9)
), 1)
As target_90;
As convexhull;
PostGIS 2.4.3 Manual 358 / 803

L Shape points overlaid with convex hull

-- this produces a table of 42 points ←-
that form an L shape
SELECT (ST_DumpPoints(ST_GeomFromText(
'MULTIPOINT(14 14,34 14,54 14,74 14,94 ←-
14,114 14,134 14,
150 14,154 14,154 6,134 6,114 6,94 6,74 ←- ST_ConcaveHull of L points at target 99% of convex hull
6,54 6,34 6,
14 6,10 6,8 6,7 7,6 8,6 10,6 30,6 50,6 ←- SELECT ST_ConcaveHull(ST_Collect(geom), ←-
70,6 90,6 110,6 130, 0.99)
6 150,6 170,6 190,6 194,14 194,14 174,14 ←- FROM l_shape;
154,14 134,14 114,
14 94,14 74,14 54,14 34,14 14)'))).geom
INTO TABLE l_shape;

SELECT ST_ConvexHull(ST_Collect(geom))
FROM l_shape;
PostGIS 2.4.3 Manual 359 / 803

multilinestring overlaid with Convex hull

Concave Hull of L points at target 80% convex hull area

-- Concave Hull L shape points
-- at target 80% of convexhull
SELECT ST_ConcaveHull(ST_Collect( ←-
geom), 0.80)
FROM l_shape;
multilinestring with overlaid with Concave hull of
linestrings at 99% target -- first hop
SELECT ST_ConcaveHull(ST_GeomFromText(' ←-
MULTILINESTRING((106 164,30 112,74 70,82 112,1
130 62,122 40,156 32,162 76,172 ←-
88),
(132 178,134 148,128 136,96 128,132 ←-
108,150 130,
170 142,174 110,156 96,158 90,158 88),
(22 64,66 28,94 38,94 68,114 76,112 30,
132 10,168 18,178 34,186 52,184 74,190 ←-
100,
190 122,182 148,178 170,176 184,156 ←-
164,146 178,
132 186,92 182,56 158,36 150,62 150,76 ←-
128,88 118))'),0.99)
PostGIS 2.4.3 Manual 360 / 803

See Also

ST_Collect, ST_ConvexHull, ST_SimplifyPreserveTopology, ST_SnapToGrid

8.11.6 ST_ConvexHull

ST_ConvexHull — The convex hull of a geometry represents the minimum convex geometry that encloses all geometries within
the set.

Synopsis

geometry ST_ConvexHull(geometry geomA);

Description

The convex hull of a geometry represents the minimum convex geometry that encloses all geometries within the set.
One can think of the convex hull as the geometry you get by wrapping an elastic band around a set of geometries. This is different
from a concave hull which is analogous to shrink-wrapping your geometries.
It is usually used with MULTI and Geometry Collections. Although it is not an aggregate - you can use it in conjunction with
ST_Collect to get the convex hull of a set of points. ST_ConvexHull(ST_Collect(somepointfield)).
It is often used to determine an affected area based on a set of point observations.
Performed by the GEOS module

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.16

This function supports 3d and will not drop the z-index.

Examples

--Get estimate of infected area based on point observations

SELECT d.disease_type,
ST_ConvexHull(ST_Collect(d.the_geom)) As the_geom
FROM disease_obs As d
GROUP BY d.disease_type;
PostGIS 2.4.3 Manual 361 / 803

Convex Hull of a MultiLinestring and a MultiPoint seen together with the MultiLinestring and MultiPoint

SELECT ST_AsText(ST_ConvexHull(
ST_Collect(
ST_GeomFromText('MULTILINESTRING((100 190,10 8),(150 10, 20 30))'),
ST_GeomFromText('MULTIPOINT(50 5, 150 30, 50 10, 10 10)')
)) );
---st_astext--
POLYGON((50 5,10 8,10 10,100 190,150 30,150 10,50 5))

See Also

ST_Collect, ST_ConcaveHull, ST_MinimumBoundingCircle

8.11.7 ST_CurveToLine

ST_CurveToLine — Converts a CIRCULARSTRING/CURVEPOLYGON to a LINESTRING/POLYGON

Synopsis

geometry ST_CurveToLine(geometry curveGeom);

geometry ST_CurveToLine(geometry curveGeom, integer segments_per_qtr_circle);
geometry ST_CurveToLine(geometry curveGeom, float tolerance, integer tolerance_type, integer flags);

Description

Converts a CIRCULAR STRING to regular LINESTRING or CURVEPOLYGON to POLYGON. Useful for outputting to de-
vices that can’t support CIRCULARSTRING geometry types
Converts a given geometry to a linear geometry. Each curved geometry or segment is converted into a linear approximation using
the given `tolerance` and options (32 segments per quadrant and no options by default).
The ’tolerance_type’ argument determines interpretation of the `tolerance` argument. It can take the following values:

• 0 (default): Tolerance is max segments per quadrant.

• 1: Tolerance is max-deviation of line from curve, in source units.
PostGIS 2.4.3 Manual 362 / 803

• 2: Tolerance is max-angle, in radians, between generating radii.

The ’flags’ argument is a bitfield. 0 by default. Supported bits are:

• 1: Symmetric (orientation idependent) output.

• 2: Retain angle, avoids reducing angles (segment lengths) when producing symmetric output. Has no effect when Symmetric
flag is off.

Availability: 1.2.2?
Enhanced: 2.4.0 added support for max-deviation and max-angle tolerance, and for symmetric output.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1.

This method implements the SQL/MM specification. SQL-MM 3: 7.1.7

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

SELECT ST_AsText(ST_CurveToLine(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 ←-

150505,220227 150406)')));

--Result --
LINESTRING(220268 150415,220269.95064912 150416.539364228,220271.823415575 ←-
150418.17258804,220273.613787707 150419.895736857,
220275.317452352 150421.704659462,220276.930305234 150423.594998003,220278.448460847 ←-
150425.562198489,
220279.868261823 150427.60152176,220281.186287736 150429.708054909,220282.399363347 ←-
150431.876723113,
220283.50456625 150434.10230186,220284.499233914 150436.379429536,220285.380970099 ←-
150438.702620341,220286.147650624 150441.066277505,
220286.797428488 150443.464706771,220287.328738321 150445.892130112,220287.740300149 ←-
150448.342699654,
220288.031122486 150450.810511759,220288.200504713 150453.289621251,220288.248038775 ←-
150455.77405574,
220288.173610157 150458.257830005,220287.977398166 150460.734960415,220287.659875492 ←-
150463.199479347,
220287.221807076 150465.64544956,220286.664248262 150468.066978495,220285.988542259 ←-
150470.458232479,220285.196316903 150472.81345077,
220284.289480732 150475.126959442,220283.270218395 150477.39318505,220282.140985384 ←-
150479.606668057,
220280.90450212 150481.762075989,220279.5637474 150483.85421628,220278.12195122 ←-
150485.87804878,
220276.582586992 150487.828697901,220274.949363179 150489.701464356,220273.226214362 ←-
150491.491836488,
220271.417291757 150493.195501133,220269.526953216 150494.808354014,220267.559752731 ←-
150496.326509628,
220265.520429459 150497.746310603,220263.41389631 150499.064336517,220261.245228106 ←-
150500.277412127,
220259.019649359 150501.38261503,220256.742521683 150502.377282695,220254.419330878 ←-
150503.259018879,
220252.055673714 150504.025699404,220249.657244448 150504.675477269,220247.229821107 ←-
150505.206787101,
PostGIS 2.4.3 Manual 363 / 803

220244.779251566 150505.61834893,220242.311439461 150505.909171266,220239.832329968 ←-

150506.078553494,
220237.347895479 150506.126087555,220234.864121215 150506.051658938,220232.386990804 ←-
150505.855446946,
220229.922471872 150505.537924272,220227.47650166 150505.099855856,220225.054972724 ←-
150504.542297043,
220222.663718741 150503.86659104,220220.308500449 150503.074365683,
220217.994991777 150502.167529512,220215.72876617 150501.148267175,
220213.515283163 150500.019034164,220211.35987523 150498.7825509,
220209.267734939 150497.441796181,220207.243902439 150496,
220205.293253319 150494.460635772,220203.420486864 150492.82741196,220201.630114732 ←-
150491.104263143,
220199.926450087 150489.295340538,220198.313597205 150487.405001997,220196.795441592 ←-
150485.437801511,
220195.375640616 150483.39847824,220194.057614703 150481.291945091,220192.844539092 ←-
150479.123276887,220191.739336189 150476.89769814,
220190.744668525 150474.620570464,220189.86293234 150472.297379659,220189.096251815 ←-
150469.933722495,
220188.446473951 150467.535293229,220187.915164118 150465.107869888,220187.50360229 ←-
150462.657300346,
220187.212779953 150460.189488241,220187.043397726 150457.710378749,220186.995863664 ←-
150455.22594426,
220187.070292282 150452.742169995,220187.266504273 150450.265039585,220187.584026947 ←-
150447.800520653,
220188.022095363 150445.35455044,220188.579654177 150442.933021505,220189.25536018 ←-
150440.541767521,
220190.047585536 150438.18654923,220190.954421707 150435.873040558,220191.973684044 ←-
150433.60681495,
220193.102917055 150431.393331943,220194.339400319 150429.237924011,220195.680155039 ←-
150427.14578372,220197.12195122 150425.12195122,
220198.661315447 150423.171302099,220200.29453926 150421.298535644,220202.017688077 ←-
150419.508163512,220203.826610682 150417.804498867,
220205.716949223 150416.191645986,220207.684149708 150414.673490372,220209.72347298 ←-
150413.253689397,220211.830006129 150411.935663483,
220213.998674333 150410.722587873,220216.22425308 150409.61738497,220218.501380756 ←-
150408.622717305,220220.824571561 150407.740981121,
220223.188228725 150406.974300596,220225.586657991 150406.324522731,220227 150406)

--3d example
SELECT ST_AsEWKT(ST_CurveToLine(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 ←-
150505 2,220227 150406 3)')));
Output
------
LINESTRING(220268 150415 1,220269.95064912 150416.539364228 1.0181172856673,
220271.823415575 150418.17258804 1.03623457133459,220273.613787707 150419.895736857 ←-
1.05435185700189,....AD INFINITUM ....
220225.586657991 150406.324522731 1.32611114201132,220227 150406 3)

--use only 2 segments to approximate quarter circle

SELECT ST_AsText(ST_CurveToLine(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 ←-
150505,220227 150406)'),2));
st_astext
------------------------------
LINESTRING(220268 150415,220287.740300149 150448.342699654,220278.12195122 ←-
150485.87804878,
220244.779251566 150505.61834893,220207.243902439 150496,220187.50360229 150462.657300346,
220197.12195122 150425.12195122,220227 150406)

-- Ensure approximated line is no further than 20 units away from

-- original curve, and make the result direction-neutral
SELECT ST_AsText(ST_CurveToLine(
'CIRCULARSTRING(0 0,100 -100,200 0)'::geometry,
PostGIS 2.4.3 Manual 364 / 803

20, -- Tolerance
1, -- Above is max distance between curve and line
1 -- Symmetric flag
));
st_astext
-------------------------------------------------------------------------------------------
LINESTRING(0 0,50 -86.6025403784438,150 -86.6025403784439,200 -1.1331077795296e-13,200 0)

See Also

ST_LineToCurve

8.11.8 ST_DelaunayTriangles

ST_DelaunayTriangles — Return a Delaunay triangulation around the given input points.

Synopsis

geometry ST_DelaunayTriangles(geometry g1, float tolerance, int4 flags);

Description

Return a Delaunay triangulation around the vertices of the input geometry. Output is a COLLECTION of polygons (for flags=0)
or a MULTILINESTRING (for flags=1) or TIN (for flags=2). The tolerance, if any, is used to snap input vertices togheter.
Availability: 2.1.0 - requires GEOS >= 3.4.0.

This function supports 3d and will not drop the z-index.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

2D Examples
PostGIS 2.4.3 Manual 365 / 803

Original polygons
-- our original geometry --
ST_Union(ST_GeomFromText('POLYGON((175 150, 20 40,
50 60, 125 100, 175 150))'),
ST_Buffer(ST_GeomFromText('POINT(110 170)'), 20)
)
PostGIS 2.4.3 Manual 366 / 803

ST_DelaunayTriangles of 2 polygons: delaunay triangle polygons each triangle themed in different color
-- geometries overlaid multilinestring triangles
SELECT
ST_DelaunayTriangles(
ST_Union(ST_GeomFromText('POLYGON((175 150, 20 40,
50 60, 125 100, 175 150))'),
ST_Buffer(ST_GeomFromText('POINT(110 170)'), 20)
))
As dtriag;
PostGIS 2.4.3 Manual 367 / 803

-- delaunay triangles as multilinestring

SELECT
ST_DelaunayTriangles(
ST_Union(ST_GeomFromText('POLYGON((175 150, 20 40,
50 60, 125 100, 175 150))'),
ST_Buffer(ST_GeomFromText('POINT(110 170)'), 20)
),0.001,1)
As dtriag;
PostGIS 2.4.3 Manual 368 / 803

-- delaunay triangles of 45 points as 55 triangle polygons

-- this produces a table of 42 points that form an L shape
SELECT (ST_DumpPoints(ST_GeomFromText(
'MULTIPOINT(14 14,34 14,54 14,74 14,94 14,114 14,134 14,
150 14,154 14,154 6,134 6,114 6,94 6,74 6,54 6,34 6,
14 6,10 6,8 6,7 7,6 8,6 10,6 30,6 50,6 70,6 90,6 110,6 130,
6 150,6 170,6 190,6 194,14 194,14 174,14 154,14 134,14 114,
14 94,14 74,14 54,14 34,14 14)'))).geom
INTO TABLE l_shape;
-- output as individual polygon triangles
SELECT ST_AsText((ST_Dump(geom)).geom) As wkt
FROM ( SELECT ST_DelaunayTriangles(ST_Collect(geom)) As geom
FROM l_shape) As foo;

---wkt ---
POLYGON((6 194,6 190,14 194,6 194))
POLYGON((14 194,6 190,14 174,14 194))
POLYGON((14 194,14 174,154 14,14 194))
POLYGON((154 14,14 174,14 154,154 14))
POLYGON((154 14,14 154,150 14,154 14))
POLYGON((154 14,150 14,154 6,154 14))
:
:

3D Examples

-- 3D multipoint --
SELECT ST_AsText(ST_DelaunayTriangles(ST_GeomFromText(
'MULTIPOINT Z(14 14 10,
150 14 100,34 6 25, 20 10 150)'))) As wkt;

-----wkt----
GEOMETRYCOLLECTION Z (POLYGON Z ((14 14 10,20 10 150,34 6 25,14 14 10))
,POLYGON Z ((14 14 10,34 6 25,150 14 100,14 14 10)))
PostGIS 2.4.3 Manual 369 / 803

See Also

ST_ConcaveHull, ST_Dump

8.11.9 ST_Difference

ST_Difference — Returns a geometry that represents that part of geometry A that does not intersect with geometry B.

Synopsis

geometry ST_Difference(geometry geomA, geometry geomB);

Description

Returns a geometry that represents that part of geometry A that does not intersect with geometry B. One can think of this as
GeometryA - ST_Intersection(A,B). If A is completely contained in B then an empty geometry collection is returned.

Note
Note - order matters. B - A will always return a portion of B

Performed by the GEOS module

Note
Do not call with a GeometryCollection as an argument

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.20

This function supports 3d and will not drop the z-index. However it seems to only consider x y when doing the difference
and tacks back on the Z-Index

Examples
PostGIS 2.4.3 Manual 370 / 803

The original linestrings shown together. The difference of the two linestrings

--Safe for 2d. This is same geometries as what is shown for st_symdifference
SELECT ST_AsText(
ST_Difference(
ST_GeomFromText('LINESTRING(50 100, 50 200)'),
ST_GeomFromText('LINESTRING(50 50, 50 150)')
)
);

st_astext
---------
LINESTRING(50 150,50 200)

--When used in 3d doesn't quite do the right thing

SELECT ST_AsEWKT(ST_Difference(ST_GeomFromEWKT('MULTIPOINT(-118.58 38.38 5,-118.60 38.329 ←-
6,-118.614 38.281 7)'), ST_GeomFromEWKT('POINT(-118.614 38.281 5)')));
st_asewkt
---------
MULTIPOINT(-118.6 38.329 6,-118.58 38.38 5)

See Also

ST_SymDifference

8.11.10 ST_Dump

ST_Dump — Returns a set of geometry_dump (geom,path) rows, that make up a geometry g1.

Synopsis

geometry_dump[] ST_Dump(geometry g1);

PostGIS 2.4.3 Manual 371 / 803

Description

This is a set-returning function (SRF). It returns a set of geometry_dump rows, formed by a geometry (geom) and an array of
integers (path). When the input geometry is a simple type (POINT,LINESTRING,POLYGON) a single record will be returned
with an empty path array and the input geometry as geom. When the input geometry is a collection or multi it will return a record
for each of the collection components, and the path will express the position of the component inside the collection.
ST_Dump is useful for expanding geometries. It is the reverse of a GROUP BY in that it creates new rows. For example it can
be use to expand MULTIPOLYGONS into POLYGONS.
Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Availability: PostGIS 1.0.0RC1. Requires PostgreSQL 7.3 or higher.

Note
Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Standard Examples

SELECT sometable.field1, sometable.field1,

(ST_Dump(sometable.the_geom)).geom AS the_geom
FROM sometable;

-- Break a compound curve into its constituent linestrings and circularstrings

SELECT ST_AsEWKT(a.geom), ST_HasArc(a.geom)
FROM ( SELECT (ST_Dump(p_geom)).geom AS geom
FROM (SELECT ST_GeomFromEWKT('COMPOUNDCURVE(CIRCULARSTRING(0 0, 1 1, 1 0),(1 0, 0 ←-
1))') AS p_geom) AS b
) AS a;
st_asewkt | st_hasarc
-----------------------------+----------
CIRCULARSTRING(0 0,1 1,1 0) | t
LINESTRING(1 0,0 1) | f
(2 rows)

Polyhedral Surfaces, TIN and Triangle Examples

-- Polyhedral surface example

-- Break a Polyhedral surface into its faces
SELECT (a.p_geom).path[1] As path, ST_AsEWKT((a.p_geom).geom) As geom_ewkt
FROM (SELECT ST_Dump(ST_GeomFromEWKT('POLYHEDRALSURFACE(
((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)), ((1 1 0, 1 1 ←-
1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1))
PostGIS 2.4.3 Manual 372 / 803

)') ) AS p_geom ) AS a;

path | geom_ewkt
------+------------------------------------------
1 | POLYGON((0 0 0,0 0 1,0 1 1,0 1 0,0 0 0))
2 | POLYGON((0 0 0,0 1 0,1 1 0,1 0 0,0 0 0))
3 | POLYGON((0 0 0,1 0 0,1 0 1,0 0 1,0 0 0))
4 | POLYGON((1 1 0,1 1 1,1 0 1,1 0 0,1 1 0))
5 | POLYGON((0 1 0,0 1 1,1 1 1,1 1 0,0 1 0))
6 | POLYGON((0 0 1,1 0 1,1 1 1,0 1 1,0 0 1))

-- TIN --
SELECT (g.gdump).path, ST_AsEWKT((g.gdump).geom) as wkt
FROM
(SELECT
ST_Dump( ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') ) AS gdump
) AS g;
-- result --
path | wkt
------+-------------------------------------
{1} | TRIANGLE((0 0 0,0 0 1,0 1 0,0 0 0))
{2} | TRIANGLE((0 0 0,0 1 0,1 1 0,0 0 0))

See Also

geometry_dump, Section 14.6, ST_Collect, ST_Collect, ST_GeometryN

8.11.11 ST_DumpPoints

ST_DumpPoints — Returns a set of geometry_dump (geom,path) rows of all points that make up a geometry.

Synopsis

geometry_dump[]ST_DumpPoints(geometry geom);

Description

This set-returning function (SRF) returns a set of geometry_dump rows formed by a geometry (geom) and an array of integers
(path).
The geom component of geometry_dump are all the POINTs that make up the supplied geometry
The path component of geometry_dump (an integer[]) is an index reference enumerating the POINTs of the supplied
geometry. For example, if a LINESTRING is supplied, a path of {i} is returned where i is the nth coordinate in the
LINESTRING. If a POLYGON is supplied, a path of {i,j} is returned where i is the ring number (1 is outer; inner rings
follow) and j enumerates the POINTs (again 1-based index).
PostGIS 2.4.3 Manual 373 / 803

Enhanced: 2.1.0 Faster speed. Reimplemented as native-C.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Availability: 1.5.0

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Classic Explode a Table of LineStrings into nodes

SELECT edge_id, (dp).path[1] As index, ST_AsText((dp).geom) As wktnode

FROM (SELECT 1 As edge_id
, ST_DumpPoints(ST_GeomFromText('LINESTRING(1 2, 3 4, 10 10)')) AS dp
UNION ALL
SELECT 2 As edge_id
, ST_DumpPoints(ST_GeomFromText('LINESTRING(3 5, 5 6, 9 10)')) AS dp
) As foo;
edge_id | index | wktnode
---------+-------+--------------
1 | 1 | POINT(1 2)
1 | 2 | POINT(3 4)
1 | 3 | POINT(10 10)
2 | 1 | POINT(3 5)
2 | 2 | POINT(5 6)
2 | 3 | POINT(9 10)

Standard Geometry Examples

PostGIS 2.4.3 Manual 374 / 803

SELECT path, ST_AsText(geom)

FROM (
SELECT (ST_DumpPoints(g.geom)).*
FROM
(SELECT
'GEOMETRYCOLLECTION(
POINT ( 0 1 ),
LINESTRING ( 0 3, 3 4 ),
POLYGON (( 2 0, 2 3, 0 2, 2 0 )),
POLYGON (( 3 0, 3 3, 6 3, 6 0, 3 0 ),
( 5 1, 4 2, 5 2, 5 1 )),
MULTIPOLYGON (
(( 0 5, 0 8, 4 8, 4 5, 0 5 ),
( 1 6, 3 6, 2 7, 1 6 )),
(( 5 4, 5 8, 6 7, 5 4 ))
)
)'::geometry AS geom
) AS g
) j;

path | st_astext
-----------+------------
{1,1} | POINT(0 1)
{2,1} | POINT(0 3)
{2,2} | POINT(3 4)
{3,1,1} | POINT(2 0)
{3,1,2} | POINT(2 3)
{3,1,3} | POINT(0 2)
{3,1,4} | POINT(2 0)
{4,1,1} | POINT(3 0)
{4,1,2} | POINT(3 3)
{4,1,3} | POINT(6 3)
{4,1,4} | POINT(6 0)
{4,1,5} | POINT(3 0)
{4,2,1} | POINT(5 1)
{4,2,2} | POINT(4 2)
{4,2,3} | POINT(5 2)
{4,2,4} | POINT(5 1)
{5,1,1,1} | POINT(0 5)
{5,1,1,2} | POINT(0 8)
{5,1,1,3} | POINT(4 8)
{5,1,1,4} | POINT(4 5)
{5,1,1,5} | POINT(0 5)
{5,1,2,1} | POINT(1 6)
{5,1,2,2} | POINT(3 6)
{5,1,2,3} | POINT(2 7)
{5,1,2,4} | POINT(1 6)
{5,2,1,1} | POINT(5 4)
{5,2,1,2} | POINT(5 8)
{5,2,1,3} | POINT(6 7)
{5,2,1,4} | POINT(5 4)
(29 rows)

Polyhedral Surfaces, TIN and Triangle Examples

-- Polyhedral surface cube --

SELECT (g.gdump).path, ST_AsEWKT((g.gdump).geom) as wkt
FROM
(SELECT
PostGIS 2.4.3 Manual 375 / 803

ST_DumpPoints(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 ←-
0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )') ) AS gdump
) AS g;
-- result --
path | wkt
---------+--------------
{1,1,1} | POINT(0 0 0)
{1,1,2} | POINT(0 0 1)
{1,1,3} | POINT(0 1 1)
{1,1,4} | POINT(0 1 0)
{1,1,5} | POINT(0 0 0)
{2,1,1} | POINT(0 0 0)
{2,1,2} | POINT(0 1 0)
{2,1,3} | POINT(1 1 0)
{2,1,4} | POINT(1 0 0)
{2,1,5} | POINT(0 0 0)
{3,1,1} | POINT(0 0 0)
{3,1,2} | POINT(1 0 0)
{3,1,3} | POINT(1 0 1)
{3,1,4} | POINT(0 0 1)
{3,1,5} | POINT(0 0 0)
{4,1,1} | POINT(1 1 0)
{4,1,2} | POINT(1 1 1)
{4,1,3} | POINT(1 0 1)
{4,1,4} | POINT(1 0 0)
{4,1,5} | POINT(1 1 0)
{5,1,1} | POINT(0 1 0)
{5,1,2} | POINT(0 1 1)
{5,1,3} | POINT(1 1 1)
{5,1,4} | POINT(1 1 0)
{5,1,5} | POINT(0 1 0)
{6,1,1} | POINT(0 0 1)
{6,1,2} | POINT(1 0 1)
{6,1,3} | POINT(1 1 1)
{6,1,4} | POINT(0 1 1)
{6,1,5} | POINT(0 0 1)
(30 rows)

-- Triangle --
SELECT (g.gdump).path, ST_AsText((g.gdump).geom) as wkt
FROM
(SELECT
ST_DumpPoints( ST_GeomFromEWKT('TRIANGLE ((
0 0,
0 9,
9 0,
0 0
))') ) AS gdump
) AS g;
-- result --
path | wkt
------+------------
{1} | POINT(0 0)
{2} | POINT(0 9)
{3} | POINT(9 0)
{4} | POINT(0 0)

-- TIN --
PostGIS 2.4.3 Manual 376 / 803

SELECT (g.gdump).path, ST_AsEWKT((g.gdump).geom) as wkt

FROM
(SELECT
ST_DumpPoints( ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') ) AS gdump
) AS g;
-- result --
path | wkt
---------+--------------
{1,1,1} | POINT(0 0 0)
{1,1,2} | POINT(0 0 1)
{1,1,3} | POINT(0 1 0)
{1,1,4} | POINT(0 0 0)
{2,1,1} | POINT(0 0 0)
{2,1,2} | POINT(0 1 0)
{2,1,3} | POINT(1 1 0)
{2,1,4} | POINT(0 0 0)
(8 rows)

See Also

geometry_dump, Section 14.6, ST_Dump, ST_DumpRings

8.11.12 ST_DumpRings

ST_DumpRings — Returns a set of geometry_dump rows, representing the exterior and interior rings of a polygon.

Synopsis

geometry_dump[] ST_DumpRings(geometry a_polygon);

Description

This is a set-returning function (SRF). It returns a set of geometry_dump rows, defined as an integer[] and a geometry,
aliased "path" and "geom" respectively. The "path" field holds the polygon ring index containing a single integer: 0 for the shell,
>0 for holes. The "geom" field contains the corresponding ring as a polygon.
Availability: PostGIS 1.1.3. Requires PostgreSQL 7.3 or higher.

Note
This only works for POLYGON geometries. It will not work for MULTIPOLYGONS

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 377 / 803

Examples

SELECT sometable.field1, sometable.field1,

(ST_DumpRings(sometable.the_geom)).geom As the_geom
FROM sometableOfpolys;

SELECT ST_AsEWKT(geom) As the_geom, path

FROM ST_DumpRings(
ST_GeomFromEWKT('POLYGON((-8149064 5133092 1,-8149064 5132986 1,-8148996 5132839 ←-
1,-8148972 5132767 1,-8148958 5132508 1,-8148941 5132466 1,-8148924 5132394 1,
-8148903 5132210 1,-8148930 5131967 1,-8148992 5131978 1,-8149237 5132093 1,-8149404 ←-
5132211 1,-8149647 5132310 1,-8149757 5132394 1,
-8150305 5132788 1,-8149064 5133092 1),
(-8149362 5132394 1,-8149446 5132501 1,-8149548 5132597 1,-8149695 5132675 1,-8149362 ←-
5132394 1))')
) as foo;
path | the_geom
-----------------------------------------------------------------------------------------------------

{0} | POLYGON((-8149064 5133092 1,-8149064 5132986 1,-8148996 5132839 1,-8148972 5132767 ←-

1,-8148958 5132508 1,
| -8148941 5132466 1,-8148924 5132394 1,
| -8148903 5132210 1,-8148930 5131967 1,
| -8148992 5131978 1,-8149237 5132093 1,
| -8149404 5132211 1,-8149647 5132310 1,-8149757 5132394 1,-8150305 5132788 ←-
1,-8149064 5133092 1))
{1} | POLYGON((-8149362 5132394 1,-8149446 5132501 1,
| -8149548 5132597 1,-8149695 5132675 1,-8149362 5132394 1))

See Also

geometry_dump, Section 14.6, ST_Dump, ST_ExteriorRing, ST_InteriorRingN

8.11.13 ST_FlipCoordinates

ST_FlipCoordinates — Returns a version of the given geometry with X and Y axis flipped. Useful for people who have built
latitude/longitude features and need to fix them.

Synopsis

geometry ST_FlipCoordinates(geometry geom);

Description

Returns a version of the given geometry with X and Y axis flipped.

Availability: 2.0.0

This method supports Circular Strings and Curves

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

PostGIS 2.4.3 Manual 378 / 803

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Example

SELECT ST_AsEWKT(ST_FlipCoordinates(GeomFromEWKT('POINT(1 2)')));

st_asewkt
------------
POINT(2 1)

See Also

ST_SwapOrdinates

8.11.14 ST_GeneratePoints

ST_GeneratePoints — Converts a polygon or multi-polygon into a multi-point composed of randomly location points within the
original areas.

Synopsis

geometry ST_GeneratePoints( g geometry , npoints numeric );

Description

ST_GeneratePoints generates pseudo-random points until the requested number are found within the input area.
Availability: 2.3.0

Examples
PostGIS 2.4.3 Manual 379 / 803

Generated 12 Points overlaid on top of original polygon

SELECT ST_GeneratePoints(
ST_Buffer(
Original Polygon ST_GeomFromText(
'LINESTRING(50 50,150 ←-
150,150 50)'
), 10, 'endcap=round join ←-
=round'), 12);

8.11.15 ST_Intersection

ST_Intersection — (T) Returns a geometry that represents the shared portion of geomA and geomB.

Synopsis

geometry ST_Intersection( geometry geomA , geometry geomB );

geography ST_Intersection( geography geogA , geography geogB );

Description

Returns a geometry that represents the point set intersection of the Geometries.
In other words - that portion of geometry A and geometry B that is shared between the two geometries.
If the geometries do not share any space (are disjoint), then an empty geometry collection is returned.
ST_Intersection in conjunction with ST_Intersects is very useful for clipping geometries such as in bounding box, buffer, region
queries where you only want to return that portion of a geometry that sits in a country or region of interest.

Note
Geography: For geography this is really a thin wrapper around the geometry implementation. It first determines the
best SRID that fits the bounding box of the 2 geography objects (if geography objects are within one half zone UTM but
not same UTM will pick one of those) (favoring UTM or Lambert Azimuthal Equal Area (LAEA) north/south pole, and
falling back on mercator in worst case scenario) and then intersection in that best fit planar spatial ref and retransforms
back to WGS84 geography.
PostGIS 2.4.3 Manual 380 / 803

Important
Do not call with a GEOMETRYCOLLECTION as an argument

Warning
This function will drop the M coordinate values if present.

Warning
If working with 3D geometries, you may want to use SFGCAL based ST_3DIntersection which does a proper 3D
intersection for 3D geometries. Although this function works with Z-coordinate, it does an averaging of Z-Coordinate
values when postgis.backend=geos. postgis.backend=sfcgal, it will return a 2D geometry regardless
ignoring the Z-Coordinate. Refer to postgis.backend for details.

Performed by the GEOS module

This method is also provided by SFCGAL backend.

Availability: 1.5 support for geography data type was introduced.

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.18

Examples

SELECT ST_AsText(ST_Intersection('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )':: ←-

geometry));
st_astext
---------------
GEOMETRYCOLLECTION EMPTY
(1 row)
SELECT ST_AsText(ST_Intersection('POINT(0 0)'::geometry, 'LINESTRING ( 0 0, 0 2 )':: ←-
geometry));
st_astext
---------------
POINT(0 0)
(1 row)

---Clip all lines (trails) by country (here we assume country geom are POLYGON or ←-
MULTIPOLYGONS)
-- NOTE: we are only keeping intersections that result in a LINESTRING or MULTILINESTRING ←-
because we don't
-- care about trails that just share a point
-- the dump is needed to expand a geometry collection into individual single MULT* parts
-- the below is fairly generic and will work for polys, etc. by just changing the where ←-
clause
SELECT clipped.gid, clipped.f_name, clipped_geom
FROM (SELECT trails.gid, trails.f_name, (ST_Dump(ST_Intersection(country.the_geom, trails. ←-
the_geom))).geom As clipped_geom
FROM country
INNER JOIN trails
PostGIS 2.4.3 Manual 381 / 803

ON ST_Intersects(country.the_geom, trails.the_geom)) As clipped

WHERE ST_Dimension(clipped.clipped_geom) = 1 ;

--For polys e.g. polygon landmarks, you can also use the sometimes faster hack that ←-
buffering anything by 0.0
-- except a polygon results in an empty geometry collection
--(so a geometry collection containing polys, lines and points)
-- buffered by 0.0 would only leave the polygons and dissolve the collection shell
SELECT poly.gid, ST_Multi(ST_Buffer(
ST_Intersection(country.the_geom, poly.the_geom),
0.0)
) As clipped_geom
FROM country
INNER JOIN poly
ON ST_Intersects(country.the_geom, poly.the_geom)
WHERE Not ST_IsEmpty(ST_Buffer(ST_Intersection(country.the_geom, poly.the_geom),0.0));

Examples: 2.5Dish

Geos is the default backend if not set. Note this is not a true intersection, compare to the same example using ST_3DIntersection.
set postgis.backend=geos;
select ST_AsText(ST_Intersection(linestring, polygon)) As wkt
from ST_GeomFromText('LINESTRING Z (2 2 6,1.5 1.5 7,1 1 8,0.5 0.5 8,0 0 10)') AS ←-
linestring
CROSS JOIN ST_GeomFromText('POLYGON((0 0 8, 0 1 8, 1 1 8, 1 0 8, 0 0 8))') AS polygon;

st_astext
---------------------------------------
LINESTRING Z (1 1 8,0.5 0.5 8,0 0 10)

If your PostGIS is compiled with sfcgal support, have option of using sfcgal, but note if basically cases down both geometries to
2D before doing intersection and returns the ST_Force2D equivalent result which is a 2D geometry
set postgis.backend=sfcgal;
select ST_AsText(ST_Intersection(linestring, polygon)) As wkt
from ST_GeomFromText('LINESTRING Z (2 2 6,1.5 1.5 7,1 1 8,0.5 0.5 8,0 0 10)') AS ←-
linestring
CROSS JOIN ST_GeomFromText('POLYGON((0 0 8, 0 1 8, 1 1 8, 1 0 8, 0 0 8))') AS polygon;

wkt
----------------------------------------------
MULTILINESTRING((0.5 0.5,0 0),(1 1,0.5 0.5))

See Also

ST_3DIntersection, ST_Difference, ST_Dimension, ST_Dump, ST_Force2D, ST_SymDifference, ST_Intersects, ST_Multi

8.11.16 ST_LineToCurve

ST_LineToCurve — Converts a LINESTRING/POLYGON to a CIRCULARSTRING, CURVEPOLYGON

Synopsis

geometry ST_LineToCurve(geometry geomANoncircular);

PostGIS 2.4.3 Manual 382 / 803

Description

Converts plain LINESTRING/POLYGON to CIRCULAR STRINGs and Curved Polygons. Note much fewer points are needed
to describe the curved equivalent.

Note
If the input LINESTRING/POLYGON is not curved enough to clearly represent a curve, the function will return the same
input geometry.

Availability: 1.2.2?

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

Examples

-- 2D Example
SELECT ST_AsText(ST_LineToCurve(foo.the_geom)) As curvedastext,ST_AsText(foo.the_geom) As ←-
non_curvedastext
FROM (SELECT ST_Buffer('POINT(1 3)'::geometry, 3) As the_geom) As foo;

curvedatext non_curvedastext
--------------------------------------------------------------------|--------------------------------

CURVEPOLYGON(CIRCULARSTRING(4 3,3.12132034355964 0.878679656440359, | POLYGON((4 ←-

3,3.94235584120969 2.41472903395162,3.77163859753386 1.85194970290473,
1 0,-1.12132034355965 5.12132034355963,4 3)) | 3.49440883690764 ←-
1.33328930094119,3.12132034355964 0.878679656440359,
| 2.66671069905881 ←-
0.505591163092366,2.148050297
0.228361402466141,
| 1.58527096604839 ←-
0.0576441587903094,1 ←-
0,
| 0.414729033951621 ←-
0.0576441587903077,-0.1480502
0.228361402466137,
| -0.666710699058802 ←-
0.505591163092361,-1.12132034
0.878679656440353,
| -1.49440883690763 ←-
1.33328930094119,-1.771638597
1.85194970290472
| --ETC-- ←-
,3.94235584120969 ←-
3.58527096604839,4 ←-
3))

--3D example
SELECT ST_AsText(ST_LineToCurve(geom)) As curved, ST_AsText(geom) AS not_curved
FROM (SELECT ST_Translate(ST_Force3D(ST_Boundary(ST_Buffer(ST_Point(1,3), 2,2))),0,0,3) AS ←-
geom) AS foo;

curved | not_curved
------------------------------------------------------+----------------------------------------------
PostGIS 2.4.3 Manual 383 / 803

CIRCULARSTRING Z (3 3 3,-1 2.99999999999999 3,3 3 3) | LINESTRING Z (3 3 3,2.4142135623731 ←-

1.58578643762691 3,1 1 3,
| -0.414213562373092 1.5857864376269 ←-
3,-1 2.99999999999999 3,
| -0.414213562373101 4.41421356237309 ←-
3,
| 0.999999999999991 5 ←-
3,2.41421356237309 4.4142135623731 ←-
3,3 3 3)
(1 row)

See Also

ST_CurveToLine

8.11.17 ST_MakeValid

ST_MakeValid — Attempts to make an invalid geometry valid without losing vertices.

Synopsis

geometry ST_MakeValid(geometry input);

Description

The function attempts to create a valid representation of a given invalid geometry without losing any of the input vertices.
Already-valid geometries are returned without further intervention.
Supported inputs are: POINTS, MULTIPOINTS, LINESTRINGS, MULTILINESTRINGS, POLYGONS, MULTIPOLYGONS
and GEOMETRYCOLLECTIONS containing any mix of them.
In case of full or partial dimensional collapses, the output geometry may be a collection of lower-to-equal dimension geometries
or a geometry of lower dimension.
Single polygons may become multi-geometries in case of self-intersections.
Availability: 2.0.0, requires GEOS-3.3.0
Enhanced: 2.0.1, speed improvements requires GEOS-3.3.4
Enhanced: 2.1.0 added support for GEOMETRYCOLLECTION and MULTIPOINT.

This function supports 3d and will not drop the z-index.

See Also

ST_IsValid ST_CollectionExtract

8.11.18 ST_MemUnion

ST_MemUnion — Same as ST_Union, only memory-friendly (uses less memory and more processor time).

Synopsis

geometry ST_MemUnion(geometry set geomfield);

PostGIS 2.4.3 Manual 384 / 803

Description

Some useful description here.

Note
Same as ST_Union, only memory-friendly (uses less memory and more processor time). This aggregate function works
by unioning the geometries one at a time to previous result as opposed to ST_Union aggregate which first creates an
array and then unions

This function supports 3d and will not drop the z-index.

Examples

See ST_Union

See Also

ST_Union

8.11.19 ST_MinimumBoundingCircle

ST_MinimumBoundingCircle — Returns the smallest circle polygon that can fully contain a geometry. Default uses 48 segments
per quarter circle.

Synopsis

geometry ST_MinimumBoundingCircle(geometry geomA, integer num_segs_per_qt_circ=48);

Description

Returns the smallest circle polygon that can fully contain a geometry.

Note
The circle is approximated by a polygon with a default of 48 segments per quarter circle. Because the polygon is an
approximation of the minimum bounding circle, some points in the input geometry may not be contained within the
polygon. The approximation can be improved by increasing the number of segments, with little performance penalty.
For applications where a polygonal approximation is not suitable, ST_MinimumBoundingRadius may be used.

It is often used with MULTI and Geometry Collections. Although it is not an aggregate - you can use it in conjunction with
ST_Collect to get the minimum bounding circle of a set of geometries. ST_MinimumBoundingCircle(ST_Collect(somepointfield)).
The ratio of the area of a polygon divided by the area of its Minimum Bounding Circle is often referred to as the Roeck test.
Availability: 1.4.0 - requires GEOS

See Also

ST_Collect, ST_MinimumBoundingRadius
PostGIS 2.4.3 Manual 385 / 803

Examples

SELECT d.disease_type,
ST_MinimumBoundingCircle(ST_Collect(d.the_geom)) As the_geom
FROM disease_obs As d
GROUP BY d.disease_type;

Minimum bounding circle of a point and linestring. Using 8 segs to approximate a quarter circle

SELECT ST_AsText(ST_MinimumBoundingCircle(
ST_Collect(
ST_GeomFromEWKT('LINESTRING(55 75,125 150)'),
ST_Point(20, 80)), 8
)) As wktmbc;
wktmbc
-----------
POLYGON((135.59714732062 115,134.384753327498 102.690357210921,130.79416296937 ←-
90.8537670908995,124.963360620072 79.9451031602111,117.116420743937 ←-
70.3835792560632,107.554896839789 62.5366393799277,96.6462329091006 ←-
56.70583703063,84.8096427890789 53.115246672502,72.5000000000001 ←-
51.9028526793802,60.1903572109213 53.1152466725019,48.3537670908996 ←-
56.7058370306299,37.4451031602112 62.5366393799276,27.8835792560632 ←-
70.383579256063,20.0366393799278 79.9451031602109,14.20583703063 ←-
90.8537670908993,10.615246672502 102.690357210921,9.40285267938019 115,10.6152466725019 ←-
127.309642789079,14.2058370306299 139.1462329091,20.0366393799275 ←-
150.054896839789,27.883579256063 159.616420743937,
37.4451031602108 167.463360620072,48.3537670908992 173.29416296937,60.190357210921 ←-
176.884753327498,
72.4999999999998 178.09714732062,84.8096427890786 176.884753327498,96.6462329091003 ←-
173.29416296937,107.554896839789 167.463360620072,
117.116420743937 159.616420743937,124.963360620072 150.054896839789,130.79416296937 ←-
139.146232909101,134.384753327498 127.309642789079,135.59714732062 115))

See Also

ST_Collect, ST_MinimumBoundingRadius
PostGIS 2.4.3 Manual 386 / 803

8.11.20 ST_MinimumBoundingRadius

ST_MinimumBoundingRadius — Returns the center point and radius of the smallest circle that can fully contain a geometry.

Synopsis

(geometry, double precision) ST_MinimumBoundingRadius(geometry geom);

Description

Returns a record containing the center point and radius of the smallest circle that can fully contain a geometry.
Can be used in conjunction with ST_Collect to get the minimum bounding circle of a set of geometries.
Availability - 2.3.0

See Also

ST_Collect, ST_MinimumBoundingCircle

Examples

SELECT ST_AsText(center), radius FROM ST_MinimumBoundingRadius('POLYGON((26426 65078,26531 ←-

65242,26075 65136,26096 65427,26426 65078))');

st_astext | radius
------------------------------------------+------------------
POINT(26284.8418027133 65267.1145090825) | 247.436045591407

8.11.21 ST_Polygonize

ST_Polygonize — Aggregate. Creates a GeometryCollection containing possible polygons formed from the constituent linework
of a set of geometries.

Synopsis

geometry ST_Polygonize(geometry set geomfield);

geometry ST_Polygonize(geometry[] geom_array);

Description

Creates a GeometryCollection containing possible polygons formed from the constituent linework of a set of geometries.

Note
Geometry Collections are often difficult to deal with with third party tools, so use ST_Polygonize in conjunction with
ST_Dump to dump the polygons out into individual polygons.

Note
Input linework must be correctly noded for this function to work properly

Availability: 1.0.0RC1 - requires GEOS >= 2.1.0.

PostGIS 2.4.3 Manual 387 / 803

Examples: Polygonizing single linestrings

SELECT ST_AsEWKT(ST_Polygonize(the_geom_4269)) As geomtextrep

FROM (SELECT the_geom_4269 FROM ma.suffolk_edges ORDER BY tlid LIMIT 45) As foo;

geomtextrep
-------------------------------------
SRID=4269;GEOMETRYCOLLECTION(POLYGON((-71.040878 42.285678,-71.040943 42.2856,-71.04096 ←-
42.285752,-71.040878 42.285678)),
POLYGON((-71.17166 42.353675,-71.172026 42.354044,-71.17239 42.354358,-71.171794 ←-
42.354971,-71.170511 42.354855,
-71.17112 42.354238,-71.17166 42.353675)))
(1 row)

--Use ST_Dump to dump out the polygonize geoms into individual polygons
SELECT ST_AsEWKT((ST_Dump(foofoo.polycoll)).geom) As geomtextrep
FROM (SELECT ST_Polygonize(the_geom_4269) As polycoll
FROM (SELECT the_geom_4269 FROM ma.suffolk_edges
ORDER BY tlid LIMIT 45) As foo) As foofoo;

geomtextrep
------------------------
SRID=4269;POLYGON((-71.040878 42.285678,-71.040943 42.2856,-71.04096 42.285752,
-71.040878 42.285678))
SRID=4269;POLYGON((-71.17166 42.353675,-71.172026 42.354044,-71.17239 42.354358
,-71.171794 42.354971,-71.170511 42.354855,-71.17112 42.354238,-71.17166 42.353675))
(2 rows)

See Also

ST_Node, ST_Dump

8.11.22 ST_Node

ST_Node — Node a set of linestrings.

Synopsis

geometry ST_Node(geometry geom);

Description

Fully node a set of linestrings using the least possible number of nodes while preserving all of the input ones.

This function supports 3d and will not drop the z-index.

Availability: 2.0.0 - requires GEOS >= 3.3.0.

Note
Due to a bug in GEOS up to 3.3.1 this function fails to node self-intersecting lines. This is fixed with GEOS 3.3.2 or
higher.
PostGIS 2.4.3 Manual 388 / 803

Note
Changed: 2.4.0 this function uses GEOSNode internally instead of GEOSUnaryUnion. This may cause the resulting
linestrings to have a different order and direction compared to Postgis < 2.4.

Examples

SELECT ST_AsText(
ST_Node('LINESTRINGZ(0 0 0, 10 10 10, 0 10 5, 10 0 3)'::geometry)
) As output;
output
-----------
MULTILINESTRING Z ((0 0 0,5 5 4.5),(5 5 4.5,10 10 10,0 10 5,5 5 4.5),(5 5 4.5,10 0 3))

See Also

ST_UnaryUnion

8.11.23 ST_OffsetCurve

ST_OffsetCurve — Return an offset line at a given distance and side from an input line. Useful for computing parallel lines
about a center line

Synopsis

geometry ST_OffsetCurve(geometry line, float signed_distance, text style_parameters=”);

Description

Return an offset line at a given distance and side from an input line. All points of the returned geometries are not further than the
given distance from the input geometry.
For positive distance the offset will be at the left side of the input line and retain the same direction. For a negative distance it’ll
be at the right side and in the opposite direction.
Availability: 2.0 - requires GEOS >= 3.2, improved with GEOS >= 3.3
The optional third parameter allows specifying a list of blank-separated key=value pairs to tweak operations as follows:

• ’quad_segs=#’ : number of segments used to approximate a quarter circle (defaults to 8).

• ’join=round|mitre|bevel’ : join style (defaults to "round"). ’miter’ is also accepted as a synonym for ’mitre’.
• ’mitre_limit=#.#’ : mitre ratio limit (only affects mitred join style). ’miter_limit’ is also accepted as a synonym for ’mitre_limit’.

Units of distance are measured in units of the spatial reference system.

The inputs can only be LINESTRINGS.
Performed by the GEOS module.

Note
This function ignores the third dimension (z) and will always give a 2-d result even when presented with a 3d-geometry.
PostGIS 2.4.3 Manual 389 / 803

Examples

Compute an open buffer around roads

SELECT ST_Union(
ST_OffsetCurve(f.the_geom, f.width/2, 'quad_segs=4 join=round'),
ST_OffsetCurve(f.the_geom, -f.width/2, 'quad_segs=4 join=round')
) as track
FROM someroadstable;

15, ’quad_segs=4 join=round’ original line and its offset 15

units.
SELECT ST_AsText(ST_OffsetCurve( ←- -15, ’quad_segs=4 join=round’ original line and its offset
ST_GeomFromText( -15 units
'LINESTRING(164 16,144 16,124 16,104 ←-
16,84 16,64 16, SELECT ST_AsText(ST_OffsetCurve(geom,
44 16,24 16,20 16,18 16,17 17, -15, 'quad_segs=4 join=round')) ←-
16 18,16 20,16 40,16 60,16 80,16 ←- As notsocurvy
100, FROM ST_GeomFromText(
16 120,16 140,16 160,16 180,16 ←- 'LINESTRING(164 16,144 16,124 16,104 ←-
195)'), 16,84 16,64 16,
15, 'quad_segs=4 join=round')); 44 16,24 16,20 16,18 16,17 17,
--output -- 16 18,16 20,16 40,16 60,16 80,16 ←-
LINESTRING(164 1,18 1,12.2597485145237 ←- 100,
2.1418070123307, 16 120,16 140,16 160,16 180,16 ←-
7.39339828220179 ←- 195)') As geom;
-- notsocurvy --
5.39339828220179,
5.39339828220179 ←- LINESTRING(31 195,31 31,164 31)
7.39339828220179,
2.14180701233067 ←-
12.2597485145237,1 18,1 195)
PostGIS 2.4.3 Manual 390 / 803

double-offset to get more curvy,combined with regular

offset 15 to get parallel lines. Overlaid with original.
SELECT ST_AsText(ST_Collect(
ST_OffsetCurve(geom, 15, ' ←-
double-offset to get more curvy, note the first reverses quad_segs=4 join=round'),
direction, so -30 + 15 = -15 ST_OffsetCurve(ST_OffsetCurve( ←-
geom,
SELECT ST_AsText(ST_OffsetCurve( ←- -30, 'quad_segs=4 join=round'), ←-
ST_OffsetCurve(geom, -15, 'quad_segs=4 join=round')
-30, 'quad_segs=4 join=round'), ←- )
-15, 'quad_segs=4 join=round')) As morecurvy ) As parallel_curves
FROM ST_GeomFromText( FROM ST_GeomFromText(
'LINESTRING(164 16,144 16,124 16,104 ←- 'LINESTRING(164 16,144 16,124 16,104 ←-
16,84 16,64 16, 16,84 16,64 16,
44 16,24 16,20 16,18 16,17 17, 44 16,24 16,20 16,18 16,17 17,
16 18,16 20,16 40,16 60,16 80,16 ←- 16 18,16 20,16 40,16 60,16 80,16 ←-
100, 100,
16 120,16 140,16 160,16 180,16 ←- 16 120,16 140,16 160,16 180,16 ←-
195)') As geom; 195)') As geom;
-- morecurvy -- -- parallel curves --
LINESTRING(164 31,46 31,40.2597485145236 ←- MULTILINESTRING((164 1,18 ←-
32.1418070123307, 1,12.2597485145237 2.1418070123307,
35.3933982822018 35.3933982822018, 7.39339828220179 ←-
32.1418070123307 40.2597485145237,31 ←- 5.39339828220179,5.39339828220179 7.393398282201
46,31 195) 2.14180701233067 12.2597485145237,1 18,1 ←-
195),
(164 31,46 31,40.2597485145236 ←-
32.1418070123307,35.3933982822018 35.39339828220
32.1418070123307 40.2597485145237,31 ←-
46,31 195))
PostGIS 2.4.3 Manual 391 / 803

15,-15 collected, join=mitre mitre_limit=2.1

15, ’quad_segs=4 join=bevel’ shown with original line SELECT ST_AsText(ST_Collect(
SELECT ST_AsText(ST_OffsetCurve( ←- ST_OffsetCurve(geom, 15, ' ←-
ST_GeomFromText( quad_segs=4 join=mitre mitre_limit=2.2'),
'LINESTRING(164 16,144 16,124 16,104 ←- ST_OffsetCurve(geom, -15, ' ←-
16,84 16,64 16, quad_segs=4 join=mitre mitre_limit=2.2')
44 16,24 16,20 16,18 16,17 17, ) )
16 18,16 20,16 40,16 60,16 80,16 ←- FROM ST_GeomFromText(
100, 'LINESTRING(164 16,144 16,124 16,104 ←-
16 120,16 140,16 160,16 180,16 ←- 16,84 16,64 16,
195)'), 44 16,24 16,20 16,18 16,17 17,
15, 'quad_segs=4 join= ←- 16 18,16 20,16 40,16 60,16 80,16 ←-
bevel')); 100,
-- output -- 16 120,16 140,16 160,16 180,16 ←-
LINESTRING(164 1,18 1,7.39339828220179 ←- 195)') As geom;
5.39339828220179, -- output --
5.39339828220179 ←- MULTILINESTRING((164 1,11.7867965644036 ←-
7.39339828220179,1 18,1 195) 1,1 11.7867965644036,1 195),
(31 195,31 31,164 31))

See Also

ST_Buffer

8.11.24 ST_RemoveRepeatedPoints

ST_RemoveRepeatedPoints — Returns a version of the given geometry with duplicated points removed.

Synopsis

geometry ST_RemoveRepeatedPoints(geometry geom, float8 tolerance);

Description

Returns a version of the given geometry with duplicated points removed. Will actually do something only with (multi)lines,
(multi)polygons and multipoints but you can safely call it with any kind of geometry. Since simplification occurs on a object-by-
PostGIS 2.4.3 Manual 392 / 803

object basis you can also feed a GeometryCollection to this function.

If the tolerance parameter is provided, vertices within the tolerance of one another will be considered the "same" for the purposes
of removal.
Availability: 2.2.0

This function supports Polyhedral surfaces.

This function supports 3d and will not drop the z-index.

See Also

ST_Simplify

8.11.25 ST_SharedPaths

ST_SharedPaths — Returns a collection containing paths shared by the two input linestrings/multilinestrings.

Synopsis

geometry ST_SharedPaths(geometry lineal1, geometry lineal2);

Description

Returns a collection containing paths shared by the two input geometries. Those going in the same direction are in the first
element of the collection, those going in the opposite direction are in the second element. The paths themselves are given in the
direction of the first geometry.
Availability: 2.0.0 requires GEOS >= 3.3.0.

Examples: Finding shared paths

A multilinestring and a linestring

PostGIS 2.4.3 Manual 393 / 803

The shared path of multilinestring and linestring overlaid with original geometries.
SELECT ST_AsText(
ST_SharedPaths(
ST_GeomFromText('MULTILINESTRING((26 125,26 200,126 200,126 125,26 125),
(51 150,101 150,76 175,51 150))'),
ST_GeomFromText('LINESTRING(151 100,126 156.25,126 125,90 161, 76 175)')
)
) As wkt

wkt
-------------------------------------------------------------
GEOMETRYCOLLECTION(MULTILINESTRING((126 156.25,126 125),
(101 150,90 161),(90 161,76 175)),MULTILINESTRING EMPTY)

-- same example but linestring orientation flipped

SELECT ST_AsText(
ST_SharedPaths(
ST_GeomFromText('LINESTRING(76 175,90 161,126 125,126 156.25,151 100)'),
ST_GeomFromText('MULTILINESTRING((26 125,26 200,126 200,126 125,26 125),
(51 150,101 150,76 175,51 150))')
)
) As wkt

wkt
-------------------------------------------------------------
GEOMETRYCOLLECTION(MULTILINESTRING EMPTY,
MULTILINESTRING((76 175,90 161),(90 161,101 150),(126 125,126 156.25)))

See Also

ST_Dump, ST_GeometryN, ST_NumGeometries

PostGIS 2.4.3 Manual 394 / 803

8.11.26 ST_ShiftLongitude

ST_ShiftLongitude — Toggle geometry coordinates between -180..180 and 0..360 ranges.

Synopsis

geometry ST_ShiftLongitude(geometry geomA);

Description

Reads every point/vertex in every component of every feature in a geometry, and if the longitude coordinate is <0, adds 360 to it.
The result would be a 0-360 version of the data to be plotted in a 180 centric map

Note
This is only useful for data in long lat e.g. 4326 (WGS 84 long lat)

Pre-1.3.4 bug prevented this from working for MULTIPOINT. 1.3.4+ works with MULTIPOINT as well.

This function supports 3d and will not drop the z-index.

Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
NOTE: this function was renamed from "ST_Shift_Longitude" in 2.2.0

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

--3d points
SELECT ST_AsEWKT(ST_ShiftLongitude(ST_GeomFromEWKT('SRID=4326;POINT(-118.58 38.38 10)'))) ←-
As geomA,
ST_AsEWKT(ST_ShiftLongitude(ST_GeomFromEWKT('SRID=4326;POINT(241.42 38.38 10)'))) As ←-
geomb
geomA geomB
---------- -----------
SRID=4326;POINT(241.42 38.38 10) SRID=4326;POINT(-118.58 38.38 10)

--regular line string

SELECT ST_AsText(ST_ShiftLongitude(ST_GeomFromText('LINESTRING(-118.58 38.38, -118.20 ←-
38.45)')))

st_astext
----------
LINESTRING(241.42 38.38,241.8 38.45)

See Also

ST_WrapX
PostGIS 2.4.3 Manual 395 / 803

8.11.27 ST_WrapX

ST_WrapX — Wrap a geometry around an X value.

Synopsis

geometry ST_WrapX(geometry geom, float8 wrap, float8 move);

Description

This function splits the input geometries and then moves every resulting component falling on the right (for negative ’move’) or
on the left (for positive ’move’) of given ’wrap’ line in the direction specified by the ’move’ parameter, finally re-unioning the
pieces togheter.

Note
This is useful to "recenter" long-lat input to have features of interest not spawned from one side to the other.

Availability: 2.3.0

This function supports 3d and will not drop the z-index.

Examples

-- Move all components of the given geometries whose bounding box

-- falls completely on the left of x=0 to +360
select ST_WrapX(the_geom, 0, 360);

-- Move all components of the given geometries whose bounding box

-- falls completely on the left of x=-30 to +360
select ST_WrapX(the_geom, -30, 360);

See Also

ST_ShiftLongitude

8.11.28 ST_Simplify

ST_Simplify — Returns a "simplified" version of the given geometry using the Douglas-Peucker algorithm.

Synopsis

geometry ST_Simplify(geometry geomA, float tolerance, boolean preserveCollapsed);

PostGIS 2.4.3 Manual 396 / 803

Description

Returns a "simplified" version of the given geometry using the Douglas-Peucker algorithm. Will actually do something only
with (multi)lines and (multi)polygons but you can safely call it with any kind of geometry. Since simplification occurs on a
object-by-object basis you can also feed a GeometryCollection to this function.
The "preserve collapsed" flag will retain objects that would otherwise be too small given the tolerance. For example, a 1m long
line simplified with a 10m tolerance. If the preserve flag is given, the line will not disappear. This flag is useful for rendering
engines, to avoid having large numbers of very small objects disappear from a map leaving surprising gaps.

Note
Note that returned geometry might lose its simplicity (see ST_IsSimple)

Note
Note topology may not be preserved and may result in invalid geometries. Use (see ST_SimplifyPreserveTopology) to
preserve topology.

Availability: 1.2.2

Examples

A circle simplified too much becomes a triangle, medium an octagon,

SELECT ST_Npoints(the_geom) As np_before, ST_NPoints(ST_Simplify(the_geom,0.1)) As ←-
np01_notbadcircle, ST_NPoints(ST_Simplify(the_geom,0.5)) As np05_notquitecircle,
ST_NPoints(ST_Simplify(the_geom,1)) As np1_octagon, ST_NPoints(ST_Simplify(the_geom,10)) As ←-
np10_triangle,
(ST_Simplify(the_geom,100) is null) As np100_geometrygoesaway
FROM (SELECT ST_Buffer('POINT(1 3)', 10,12) As the_geom) As foo;
-result
np_before | np01_notbadcircle | np05_notquitecircle | np1_octagon | np10_triangle | ←-
np100_geometrygoesaway
-----------+-------------------+---------------------+-------------+---------------+-----------------

49 | 33 | 17 | 9 | 4 | t

See Also

ST_IsSimple, ST_SimplifyPreserveTopology, Topology ST_Simplify

8.11.29 ST_SimplifyPreserveTopology

ST_SimplifyPreserveTopology — Returns a "simplified" version of the given geometry using the Douglas-Peucker algorithm.
Will avoid creating derived geometries (polygons in particular) that are invalid.

Synopsis

geometry ST_SimplifyPreserveTopology(geometry geomA, float tolerance);

PostGIS 2.4.3 Manual 397 / 803

Description

Returns a "simplified" version of the given geometry using the Douglas-Peucker algorithm. Will avoid creating derived ge-
ometries (polygons in particular) that are invalid. Will actually do something only with (multi)lines and (multi)polygons but
you can safely call it with any kind of geometry. Since simplification occurs on a object-by-object basis you can also feed a
GeometryCollection to this function.
Performed by the GEOS module.

Note
Requires GEOS 3.0.0+

Availability: 1.3.3

Examples

Same example as Simplify, but we see Preserve Topology prevents oversimplification. The circle can at most become a square.
SELECT ST_Npoints(the_geom) As np_before, ST_NPoints(ST_SimplifyPreserveTopology(the_geom ←-
,0.1)) As np01_notbadcircle, ST_NPoints(ST_SimplifyPreserveTopology(the_geom,0.5)) As ←-
np05_notquitecircle,
ST_NPoints(ST_SimplifyPreserveTopology(the_geom,1)) As np1_octagon, ST_NPoints( ←-
ST_SimplifyPreserveTopology(the_geom,10)) As np10_square,
ST_NPoints(ST_SimplifyPreserveTopology(the_geom,100)) As np100_stillsquare
FROM (SELECT ST_Buffer('POINT(1 3)', 10,12) As the_geom) As foo;

--result--
np_before | np01_notbadcircle | np05_notquitecircle | np1_octagon | np10_square | ←-
np100_stillsquare
-----------+-------------------+---------------------+-------------+---------------+-----------------

49 | 33 | 17 | 9 | 5 | ←-
5

See Also

ST_Simplify

8.11.30 ST_SimplifyVW

ST_SimplifyVW — Returns a "simplified" version of the given geometry using the Visvalingam-Whyatt algorithm

Synopsis

geometry ST_SimplifyVW(geometry geomA, float tolerance);

Description

Returns a "simplified" version of the given geometry using the Visvalingam-Whyatt algorithm. Will actually do something only
with (multi)lines and (multi)polygons but you can safely call it with any kind of geometry. Since simplification occurs on a
object-by-object basis you can also feed a GeometryCollection to this function.
PostGIS 2.4.3 Manual 398 / 803

Note
Note that returned geometry might lose its simplicity (see ST_IsSimple)

Note
Note topology may not be preserved and may result in invalid geometries. Use (see ST_SimplifyPreserveTopology) to
preserve topology.

Note
This function handles 3D and the third dimension will affect the result.

Availability: 2.2.0

Examples

A LineString is simplified with a minimum area threshold of 30.

select ST_AsText(ST_SimplifyVW(geom,30)) simplified

FROM (SELECT 'LINESTRING(5 2, 3 8, 6 20, 7 25, 10 10)'::geometry geom) As foo;
-result
simplified
-----------+-------------------+
LINESTRING(5 2,7 25,10 10)

See Also

ST_SetEffectiveArea, ST_Simplify, ST_SimplifyPreserveTopology, Topology ST_Simplify

8.11.31 ST_SetEffectiveArea

ST_SetEffectiveArea — Sets the effective area for each vertex, storing the value in the M ordinate. A simplified geometry can
then be generated by filtering on the M ordinate.

Synopsis

geometry ST_SetEffectiveArea(geometry geomA, float threshold = 0, integer set_area = 1);

Description

Sets the effective area for each vertex, using the Visvalingam-Whyatt algorithm. The effective area is stored as the M-value of
the vertex. If the optional "theshold" parameter is used, a simplified geometry will be returned, containing only vertices with an
effective area greater than or equal to the threshold value.
This function can be used for server-side simplification when a threshold is specified. Another option is to use a threshold value
of zero. In this case, the full geometry will be returned with effective areas as M-values, which can be used by the client to
simplify very quickly.
Will actually do something only with (multi)lines and (multi)polygons but you can safely call it with any kind of geometry. Since
simplification occurs on a object-by-object basis you can also feed a GeometryCollection to this function.
PostGIS 2.4.3 Manual 399 / 803

Note
Note that returned geometry might lose its simplicity (see ST_IsSimple)

Note
Note topology may not be preserved and may result in invalid geometries. Use (see ST_SimplifyPreserveTopology) to
preserve topology.

Note
The output geometry will lose all previous information in the M-values

Note
This function handles 3D and the third dimension will affect the effective area

Availability: 2.2.0

Examples

Calculating the effective area of a LineString. Because we use a threshold value of zero, all vertices in the input geometry are
returned.

select ST_AsText(ST_SetEffectiveArea(geom)) all_pts, ST_AsText(ST_SetEffectiveArea(geom,30) ←-

) thrshld_30
FROM (SELECT 'LINESTRING(5 2, 3 8, 6 20, 7 25, 10 10)'::geometry geom) As foo;
-result
all_pts | thrshld_30
-----------+-------------------+
LINESTRING M (5 2 3.40282346638529e+38,3 8 29,6 20 1.5,7 25 49.5,10 10 3.40282346638529e ←-
+38) | LINESTRING M (5 2 3.40282346638529e+38,7 25 49.5,10 10 3.40282346638529e+38)

See Also

ST_SimplifyVW

8.11.32 ST_Split

ST_Split — Returns a collection of geometries resulting by splitting a geometry.

Synopsis

geometry ST_Split(geometry input, geometry blade);

PostGIS 2.4.3 Manual 400 / 803

Description

The function supports splitting a line by (multi)point, (multi)line or (multi)polygon boundary, a (multi)polygon by line. The
returned geometry is always a collection.
Think of this function as the opposite of ST_Union. Theoretically applying ST_Union to the elements of the returned collection
should always yield the original geometry.
Availability: 2.0.0
Changed: 2.2.0 support for splitting a line by a multiline, a multipoint or (multi)polygon boundary was introduced.

Note
To improve the robustness of ST_Split it may be convenient to ST_Snap the input to the blade in advance using a very
low tolerance. Otherwise the internally used coordinate grid may cause tolerance problems, where coordinates of input
and blade do not fall onto each other and the input is not being split correctly (see #2192).

Note
When a (multi)polygon is passed as as the blade, its linear component (the boundary) is used for cutting the input.

Examples

Polygon Cut by Line

Before Split After split

-- this creates a geometry collection consisting of the 2 halves of the polygon

-- this is similar to the example we demonstrated in ST_BuildArea
SELECT ST_Split(circle, line)
FROM (SELECT
ST_MakeLine(ST_MakePoint(10, 10),ST_MakePoint(190, 190)) As line,
ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As circle) As foo;
PostGIS 2.4.3 Manual 401 / 803

-- result --
GEOMETRYCOLLECTION(POLYGON((150 90,149.039264020162 80.2454838991936,146.193976625564 ←-
70.8658283817455,..), POLYGON(..)))

-- To convert to individual polygons, you can use ST_Dump or ST_GeometryN

SELECT ST_AsText((ST_Dump(ST_Split(circle, line))).geom) As wkt
FROM (SELECT
ST_MakeLine(ST_MakePoint(10, 10),ST_MakePoint(190, 190)) As line,
ST_Buffer(ST_GeomFromText('POINT(100 90)'), 50) As circle) As foo;

-- result --
wkt
---------------
POLYGON((150 90,149.039264020162 80.2454838991936,..))
POLYGON((60.1371179574584 60.1371179574584,58.4265193848728 ←-
62.2214883490198,53.8060233744357 ..))

Multilinestring Cut by point

Before Split After split

SELECT ST_AsText(ST_Split(mline, pt)) As wktcut

FROM (SELECT
ST_GeomFromText('MULTILINESTRING((10 10, 190 190), (15 15, 30 30, 100 90))') As mline,
ST_Point(30,30) As pt) As foo;

wktcut
------
GEOMETRYCOLLECTION(
LINESTRING(10 10,30 30),
LINESTRING(30 30,190 190),
LINESTRING(15 15,30 30),
LINESTRING(30 30,100 90)
)
PostGIS 2.4.3 Manual 402 / 803

See Also

ST_AsText, ST_BuildArea, ST_Dump, ST_GeometryN, ST_Union, ST_Subdivide

8.11.33 ST_SymDifference

ST_SymDifference — Returns a geometry that represents the portions of A and B that do not intersect. It is called a symmetric
difference because ST_SymDifference(A,B) = ST_SymDifference(B,A).

Synopsis

geometry ST_SymDifference(geometry geomA, geometry geomB);

Description

Returns a geometry that represents the portions of A and B that do not intersect. It is called a symmetric difference because
ST_SymDifference(A,B) = ST_SymDifference(B,A). One can think of this as ST_Union(geomA,geomB) - ST_Intersection(A,B).
Performed by the GEOS module

Note
Do not call with a GeometryCollection as an argument

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.3

This method implements the SQL/MM specification. SQL-MM 3: 5.1.21

This function supports 3d and will not drop the z-index. However it seems to only consider x y when doing the difference
and tacks back on the Z-Index

Examples
PostGIS 2.4.3 Manual 403 / 803

The original linestrings shown together The symmetric difference of the two linestrings

--Safe for 2d - symmetric difference of 2 linestrings

SELECT ST_AsText(
ST_SymDifference(
ST_GeomFromText('LINESTRING(50 100, 50 200)'),
ST_GeomFromText('LINESTRING(50 50, 50 150)')
)
);

st_astext
---------
MULTILINESTRING((50 150,50 200),(50 50,50 100))

--When used in 3d doesn't quite do the right thing

SELECT ST_AsEWKT(ST_SymDifference(ST_GeomFromEWKT('LINESTRING(1 2 1, 1 4 2)'),
ST_GeomFromEWKT('LINESTRING(1 1 3, 1 3 4)')))

st_astext
------------
MULTILINESTRING((1 3 2.75,1 4 2),(1 1 3,1 2 2.25))

See Also

ST_Difference, ST_Intersection, ST_Union

8.11.34 ST_Subdivide

ST_Subdivide — Returns a set of geometry where no geometry in the set has more than the specified number of vertices.

Synopsis

setof geometry ST_Subdivide(geometry geom, integer max_vertices=256);

PostGIS 2.4.3 Manual 404 / 803

Description

Turns a single geometry into a set in which each element has fewer than the maximum allowed number of vertices. Useful for
converting excessively large polygons and other objects into small portions that fit within the database page size. Uses the same
envelope clipping as ST_ClipByBox2D does, recursively subdividing the input geometry until all portions have less than the
maximum vertex count. Minimum vertice count allowed is 8 and if you try to specify lower than 8, it will throw an error.
Clipping performed by the GEOS module.

Note
Requires GEOS 3.5.0+

Availability: 2.2.0 requires GEOS >= 3.5.0.

Examples

-- Create a new subdivided table suitable for joining to the original

CREATE TABLE subdivided_geoms AS
SELECT pkey, ST_Subdivide(geom) AS geom
FROM original_geoms;
PostGIS 2.4.3 Manual 405 / 803

Subdivide max 10 vertices

SELECT row_number() OVER() As rn, ST_AsText(geom) As wkt
FROM ( SELECT ST_SubDivide('POLYGON((132 10,119 23,85 35,68 29,66 28,49 42,32 56,22 ←-
64,32 110,40 119,36 150,
57 158,75 171,92 182,114 184,132 186,146 178,176 184,179 162,184 141,190 122,
190 100,185 79,186 56,186 52,178 34,168 18,147 13,132 10))'::geometry,10)) As f(geom);

rn | wkt
---+---------------------------------------------------------------------------
1 | POLYGON((22 64,29.3913043478263 98.000000000001,106.000000000001 98.00000000001,
106.000000000001 27.5882352941173,85 35,68 29,66 28,49 42,32 56,22 64))
2 | POLYGON((29.3913043478263 98.000000000001,32 110,40 119,36 150,57 158,
75 11,92 182,106.000000000001 183.272727272727,106.000000000001 ←-
98.000000000001,
29.913043478263 98.000000000001))
3 | POLYGON((106.000000000001 27.5882352941173,106.000000000001 98.00000000000,
189.52380952381 98.000000000001,185 79,186 56,186 52,178 34,168 18,147 13,
132 0,119 23,106.000000000001 27.5882352941173))
4 | POLYGON((106.000000000001 98.000000000001,106.000000000001 183.27272727272,
114 184,132 186,146 178,176 184,179 162,184 141,190 122,190 100,189.5238095238
98.000000000001,106.000000000001 98.000000000001))
PostGIS 2.4.3 Manual 406 / 803

Useful in conjunction with ST_Segmentize to create additional vertices that can then be used for splitting
SELECT ST_AsText(ST_SubDivide(ST_Segmentize('LINESTRING(0 0, 100 100, 150 150)':: ←-
geometry,10),8));

LINESTRING(0 0,7.07106781186547 7.07106781186547,14.1421356237309 ←-

14.1421356237309,21.2132034355964 21.2132034355964,28.2842712474619 ←-
28.2842712474619,35.3553390593274 35.3553390593274,37.499999999998 37.499999999998)
LINESTRING(37.499999999998 37.499999999998,42.4264068711929 ←-
42.4264068711929,49.4974746830583 49.4974746830583,56.5685424949238 ←-
56.5685424949238,63.6396103067893 63.6396103067893,70.7106781186548 ←-
70.7106781186548,74.999999999998 74.999999999998)
LINESTRING(74.999999999998 74.999999999998,77.7817459305202 ←-
77.7817459305202,84.8528137423857 84.8528137423857,91.9238815542512 ←-
91.9238815542512,98.9949493661167 98.9949493661167,100 100,107.071067811865 ←-
107.071067811865,112.499999999998 112.499999999998)
LINESTRING(112.499999999998 112.499999999998,114.142135623731 ←-
114.142135623731,121.213203435596 121.213203435596,128.284271247462 ←-
128.284271247462,135.355339059327 135.355339059327,142.426406871193 ←-
142.426406871193,149.497474683058 149.497474683058,149.999999999998 149.999999999998)

See Also

ST_AsText, ST_ClipByBox2D, ST_Segmentize, ST_Split

8.11.35 ST_SwapOrdinates

ST_SwapOrdinates — Returns a version of the given geometry with given ordinate values swapped.

Synopsis

geometry ST_SwapOrdinates(geometry geom, cstring ords);

Description

Returns a version of the given geometry with given ordinates swapped.

PostGIS 2.4.3 Manual 407 / 803

The ords parameter is a 2-characters string naming the ordinates to swap. Valid names are: x,y,z and m.
Availability: 2.2.0

This method supports Circular Strings and Curves

This function supports 3d and will not drop the z-index.

This function supports M coordinates.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Example

-- Scale M value by 2
SELECT ST_AsText(
ST_SwapOrdinates(
ST_Scale(
ST_SwapOrdinates(g,'xm'),
2, 1
),
'xm')
) FROM ( SELECT 'POINT ZM (0 0 0 2)'::geometry g ) foo;
st_astext
--------------------
POINT ZM (0 0 0 4)

See Also

ST_FlipCoordinates

8.11.36 ST_Union

ST_Union — Returns a geometry that represents the point set union of the Geometries.

Synopsis

geometry ST_Union(geometry set g1field);

geometry ST_Union(geometry g1, geometry g2);
geometry ST_Union(geometry[] g1_array);

Description

Output type can be a MULTI*, single geometry, or Geometry Collection. Comes in 2 variants. Variant 1 unions 2 geometries
resulting in a new geometry with no intersecting regions. Variant 2 is an aggregate function that takes a set of geometries and
unions them into a single ST_Geometry resulting in no intersecting regions.
Aggregate version: This function returns a MULTI geometry or NON-MULTI geometry from a set of geometries. The ST_Union()
function is an "aggregate" function in the terminology of PostgreSQL. That means that it operates on rows of data, in the same
way the SUM() and AVG() functions do and like most aggregates, it also ignores NULL geometries.
Non-Aggregate version: This function returns a geometry being a union of two input geometries. Output type can be a MULTI*,
NON-MULTI or GEOMETRYCOLLECTION. If any are NULL, then NULL is returned.
PostGIS 2.4.3 Manual 408 / 803

Note
ST_Collect and ST_Union are often interchangeable. ST_Union is in general orders of magnitude slower than
ST_Collect because it tries to dissolve boundaries and reorder geometries to ensure that a constructed Multi* doesn’t
have intersecting regions.

Performed by the GEOS module.

NOTE: this function was formerly called GeomUnion(), which was renamed from "Union" because UNION is an SQL reserved
word.
Availability: 1.4.0 - ST_Union was enhanced. ST_Union(geomarray) was introduced and also faster aggregate collection in Post-
greSQL. If you are using GEOS 3.1.0+ ST_Union will use the faster Cascaded Union algorithm described in http://blog.cleverelephant.ca/
2009/01/must-faster-unions-in-postgis-14.html

This method implements the OpenGIS Simple Features Implementation Specification for SQL 1.1. s2.1.1.3

Note
Aggregate version is not explicitly defined in OGC SPEC.

This method implements the SQL/MM specification. SQL-MM 3: 5.1.19 the z-index (elevation) when polygons are
involved.

Examples

Aggregate example
SELECT stusps,
ST_Multi(ST_Union(f.the_geom)) as singlegeom
FROM sometable As f
GROUP BY stusps

Non-Aggregate example
SELECT ST_AsText(ST_Union(ST_GeomFromText('POINT(1 2)'),
ST_GeomFromText('POINT(-2 3)') ) )

st_astext
----------
MULTIPOINT(-2 3,1 2)

SELECT ST_AsText(ST_Union(ST_GeomFromText('POINT(1 2)'),

ST_GeomFromText('POINT(1 2)') ) );
st_astext
----------
POINT(1 2)

--3d example - sort of supports 3d (and with mixed dimensions!)

SELECT ST_AsEWKT(st_union(the_geom))
FROM
(SELECT ST_GeomFromEWKT('POLYGON((-7 4.2,-7.1 4.2,-7.1 4.3,
-7 4.2))') as the_geom
UNION ALL
SELECT ST_GeomFromEWKT('POINT(5 5 5)') as the_geom
PostGIS 2.4.3 Manual 409 / 803

UNION ALL
SELECT ST_GeomFromEWKT('POINT(-2 3 1)') as the_geom
UNION ALL
SELECT ST_GeomFromEWKT('LINESTRING(5 5 5, 10 10 10)') as the_geom ) as foo;

st_asewkt
---------
GEOMETRYCOLLECTION(POINT(-2 3 1),LINESTRING(5 5 5,10 10 10),POLYGON((-7 4.2 5,-7.1 4.2 ←-
5,-7.1 4.3 5,-7 4.2 5)));

--3d example not mixing dimensions

SELECT ST_AsEWKT(st_union(the_geom))
FROM
(SELECT ST_GeomFromEWKT('POLYGON((-7 4.2 2,-7.1 4.2 3,-7.1 4.3 2,
-7 4.2 2))') as the_geom
UNION ALL
SELECT ST_GeomFromEWKT('POINT(5 5 5)') as the_geom
UNION ALL
SELECT ST_GeomFromEWKT('POINT(-2 3 1)') as the_geom
UNION ALL
SELECT ST_GeomFromEWKT('LINESTRING(5 5 5, 10 10 10)') as the_geom ) as foo;

st_asewkt
---------
GEOMETRYCOLLECTION(POINT(-2 3 1),LINESTRING(5 5 5,10 10 10),POLYGON((-7 4.2 2,-7.1 4.2 ←-
3,-7.1 4.3 2,-7 4.2 2)))

--Examples using new Array construct

SELECT ST_Union(ARRAY(SELECT the_geom FROM sometable));

SELECT ST_AsText(ST_Union(ARRAY[ST_GeomFromText('LINESTRING(1 2, 3 4)'),

ST_GeomFromText('LINESTRING(3 4, 4 5)')])) As wktunion;

--wktunion---
MULTILINESTRING((3 4,4 5),(1 2,3 4))

See Also

ST_Collect ST_UnaryUnion

8.11.37 ST_UnaryUnion

ST_UnaryUnion — Like ST_Union, but working at the geometry component level.

Synopsis

geometry ST_UnaryUnion(geometry geom);

Description

Unlike ST_Union, ST_UnaryUnion does dissolve boundaries between components of a multipolygon (invalid) and does perform
union between the components of a geometrycollection. Each components of the input geometry is assumed to be valid, so you
won’t get a valid multipolygon out of a bow-tie polygon (invalid).
You may use this function to node a set of linestrings. You may mix ST_UnaryUnion with ST_Collect to fine-tune how many
geometries at once you want to dissolve to be nice on both memory size and CPU time, finding the balance between ST_Union
and ST_MemUnion.
PostGIS 2.4.3 Manual 410 / 803

This function supports 3d and will not drop the z-index.

Availability: 2.0.0 - requires GEOS >= 3.3.0.

See Also

ST_Union, ST_MemUnion, ST_Collect, ST_Node

8.11.38 ST_VoronoiLines

ST_VoronoiLines — Returns the boundaries between the cells of the Voronoi diagram constructed from the vertices of a geome-
try.

Synopsis

geometry ST_VoronoiLines( g1 geometry , tolerance float8 , extend_to geometry );

Description

ST_VoronoiLines computes a two-dimensional Voronoi diagram from the vertices of the supplied geometry and returns the
boundaries between cells in that diagram as a MultiLineString.
Optional parameters:

• ’tolerance’ : The distance within which vertices will be considered equivalent. Robustness of the algorithm can be improved
by supplying a nonzero tolerance distance. (default = 0.0)
• ’extend_to’ : If a geometry is supplied as the "extend_to" parameter, the diagram will be extended to cover the envelope of the
"extend_to" geometry, unless that envelope is smaller than the default envelope. (default = NULL)

Availability: 2.3.0 - requires GEOS >= 3.5.0.

Examples
PostGIS 2.4.3 Manual 411 / 803

Voronoi lines with tolerance of 30 units

SELECT ST_VoronoiLines(geom, 30) As geom
FROM (SELECT 'MULTIPOINT (50 30, 60 30, 100 100,10 150, 110 120)'::geometry As geom ) ←-
As g

-- ST_AsText output
MULTILINESTRING((135.555555555556 270,36.8181818181818 92.2727272727273) ←-
,(36.8181818181818 92.2727272727273,-110 43.3333333333333),(230 ←-
-45.7142857142858,36.8181818181818 92.2727272727273))

See Also

ST_DelaunayTriangles, ST_VoronoiPolygons, ST_Collect

8.11.39 ST_VoronoiPolygons

ST_VoronoiPolygons — Returns the cells of the Voronoi diagram constructed from the vertices of a geometry.

Synopsis

geometry ST_VoronoiPolygons( g1 geometry , tolerance float8 , extend_to geometry );

Description

ST_VoronoiPolygons computes a two-dimensional Voronoi diagram from the vertices of the supplied geometry. The result is a
GeometryCollection of Polygons that covers an envelope larger than the extent of the input vertices.
Optional parameters:

• ’tolerance’ : The distance within which vertices will be considered equivalent. Robustness of the algorithm can be improved
by supplying a nonzero tolerance distance. (default = 0.0)
• ’extend_to’ : If a geometry is supplied as the "extend_to" parameter, the diagram will be extended to cover the envelope of the
"extend_to" geometry, unless that envelope is smaller than the default envelope. (default = NULL)

Availability: 2.3.0 - requires GEOS >= 3.5.0.

PostGIS 2.4.3 Manual 412 / 803

Examples

Points overlaid on top of Voronoi diagram

SELECT
ST_VoronoiPolygons(geom) As geom
FROM (SELECT 'MULTIPOINT (50 30, 60 30, 100 100,10 150, 110 120)'::geometry As geom ) ←-
As g;

-- ST_AsText output
GEOMETRYCOLLECTION(POLYGON((-110 43.3333333333333,-110 270,100.5 270,59.3478260869565 ←-
132.826086956522,36.8181818181818 92.2727272727273,-110 43.3333333333333)),
POLYGON((55 -90,-110 -90,-110 43.3333333333333,36.8181818181818 92.2727272727273,55 ←-
79.2857142857143,55 -90)),
POLYGON((230 47.5,230 -20.7142857142857,55 79.2857142857143,36.8181818181818 ←-
92.2727272727273,59.3478260869565 132.826086956522,230 47.5)),POLYGON((230 ←-
-20.7142857142857,230 -90,55 -90,55 79.2857142857143,230 -20.7142857142857)),
POLYGON((100.5 270,230 270,230 47.5,59.3478260869565 132.826086956522,100.5 270)))
PostGIS 2.4.3 Manual 413 / 803

Voronoi with tolerance of 30 units

SELECT ST_VoronoiPolygons(geom, 30) As geom
FROM (SELECT 'MULTIPOINT (50 30, 60 30, 100 100,10 150, 110 120)'::geometry As geom ) ←-
As g;

-- ST_AsText output
GEOMETRYCOLLECTION(POLYGON((-110 43.3333333333333,-110 270,100.5 270,59.3478260869565 ←-
132.826086956522,36.8181818181818 92.2727272727273,-110 43.3333333333333)),
POLYGON((230 47.5,230 -45.7142857142858,36.8181818181818 ←-
92.2727272727273,59.3478260869565 132.826086956522,230 47.5)),POLYGON((230 ←-
-45.7142857142858,230 -90,-110 -90,-110 43.3333333333333,36.8181818181818 ←-
92.2727272727273,230 -45.7142857142858)),
POLYGON((100.5 270,230 270,230 47.5,59.3478260869565 132.826086956522,100.5 270)))
PostGIS 2.4.3 Manual 414 / 803

Voronoi with tolerance of 30 units as MultiLineString

SELECT ST_VoronoiLines(geom, 30) As geom
FROM (SELECT 'MULTIPOINT (50 30, 60 30, 100 100,10 150, 110 120)'::geometry As geom ) ←-
As g

-- ST_AsText output
MULTILINESTRING((135.555555555556 270,36.8181818181818 92.2727272727273) ←-
,(36.8181818181818 92.2727272727273,-110 43.3333333333333),(230 ←-
-45.7142857142858,36.8181818181818 92.2727272727273))

See Also

ST_DelaunayTriangles, ST_VoronoiLines, ST_Collect

8.12 Linear Referencing

8.12.1 ST_LineInterpolatePoint

ST_LineInterpolatePoint — Returns a point interpolated along a line. Second argument is a float8 between 0 and 1 representing
fraction of total length of linestring the point has to be located.

Synopsis

geometry ST_LineInterpolatePoint(geometry a_linestring, float8 a_fraction);

Description

Returns a point interpolated along a line. First argument must be a LINESTRING. Second argument is a float8 between 0 and 1
representing fraction of total linestring length the point has to be located.
See ST_LineLocatePoint for computing the line location nearest to a Point.
PostGIS 2.4.3 Manual 415 / 803

Note
Since release 1.1.1 this function also interpolates M and Z values (when present), while prior releases set them to 0.0.

Availability: 0.8.2, Z and M supported added in 1.1.1

Changed: 2.1.0. Up to 2.0.x this was called ST_Line_Interpolate_Point.

This function supports 3d and will not drop the z-index.

Examples

A linestring with the interpolated point at 20% position (0.20)

--Return point 20% along 2d line
SELECT ST_AsEWKT(ST_LineInterpolatePoint(the_line, 0.20))
FROM (SELECT ST_GeomFromEWKT('LINESTRING(25 50, 100 125, 150 190)') as the_line) As foo;
st_asewkt
----------------
POINT(51.5974135047432 76.5974135047432)

--Return point mid-way of 3d line

SELECT ST_AsEWKT(ST_LineInterpolatePoint(the_line, 0.5))
FROM (SELECT ST_GeomFromEWKT('LINESTRING(1 2 3, 4 5 6, 6 7 8)') as the_line) As foo;

st_asewkt
--------------------
POINT(3.5 4.5 5.5)

--find closest point on a line to a point or other geometry

SELECT ST_AsText(ST_LineInterpolatePoint(foo.the_line, ST_LineLocatePoint(foo.the_line, ←-
ST_GeomFromText('POINT(4 3)'))))
FROM (SELECT ST_GeomFromText('LINESTRING(1 2, 4 5, 6 7)') As the_line) As foo;
st_astext
----------------
POINT(3 4)
PostGIS 2.4.3 Manual 416 / 803

See Also

ST_AsText, ST_AsEWKT, ST_Length, ST_LineLocatePoint

8.12.2 ST_LineLocatePoint

ST_LineLocatePoint — Returns a float between 0 and 1 representing the location of the closest point on LineString to the given
Point, as a fraction of total 2d line length.

Synopsis

float8 ST_LineLocatePoint(geometry a_linestring, geometry a_point);

Description

Returns a float between 0 and 1 representing the location of the closest point on LineString to the given Point, as a fraction of
total 2d line length.
You can use the returned location to extract a Point (ST_LineInterpolatePoint) or a substring (ST_LineSubstring).
This is useful for approximating numbers of addresses
Availability: 1.1.0
Changed: 2.1.0. Up to 2.0.x this was called ST_Line_Locate_Point.

Examples

--Rough approximation of finding the street number of a point along the street
--Note the whole foo thing is just to generate dummy data that looks
--like house centroids and street
--We use ST_DWithin to exclude
--houses too far away from the street to be considered on the street
SELECT ST_AsText(house_loc) As as_text_house_loc,
startstreet_num +
CAST( (endstreet_num - startstreet_num)
* ST_LineLocatePoint(street_line, house_loc) As integer) As street_num
FROM
(SELECT ST_GeomFromText('LINESTRING(1 2, 3 4)') As street_line,
ST_MakePoint(x*1.01,y*1.03) As house_loc, 10 As startstreet_num,
20 As endstreet_num
FROM generate_series(1,3) x CROSS JOIN generate_series(2,4) As y)
As foo
WHERE ST_DWithin(street_line, house_loc, 0.2);

as_text_house_loc | street_num
-------------------+------------
POINT(1.01 2.06) | 10
POINT(2.02 3.09) | 15
POINT(3.03 4.12) | 20

--find closest point on a line to a point or other geometry

SELECT ST_AsText(ST_LineInterpolatePoint(foo.the_line, ST_LineLocatePoint(foo.the_line, ←-
ST_GeomFromText('POINT(4 3)'))))
FROM (SELECT ST_GeomFromText('LINESTRING(1 2, 4 5, 6 7)') As the_line) As foo;
st_astext
----------------
POINT(3 4)
PostGIS 2.4.3 Manual 417 / 803

See Also

ST_DWithin, ST_Length2D, ST_LineInterpolatePoint, ST_LineSubstring

8.12.3 ST_LineSubstring

ST_LineSubstring — Return a linestring being a substring of the input one starting and ending at the given fractions of total 2d
length. Second and third arguments are float8 values between 0 and 1.

Synopsis

geometry ST_LineSubstring(geometry a_linestring, float8 startfraction, float8 endfraction);

Description

Return a linestring being a substring of the input one starting and ending at the given fractions of total 2d length. Second and
third arguments are float8 values between 0 and 1. This only works with LINESTRINGs. To use with contiguous MULTI-
LINESTRINGs use in conjunction with ST_LineMerge.
If ’start’ and ’end’ have the same value this is equivalent to ST_LineInterpolatePoint.
See ST_LineLocatePoint for computing the line location nearest to a Point.

Note
Since release 1.1.1 this function also interpolates M and Z values (when present), while prior releases set them to
unspecified values.

Availability: 1.1.0, Z and M supported added in 1.1.1

Changed: 2.1.0. Up to 2.0.x this was called ST_Line_Substring.

This function supports 3d and will not drop the z-index.

Examples

A linestring seen with 1/3 midrange overlaid (0.333, 0.666)

PostGIS 2.4.3 Manual 418 / 803

--Return the approximate 1/3 mid-range part of a linestring

SELECT ST_AsText(ST_Line_SubString(ST_GeomFromText('LINESTRING(25 50, 100 125, 150 190)'), ←-
0.333, 0.666));

st_astext
------------------------------------------------------------------------------------------------ ←-

LINESTRING(69.2846934853974 94.2846934853974,100 125,111.700356260683 140.210463138888)

--The below example simulates a while loop in

--SQL using PostgreSQL generate_series() to cut all
--linestrings in a table to 100 unit segments
-- of which no segment is longer than 100 units
-- units are measured in the SRID units of measurement
-- It also assumes all geometries are LINESTRING or contiguous MULTILINESTRING
--and no geometry is longer than 100 units*10000
--for better performance you can reduce the 10000
--to match max number of segments you expect

SELECT field1, field2, ST_LineSubstring(the_geom, 100.00*n/length,

CASE
WHEN 100.00*(n+1) < length THEN 100.00*(n+1)/length
ELSE 1
END) As the_geom
FROM
(SELECT sometable.field1, sometable.field2,
ST_LineMerge(sometable.the_geom) AS the_geom,
ST_Length(sometable.the_geom) As length
FROM sometable
) AS t
CROSS JOIN generate_series(0,10000) AS n
WHERE n*100.00/length < 1;

See Also

ST_Length, ST_LineInterpolatePoint, ST_LineMerge

8.12.4 ST_LocateAlong

ST_LocateAlong — Return a derived geometry collection value with elements that match the specified measure. Polygonal
elements are not supported.

Synopsis

geometry ST_LocateAlong(geometry ageom_with_measure, float8 a_measure, float8 offset);

Description

Return a derived geometry collection value with elements that match the specified measure. Polygonal elements are not sup-
ported.
If an offset is provided, the resultant will be offset to the left or right of the input line by the specified number of units. A positive
offset will be to the left, and a negative one to the right.
Semantic is specified by: ISO/IEC CD 13249-3:200x(E) - Text for Continuation CD Editing Meeting
Availability: 1.1.0 by old name ST_Locate_Along_Measure.
PostGIS 2.4.3 Manual 419 / 803

Changed: 2.0.0 in prior versions this used to be called ST_Locate_Along_Measure. The old name has been deprecated and will
be removed in the future but is still available.

Note
Use this function only for geometries with an M component

This function supports M coordinates.

Examples

SELECT ST_AsText(the_geom)
FROM
(SELECT ST_LocateAlong(
ST_GeomFromText('MULTILINESTRINGM((1 2 3, 3 4 2, 9 4 3),
(1 2 3, 5 4 5))'),3) As the_geom) As foo;

st_asewkt
-----------------------------------------------------------
MULTIPOINT M (1 2 3)

--Geometry collections are difficult animals so dump them

--to make them more digestable
SELECT ST_AsText((ST_Dump(the_geom)).geom)
FROM
(SELECT ST_LocateAlong(
ST_GeomFromText('MULTILINESTRINGM((1 2 3, 3 4 2, 9 4 3),
(1 2 3, 5 4 5))'),3) As the_geom) As foo;

st_asewkt
---------------
POINTM(1 2 3)
POINTM(9 4 3)
POINTM(1 2 3)

See Also

ST_Dump, ST_LocateBetween

8.12.5 ST_LocateBetween

ST_LocateBetween — Return a derived geometry collection value with elements that match the specified range of measures
inclusively. Polygonal elements are not supported.

Synopsis

geometry ST_LocateBetween(geometry geomA, float8 measure_start, float8 measure_end, float8 offset);

PostGIS 2.4.3 Manual 420 / 803

Description

Return a derived geometry collection value with elements that match the specified range of measures inclusively. Polygonal
elements are not supported.
Semantic is specified by: ISO/IEC CD 13249-3:200x(E) - Text for Continuation CD Editing Meeting
Availability: 1.1.0 by old name ST_Locate_Between_Measures.
Changed: 2.0.0 - in prior versions this used to be called ST_Locate_Between_Measures. The old name has been deprecated and
will be removed in the future but is still available for backward compatibility.

This function supports M coordinates.

Examples

SELECT ST_AsText(the_geom)
FROM
(SELECT ST_LocateBetween(
ST_GeomFromText('MULTILINESTRING M ((1 2 3, 3 4 2, 9 4 3),
(1 2 3, 5 4 5))'),1.5, 3) As the_geom) As foo;

st_asewkt
------------------------------------------------------------------------
GEOMETRYCOLLECTION M (LINESTRING M (1 2 3,3 4 2,9 4 3),POINT M (1 2 3))

--Geometry collections are difficult animals so dump them

--to make them more digestable
SELECT ST_AsText((ST_Dump(the_geom)).geom)
FROM
(SELECT ST_LocateBetween(
ST_GeomFromText('MULTILINESTRING M ((1 2 3, 3 4 2, 9 4 3),
(1 2 3, 5 4 5))'),1.5, 3) As the_geom) As foo;

st_asewkt
--------------------------------
LINESTRING M (1 2 3,3 4 2,9 4 3)
POINT M (1 2 3)

See Also

ST_Dump, ST_LocateAlong

8.12.6 ST_LocateBetweenElevations

ST_LocateBetweenElevations — Return a derived geometry (collection) value with elements that intersect the specified range of
elevations inclusively. Only 3D, 4D LINESTRINGS and MULTILINESTRINGS are supported.

Synopsis

geometry ST_LocateBetweenElevations(geometry geom_mline, float8 elevation_start, float8 elevation_end);

PostGIS 2.4.3 Manual 421 / 803

Description

Return a derived geometry (collection) value with elements that intersect the specified range of elevations inclusively. Only 3D,
3DM LINESTRINGS and MULTILINESTRINGS are supported.
Availability: 1.4.0

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_AsEWKT(ST_LocateBetweenElevations(
ST_GeomFromEWKT('LINESTRING(1 2 3, 4 5 6)'),2,4)) As ewelev;
ewelev
----------------------------------------------------------------
MULTILINESTRING((1 2 3,2 3 4))

SELECT ST_AsEWKT(ST_LocateBetweenElevations(
ST_GeomFromEWKT('LINESTRING(1 2 6, 4 5 -1, 7 8 9)'),6,9)) As ewelev;

ewelev
----------------------------------------------------------------
GEOMETRYCOLLECTION(POINT(1 2 6),LINESTRING(6.1 7.1 6,7 8 9))

--Geometry collections are difficult animals so dump them

--to make them more digestable
SELECT ST_AsEWKT((ST_Dump(the_geom)).geom)
FROM
(SELECT ST_LocateBetweenElevations(
ST_GeomFromEWKT('LINESTRING(1 2 6, 4 5 -1, 7 8 9)'),6,9) As the_geom) As foo;

st_asewkt
--------------------------------
POINT(1 2 6)
LINESTRING(6.1 7.1 6,7 8 9)

See Also

ST_Dump

8.12.7 ST_InterpolatePoint

ST_InterpolatePoint — Return the value of the measure dimension of a geometry at the point closed to the provided point.

Synopsis

float8 ST_InterpolatePoint(geometry line, geometry point);

Description

Return the value of the measure dimension of a geometry at the point closed to the provided point.
Availability: 2.0.0

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 422 / 803

Examples

SELECT ST_InterpolatePoint('LINESTRING M (0 0 0, 10 0 20)', 'POINT(5 5)');

st_interpolatepoint
---------------------
10

See Also

ST_AddMeasure, ST_LocateAlong, ST_LocateBetween

8.12.8 ST_AddMeasure

ST_AddMeasure — Return a derived geometry with measure elements linearly interpolated between the start and end points.

Synopsis

geometry ST_AddMeasure(geometry geom_mline, float8 measure_start, float8 measure_end);

Description

Return a derived geometry with measure elements linearly interpolated between the start and end points. If the geometry has
no measure dimension, one is added. If the geometry has a measure dimension, it is over-written with new values. Only
LINESTRINGS and MULTILINESTRINGS are supported.
Availability: 1.5.0

This function supports 3d and will not drop the z-index.

Examples

SELECT ST_AsText(ST_AddMeasure(
ST_GeomFromEWKT('LINESTRING(1 0, 2 0, 4 0)'),1,4)) As ewelev;
ewelev
--------------------------------
LINESTRINGM(1 0 1,2 0 2,4 0 4)

SELECT ST_AsText(ST_AddMeasure(
ST_GeomFromEWKT('LINESTRING(1 0 4, 2 0 4, 4 0 4)'),10,40)) As ewelev;
ewelev
----------------------------------------
LINESTRING(1 0 4 10,2 0 4 20,4 0 4 40)

SELECT ST_AsText(ST_AddMeasure(
ST_GeomFromEWKT('LINESTRINGM(1 0 4, 2 0 4, 4 0 4)'),10,40)) As ewelev;
ewelev
----------------------------------------
LINESTRINGM(1 0 10,2 0 20,4 0 40)

SELECT ST_AsText(ST_AddMeasure(
ST_GeomFromEWKT('MULTILINESTRINGM((1 0 4, 2 0 4, 4 0 4),(1 0 4, 2 0 4, 4 0 4))'),10,70)) As ←-
ewelev;
ewelev
-----------------------------------------------------------------
MULTILINESTRINGM((1 0 10,2 0 20,4 0 40),(1 0 40,2 0 50,4 0 70))
PostGIS 2.4.3 Manual 423 / 803

8.13 Temporal Support

8.13.1 ST_IsValidTrajectory

ST_IsValidTrajectory — Returns true if the geometry is a valid trajectory.

Synopsis

boolean ST_IsValidTrajectory(geometry line);

Description

Tell if a geometry encodes a valid trajectory. Valid trajectories are encoded as LINESTRING with M value growing from each
vertex to the next.
Valid trajectories are expected as input to some spatio-temporal queries like ST_ClosestPointOfApproach
Availability: 2.2.0

This function supports 3d and will not drop the z-index.

Examples

-- A valid trajectory
SELECT ST_IsValidTrajectory(ST_MakeLine(
ST_MakePointM(0,0,1),
ST_MakePointM(0,1,2))
);
t

-- An invalid trajectory
SELECT ST_IsValidTrajectory(ST_MakeLine(ST_MakePointM(0,0,1), ST_MakePointM(0,1,0)));
NOTICE: Measure of vertex 1 (0) not bigger than measure of vertex 0 (1)
st_isvalidtrajectory
----------------------
f

See Also

ST_ClosestPointOfApproach

8.13.2 ST_ClosestPointOfApproach

ST_ClosestPointOfApproach — Returns the measure at which points interpolated along two lines are closest.

Synopsis

float8 ST_ClosestPointOfApproach(geometry track1, geometry track2);

PostGIS 2.4.3 Manual 424 / 803

Description

Returns the smallest measure at which point interpolated along the given lines are at the smallest distance. Inputs must be valid
trajectories as checked by ST_IsValidTrajectory. Null is returned if the trajectories do not overlap on the M range.
See ST_LocateAlong for getting the actual points at the given measure.
Availability: 2.2.0

This function supports 3d and will not drop the z-index.

Examples

-- Return the time in which two objects moving between 10:00 and 11:00
-- are closest to each other and their distance at that point
WITH inp AS ( SELECT
ST_AddMeasure('LINESTRING Z (0 0 0, 10 0 5)'::geometry,
extract(epoch from '2015-05-26 10:00'::timestamptz),
extract(epoch from '2015-05-26 11:00'::timestamptz)
) a,
ST_AddMeasure('LINESTRING Z (0 2 10, 12 1 2)'::geometry,
extract(epoch from '2015-05-26 10:00'::timestamptz),
extract(epoch from '2015-05-26 11:00'::timestamptz)
) b
), cpa AS (
SELECT ST_ClosestPointOfApproach(a,b) m FROM inp
), points AS (
SELECT ST_Force3DZ(ST_GeometryN(ST_LocateAlong(a,m),1)) pa,
ST_Force3DZ(ST_GeometryN(ST_LocateAlong(b,m),1)) pb
FROM inp, cpa
)
SELECT to_timestamp(m) t,
ST_Distance(pa,pb) distance
FROM points, cpa;

t | distance
-------------------------------+------------------
2015-05-26 10:45:31.034483+02 | 1.96036833151395

See Also

ST_IsValidTrajectory, ST_DistanceCPA, ST_LocateAlong, ST_AddMeasure

8.13.3 ST_DistanceCPA

ST_DistanceCPA — Returns the distance between closest points of approach in two trajectories.

Synopsis

float8 ST_DistanceCPA(geometry track1, geometry track2);

Description

Returns the minimum distance two moving objects have ever been each-other. Inputs must be valid trajectories as checked by
ST_IsValidTrajectory. Null is returned if the trajectories do not overlap on the M range.
PostGIS 2.4.3 Manual 425 / 803

Availability: 2.2.0

This function supports 3d and will not drop the z-index.

Examples

-- Return the minimum distance of two objects moving between 10:00 and 11:00
WITH inp AS ( SELECT
ST_AddMeasure('LINESTRING Z (0 0 0, 10 0 5)'::geometry,
extract(epoch from '2015-05-26 10:00'::timestamptz),
extract(epoch from '2015-05-26 11:00'::timestamptz)
) a,
ST_AddMeasure('LINESTRING Z (0 2 10, 12 1 2)'::geometry,
extract(epoch from '2015-05-26 10:00'::timestamptz),
extract(epoch from '2015-05-26 11:00'::timestamptz)
) b
)
SELECT ST_DistanceCPA(a,b) distance FROM inp;

distance
------------------
1.96036833151395

See Also

ST_IsValidTrajectory, ST_ClosestPointOfApproach, ST_AddMeasure, |=|

8.13.4 ST_CPAWithin

ST_CPAWithin — Returns true if the trajectories’ closest points of approach are within the specified distance.

Synopsis

float8 ST_CPAWithin(geometry track1, geometry track2, float8 maxdist);

Description

Checks whether two moving objects have ever been within the specified max distance.
Inputs must be valid trajectories as checked by ST_IsValidTrajectory. False is returned if the trajectories do not overlap on the
M range.
Availability: 2.2.0

This function supports 3d and will not drop the z-index.

Examples

WITH inp AS ( SELECT

ST_AddMeasure('LINESTRING Z (0 0 0, 10 0 5)'::geometry,
extract(epoch from '2015-05-26 10:00'::timestamptz),
extract(epoch from '2015-05-26 11:00'::timestamptz)
) a,
ST_AddMeasure('LINESTRING Z (0 2 10, 12 1 2)'::geometry,
PostGIS 2.4.3 Manual 426 / 803

extract(epoch from '2015-05-26 10:00'::timestamptz),

extract(epoch from '2015-05-26 11:00'::timestamptz)
) b
)
SELECT ST_CPAWithin(a,b,2), ST_DistanceCPA(a,b) distance FROM inp;

st_cpawithin | distance
--------------+------------------
t | 1.96521473776207

See Also

ST_IsValidTrajectory, ST_ClosestPointOfApproach, ST_DistanceCPA, |=|

8.14 Long Transactions Support

This module and associated pl/pgsql functions have been implemented to provide long locking support required by Web Feature
Service specification.

Note
Users must use serializable transaction level otherwise locking mechanism would break.

8.14.1 AddAuth

AddAuth — Add an authorization token to be used in current transaction.

Synopsis

boolean AddAuth(text auth_token);

Description

Add an authorization token to be used in current transaction.

Creates/adds to a temp table called temp_lock_have_table the current transaction identifier and authorization token key.
Availability: 1.1.3

Examples

SELECT LockRow('towns', '353', 'priscilla');

BEGIN TRANSACTION;
SELECT AddAuth('joey');
UPDATE towns SET the_geom = ST_Translate(the_geom,2,2) WHERE gid = 353;
COMMIT;

---Error--
ERROR: UPDATE where "gid" = '353' requires authorization 'priscilla'
PostGIS 2.4.3 Manual 427 / 803

See Also

LockRow

8.14.2 CheckAuth

CheckAuth — Creates trigger on a table to prevent/allow updates and deletes of rows based on authorization token.

Synopsis

integer CheckAuth(text a_schema_name, text a_table_name, text a_key_column_name);

integer CheckAuth(text a_table_name, text a_key_column_name);

Description

Creates trigger on a table to prevent/allow updates and deletes of rows based on authorization token. Identify rows using
<rowid_col> column.
If a_schema_name is not passed in, then searches for table in current schema.

Note
If an authorization trigger already exists on this table function errors.
If Transaction support is not enabled, function throws an exception.

Availability: 1.1.3

Examples

SELECT CheckAuth('public', 'towns', 'gid');

result
------
0

See Also

EnableLongTransactions

8.14.3 DisableLongTransactions

DisableLongTransactions — Disable long transaction support. This function removes the long transaction support metadata
tables, and drops all triggers attached to lock-checked tables.

Synopsis

text DisableLongTransactions();
PostGIS 2.4.3 Manual 428 / 803

Description

Disable long transaction support. This function removes the long transaction support metadata tables, and drops all triggers
attached to lock-checked tables.
Drops meta table called authorization_table and a view called authorized_tables and all triggers called checkauthtri
Availability: 1.1.3

Examples

SELECT DisableLongTransactions();
--result--
Long transactions support disabled

See Also

EnableLongTransactions

8.14.4 EnableLongTransactions

EnableLongTransactions — Enable long transaction support. This function creates the required metadata tables, needs to be
called once before using the other functions in this section. Calling it twice is harmless.

Synopsis

text EnableLongTransactions();

Description

Enable long transaction support. This function creates the required metadata tables, needs to be called once before using the
other functions in this section. Calling it twice is harmless.
Creates a meta table called authorization_table and a view called authorized_tables
Availability: 1.1.3

Examples

SELECT EnableLongTransactions();
--result--
Long transactions support enabled

See Also

DisableLongTransactions

8.14.5 LockRow

LockRow — Set lock/authorization for specific row in table

PostGIS 2.4.3 Manual 429 / 803

Synopsis

integer LockRow(text a_schema_name, text a_table_name, text a_row_key, text an_auth_token, timestamp expire_dt);
integer LockRow(text a_table_name, text a_row_key, text an_auth_token, timestamp expire_dt);
integer LockRow(text a_table_name, text a_row_key, text an_auth_token);

Description

Set lock/authorization for specific row in table <authid> is a text value, <expires> is a timestamp defaulting to now()+1hour.
Returns 1 if lock has been assigned, 0 otherwise (already locked by other auth)
Availability: 1.1.3

Examples

SELECT LockRow('public', 'towns', '2', 'joey');

LockRow
-------
1

--Joey has already locked the record and Priscilla is out of luck
SELECT LockRow('public', 'towns', '2', 'priscilla');
LockRow
-------
0

See Also

UnlockRows

8.14.6 UnlockRows

UnlockRows — Remove all locks held by specified authorization id. Returns the number of locks released.

Synopsis

integer UnlockRows(text auth_token);

Description

Remove all locks held by specified authorization id. Returns the number of locks released.
Availability: 1.1.3

Examples

SELECT LockRow('towns', '353', 'priscilla');

SELECT LockRow('towns', '2', 'priscilla');
SELECT UnLockRows('priscilla');
UnLockRows
------------
2
PostGIS 2.4.3 Manual 430 / 803

See Also

LockRow

8.15 Miscellaneous Functions

8.15.1 ST_Accum

ST_Accum — Aggregate. Constructs an array of geometries.

Synopsis

geometry[] ST_Accum(geometry set geomfield);

Description

Aggregate. Constructs an array of geometries.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT (ST_Accum(the_geom)) As all_em, ST_AsText((ST_Accum(the_geom))[1]) As grabone,

(ST_Accum(the_geom))[2:4] as grab_rest
FROM (SELECT ST_MakePoint(a*CAST(random()*10 As integer), a*CAST(random()*10 As ←-
integer), a*CAST(random()*10 As integer)) As the_geom
FROM generate_series(1,4) a) As foo;

all_em|grabone | grab_rest

-------------------------------------------------------------------------------+

{0101000080000000000000144000000000000024400000000000001040:
0101000080000000000
00018400000000000002C400000000000003040:
0101000080000000000000354000000000000038400000000000001840:
010100008000000000000040400000000000003C400000000000003040} |
POINT(5 10) | {010100008000000000000018400000000000002C400000000000003040:
0101000080000000000000354000000000000038400000000000001840:
010100008000000000000040400000000000003C400000000000003040}
(1 row)

See Also

ST_Collect
PostGIS 2.4.3 Manual 431 / 803

8.15.2 Box2D

Box2D — Returns a BOX2D representing the maximum extents of the geometry.

Synopsis

box2d Box2D(geometry geomA);

Description

Returns a BOX2D representing the maximum extents of the geometry.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

SELECT Box2D(ST_GeomFromText('LINESTRING(1 2, 3 4, 5 6)'));

box2d
---------
BOX(1 2,5 6)

SELECT Box2D(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)') ←-

);
box2d
--------
BOX(220186.984375 150406,220288.25 150506.140625)

See Also

Box3D, ST_GeomFromText

8.15.3 Box3D

Box3D — Returns a BOX3D representing the maximum extents of the geometry.

Synopsis

box3d Box3D(geometry geomA);

PostGIS 2.4.3 Manual 432 / 803

Description

Returns a BOX3D representing the maximum extents of the geometry.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

This function supports 3d and will not drop the z-index.

Examples

SELECT Box3D(ST_GeomFromEWKT('LINESTRING(1 2 3, 3 4 5, 5 6 5)'));

Box3d
---------
BOX3D(1 2 3,5 6 5)

SELECT Box3D(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 1,220227 ←-

150406 1)'));
Box3d
--------
BOX3D(220227 150406 1,220268 150415 1)

See Also

Box2D, ST_GeomFromEWKT

8.15.4 ST_EstimatedExtent

ST_EstimatedExtent — Return the ’estimated’ extent of the given spatial table. The estimated is taken from the geometry
column’s statistics. The current schema will be used if not specified.

Synopsis

box2d ST_EstimatedExtent(text schema_name, text table_name, text geocolumn_name, boolean parent_ony);

box2d ST_EstimatedExtent(text schema_name, text table_name, text geocolumn_name);
box2d ST_EstimatedExtent(text table_name, text geocolumn_name);

Description

Return the ’estimated’ extent of the given spatial table. The estimated is taken from the geometry column’s statistics. The
current schema will be used if not specified. The default behavior is to also use statistics collected from children tables (tables
with INHERITS) if available. If ’parent_ony’ is set to TRUE, only statistics for the given table are used and children tables are
ignored.
For PostgreSQL>=8.0.0 statistics are gathered by VACUUM ANALYZE and resulting extent will be about 95% of the real one.
PostGIS 2.4.3 Manual 433 / 803

Note
In absence of statistics (empty table or no ANALYZE called) this function returns NULL. Prior to version 1.5.4 an
exception was thrown instead.

For PostgreSQL<8.0.0 statistics are gathered by update_geometry_stats() and resulting extent will be exact.
Availability: 1.0.0
Changed: 2.1.0. Up to 2.0.x this was called ST_Estimated_Extent.

This method supports Circular Strings and Curves

Examples

SELECT ST_EstimatedExtent('ny', 'edges', 'the_geom');

--result--
BOX(-8877653 4912316,-8010225.5 5589284)

SELECT ST_EstimatedExtent('feature_poly', 'the_geom');

--result--
BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332)

See Also

ST_Extent

8.15.5 ST_Expand

ST_Expand — Returns bounding box expanded in all directions from the bounding box of the input geometry. Uses double-
precision

Synopsis

geometry ST_Expand(geometry geom, float units_to_expand);

geometry ST_Expand(geometry geom, float dx, float dy, float dz=0, float dm=0);
box2d ST_Expand(box2d box, float units_to_expand);
box2d ST_Expand(box2d box, float dx, float dy);
box3d ST_Expand(box3d box, float units_to_expand);
box3d ST_Expand(box3d box, float dx, float dy, float dz=0);

Description

This function returns a bounding box expanded from the bounding box of the input, either by specifying a single distance with
which the box should be expanded in all directions, or by specifying an expansion distance for each direction. Uses double-
precision. Can be very useful for distance queries, or to add a bounding box filter to a query to take advantage of a spatial
index.
In addition to the geometry version of ST_Expand, which is the most commonly used, variants are provided that accept and
produce internal BOX2D and BOX3D data types.
ST_Expand is similar in concept to ST_Buffer, except while buffer expands the geometry in all directions, ST_Expand expands
the bounding box an x,y,z unit amount.
Units are in the units of the spatial reference system in use denoted by the SRID.
PostGIS 2.4.3 Manual 434 / 803

Note
Pre 1.3, ST_Expand was used in conjunction with distance to do indexable queries. Something of the form the_geom
&& ST_Expand(’POINT(10 20)’, 10) AND ST_Distance(the_geom, ’POINT(10 20)’) <
10 Post 1.2, this was replaced with the easier ST_DWithin construct.

Note
Availability: 1.5.0 behavior changed to output double precision instead of float4 coordinates.
Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Enhanced: 2.3.0 support was added to expand a box by different amounts in different dimensions.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

Note
Examples below use US National Atlas Equal Area (SRID=2163) which is a meter projection

--10 meter expanded box around bbox of a linestring

SELECT CAST(ST_Expand(ST_GeomFromText('LINESTRING(2312980 110676,2312923 110701,2312892 ←-
110714)', 2163),10) As box2d);
st_expand
------------------------------------
BOX(2312882 110666,2312990 110724)

--10 meter expanded 3d box of a 3d box

SELECT ST_Expand(CAST('BOX3D(778783 2951741 1,794875 2970042.61545891 10)' As box3d),10)
st_expand
-----------------------------------------------------
BOX3D(778773 2951731 -9,794885 2970052.61545891 20)

--10 meter geometry astext rep of a expand box around a point geometry
SELECT ST_AsEWKT(ST_Expand(ST_GeomFromEWKT('SRID=2163;POINT(2312980 110676)'),10));
st_asewkt
------------------------------------------------------------------------------------------------- ←-

SRID=2163;POLYGON((2312970 110666,2312970 110686,2312990 110686,2312990 110666,2312970 ←-

110666))

See Also

ST_AsEWKT, ST_Buffer, ST_DWithin, ST_GeomFromEWKT, ST_GeomFromText, ST_SRID

8.15.6 ST_Extent

ST_Extent — an aggregate function that returns the bounding box that bounds rows of geometries.
PostGIS 2.4.3 Manual 435 / 803

Synopsis

box2d ST_Extent(geometry set geomfield);

Description

ST_Extent returns a bounding box that encloses a set of geometries. The ST_Extent function is an "aggregate" function in the
terminology of SQL. That means that it operates on lists of data, in the same way the SUM() and AVG() functions do.
Since it returns a bounding box, the spatial Units are in the units of the spatial reference system in use denoted by the SRID
ST_Extent is similar in concept to Oracle Spatial/Locator’s SDO_AGGR_MBR

Note
Since ST_Extent returns a bounding box, the SRID meta-data is lost. Use ST_SetSRID to force it back into a geometry
with SRID meta data. The coordinates are in the units of the spatial ref of the orginal geometries.

Note
ST_Extent will return boxes with only an x and y component even with (x,y,z) coordinate geometries. To maintain x,y,z
use ST_3DExtent instead.

Note
Availability: 1.4.0

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

Examples

Note
Examples below use Massachusetts State Plane ft (SRID=2249)

SELECT ST_Extent(the_geom) as bextent FROM sometable;

st_bextent
------------------------------------
BOX(739651.875 2908247.25,794875.8125 2970042.75)

--Return extent of each category of geometries

SELECT ST_Extent(the_geom) as bextent
FROM sometable
GROUP BY category ORDER BY category;
PostGIS 2.4.3 Manual 436 / 803

bextent | name
----------------------------------------------------+----------------
BOX(778783.5625 2951741.25,794875.8125 2970042.75) | A
BOX(751315.8125 2919164.75,765202.6875 2935417.25) | B
BOX(739651.875 2917394.75,756688.375 2935866) | C

--Force back into a geometry

-- and render the extended text representation of that geometry
SELECT ST_SetSRID(ST_Extent(the_geom),2249) as bextent FROM sometable;

bextent
--------------------------------------------------------------------------------
SRID=2249;POLYGON((739651.875 2908247.25,739651.875 2970042.75,794875.8125 2970042.75,
794875.8125 2908247.25,739651.875 2908247.25))

See Also

ST_AsEWKT, ST_3DExtent, ST_SetSRID, ST_SRID

8.15.7 ST_3DExtent

ST_3DExtent — an aggregate function that returns the box3D bounding box that bounds rows of geometries.

Synopsis

box3d ST_3DExtent(geometry set geomfield);

Description

ST_3DExtent returns a box3d (includes Z coordinate) bounding box that encloses a set of geometries. The ST_3DExtent function
is an "aggregate" function in the terminology of SQL. That means that it operates on lists of data, in the same way the SUM()
and AVG() functions do.
Since it returns a bounding box, the spatial Units are in the units of the spatial reference system in use denoted by the SRID

Note
Since ST_3DExtent returns a bounding box, the SRID meta-data is lost. Use ST_SetSRID to force it back into a
geometry with SRID meta data. The coordinates are in the units of the spatial ref of the orginal geometries.

Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Changed: 2.0.0 In prior versions this used to be called ST_Extent3D

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
PostGIS 2.4.3 Manual 437 / 803

Examples

SELECT ST_3DExtent(foo.the_geom) As b3extent

FROM (SELECT ST_MakePoint(x,y,z) As the_geom
FROM generate_series(1,3) As x
CROSS JOIN generate_series(1,2) As y
CROSS JOIN generate_series(0,2) As Z) As foo;
b3extent
--------------------
BOX3D(1 1 0,3 2 2)

--Get the extent of various elevated circular strings

SELECT ST_3DExtent(foo.the_geom) As b3extent
FROM (SELECT ST_Translate(ST_Force_3DZ(ST_LineToCurve(ST_Buffer(ST_MakePoint(x,y),1))),0,0, ←-
z) As the_geom
FROM generate_series(1,3) As x
CROSS JOIN generate_series(1,2) As y
CROSS JOIN generate_series(0,2) As Z) As foo;

b3extent
--------------------
BOX3D(1 0 0,4 2 2)

See Also

ST_Extent, ST_Force3DZ

8.15.8 Find_SRID

Find_SRID — The syntax is find_srid(a_db_schema, a_table, a_column) and the function returns the integer SRID of the speci-
fied column by searching through the GEOMETRY_COLUMNS table.

Synopsis

integer Find_SRID(varchar a_schema_name, varchar a_table_name, varchar a_geomfield_name);

Description

The syntax is find_srid(<db/schema>, <table>, <column>) and the function returns the integer SRID of the specified column by
searching through the GEOMETRY_COLUMNS table. If the geometry column has not been properly added with the AddGe-
ometryColumns() function, this function will not work either.

Examples

SELECT Find_SRID('public', 'tiger_us_state_2007', 'the_geom_4269');

find_srid
----------
4269

See Also

ST_SRID
PostGIS 2.4.3 Manual 438 / 803

8.15.9 ST_MemSize

ST_MemSize — Returns the amount of space (in bytes) the geometry takes.

Synopsis

integer ST_MemSize(geometry geomA);

Description

Returns the amount of space (in bytes) the geometry takes.

This is a nice compliment to PostgreSQL built in functions pg_column_size, pg_size_pretty, pg_relation_size, pg_total_relation_size.

Note
pg_relation_size which gives the byte size of a table may return byte size lower than ST_MemSize. This is because
pg_relation_size does not add toasted table contribution and large geometries are stored in TOAST tables.
pg_total_relation_size - includes, the table, the toasted tables, and the indexes.
pg_column_size returns how much space a geometry would take in a column considering compression, so may be
lower than ST_MemSize

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
Changed: 2.2.0 name changed to ST_MemSize to follow naming convention. In prior versions this function was called ST_Mem_Size,
old name deprecated though still available.

Examples

--Return how much byte space Boston takes up in our Mass data set
SELECT pg_size_pretty(SUM(ST_MemSize(the_geom))) as totgeomsum,
pg_size_pretty(SUM(CASE WHEN town = 'BOSTON' THEN ST_MemSize(the_geom) ELSE 0 END)) As ←-
bossum,
CAST(SUM(CASE WHEN town = 'BOSTON' THEN ST_MemSize(the_geom) ELSE 0 END)*1.00 /
SUM(ST_MemSize(the_geom))*100 As numeric(10,2)) As perbos
FROM towns;

totgeomsum bossum perbos

---------- ------ ------
1522 kB 30 kB 1.99

SELECT ST_MemSize(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 ←-

150406)'));

---
73

--What percentage of our table is taken up by just the geometry

PostGIS 2.4.3 Manual 439 / 803

SELECT pg_total_relation_size('public.neighborhoods') As fulltable_size, sum(ST_MemSize( ←-

the_geom)) As geomsize,
sum(ST_MemSize(the_geom))*1.00/pg_total_relation_size('public.neighborhoods')*100 As ←-
pergeom
FROM neighborhoods;
fulltable_size geomsize pergeom
------------------------------------------------
262144 96238 36.71188354492187500000

See Also

8.15.10 ST_PointInsideCircle

ST_PointInsideCircle — Is the point geometry inside the circle defined by center_x, center_y, radius

Synopsis

boolean ST_PointInsideCircle(geometry a_point, float center_x, float center_y, float radius);

Description

The syntax for this functions is ST_PointInsideCircle(<geometry>,<circle_center_x>,<circle_center_y>,<radius>). Returns the

true if the geometry is a point and is inside the circle. Returns false otherwise.

Note
This only works for points as the name suggests

Availability: 1.2
Changed: 2.2.0 In prior versions this used to be called ST_Point_Inside_Circle

Examples

SELECT ST_PointInsideCircle(ST_Point(1,2), 0.5, 2, 3);

st_pointinsidecircle
------------------------
t

See Also

ST_DWithin

8.16 Exceptional Functions

These functions are rarely used functions that should only be used if your data is corrupted in someway. They are used for
troubleshooting corruption and also fixing things that should under normal circumstances, never happen.
PostGIS 2.4.3 Manual 440 / 803

8.16.1 PostGIS_AddBBox

PostGIS_AddBBox — Add bounding box to the geometry.

Synopsis

geometry PostGIS_AddBBox(geometry geomA);

Description

Add bounding box to the geometry. This would make bounding box based queries faster, but will increase the size of the
geometry.

Note
Bounding boxes are automatically added to geometries so in general this is not needed unless the generated bounding
box somehow becomes corrupted or you have an old install that is lacking bounding boxes. Then you need to drop the
old and readd.

This method supports Circular Strings and Curves

Examples

UPDATE sometable
SET the_geom = PostGIS_AddBBox(the_geom)
WHERE PostGIS_HasBBox(the_geom) = false;

See Also

PostGIS_DropBBox, PostGIS_HasBBox

8.16.2 PostGIS_DropBBox

PostGIS_DropBBox — Drop the bounding box cache from the geometry.

Synopsis

geometry PostGIS_DropBBox(geometry geomA);

Description

Drop the bounding box cache from the geometry. This reduces geometry size, but makes bounding-box based queries slower. It
is also used to drop a corrupt bounding box. A tale-tell sign of a corrupt cached bounding box is when your ST_Intersects and
other relation queries leave out geometries that rightfully should return true.

Note
Bounding boxes are automatically added to geometries and improve speed of queries so in general this is not needed
unless the generated bounding box somehow becomes corrupted or you have an old install that is lacking bounding
boxes. Then you need to drop the old and readd. This kind of corruption has been observed in 8.3-8.3.6 series whereby
cached bboxes were not always recalculated when a geometry changed and upgrading to a newer version without a
dump reload will not correct already corrupted boxes. So one can manually correct using below and readd the bbox or
do a dump reload.
PostGIS 2.4.3 Manual 441 / 803

This method supports Circular Strings and Curves

Examples

--This example drops bounding boxes where the cached box is not correct
--The force to ST_AsBinary before applying Box2D forces a recalculation of the box, ←-
and Box2D applied to the table geometry always
-- returns the cached bounding box.
UPDATE sometable
SET the_geom = PostGIS_DropBBox(the_geom)
WHERE Not (Box2D(ST_AsBinary(the_geom)) = Box2D(the_geom));

UPDATE sometable
SET the_geom = PostGIS_AddBBox(the_geom)
WHERE Not PostGIS_HasBBOX(the_geom);

See Also

PostGIS_AddBBox, PostGIS_HasBBox, Box2D

8.16.3 PostGIS_HasBBox

PostGIS_HasBBox — Returns TRUE if the bbox of this geometry is cached, FALSE otherwise.

Synopsis

boolean PostGIS_HasBBox(geometry geomA);

Description

Returns TRUE if the bbox of this geometry is cached, FALSE otherwise. Use PostGIS_AddBBox and PostGIS_DropBBox to
control caching.

This method supports Circular Strings and Curves

Examples

SELECT the_geom
FROM sometable WHERE PostGIS_HasBBox(the_geom) = false;

See Also

PostGIS_AddBBox, PostGIS_DropBBox
PostGIS 2.4.3 Manual 442 / 803

Chapter 9

Raster Reference

The functions given below are the ones which a user of PostGIS Raster is likely to need and which are currently available in
PostGIS Raster. There are other functions which are required support functions to the raster objects which are not of use to a
general user.
raster is a new PostGIS type for storing and analyzing raster data.
For loading rasters from raster files please refer to Section 5.1
For the examples in this reference we will be using a raster table of dummy rasters - Formed with the following code
CREATE TABLE dummy_rast(rid integer, rast raster);
INSERT INTO dummy_rast(rid, rast)
VALUES (1,
('01' -- little endian (uint8 ndr)
||
'0000' -- version (uint16 0)
||
'0000' -- nBands (uint16 0)
||
'0000000000000040' -- scaleX (float64 2)
||
'0000000000000840' -- scaleY (float64 3)
||
'000000000000E03F' -- ipX (float64 0.5)
||
'000000000000E03F' -- ipY (float64 0.5)
||
'0000000000000000' -- skewX (float64 0)
||
'0000000000000000' -- skewY (float64 0)
||
'00000000' -- SRID (int32 0)
||
'0A00' -- width (uint16 10)
||
'1400' -- height (uint16 20)
)::raster
),
-- Raster: 5 x 5 pixels, 3 bands, PT_8BUI pixel type, NODATA = 0
(2, ('01000003009A9999999999A93F9A9999999999A9BF000000E02B274A' ||
'41000000007719564100000000000000000000000000000000 ←-
FFFFFFFF050005000400FDFEFDFEFEFDFEFEFDF9FAFEF' ||
' ←-
EFCF9FBFDFEFEFDFCFAFEFEFE04004E627AADD16076B4F9FE6370A9F5FE59637AB0E54F58617087040046566487A1506C
')::raster);
PostGIS 2.4.3 Manual 443 / 803

9.1 Raster Support Data types

9.1.1 geomval

geomval — A spatial datatype with two fields - geom (holding a geometry object) and val (holding a double precision pixel value
from a raster band).

Description

geomval is a compound data type consisting of a geometry object referenced by the .geom field and val, a double precision value
that represents the pixel value at a particular geometric location in a raster band. It is used by the ST_DumpAsPolygon and
Raster intersection family of functions as an output type to explode a raster band into geometry polygons.

See Also

Section 14.6

9.1.2 addbandarg

addbandarg — A composite type used as input into the ST_AddBand function defining the attributes and initial value of the new
band.

Description

A composite type used as input into the ST_AddBand function defining the attributes and initial value of the new band.

index integer 1-based value indicating the position where the new band will be added amongst the raster’s bands. If NULL,
the new band will be added at the end of the raster’s bands.

pixeltype text Pixel type of the new band. One of defined pixel types as described in ST_BandPixelType.

initialvalue double precision Initial value that all pixels of new band will be set to.

nodataval double precision NODATA value of the new band. If NULL, the new band will not have a NODATA value
assigned.

See Also

ST_AddBand

9.1.3 rastbandarg

rastbandarg — A composite type for use when needing to express a raster and a band index of that raster.

Description

A composite type for use when needing to express a raster and a band index of that raster.

rast raster The raster in question/

nband integer 1-based value indicating the band of raster

PostGIS 2.4.3 Manual 444 / 803

See Also

ST_MapAlgebra

9.1.4 raster

raster — raster spatial data type.

Description

raster is a spatial data type used to represent raster data such as those imported from jpegs, tiffs, pngs, digital elevation models.
Each raster has 1 or more bands each having a set of pixel values. Rasters can be georeferenced.

Note
Requires PostGIS be compiled with GDAL support. Currently rasters can be implicitly converted to geometry type, but
the conversion returns the ST_ConvexHull of the raster. This auto casting may be removed in the near future so don’t
rely on it.

Casting Behavior

This section lists the automatic as well as explicit casts allowed for this data type

Cast To Behavior
geometry automatic

See Also

Chapter 9

9.1.5 reclassarg

reclassarg — A composite type used as input into the ST_Reclass function defining the behavior of reclassification.

Description

A composite type used as input into the ST_Reclass function defining the behavior of reclassification.

nband integer The band number of band to reclassify.

reclassexpr text range expression consisting of comma delimited range:map_range mappings. : to define mapping that
defines how to map old band values to new band values. ( means >, ) means less than, ] < or equal, [ means > or equal
1. [a-b] = a <= x <= b

2. (a-b] = a < x <= b

3. [a-b) = a <= x < b

4. (a-b) = a < x < b

( notation is optional so a-b means the same as (a-b)

pixeltype text One of defined pixel types as described in ST_BandPixelType

nodataval double precision Value to treat as no data. For image outputs that support transparency, these will be blank.
PostGIS 2.4.3 Manual 445 / 803

Example: Reclassify band 2 as an 8BUI where 255 is nodata value

SELECT ROW(2, '0-100:1-10, 101-500:11-150,501 - 10000: 151-254', '8BUI', 255)::reclassarg;

Example: Reclassify band 1 as an 1BB and no nodata value defined

SELECT ROW(1, '0-100]:0, (100-255:1', '1BB', NULL)::reclassarg;

See Also

ST_Reclass

9.1.6 summarystats

summarystats — A composite type returned by the ST_SummaryStats and ST_SummaryStatsAgg functions.

Description

A composite type returned by the ST_SummaryStats and ST_SummaryStatsAgg functions.

count integer Number of pixels counted for the summary statistics.

sum double precision Sum of all counted pixel values.

mean double precision Arithmetic mean of all counted pixel values.

stddev double precision Standard deviation of all counted pixel values.

min double precision Minimum value of counted pixel values.

max double precision Maximum value of counted pixel values.

See Also

ST_SummaryStats, ST_SummaryStatsAgg

9.1.7 unionarg

unionarg — A composite type used as input into the ST_Union function defining the bands to be processed and behavior of the
UNION operation.

Description

A composite type used as input into the ST_Union function defining the bands to be processed and behavior of the UNION
operation.

nband integer 1-based value indicating the band of each input raster to be processed.

uniontype text Type of UNION operation. One of defined types as described in ST_Union.

See Also

ST_Union
PostGIS 2.4.3 Manual 446 / 803

9.2 Raster Management

9.2.1 AddRasterConstraints

AddRasterConstraints — Adds raster constraints to a loaded raster table for a specific column that constrains spatial ref, scaling,
blocksize, alignment, bands, band type and a flag to denote if raster column is regularly blocked. The table must be loaded with
data for the constraints to be inferred. Returns true of the constraint setting was accomplished and if issues a notice.

Synopsis

boolean AddRasterConstraints(name rasttable, name rastcolumn, boolean srid, boolean scale_x, boolean scale_y, boolean
blocksize_x, boolean blocksize_y, boolean same_alignment, boolean regular_blocking, boolean num_bands=true , boolean
pixel_types=true , boolean nodata_values=true , boolean out_db=true , boolean extent=true );
boolean AddRasterConstraints(name rasttable, name rastcolumn, text[] VARIADIC constraints);
boolean AddRasterConstraints(name rastschema, name rasttable, name rastcolumn, text[] VARIADIC constraints);
boolean AddRasterConstraints(name rastschema, name rasttable, name rastcolumn, boolean srid=true, boolean scale_x=true,
boolean scale_y=true, boolean blocksize_x=true, boolean blocksize_y=true, boolean same_alignment=true, boolean regular_blocking=fa
boolean num_bands=true, boolean pixel_types=true, boolean nodata_values=true , boolean out_db=true , boolean extent=true );

Description

Generates constraints on a raster column that are used to display information in the raster_columns raster catalog. The
rastschema is the name of the table schema the table resides in. The srid must be an integer value reference to an entry in
the SPATIAL_REF_SYS table.
raster2pgsql loader uses this function to register raster tables
Valid constraint names to pass in: refer to Section 5.2.1 for more details.

• blocksize sets both X and Y blocksize

• blocksize_x sets X tile (width in pixels of each tile)

• blocksize_y sets Y tile (height in pixels of each tile)
• extent computes extent of whole table and applys constraint all rasters must be within that extent
• num_bands number of bands

• pixel_types reads array of pixel types for each band ensure all band n have same pixel type
• regular_blocking sets spatially unique (no two rasters can be spatially the same) and coverage tile (raster is aligned to a
coverage) constraints
• same_alignment ensures they all have same alignment meaning any two tiles you compare will return true for. Refer to
ST_SameAlignment.
• srid ensures all have same srid
• More -- any listed as inputs into the above functions

Note
This function infers the constraints from the data already present in the table. As such for it to work, you must create
the raster column first and then load it with data.
PostGIS 2.4.3 Manual 447 / 803

Note
If you need to load more data in your tables after you have already applied constraints, you may want to run the
DropRasterConstraints if the extent of your data has changed.

Availability: 2.0.0

Examples: Apply all possible constraints on column based on data

CREATE TABLE myrasters(rid SERIAL primary key, rast raster);

INSERT INTO myrasters(rast)
SELECT ST_AddBand(ST_MakeEmptyRaster(1000, 1000, 0.3, -0.3, 2, 2, 0, 0,4326), 1, '8BSI':: ←-
text, -129, NULL);

SELECT AddRasterConstraints('myrasters'::name, 'rast'::name);

-- verify if registered correctly in the raster_columns view --

SELECT srid, scale_x, scale_y, blocksize_x, blocksize_y, num_bands, pixel_types, ←-
nodata_values
FROM raster_columns
WHERE r_table_name = 'myrasters';

srid | scale_x | scale_y | blocksize_x | blocksize_y | num_bands | pixel_types| ←-

nodata_values
------+---------+---------+-------------+-------------+-----------+-------------+--------------- ←-

4326 | 2 | 2 | 1000 | 1000 | 1 | {8BSI} | {0}

Examples: Apply single constraint

CREATE TABLE public.myrasters2(rid SERIAL primary key, rast raster);

INSERT INTO myrasters2(rast)
SELECT ST_AddBand(ST_MakeEmptyRaster(1000, 1000, 0.3, -0.3, 2, 2, 0, 0,4326), 1, '8BSI':: ←-
text, -129, NULL);

SELECT AddRasterConstraints('public'::name, 'myrasters2'::name, 'rast'::name,' ←-

regular_blocking', 'blocksize');
-- get notice--
NOTICE: Adding regular blocking constraint
NOTICE: Adding blocksize-X constraint
NOTICE: Adding blocksize-Y constraint

See Also

Section 5.2.1, ST_AddBand, ST_MakeEmptyRaster, DropRasterConstraints, ST_BandPixelType, ST_SRID

9.2.2 DropRasterConstraints

DropRasterConstraints — Drops PostGIS raster constraints that refer to a raster table column. Useful if you need to reload data
or update your raster column data.
PostGIS 2.4.3 Manual 448 / 803

Synopsis

boolean DropRasterConstraints(name rasttable, name rastcolumn, boolean srid, boolean scale_x, boolean scale_y, boolean
blocksize_x, boolean blocksize_y, boolean same_alignment, boolean regular_blocking, boolean num_bands=true, boolean pixel_types=t
boolean nodata_values=true, boolean out_db=true , boolean extent=true);
boolean DropRasterConstraints(name rastschema, name rasttable, name rastcolumn, boolean srid=true, boolean scale_x=true,
boolean scale_y=true, boolean blocksize_x=true, boolean blocksize_y=true, boolean same_alignment=true, boolean regular_blocking=fa
boolean num_bands=true, boolean pixel_types=true, boolean nodata_values=true, boolean out_db=true , boolean extent=true);
boolean DropRasterConstraints(name rastschema, name rasttable, name rastcolumn, text[] constraints);

Description

Drops PostGIS raster constraints that refer to a raster table column that were added by AddRasterConstraints. Useful if you need
to load more data or update your raster column data. You do not need to do this if you want to get rid of a raster table or a raster
column.
To drop a raster table use the standard
DROP TABLE mytable

To drop just a raster column and leave the rest of the table, use standard SQL
ALTER TABLE mytable DROP COLUMN rast

the table will disappear from the raster_columns catalog if the column or table is dropped. However if only the constraints
are dropped, the raster column will still be listed in the raster_columns catalog, but there will be no other information about
it aside from the column name and table.
Availability: 2.0.0

Examples

SELECT DropRasterConstraints ('myrasters','rast');

----RESULT output ---
t

-- verify change in raster_columns --

SELECT srid, scale_x, scale_y, blocksize_x, blocksize_y, num_bands, pixel_types, ←-
nodata_values
FROM raster_columns
WHERE r_table_name = 'myrasters';

srid | scale_x | scale_y | blocksize_x | blocksize_y | num_bands | pixel_types| ←-

nodata_values
------+---------+---------+-------------+-------------+-----------+-------------+--------------- ←-

0 | | | | | | |

See Also

AddRasterConstraints

9.2.3 AddOverviewConstraints

AddOverviewConstraints — Tag a raster column as being an overview of another.

PostGIS 2.4.3 Manual 449 / 803

Synopsis

boolean AddOverviewConstraints(name ovschema, name ovtable, name ovcolumn, name refschema, name reftable, name
refcolumn, int ovfactor);
boolean AddOverviewConstraints(name ovtable, name ovcolumn, name reftable, name refcolumn, int ovfactor);

Description

Adds constraints on a raster column that are used to display information in the raster_overviews raster catalog.
The ovfactor parameter represents the scale multiplier in the overview column: higher overview factors have lower resolution.
When the ovschema and refschema parameters are omitted, the first table found scanning the search_path will be used.
Availability: 2.0.0

Examples

CREATE TABLE res1 AS SELECT

ST_AddBand(
ST_MakeEmptyRaster(1000, 1000, 0, 0, 2),
1, '8BSI'::text, -129, NULL
) r1;

CREATE TABLE res2 AS SELECT

ST_AddBand(
ST_MakeEmptyRaster(500, 500, 0, 0, 4),
1, '8BSI'::text, -129, NULL
) r2;

SELECT AddOverviewConstraints('res2', 'r2', 'res1', 'r1', 2);

-- verify if registered correctly in the raster_overviews view --

SELECT o_table_name ot, o_raster_column oc,
r_table_name rt, r_raster_column rc,
overview_factor f
FROM raster_overviews WHERE o_table_name = 'res2';
ot | oc | rt | rc | f
------+----+------+----+---
res2 | r2 | res1 | r1 | 2
(1 row)

See Also

Section 5.2.2, DropOverviewConstraints, ST_CreateOverview, AddRasterConstraints

9.2.4 DropOverviewConstraints

DropOverviewConstraints — Untag a raster column from being an overview of another.

Synopsis

boolean DropOverviewConstraints(name ovschema, name ovtable, name ovcolumn);

boolean DropOverviewConstraints(name ovtable, name ovcolumn);
PostGIS 2.4.3 Manual 450 / 803

Description

Remove from a raster column the constraints used to show it as being an overview of another in the raster_overviews
raster catalog.
When the ovschema parameter is omitted, the first table found scanning the search_path will be used.
Availability: 2.0.0

See Also

Section 5.2.2, AddOverviewConstraints, DropRasterConstraints

9.2.5 PostGIS_GDAL_Version

PostGIS_GDAL_Version — Reports the version of the GDAL library in use by PostGIS.

Synopsis

text PostGIS_GDAL_Version();

Description

Reports the version of the GDAL library in use by PostGIS. Will also check and report if GDAL can find its data files.

Examples

SELECT PostGIS_GDAL_Version();
postgis_gdal_version
-----------------------------------
GDAL 1.11dev, released 2013/04/13

See Also

postgis.gdal_datapath

9.2.6 PostGIS_Raster_Lib_Build_Date

PostGIS_Raster_Lib_Build_Date — Reports full raster library build date.

Synopsis

text PostGIS_Raster_Lib_Build_Date();

Description

Reports raster build date

PostGIS 2.4.3 Manual 451 / 803

Examples

SELECT PostGIS_Raster_Lib_Build_Date();
postgis_raster_lib_build_date
-----------------------------
2010-04-28 21:15:10

See Also

PostGIS_Raster_Lib_Version

9.2.7 PostGIS_Raster_Lib_Version

PostGIS_Raster_Lib_Version — Reports full raster version and build configuration infos.

Synopsis

text PostGIS_Raster_Lib_Version();

Description

Reports full raster version and build configuration infos.

Examples

SELECT PostGIS_Raster_Lib_Version();
postgis_raster_lib_version
-----------------------------
2.0.0

See Also

PostGIS_Lib_Version

9.2.8 ST_GDALDrivers

ST_GDALDrivers — Returns a list of raster formats supported by your lib gdal. These are the formats you can output your raster
using ST_AsGDALRaster.

Synopsis

setof record ST_GDALDrivers(integer OUT idx, text OUT short_name, text OUT long_name, text OUT create_options);

Description

Returns a list of raster formats short_name,long_name and creator options of each format supported by your lib gdal. Use the
short_name as input in the format parameter of ST_AsGDALRaster. Options vary depending on what drivers your libgdal was
compiled with. create_options returns an xml formatted set of CreationOptionList/Option consisting of name and optional
type, description and set of VALUE for each creator option for the specific driver.
Changed: 2.0.6, 2.1.3 - by default no drivers are enabled, unless GUC or Environment variable gdal_enabled_drivers is set.
Availability: 2.0.0 - requires GDAL >= 1.6.0.
PostGIS 2.4.3 Manual 452 / 803

Examples: List of Drivers

SET postgis.gdal_enabled_drivers = 'ENABLE_ALL';

SELECT short_name, long_name
FROM st_gdaldrivers()
ORDER BY short_name;
short_name | long_name
-----------------+--------------------------------------
AAIGrid | Arc/Info ASCII Grid
ARG | Azavea Raster Grid format
DTED | DTED Elevation Raster
EHdr | ESRI .hdr Labelled
FIT | FIT Image
GIF | Graphics Interchange Format (.gif)
GPKG | GeoPackage
GS7BG | Golden Software 7 Binary Grid (.grd)
GSAG | Golden Software ASCII Grid (.grd)
GSBG | Golden Software Binary Grid (.grd)
GTiff | GeoTIFF
HF2 | HF2/HFZ heightfield raster
HFA | Erdas Imagine Images (.img)
ILWIS | ILWIS Raster Map
INGR | Intergraph Raster
JPEG | JPEG JFIF
KMLSUPEROVERLAY | Kml Super Overlay
LCP | FARSITE v.4 Landscape File (.lcp)
MFF | Vexcel MFF Raster
NITF | National Imagery Transmission Format
PNG | Portable Network Graphics
R | R Object Data Store
RST | Idrisi Raster A.1
SAGA | SAGA GIS Binary Grid (.sdat)
SRTMHGT | SRTMHGT File Format
USGSDEM | USGS Optional ASCII DEM (and CDED)
VRT | Virtual Raster
WMS | OGC Web Map Service
XPM | X11 PixMap Format
XYZ | ASCII Gridded XYZ
ZMap | ZMap Plus Grid
(31 rows)

Example: List of options for each driver

-- Output the create options XML column of JPEG as a table --

-- Note you can use these creator options in ST_AsGDALRaster options argument
SELECT (xpath('@name', g.opt))[1]::text As oname,
(xpath('@type', g.opt))[1]::text As otype,
(xpath('@description', g.opt))[1]::text As descrip
FROM (SELECT unnest(xpath('/CreationOptionList/Option', create_options::xml)) As opt
FROM st_gdaldrivers()
WHERE short_name = 'JPEG') As g;

oname | otype | descrip

--------------------+---------+-------------------------------------------------
PROGRESSIVE | boolean | whether to generate a progressive JPEG
QUALITY | int | good=100, bad=0, default=75
WORLDFILE | boolean | whether to geneate a worldfile
INTERNAL_MASK | boolean | whether to generate a validity mask
COMMENT | string | Comment
SOURCE_ICC_PROFILE | string | ICC profile encoded in Base64
PostGIS 2.4.3 Manual 453 / 803

EXIF_THUMBNAIL | boolean | whether to generate an EXIF thumbnail(overview).

By default its max dimension will be 128
THUMBNAIL_WIDTH | int | Forced thumbnail width
THUMBNAIL_HEIGHT | int | Forced thumbnail height
(9 rows)

-- raw xml output for creator options for GeoTiff --

SELECT create_options
FROM st_gdaldrivers()
WHERE short_name = 'GTiff';

<CreationOptionList>
<Option name="COMPRESS" type="string-select">
<Value>NONE</Value>
<Value>LZW</Value>
<Value>PACKBITS</Value>
<Value>JPEG</Value>
<Value>CCITTRLE</Value>
<Value>CCITTFAX3</Value>
<Value>CCITTFAX4</Value>
<Value>DEFLATE</Value>
</Option>
<Option name="PREDICTOR" type="int" description="Predictor Type"/>
<Option name="JPEG_QUALITY" type="int" description="JPEG quality 1-100" default="75"/>
<Option name="ZLEVEL" type="int" description="DEFLATE compression level 1-9" default ←-
="6"/>
<Option name="NBITS" type="int" description="BITS for sub-byte files (1-7), sub-uint16 ←-
(9-15), sub-uint32 (17-31)"/>
<Option name="INTERLEAVE" type="string-select" default="PIXEL">
<Value>BAND</Value>
<Value>PIXEL</Value>
</Option>
<Option name="TILED" type="boolean" description="Switch to tiled format"/>
<Option name="TFW" type="boolean" description="Write out world file"/>
<Option name="RPB" type="boolean" description="Write out .RPB (RPC) file"/>
<Option name="BLOCKXSIZE" type="int" description="Tile Width"/>
<Option name="BLOCKYSIZE" type="int" description="Tile/Strip Height"/>
<Option name="PHOTOMETRIC" type="string-select">
<Value>MINISBLACK</Value>
<Value>MINISWHITE</Value>
<Value>PALETTE</Value>
<Value>RGB</Value>
<Value>CMYK</Value>
<Value>YCBCR</Value>
<Value>CIELAB</Value>
<Value>ICCLAB</Value>
<Value>ITULAB</Value>
</Option>
<Option name="SPARSE_OK" type="boolean" description="Can newly created files have ←-
missing blocks?" default="FALSE"/>
<Option name="ALPHA" type="boolean" description="Mark first extrasample as being alpha ←-
"/>
<Option name="PROFILE" type="string-select" default="GDALGeoTIFF">
<Value>GDALGeoTIFF</Value>
<Value>GeoTIFF</Value>
<Value>BASELINE</Value>
</Option>
<Option name="PIXELTYPE" type="string-select">
<Value>DEFAULT</Value>
<Value>SIGNEDBYTE</Value>
</Option>
<Option name="BIGTIFF" type="string-select" description="Force creation of BigTIFF file ←-
PostGIS 2.4.3 Manual 454 / 803

">
<Value>YES</Value>
<Value>NO</Value>
<Value>IF_NEEDED</Value>
<Value>IF_SAFER</Value>
</Option>
<Option name="ENDIANNESS" type="string-select" default="NATIVE" description="Force ←-
endianness of created file. For DEBUG purpose mostly">
<Value>NATIVE</Value>
<Value>INVERTED</Value>
<Value>LITTLE</Value>
<Value>BIG</Value>
</Option>
<Option name="COPY_SRC_OVERVIEWS" type="boolean" default="NO" description="Force copy ←-
of overviews of source dataset (CreateCopy())"/>
</CreationOptionList>

-- Output the create options XML column for GTiff as a table --

SELECT (xpath('@name', g.opt))[1]::text As oname,
(xpath('@type', g.opt))[1]::text As otype,
(xpath('@description', g.opt))[1]::text As descrip,
array_to_string(xpath('Value/text()', g.opt),', ') As vals
FROM (SELECT unnest(xpath('/CreationOptionList/Option', create_options::xml)) As opt
FROM st_gdaldrivers()
WHERE short_name = 'GTiff') As g;

oname | otype | descrip ←-

| vals
--------------------+---------------+----------------------------------------------------------------

COMPRESS | string-select | ←-
| NONE, LZW, ←-
PACKBITS, JPEG, CCITTRLE, CCITTFAX3, CCITTFAX4, DEFLATE
PREDICTOR | int | Predictor Type ←-
|
JPEG_QUALITY | int | JPEG quality 1-100 ←-
|
ZLEVEL | int | DEFLATE compression level 1-9 ←-
|
NBITS | int | BITS for sub-byte files (1-7), sub-uint16 (9-15), sub ←-
-uint32 (17-31) |
INTERLEAVE | string-select | ←-
| BAND, PIXEL
TILED | boolean | Switch to tiled format ←-
|
TFW | boolean | Write out world file ←-
|
RPB | boolean | Write out .RPB (RPC) file ←-
|
BLOCKXSIZE | int | Tile Width ←-
|
BLOCKYSIZE | int | Tile/Strip Height ←-
|
PHOTOMETRIC | string-select | ←-
| MINISBLACK, ←-
MINISWHITE, PALETTE, RGB, CMYK, YCBCR, CIELAB, ICCLAB, ITULAB
SPARSE_OK | boolean | Can newly created files have missing blocks? ←-
|
ALPHA | boolean | Mark first extrasample as being alpha ←-
|
PROFILE | string-select | ←-
| GDALGeoTIFF, ←-
PostGIS 2.4.3 Manual 455 / 803

GeoTIFF, BASELINE
PIXELTYPE | string-select | ←-
| DEFAULT, ←-
SIGNEDBYTE
BIGTIFF | string-select | Force creation of BigTIFF file ←-
| YES, NO, IF_NEEDED, IF_SAFER
ENDIANNESS | string-select | Force endianness of created file. For DEBUG purpose ←-
mostly | NATIVE, INVERTED, LITTLE, BIG
COPY_SRC_OVERVIEWS | boolean | Force copy of overviews of source dataset (CreateCopy ←-
()) |
(19 rows)

See Also

ST_AsGDALRaster, ST_SRID, postgis.gdal_enabled_drivers

9.2.9 UpdateRasterSRID

UpdateRasterSRID — Change the SRID of all rasters in the user-specified column and table.

Synopsis

raster UpdateRasterSRID(name schema_name, name table_name, name column_name, integer new_srid);

raster UpdateRasterSRID(name table_name, name column_name, integer new_srid);

Description

Change the SRID of all rasters in the user-specified column and table. The function will drop all appropriate column constraints
(extent, alignment and SRID) before changing the SRID of the specified column’s rasters.

Note
The data (band pixel values) of the rasters are not touched by this function. Only the raster’s metadata is changed.

Availability: 2.1.0

See Also

UpdateGeometrySRID

9.2.10 ST_CreateOverview

ST_CreateOverview — Create an reduced resolution version of a given raster coverage.

Synopsis

regclass ST_CreateOverview(regclass tab, name col, int factor, text algo=’NearestNeighbor’);

PostGIS 2.4.3 Manual 456 / 803

Description

Create an overview table with resampled tiles from the source table. Output tiles will have the same size of input tiles and cover
the same spatial extent with a lower resolution (pixel size will be 1/factor of the original in both directions).
The overview table will be made available in the raster_overviews catalog and will have raster constraints enforced.
Algorithm options are: ’NearestNeighbor’, ’Bilinear’, ’Cubic’, ’CubicSpline’, and ’Lanczos’. Refer to: GDAL Warp resampling
methods for more details.
Availability: 2.2.0

Example

Output to generally better quality but slower to product format

SELECT ST_CreateOverview('mydata.mytable'::regclass, 'rast', 2, 'Lanczos');

Output to faster to process default nearest neighbor

SELECT ST_CreateOverview('mydata.mytable'::regclass, 'rast', 2);

See Also

ST_Retile, AddOverviewConstraints, AddRasterConstraints, Section 5.2.2

9.3 Raster Constructors

9.3.1 ST_AddBand

ST_AddBand — Returns a raster with the new band(s) of given type added with given initial value in the given index location.
If no index is specified, the band is added to the end.

Synopsis

(1) raster ST_AddBand(raster rast, addbandarg[] addbandargset);

(2) raster ST_AddBand(raster rast, integer index, text pixeltype, double precision initialvalue=0, double precision nodataval=NULL);
(3) raster ST_AddBand(raster rast, text pixeltype, double precision initialvalue=0, double precision nodataval=NULL);
(4) raster ST_AddBand(raster torast, raster fromrast, integer fromband=1, integer torastindex=at_end);
(5) raster ST_AddBand(raster torast, raster[] fromrasts, integer fromband=1, integer torastindex=at_end);
(6) raster ST_AddBand(raster rast, integer index, text outdbfile, integer[] outdbindex, double precision nodataval=NULL);
(7) raster ST_AddBand(raster rast, text outdbfile, integer[] outdbindex, integer index=at_end, double precision nodataval=NULL);

Description

Returns a raster with a new band added in given position (index), of given type, of given initial value, and of given nodata value.
If no index is specified, the band is added to the end. If no fromband is specified, band 1 is assumed. Pixel type is a string
representation of one of the pixel types specified in ST_BandPixelType. If an existing index is specified all subsequent bands >=
that index are incremented by 1. If an initial value greater than the max of the pixel type is specified, then the initial value is set
to the highest value allowed by the pixel type.
For the variant that takes an array of addbandarg (Variant 1), a specific addbandarg’s index value is relative to the raster at the
time when the band described by that addbandarg is being added to the raster. See the Multiple New Bands example below.
PostGIS 2.4.3 Manual 457 / 803

For the variant that takes an array of rasters (Variant 5), if torast is NULL then the fromband band of each raster in the array
is accumulated into a new raster.
For the variants that take outdbfile (Variants 6 and 7), the value must include the full path to the raster file. The file must also
be accessible to the postgres server process.
Enhanced: 2.1.0 support for addbandarg added.
Enhanced: 2.1.0 support for new out-db bands added.

Examples: Single New Band

-- Add another band of type 8 bit unsigned integer with pixels initialized to 200
UPDATE dummy_rast
SET rast = ST_AddBand(rast,'8BUI'::text,200)
WHERE rid = 1;

-- Create an empty raster 100x100 units, with upper left right at 0, add 2 bands (band 1 ←-
is 0/1 boolean bit switch, band2 allows values 0-15)
-- uses addbandargs
INSERT INTO dummy_rast(rid,rast)
VALUES(10, ST_AddBand(ST_MakeEmptyRaster(100, 100, 0, 0, 1, -1, 0, 0, 0),
ARRAY[
ROW(1, '1BB'::text, 0, NULL),
ROW(2, '4BUI'::text, 0, NULL)
]::addbandarg[]
)
);

-- output meta data of raster bands to verify all is right --

SELECT (bmd).*
FROM (SELECT ST_BandMetaData(rast,generate_series(1,2)) As bmd
FROM dummy_rast WHERE rid = 10) AS foo;
--result --
pixeltype | nodatavalue | isoutdb | path
-----------+----------------+-------------+---------+------
1BB | | f |
4BUI | | f |

-- output meta data of raster -

SELECT (rmd).width, (rmd).height, (rmd).numbands
FROM (SELECT ST_MetaData(rast) As rmd
FROM dummy_rast WHERE rid = 10) AS foo;
-- result --
upperleftx | upperlefty | width | height | scalex | scaley | skewx | skewy | srid | ←-
numbands
------------+------------+-------+--------+------------+------------+-------+-------+------+---------

0 | 0 | 100 | 100 | 1 | -1 | 0 | 0 | 0 | ←-
2

Examples: Multiple New Bands

SELECT
*
FROM ST_BandMetadata(
ST_AddBand(
ST_MakeEmptyRaster(10, 10, 0, 0, 1, -1, 0, 0, 0),
ARRAY[
PostGIS 2.4.3 Manual 458 / 803

ROW(NULL, '8BUI', 255, 0),

ROW(NULL, '16BUI', 1, 2),
ROW(2, '32BUI', 100, 12),
ROW(2, '32BF', 3.14, -1)
]::addbandarg[]
),
ARRAY[]::integer[]
);

bandnum | pixeltype | nodatavalue | isoutdb | path

---------+-----------+-------------+---------+------
1 | 8BUI | 0 | f |
2 | 32BF | -1 | f |
3 | 32BUI | 12 | f |
4 | 16BUI | 2 | f |

-- Aggregate the 1st band of a table of like rasters into a single raster
-- with as many bands as there are test_types and as many rows (new rasters) as there are ←-
mice
-- NOTE: The ORDER BY test_type is only supported in PostgreSQL 9.0+
-- for 8.4 and below it usually works to order your data in a subselect (but not guaranteed ←-
)
-- The resulting raster will have a band for each test_type alphabetical by test_type
-- For mouse lovers: No mice were harmed in this exercise
SELECT
mouse,
ST_AddBand(NULL, array_agg(rast ORDER BY test_type), 1) As rast
FROM mice_studies
GROUP BY mouse;

Examples: New Out-db band

SELECT
*
FROM ST_BandMetadata(
ST_AddBand(
ST_MakeEmptyRaster(10, 10, 0, 0, 1, -1, 0, 0, 0),
'/home/raster/mytestraster.tif'::text, NULL::int[]
),
ARRAY[]::integer[]
);

bandnum | pixeltype | nodatavalue | isoutdb | path

---------+-----------+-------------+---------+------
1 | 8BUI | | t | /home/raster/mytestraster.tif
2 | 8BUI | | t | /home/raster/mytestraster.tif
3 | 8BUI | | t | /home/raster/mytestraster.tif

See Also

ST_BandMetaData, ST_BandPixelType, ST_MakeEmptyRaster, ST_MetaData, ST_NumBands, ST_Reclass

9.3.2 ST_AsRaster

ST_AsRaster — Converts a PostGIS geometry to a PostGIS raster.

PostGIS 2.4.3 Manual 459 / 803

Synopsis

raster ST_AsRaster(geometry geom, raster ref, text pixeltype, double precision value=1, double precision nodataval=0, boolean
touched=false);
raster ST_AsRaster(geometry geom, raster ref, text[] pixeltype=ARRAY[’8BUI’], double precision[] value=ARRAY[1], double
precision[] nodataval=ARRAY[0], boolean touched=false);
raster ST_AsRaster(geometry geom, double precision scalex, double precision scaley, double precision gridx, double preci-
sion gridy, text pixeltype, double precision value=1, double precision nodataval=0, double precision skewx=0, double precision
skewy=0, boolean touched=false);
raster ST_AsRaster(geometry geom, double precision scalex, double precision scaley, double precision gridx=NULL, dou-
ble precision gridy=NULL, text[] pixeltype=ARRAY[’8BUI’], double precision[] value=ARRAY[1], double precision[] no-
dataval=ARRAY[0], double precision skewx=0, double precision skewy=0, boolean touched=false);
raster ST_AsRaster(geometry geom, double precision scalex, double precision scaley, text pixeltype, double precision value=1,
double precision nodataval=0, double precision upperleftx=NULL, double precision upperlefty=NULL, double precision skewx=0,
double precision skewy=0, boolean touched=false);
raster ST_AsRaster(geometry geom, double precision scalex, double precision scaley, text[] pixeltype, double precision[]
value=ARRAY[1], double precision[] nodataval=ARRAY[0], double precision upperleftx=NULL, double precision upperlefty=NULL,
double precision skewx=0, double precision skewy=0, boolean touched=false);
raster ST_AsRaster(geometry geom, integer width, integer height, double precision gridx, double precision gridy, text pixel-
type, double precision value=1, double precision nodataval=0, double precision skewx=0, double precision skewy=0, boolean
touched=false);
raster ST_AsRaster(geometry geom, integer width, integer height, double precision gridx=NULL, double precision gridy=NULL,
text[] pixeltype=ARRAY[’8BUI’], double precision[] value=ARRAY[1], double precision[] nodataval=ARRAY[0], double pre-
cision skewx=0, double precision skewy=0, boolean touched=false);
raster ST_AsRaster(geometry geom, integer width, integer height, text pixeltype, double precision value=1, double precision
nodataval=0, double precision upperleftx=NULL, double precision upperlefty=NULL, double precision skewx=0, double preci-
sion skewy=0, boolean touched=false);
raster ST_AsRaster(geometry geom, integer width, integer height, text[] pixeltype, double precision[] value=ARRAY[1], dou-
ble precision[] nodataval=ARRAY[0], double precision upperleftx=NULL, double precision upperlefty=NULL, double precision
skewx=0, double precision skewy=0, boolean touched=false);

Description

Converts a PostGIS geometry to a PostGIS raster. The many variants offers three groups of possibilities for setting the alignment
and pixelsize of the resulting raster.
The first group, composed of the two first variants, produce a raster having the same alignment (scalex, scaley, gridx and
gridy), pixel type and nodata value as the provided reference raster. You generally pass this reference raster by joining the table
containing the geometry with the table containing the reference raster.
The second group, composed of four variants, let you set the dimensions of the raster by providing the parameters of a pixel size
(scalex & scaley and skewx & skewy). The width & height of the resulting raster will be adjusted to fit the extent
of the geometry. In most cases, you must cast integer scalex & scaley arguments to double precision so that PostgreSQL
choose the right variant.
The third group, composed of four variants, let you fix the dimensions of the raster by providing the dimensions of the raster
(width & height). The parameters of the pixel size (scalex & scaley and skewx & skewy) of the resulting raster will
be adjusted to fit the extent of the geometry.
The two first variants of each of those two last groups let you specify the alignment with an arbitrary corner of the alignment grid
(gridx & gridy) and the two last variants takes the upper left corner (upperleftx & upperlefty).
Each group of variant allows producing a one band raster or a multiple bands raster. To produce a multiple bands raster,
you must provide an array of pixel types (pixeltype[]), an array of initial values (value) and an array of nodata values
(nodataval). If not provided pixeltyped defaults to 8BUI, values to 1 and nodataval to 0.
The output raster will be in the same spatial reference as the source geometry. The only exception is for variants with a reference
raster. In this case the resulting raster will get the same SRID as the reference raster.
PostGIS 2.4.3 Manual 460 / 803

The optional touched parameter defaults to false and maps to the GDAL ALL_TOUCHED rasterization option, which deter-
mines if pixels touched by lines or polygons will be burned. Not just those on the line render path, or whose center point is within
the polygon.
This is particularly useful for rendering jpegs and pngs of geometries directly from the database when using in combination with
ST_AsPNG and other ST_AsGDALRaster family of functions.
Availability: 2.0.0 - requires GDAL >= 1.6.0.

Note
Not yet capable of rendering complex geometry types such as curves, TINS, and PolyhedralSurfaces, but should be
able too once GDAL can.

Examples: Output geometries as PNG files

black circle
-- this will output a black circle taking up 150 x 150 pixels --
SELECT ST_AsPNG(ST_AsRaster(ST_Buffer(ST_Point(1,5),10),150, 150, '2BUI'));

example from buffer rendered with just PostGIS

-- the bands map to RGB bands - the value (118,154,118) - teal --
SELECT ST_AsPNG(
ST_AsRaster(
ST_Buffer(
ST_GeomFromText('LINESTRING(50 50,150 150,150 50)'), 10,'join=bevel'),
200,200,ARRAY['8BUI', '8BUI', '8BUI'], ARRAY[118,154,118], ARRAY[0,0,0]));

See Also

ST_BandPixelType, ST_Buffer, ST_GDALDrivers, ST_AsGDALRaster, ST_AsPNG, ST_AsJPEG, ST_SRID

PostGIS 2.4.3 Manual 461 / 803

9.3.3 ST_Band

ST_Band — Returns one or more bands of an existing raster as a new raster. Useful for building new rasters from existing rasters.

Synopsis

raster ST_Band(raster rast, integer[] nbands = ARRAY[1]);

raster ST_Band(raster rast, integer nband);
raster ST_Band(raster rast, text nbands, character delimiter=,);

Description

Returns one or more bands of an existing raster as a new raster. Useful for building new rasters from existing rasters or export of
only selected bands of a raster or rearranging the order of bands in a raster. If no band is specified, band 1 is assumed. Used as a
helper function in various functions such as for deleting a band.

Warning
For the nbands as text variant of function, the default delimiter is , which means you can ask for ’1,2,3’ and if
you wanted to use a different delimeter you would do ST_Band(rast, ’1@2@3’, ’@’). For asking for multiple
bands, we strongly suggest you use the array form of this function e.g. ST_Band(rast, ’{1,2,3}’::int[]);
since the text list of bands form may be removed in future versions of PostGIS.

Availability: 2.0.0

Examples

-- Make 2 new rasters: 1 containing band 1 of dummy, second containing band 2 of dummy and ←-
then reclassified as a 2BUI
SELECT ST_NumBands(rast1) As numb1, ST_BandPixelType(rast1) As pix1,
ST_NumBands(rast2) As numb2, ST_BandPixelType(rast2) As pix2
FROM (
SELECT ST_Band(rast) As rast1, ST_Reclass(ST_Band(rast,3), '100-200):1, [200-254:2', '2 ←-
BUI') As rast2
FROM dummy_rast
WHERE rid = 2) As foo;

numb1 | pix1 | numb2 | pix2

-------+------+-------+------
1 | 8BUI | 1 | 2BUI

-- Return bands 2 and 3. Using array cast syntax

SELECT ST_NumBands(ST_Band(rast, '{2,3}'::int[])) As num_bands
FROM dummy_rast WHERE rid=2;

num_bands
----------
2

-- Return bands 2 and 3. Use array to define bands

SELECT ST_NumBands(ST_Band(rast, ARRAY[2,3])) As num_bands
FROM dummy_rast
WHERE rid=2;
PostGIS 2.4.3 Manual 462 / 803

original (column rast) dupe_band sing_band

--Make a new raster with 2nd band of original and 1st band repeated twice,
and another with just the third band
SELECT rast, ST_Band(rast, ARRAY[2,1,1]) As dupe_band,
ST_Band(rast, 3) As sing_band
FROM samples.than_chunked
WHERE rid=35;

See Also

ST_AddBand, ST_NumBands, ST_Reclass, Chapter 9

9.3.4 ST_MakeEmptyCoverage

ST_MakeEmptyCoverage — Cover georeferenced area with a grid of empty raster tiles.

Synopsis

raster ST_MakeEmptyCoverage(integer tilewidth, integer tileheight, integer width, integer height, double precision upperleftx,
double precision upperlefty, double precision scalex, double precision scaley, double precision skewx, double precision skewy,
integer srid=unknown);

Description

Create a set of raster tiles with ST_MakeEmptyRaster. Grid dimension is width & height. Tile dimension is tilewidth &
tileheight. The covered georeferenced area is from upper left corner (upperleftx, upperlefty) to lower right corner
(upperleftx + width * scalex, upperlefty + height * scaley).

Note
Note that scaley is generally negative for rasters and scalex is generally positive. So lower right corner will have a lower
y value and higher x value than the upper left corner.

Availability: 2.4.0
PostGIS 2.4.3 Manual 463 / 803

Examples Basic

Create 16 tiles in a 4x4 grid to cover the WGS84 area from upper left corner (22, 77) to lower right corner (55, 33).
SELECT (ST_MetaData(tile)).* FROM ST_MakeEmptyCoverage(1, 1, 4, 4, 22, 33, (55 - 22)/(4):: ←-
float, (33 - 77)/(4)::float, 0., 0., 4326) tile;

upperleftx | upperlefty | width | height | scalex | scaley | skewx | skewy | srid | ←-

numbands
-------------------------------------------------------------------------------------
22 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
30.25 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
38.5 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
46.75 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
22 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
30.25 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
38.5 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
46.75 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
22 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
30.25 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
38.5 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
46.75 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
22 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
30.25 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
38.5 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0
46.75 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | ←-
0

See Also

ST_MakeEmptyRaster

9.3.5 ST_MakeEmptyRaster

ST_MakeEmptyRaster — Returns an empty raster (having no bands) of given dimensions (width & height), upperleft X and Y,
pixel size and rotation (scalex, scaley, skewx & skewy) and reference system (srid). If a raster is passed in, returns a new raster
with the same size, alignment and SRID. If srid is left out, the spatial ref is set to unknown (0).

Synopsis

raster ST_MakeEmptyRaster(raster rast);

raster ST_MakeEmptyRaster(integer width, integer height, float8 upperleftx, float8 upperlefty, float8 scalex, float8 scaley,
float8 skewx, float8 skewy, integer srid=unknown);
raster ST_MakeEmptyRaster(integer width, integer height, float8 upperleftx, float8 upperlefty, float8 pixelsize);
PostGIS 2.4.3 Manual 464 / 803

Description

Returns an empty raster (having no band) of given dimensions (width & height) and georeferenced in spatial (or world) coor-
dinates with upper left X (upperleftx), upper left Y (upperlefty), pixel size and rotation (scalex, scaley, skewx & skewy) and
reference system (srid).
The last version use a single parameter to specify the pixel size (pixelsize). scalex is set to this argument and scaley is set to the
negative value of this argument. skewx and skewy are set to 0.
If an existing raster is passed in, it returns a new raster with the same meta data settings (without the bands).
If no srid is specified it defaults to 0. After you create an empty raster you probably want to add bands to it and maybe edit it.
Refer to ST_AddBand to define bands and ST_SetValue to set initial pixel values.

Examples

INSERT INTO dummy_rast(rid,rast)

VALUES(3, ST_MakeEmptyRaster( 100, 100, 0.0005, 0.0005, 1, 1, 0, 0, 4326) );

--use an existing raster as template for new raster

INSERT INTO dummy_rast(rid,rast)
SELECT 4, ST_MakeEmptyRaster(rast)
FROM dummy_rast WHERE rid = 3;

-- output meta data of rasters we just added

SELECT rid, (md).*
FROM (SELECT rid, ST_MetaData(rast) As md
FROM dummy_rast
WHERE rid IN(3,4)) As foo;

-- output --
rid | upperleftx | upperlefty | width | height | scalex | scaley | skewx | skewy | srid | ←-
numbands
-----+------------+------------+-------+--------+------------+------------+-------+-------+------+---

3 | 0.0005 | 0.0005 | 100 | 100 | 1 | 1 | 0 | 0 | ←-

4326 | 0
4 | 0.0005 | 0.0005 | 100 | 100 | 1 | 1 | 0 | 0 | ←-
4326 | 0

See Also

ST_AddBand, ST_MetaData, ST_ScaleX, ST_ScaleY, ST_SetValue, ST_SkewX, , ST_SkewY

9.3.6 ST_Tile

ST_Tile — Returns a set of rasters resulting from the split of the input raster based upon the desired dimensions of the output
rasters.

Synopsis

setof raster ST_Tile(raster rast, int[] nband, integer width, integer height, boolean padwithnodata=FALSE, double precision no-
dataval=NULL);
setof raster ST_Tile(raster rast, integer nband, integer width, integer height, boolean padwithnodata=FALSE, double precision
nodataval=NULL);
setof raster ST_Tile(raster rast, integer width, integer height, boolean padwithnodata=FALSE, double precision nodataval=NULL);
PostGIS 2.4.3 Manual 465 / 803

Description

Returns a set of rasters resulting from the split of the input raster based upon the desired dimensions of the output rasters.
If padwithnodata = FALSE, edge tiles on the right and bottom sides of the raster may have different dimensions than the
rest of the tiles. If padwithnodata = TRUE, all tiles will have the same dimensions with the possibility that edge tiles
being padded with NODATA values. If raster band(s) do not have NODATA value(s) specified, one can be specified by setting
nodataval.

Note
If a specified band of the input raster is out-of-db, the corresponding band in the output rasters will also be out-of-db.

Availability: 2.1.0

Examples

WITH foo AS (
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0), 1, '8BUI', ←-
1, 0), 2, '8BUI', 10, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 3, 0, 1, -1, 0, 0, 0), 1, '8BUI', ←-
2, 0), 2, '8BUI', 20, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 6, 0, 1, -1, 0, 0, 0), 1, '8BUI', ←-
3, 0), 2, '8BUI', 30, 0) AS rast UNION ALL

SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, -3, 1, -1, 0, 0, 0), 1, '8BUI', ←-

4, 0), 2, '8BUI', 40, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 3, -3, 1, -1, 0, 0, 0), 1, '8BUI', ←-
5, 0), 2, '8BUI', 50, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 6, -3, 1, -1, 0, 0, 0), 1, '8BUI', ←-
6, 0), 2, '8BUI', 60, 0) AS rast UNION ALL

SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, -6, 1, -1, 0, 0, 0), 1, '8BUI', ←-

7, 0), 2, '8BUI', 70, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 3, -6, 1, -1, 0, 0, 0), 1, '8BUI', ←-
8, 0), 2, '8BUI', 80, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 6, -6, 1, -1, 0, 0, 0), 1, '8BUI', ←-
9, 0), 2, '8BUI', 90, 0) AS rast
), bar AS (
SELECT ST_Union(rast) AS rast FROM foo
), baz AS (
SELECT ST_Tile(rast, 3, 3, TRUE) AS rast FROM bar
)
SELECT
ST_DumpValues(rast)
FROM baz;

st_dumpvalues
------------------------------------------
(1,"{{1,1,1},{1,1,1},{1,1,1}}")
(2,"{{10,10,10},{10,10,10},{10,10,10}}")
(1,"{{2,2,2},{2,2,2},{2,2,2}}")
(2,"{{20,20,20},{20,20,20},{20,20,20}}")
(1,"{{3,3,3},{3,3,3},{3,3,3}}")
(2,"{{30,30,30},{30,30,30},{30,30,30}}")
(1,"{{4,4,4},{4,4,4},{4,4,4}}")
(2,"{{40,40,40},{40,40,40},{40,40,40}}")
(1,"{{5,5,5},{5,5,5},{5,5,5}}")
PostGIS 2.4.3 Manual 466 / 803

(2,"{{50,50,50},{50,50,50},{50,50,50}}")
(1,"{{6,6,6},{6,6,6},{6,6,6}}")
(2,"{{60,60,60},{60,60,60},{60,60,60}}")
(1,"{{7,7,7},{7,7,7},{7,7,7}}")
(2,"{{70,70,70},{70,70,70},{70,70,70}}")
(1,"{{8,8,8},{8,8,8},{8,8,8}}")
(2,"{{80,80,80},{80,80,80},{80,80,80}}")
(1,"{{9,9,9},{9,9,9},{9,9,9}}")
(2,"{{90,90,90},{90,90,90},{90,90,90}}")
(18 rows)

WITH foo AS (
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0), 1, '8BUI', ←-
1, 0), 2, '8BUI', 10, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 3, 0, 1, -1, 0, 0, 0), 1, '8BUI', ←-
2, 0), 2, '8BUI', 20, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 6, 0, 1, -1, 0, 0, 0), 1, '8BUI', ←-
3, 0), 2, '8BUI', 30, 0) AS rast UNION ALL

SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, -3, 1, -1, 0, 0, 0), 1, '8BUI', ←-

4, 0), 2, '8BUI', 40, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 3, -3, 1, -1, 0, 0, 0), 1, '8BUI', ←-
5, 0), 2, '8BUI', 50, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 6, -3, 1, -1, 0, 0, 0), 1, '8BUI', ←-
6, 0), 2, '8BUI', 60, 0) AS rast UNION ALL

SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, -6, 1, -1, 0, 0, 0), 1, '8BUI', ←-

7, 0), 2, '8BUI', 70, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 3, -6, 1, -1, 0, 0, 0), 1, '8BUI', ←-
8, 0), 2, '8BUI', 80, 0) AS rast UNION ALL
SELECT ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 6, -6, 1, -1, 0, 0, 0), 1, '8BUI', ←-
9, 0), 2, '8BUI', 90, 0) AS rast
), bar AS (
SELECT ST_Union(rast) AS rast FROM foo
), baz AS (
SELECT ST_Tile(rast, 3, 3, 2) AS rast FROM bar
)
SELECT
ST_DumpValues(rast)
FROM baz;

st_dumpvalues
------------------------------------------
(1,"{{10,10,10},{10,10,10},{10,10,10}}")
(1,"{{20,20,20},{20,20,20},{20,20,20}}")
(1,"{{30,30,30},{30,30,30},{30,30,30}}")
(1,"{{40,40,40},{40,40,40},{40,40,40}}")
(1,"{{50,50,50},{50,50,50},{50,50,50}}")
(1,"{{60,60,60},{60,60,60},{60,60,60}}")
(1,"{{70,70,70},{70,70,70},{70,70,70}}")
(1,"{{80,80,80},{80,80,80},{80,80,80}}")
(1,"{{90,90,90},{90,90,90},{90,90,90}}")
(9 rows)

See Also

ST_Union, ST_Retile
PostGIS 2.4.3 Manual 467 / 803

9.3.7 ST_Retile

ST_Retile — Return a set of configured tiles from an arbitrarily tiled raster coverage.

Synopsis

SETOF raster ST_Retile(regclass tab, name col, geometry ext, float8 sfx, float8 sfy, int tw, int th, text algo=’NearestNeighbor’);

Description

Return a set of tiles having the specified scale (sfx, sfy) and max size (tw, th) and covering the specified extent (ext) with
data coming from the specified raster coverage (tab, col).
Algorithm options are: ’NearestNeighbor’, ’Bilinear’, ’Cubic’, ’CubicSpline’, and ’Lanczos’. Refer to: GDAL Warp resampling
methods for more details.
Availability: 2.2.0

See Also

ST_CreateOverview

9.3.8 ST_FromGDALRaster

ST_FromGDALRaster — Returns a raster from a supported GDAL raster file.

Synopsis

raster ST_FromGDALRaster(bytea gdaldata, integer srid=NULL);

Description

Returns a raster from a supported GDAL raster file. gdaldata is of type bytea and should be the contents of the GDAL raster
file.
If srid is NULL, the function will try to automatically assign the SRID from the GDAL raster. If srid is provided, the value
provided will override any automatically assigned SRID.
Availability: 2.1.0

Examples

WITH foo AS (
SELECT ST_AsPNG(ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 0.1, ←-
-0.1, 0, 0, 4326), 1, '8BUI', 1, 0), 2, '8BUI', 2, 0), 3, '8BUI', 3, 0)) AS png
),
bar AS (
SELECT 1 AS rid, ST_FromGDALRaster(png) AS rast FROM foo
UNION ALL
SELECT 2 AS rid, ST_FromGDALRaster(png, 3310) AS rast FROM foo
)
SELECT
rid,
ST_Metadata(rast) AS metadata,
ST_SummaryStats(rast, 1) AS stats1,
PostGIS 2.4.3 Manual 468 / 803

ST_SummaryStats(rast, 2) AS stats2,
ST_SummaryStats(rast, 3) AS stats3
FROM bar
ORDER BY rid;

rid | metadata | stats1 | stats2 | stats3

-----+---------------------------+---------------+---------------+----------------
1 | (0,0,2,2,1,-1,0,0,0,3) | (4,4,1,0,1,1) | (4,8,2,0,2,2) | (4,12,3,0,3,3)
2 | (0,0,2,2,1,-1,0,0,3310,3) | (4,4,1,0,1,1) | (4,8,2,0,2,2) | (4,12,3,0,3,3)
(2 rows)

See Also

ST_AsGDALRaster

9.4 Raster Accessors

9.4.1 ST_GeoReference

ST_GeoReference — Returns the georeference meta data in GDAL or ESRI format as commonly seen in a world file. Default is
GDAL.

Synopsis

text ST_GeoReference(raster rast, text format=GDAL);

Description

Returns the georeference meta data including carriage return in GDAL or ESRI format as commonly seen in a world file. Default
is GDAL if no type specified. type is string ’GDAL’ or ’ESRI’.
Difference between format representations is as follows:
GDAL:
scalex
skewy
skewx
scaley
upperleftx
upperlefty

ESRI:
scalex
skewy
skewx
scaley
upperleftx + scalex*0.5
upperlefty + scaley*0.5
PostGIS 2.4.3 Manual 469 / 803

Examples

SELECT ST_GeoReference(rast, 'ESRI') As esri_ref, ST_GeoReference(rast, 'GDAL') As gdal_ref

FROM dummy_rast WHERE rid=1;

esri_ref | gdal_ref
--------------+--------------
2.0000000000 | 2.0000000000
0.0000000000 : 0.0000000000
0.0000000000 : 0.0000000000
3.0000000000 : 3.0000000000
1.5000000000 : 0.5000000000
2.0000000000 : 0.5000000000

See Also

ST_SetGeoReference, ST_ScaleX, ST_ScaleY

9.4.2 ST_Height

ST_Height — Returns the height of the raster in pixels.

Synopsis

integer ST_Height(raster rast);

Description

Returns the height of the raster.

Examples

SELECT rid, ST_Height(rast) As rastheight

FROM dummy_rast;

rid | rastheight
-----+------------
1 | 20
2 | 5

See Also

ST_Width

9.4.3 ST_IsEmpty

ST_IsEmpty — Returns true if the raster is empty (width = 0 and height = 0). Otherwise, returns false.

Synopsis

boolean ST_IsEmpty(raster rast);

PostGIS 2.4.3 Manual 470 / 803

Description

Returns true if the raster is empty (width = 0 and height = 0). Otherwise, returns false.
Availability: 2.0.0

Examples

SELECT ST_IsEmpty(ST_MakeEmptyRaster(100, 100, 0, 0, 0, 0, 0, 0))

st_isempty |
-----------+
f |

SELECT ST_IsEmpty(ST_MakeEmptyRaster(0, 0, 0, 0, 0, 0, 0, 0))

st_isempty |
-----------+
t |

See Also

ST_HasNoBand

9.4.4 ST_MemSize

ST_MemSize — Returns the amount of space (in bytes) the raster takes.

Synopsis

integer ST_MemSize(raster rast);

Description

Returns the amount of space (in bytes) the raster takes.

This is a nice compliment to PostgreSQL built in functions pg_column_size, pg_size_pretty, pg_relation_size, pg_total_relation_size.

Note
pg_relation_size which gives the byte size of a table may return byte size lower than ST_MemSize. This is be-
cause pg_relation_size does not add toasted table contribution and large geometries are stored in TOAST tables.
pg_column_size might return lower because it returns the compressed size.
pg_total_relation_size - includes, the table, the toasted tables, and the indexes.

Availability: 2.2.0

Examples

SELECT ST_MemSize(ST_AsRaster(ST_Buffer(ST_Point(1,5),10,1000),150, 150, '8BUI')) As ←-

rast_mem;

rast_mem
--------
22568
PostGIS 2.4.3 Manual 471 / 803

See Also

9.4.5 ST_MetaData

ST_MetaData — Returns basic meta data about a raster object such as pixel size, rotation (skew), upper, lower left, etc.

Synopsis

record ST_MetaData(raster rast);

Description

Returns basic meta data about a raster object such as pixel size, rotation (skew), upper, lower left, etc. Columns returned:
upperleftx | upperlefty | width | height | scalex | scaley | skewx | skewy | srid | numbands

Examples

SELECT rid, (foo.md).*

FROM (SELECT rid, ST_MetaData(rast) As md
FROM dummy_rast) As foo;

rid | upperleftx | upperlefty | width | height | scalex | scaley | skewx | skewy | srid | ←-
numbands
----+------------+------------+-------+--------+--------+-----------+-------+-------+------+-------

1 | 0.5 | 0.5 | 10 | 20 | 2 | 3 | 0 | 0 | 0 | ←-
0
2 | 3427927.75 | 5793244 | 5 | 5 | 0.05 | -0.05 | 0 | 0 | 0 | ←-
3

See Also

ST_BandMetaData, ST_NumBands

9.4.6 ST_NumBands

ST_NumBands — Returns the number of bands in the raster object.

Synopsis

integer ST_NumBands(raster rast);

Description

Returns the number of bands in the raster object.

PostGIS 2.4.3 Manual 472 / 803

Examples

SELECT rid, ST_NumBands(rast) As numbands

FROM dummy_rast;

rid | numbands
----+----------
1 | 0
2 | 3

See Also

ST_Value

9.4.7 ST_PixelHeight

ST_PixelHeight — Returns the pixel height in geometric units of the spatial reference system.

Synopsis

double precision ST_PixelHeight(raster rast);

Description

Returns the height of a pixel in geometric units of the spatial reference system. In the common case where there is no skew, the
pixel height is just the scale ratio between geometric coordinates and raster pixels.
Refer to ST_PixelWidth for a diagrammatic visualization of the relationship.

Examples: Rasters with no skew

SELECT ST_Height(rast) As rastheight, ST_PixelHeight(rast) As pixheight,

ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx,
ST_SkewY(rast) As skewy
FROM dummy_rast;

rastheight | pixheight | scalex | scaley | skewx | skewy

------------+-----------+--------+--------+-------+----------
20 | 3 | 2 | 3 | 0 | 0
5 | 0.05 | 0.05 | -0.05 | 0 | 0

Examples: Rasters with skew different than 0

SELECT ST_Height(rast) As rastheight, ST_PixelHeight(rast) As pixheight,

ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx,
ST_SkewY(rast) As skewy
FROM (SELECT ST_SetSKew(rast,0.5,0.5) As rast
FROM dummy_rast) As skewed;

rastheight | pixheight | scalex | scaley | skewx | skewy

-----------+-------------------+--------+--------+-------+----------
20 | 3.04138126514911 | 2 | 3 | 0.5 | 0.5
5 | 0.502493781056044 | 0.05 | -0.05 | 0.5 | 0.5
PostGIS 2.4.3 Manual 473 / 803

See Also

ST_PixelWidth, ST_ScaleX, ST_ScaleY, ST_SkewX, ST_SkewY

9.4.8 ST_PixelWidth

ST_PixelWidth — Returns the pixel width in geometric units of the spatial reference system.

Synopsis

double precision ST_PixelWidth(raster rast);

Description

Returns the width of a pixel in geometric units of the spatial reference system. In the common case where there is no skew, the
pixel width is just the scale ratio between geometric coordinates and raster pixels.
The following diagram demonstrates the relationship:

Pixel Width: Pixel size in the i direction

Pixel Height: Pixel size in the j direction

Examples: Rasters with no skew

SELECT ST_Width(rast) As rastwidth, ST_PixelWidth(rast) As pixwidth,

ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx,
ST_SkewY(rast) As skewy
FROM dummy_rast;

rastwidth | pixwidth | scalex | scaley | skewx | skewy

-----------+----------+--------+--------+-------+----------
10 | 2 | 2 | 3 | 0 | 0
5 | 0.05 | 0.05 | -0.05 | 0 | 0
PostGIS 2.4.3 Manual 474 / 803

Examples: Rasters with skew different than 0

SELECT ST_Width(rast) As rastwidth, ST_PixelWidth(rast) As pixwidth,

ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx,
ST_SkewY(rast) As skewy
FROM (SELECT ST_SetSkew(rast,0.5,0.5) As rast
FROM dummy_rast) As skewed;

rastwidth | pixwidth | scalex | scaley | skewx | skewy

-----------+-------------------+--------+--------+-------+----------
10 | 2.06155281280883 | 2 | 3 | 0.5 | 0.5
5 | 0.502493781056044 | 0.05 | -0.05 | 0.5 | 0.5

See Also

ST_PixelHeight, ST_ScaleX, ST_ScaleY, ST_SkewX, ST_SkewY

9.4.9 ST_ScaleX

ST_ScaleX — Returns the X component of the pixel width in units of coordinate reference system.

Synopsis

float8 ST_ScaleX(raster rast);

Description

Returns the X component of the pixel width in units of coordinate reference system. Refer to World File for more details.
Changed: 2.0.0. In WKTRaster versions this was called ST_PixelSizeX.

Examples

SELECT rid, ST_ScaleX(rast) As rastpixwidth

FROM dummy_rast;

rid | rastpixwidth
-----+--------------
1 | 2
2 | 0.05

See Also

ST_Width

9.4.10 ST_ScaleY

ST_ScaleY — Returns the Y component of the pixel height in units of coordinate reference system.

Synopsis

float8 ST_ScaleY(raster rast);

PostGIS 2.4.3 Manual 475 / 803

Description

Returns the Y component of the pixel height in units of coordinate reference system. May be negative. Refer to World File for
more details.
Changed: 2.0.0. In WKTRaster versions this was called ST_PixelSizeY.

Examples

SELECT rid, ST_ScaleY(rast) As rastpixheight

FROM dummy_rast;

rid | rastpixheight
-----+---------------
1 | 3
2 | -0.05

See Also

ST_Height

9.4.11 ST_RasterToWorldCoord

ST_RasterToWorldCoord — Returns the raster’s upper left corner as geometric X and Y (longitude and latitude) given a column
and row. Column and row starts at 1.

Synopsis

record ST_RasterToWorldCoord(raster rast, integer xcolumn, integer yrow);

Description

Returns the upper left corner as geometric X and Y (longitude and latitude) given a column and row. Returned X and Y are in
geometric units of the georeferenced raster. Numbering of column and row starts at 1 but if either parameter is passed a zero, a
negative number or a number greater than the respective dimension of the raster, it will return coordinates outside of the raster
assuming the raster’s grid is applicable outside the raster’s bounds.
Availability: 2.1.0

Examples

-- non-skewed raster
SELECT
rid,
(ST_RasterToWorldCoord(rast,1, 1)).*,
(ST_RasterToWorldCoord(rast,2, 2)).*
FROM dummy_rast

rid | longitude | latitude | longitude | latitude

-----+------------+----------+-----------+------------
1 | 0.5 | 0.5 | 2.5 | 3.5
2 | 3427927.75 | 5793244 | 3427927.8 | 5793243.95
PostGIS 2.4.3 Manual 476 / 803

-- skewed raster
SELECT
rid,
(ST_RasterToWorldCoord(rast, 1, 1)).*,
(ST_RasterToWorldCoord(rast, 2, 3)).*
FROM (
SELECT
rid,
ST_SetSkew(rast, 100.5, 0) As rast
FROM dummy_rast
) As foo

rid | longitude | latitude | longitude | latitude

-----+------------+----------+-----------+-----------
1 | 0.5 | 0.5 | 203.5 | 6.5
2 | 3427927.75 | 5793244 | 3428128.8 | 5793243.9

See Also

ST_RasterToWorldCoordX, ST_RasterToWorldCoordY, ST_SetSkew

9.4.12 ST_RasterToWorldCoordX

ST_RasterToWorldCoordX — Returns the geometric X coordinate upper left of a raster, column and row. Numbering of columns
and rows starts at 1.

Synopsis

float8 ST_RasterToWorldCoordX(raster rast, integer xcolumn);

float8 ST_RasterToWorldCoordX(raster rast, integer xcolumn, integer yrow);

Description

Returns the upper left X coordinate of a raster column row in geometric units of the georeferenced raster. Numbering of columns
and rows starts at 1 but if you pass in a negative number or number higher than number of columns in raster, it will give you
coordinates outside of the raster file to left or right with the assumption that the skew and pixel sizes are same as selected raster.

Note
For non-skewed rasters, providing the X column is sufficient. For skewed rasters, the georeferenced coordinate is a
function of the ST_ScaleX and ST_SkewX and row and column. An error will be raised if you give just the X column for
a skewed raster.

Changed: 2.1.0 In prior versions, this was called ST_Raster2WorldCoordX

Examples

-- non-skewed raster providing column is sufficient

SELECT rid, ST_RasterToWorldCoordX(rast,1) As x1coord,
ST_RasterToWorldCoordX(rast,2) As x2coord,
ST_ScaleX(rast) As pixelx
FROM dummy_rast;
PostGIS 2.4.3 Manual 477 / 803

rid | x1coord | x2coord | pixelx

-----+------------+-----------+--------
1 | 0.5 | 2.5 | 2
2 | 3427927.75 | 3427927.8 | 0.05

-- for fun lets skew it

SELECT rid, ST_RasterToWorldCoordX(rast, 1, 1) As x1coord,
ST_RasterToWorldCoordX(rast, 2, 3) As x2coord,
ST_ScaleX(rast) As pixelx
FROM (SELECT rid, ST_SetSkew(rast, 100.5, 0) As rast FROM dummy_rast) As foo;

rid | x1coord | x2coord | pixelx

-----+------------+-----------+--------
1 | 0.5 | 203.5 | 2
2 | 3427927.75 | 3428128.8 | 0.05

See Also

ST_ScaleX, ST_RasterToWorldCoordY, ST_SetSkew, ST_SkewX

9.4.13 ST_RasterToWorldCoordY

ST_RasterToWorldCoordY — Returns the geometric Y coordinate upper left corner of a raster, column and row. Numbering of
columns and rows starts at 1.

Synopsis

float8 ST_RasterToWorldCoordY(raster rast, integer yrow);

float8 ST_RasterToWorldCoordY(raster rast, integer xcolumn, integer yrow);

Description

Returns the upper left Y coordinate of a raster column row in geometric units of the georeferenced raster. Numbering of columns
and rows starts at 1 but if you pass in a negative number or number higher than number of columns/rows in raster, it will give
you coordinates outside of the raster file to left or right with the assumption that the skew and pixel sizes are same as selected
raster tile.

Note
For non-skewed rasters, providing the Y column is sufficient. For skewed rasters, the georeferenced coordinate is a
function of the ST_ScaleY and ST_SkewY and row and column. An error will be raised if you give just the Y row for a
skewed raster.

Changed: 2.1.0 In prior versions, this was called ST_Raster2WorldCoordY

Examples

-- non-skewed raster providing row is sufficient

SELECT rid, ST_RasterToWorldCoordY(rast,1) As y1coord,
ST_RasterToWorldCoordY(rast,3) As y2coord,
ST_ScaleY(rast) As pixely
FROM dummy_rast;
PostGIS 2.4.3 Manual 478 / 803

rid | y1coord | y2coord | pixely

-----+---------+-----------+--------
1 | 0.5 | 6.5 | 3
2 | 5793244 | 5793243.9 | -0.05

-- for fun lets skew it

SELECT rid, ST_RasterToWorldCoordY(rast,1,1) As y1coord,
ST_RasterToWorldCoordY(rast,2,3) As y2coord,
ST_ScaleY(rast) As pixely
FROM (SELECT rid, ST_SetSkew(rast,0,100.5) As rast FROM dummy_rast) As foo;

rid | y1coord | y2coord | pixely

-----+---------+-----------+--------
1 | 0.5 | 107 | 3
2 | 5793244 | 5793344.4 | -0.05

See Also

ST_ScaleY, ST_RasterToWorldCoordX, ST_SetSkew, ST_SkewY

9.4.14 ST_Rotation

ST_Rotation — Returns the rotation of the raster in radian.

Synopsis

float8 ST_Rotation(raster rast);

Description

Returns the uniform rotation of the raster in radian. If a raster does not have uniform rotation, NaN is returned. Refer to World
File for more details.

Examples

SELECT rid, ST_Rotation(ST_SetScale(ST_SetSkew(rast, sqrt(2)), sqrt(2))) as rot FROM ←-

dummy_rast;

rid | rot
-----+-------------------
1 | 0.785398163397448
2 | 0.785398163397448

See Also

ST_SetRotation, ST_SetScale, ST_SetSkew

9.4.15 ST_SkewX

ST_SkewX — Returns the georeference X skew (or rotation parameter).

PostGIS 2.4.3 Manual 479 / 803

Synopsis

float8 ST_SkewX(raster rast);

Description

Returns the georeference X skew (or rotation parameter). Refer to World File for more details.

Examples

SELECT rid, ST_SkewX(rast) As skewx, ST_SkewY(rast) As skewy,

ST_GeoReference(rast) as georef
FROM dummy_rast;

rid | skewx | skewy | georef

-----+-------+-------+--------------------
1 | 0 | 0 | 2.0000000000
: 0.0000000000
: 0.0000000000
: 3.0000000000
: 0.5000000000
: 0.5000000000
:
2 | 0 | 0 | 0.0500000000
: 0.0000000000
: 0.0000000000
: -0.0500000000
: 3427927.7500000000
: 5793244.0000000000

See Also

ST_GeoReference, ST_SkewY, ST_SetSkew

9.4.16 ST_SkewY

ST_SkewY — Returns the georeference Y skew (or rotation parameter).

Synopsis

float8 ST_SkewY(raster rast);

Description

Returns the georeference Y skew (or rotation parameter). Refer to World File for more details.

Examples

SELECT rid, ST_SkewX(rast) As skewx, ST_SkewY(rast) As skewy,

ST_GeoReference(rast) as georef
FROM dummy_rast;

rid | skewx | skewy | georef

PostGIS 2.4.3 Manual 480 / 803

-----+-------+-------+--------------------
1 | 0 | 0 | 2.0000000000
: 0.0000000000
: 0.0000000000
: 3.0000000000
: 0.5000000000
: 0.5000000000
:
2 | 0 | 0 | 0.0500000000
: 0.0000000000
: 0.0000000000
: -0.0500000000
: 3427927.7500000000
: 5793244.0000000000

See Also

ST_GeoReference, ST_SkewX, ST_SetSkew

9.4.17 ST_SRID

ST_SRID — Returns the spatial reference identifier of the raster as defined in spatial_ref_sys table.

Synopsis

integer ST_SRID(raster rast);

Description

Returns the spatial reference identifier of the raster object as defined in the spatial_ref_sys table.

Note
From PostGIS 2.0+ the srid of a non-georeferenced raster/geometry is 0 instead of the prior -1.

Examples

SELECT ST_SRID(rast) As srid

FROM dummy_rast WHERE rid=1;

srid
----------------
0

See Also

Section 4.3.1, ST_SRID

9.4.18 ST_Summary

ST_Summary — Returns a text summary of the contents of the raster.

PostGIS 2.4.3 Manual 481 / 803

Synopsis

text ST_Summary(raster rast);

Description

Returns a text summary of the contents of the raster.

Availability: 2.1.0

Examples

SELECT ST_Summary(
ST_AddBand(
ST_AddBand(
ST_AddBand(
ST_MakeEmptyRaster(10, 10, 0, 0, 1, -1, 0, 0, 0)
, 1, '8BUI', 1, 0
)
, 2, '32BF', 0, -9999
)
, 3, '16BSI', 0, NULL
)
);

st_summary
------------------------------------------------------------------
Raster of 10x10 pixels has 3 bands and extent of BOX(0 -10,10 0)+
band 1 of pixtype 8BUI is in-db with NODATA value of 0 +
band 2 of pixtype 32BF is in-db with NODATA value of -9999 +
band 3 of pixtype 16BSI is in-db with no NODATA value
(1 row)

See Also

ST_MetaData, ST_BandMetaData, ST_Summary ST_Extent

9.4.19 ST_UpperLeftX

ST_UpperLeftX — Returns the upper left X coordinate of raster in projected spatial ref.

Synopsis

float8 ST_UpperLeftX(raster rast);

Description

Returns the upper left X coordinate of raster in projected spatial ref.

PostGIS 2.4.3 Manual 482 / 803

Examples

SELECt rid, ST_UpperLeftX(rast) As ulx

FROM dummy_rast;

rid | ulx
-----+------------
1 | 0.5
2 | 3427927.75

See Also

ST_UpperLeftY, ST_GeoReference, Box3D

9.4.20 ST_UpperLeftY

ST_UpperLeftY — Returns the upper left Y coordinate of raster in projected spatial ref.

Synopsis

float8 ST_UpperLeftY(raster rast);

Description

Returns the upper left Y coordinate of raster in projected spatial ref.

Examples

SELECT rid, ST_UpperLeftY(rast) As uly

FROM dummy_rast;

rid | uly
-----+---------
1 | 0.5
2 | 5793244

See Also

ST_UpperLeftX, ST_GeoReference, Box3D

9.4.21 ST_Width

ST_Width — Returns the width of the raster in pixels.

Synopsis

integer ST_Width(raster rast);

Description

Returns the width of the raster in pixels.

PostGIS 2.4.3 Manual 483 / 803

Examples

SELECT ST_Width(rast) As rastwidth

FROM dummy_rast WHERE rid=1;

rastwidth
----------------
10

See Also

ST_Height

9.4.22 ST_WorldToRasterCoord

ST_WorldToRasterCoord — Returns the upper left corner as column and row given geometric X and Y (longitude and latitude)
or a point geometry expressed in the spatial reference coordinate system of the raster.

Synopsis

record ST_WorldToRasterCoord(raster rast, geometry pt);

record ST_WorldToRasterCoord(raster rast, double precision longitude, double precision latitude);

Description

Returns the upper left corner as column and row given geometric X and Y (longitude and latitude) or a point geometry. This
function works regardless of whether or not the geometric X and Y or point geometry is outside the extent of the raster. Geometric
X and Y must be expressed in the spatial reference coordinate system of the raster.
Availability: 2.1.0

Examples

SELECT
rid,
(ST_WorldToRasterCoord(rast,3427927.8,20.5)).*,
(ST_WorldToRasterCoord(rast,ST_GeomFromText('POINT(3427927.8 20.5)',ST_SRID(rast)))).*
FROM dummy_rast;

rid | columnx | rowy | columnx | rowy

-----+---------+-----------+---------+-----------
1 | 1713964 | 7 | 1713964 | 7
2 | 2 | 115864471 | 2 | 115864471

See Also

ST_WorldToRasterCoordX, ST_WorldToRasterCoordY, ST_RasterToWorldCoordX, ST_RasterToWorldCoordY, ST_SRID

9.4.23 ST_WorldToRasterCoordX

ST_WorldToRasterCoordX — Returns the column in the raster of the point geometry (pt) or a X and Y world coordinate (xw,
yw) represented in world spatial reference system of raster.
PostGIS 2.4.3 Manual 484 / 803

Synopsis

integer ST_WorldToRasterCoordX(raster rast, geometry pt);

integer ST_WorldToRasterCoordX(raster rast, double precision xw);
integer ST_WorldToRasterCoordX(raster rast, double precision xw, double precision yw);

Description

Returns the column in the raster of the point geometry (pt) or a X and Y world coordinate (xw, yw). A point, or (both xw and yw
world coordinates are required if a raster is skewed). If a raster is not skewed then xw is sufficient. World coordinates are in the
spatial reference coordinate system of the raster.
Changed: 2.1.0 In prior versions, this was called ST_World2RasterCoordX

Examples

SELECT rid, ST_WorldToRasterCoordX(rast,3427927.8) As xcoord,

ST_WorldToRasterCoordX(rast,3427927.8,20.5) As xcoord_xwyw,
ST_WorldToRasterCoordX(rast,ST_GeomFromText('POINT(3427927.8 20.5)',ST_SRID(rast))) As ←-
ptxcoord
FROM dummy_rast;

rid | xcoord | xcoord_xwyw | ptxcoord

-----+---------+---------+----------
1 | 1713964 | 1713964 | 1713964
2 | 1 | 1 | 1

See Also

ST_RasterToWorldCoordX, ST_RasterToWorldCoordY, ST_SRID

9.4.24 ST_WorldToRasterCoordY

ST_WorldToRasterCoordY — Returns the row in the raster of the point geometry (pt) or a X and Y world coordinate (xw, yw)
represented in world spatial reference system of raster.

Synopsis

integer ST_WorldToRasterCoordY(raster rast, geometry pt);

integer ST_WorldToRasterCoordY(raster rast, double precision xw);
integer ST_WorldToRasterCoordY(raster rast, double precision xw, double precision yw);

Description

Returns the row in the raster of the point geometry (pt) or a X and Y world coordinate (xw, yw). A point, or (both xw and yw
world coordinates are required if a raster is skewed). If a raster is not skewed then xw is sufficient. World coordinates are in the
spatial reference coordinate system of the raster.
Changed: 2.1.0 In prior versions, this was called ST_World2RasterCoordY
PostGIS 2.4.3 Manual 485 / 803

Examples

SELECT rid, ST_WorldToRasterCoordY(rast,20.5) As ycoord,

ST_WorldToRasterCoordY(rast,3427927.8,20.5) As ycoord_xwyw,
ST_WorldToRasterCoordY(rast,ST_GeomFromText('POINT(3427927.8 20.5)',ST_SRID(rast))) As ←-
ptycoord
FROM dummy_rast;

rid | ycoord | ycoord_xwyw | ptycoord

-----+-----------+-------------+-----------
1 | 7 | 7 | 7
2 | 115864471 | 115864471 | 115864471

See Also

ST_RasterToWorldCoordX, ST_RasterToWorldCoordY, ST_SRID

9.5 Raster Band Accessors

9.5.1 ST_BandMetaData

ST_BandMetaData — Returns basic meta data for a specific raster band. band num 1 is assumed if none-specified.

Synopsis

record ST_BandMetaData(raster rast, integer bandnum=1);

Description

Returns basic meta data about a raster band. Columns returned pixeltype | nodatavalue | isoutdb | path.

Note
If raster contains no bands then an error is thrown.

Note
If band has no NODATA value, nodatavalue will be NULL.

Examples

SELECT rid, (foo.md).*

FROM (SELECT rid, ST_BandMetaData(rast,1) As md
FROM dummy_rast WHERE rid=2) As foo;

rid | pixeltype | nodatavalue | isoutdb | path

-----+-----------+----------------+-------------+---------+------
2 | 8BUI | 0 | f |
PostGIS 2.4.3 Manual 486 / 803

See Also

ST_MetaData, ST_BandPixelType

9.5.2 ST_BandNoDataValue

ST_BandNoDataValue — Returns the value in a given band that represents no data. If no band num 1 is assumed.

Synopsis

double precision ST_BandNoDataValue(raster rast, integer bandnum=1);

Description

Returns the value that represents no data for the band

Examples

SELECT ST_BandNoDataValue(rast,1) As bnval1,

ST_BandNoDataValue(rast,2) As bnval2, ST_BandNoDataValue(rast,3) As bnval3
FROM dummy_rast
WHERE rid = 2;

bnval1 | bnval2 | bnval3

--------+--------+--------
0 | 0 | 0

See Also

ST_NumBands

9.5.3 ST_BandIsNoData

ST_BandIsNoData — Returns true if the band is filled with only nodata values.

Synopsis

boolean ST_BandIsNoData(raster rast, integer band, boolean forceChecking=true);

boolean ST_BandIsNoData(raster rast, boolean forceChecking=true);

Description

Returns true if the band is filled with only nodata values. Band 1 is assumed if not specified. If the last argument is TRUE, the
entire band is checked pixel by pixel. Otherwise, the function simply returns the value of the isnodata flag for the band. The
default value for this parameter is FALSE, if not specified.
Availability: 2.0.0

Note
If the flag is dirty (this is, the result is different using TRUE as last parameter and not using it) you should update
the raster to set this flag to true, by using ST_SetBandIsNodata(), or ST_SetBandNodataValue() with TRUE as last
argument. See ST_SetBandIsNoData.
PostGIS 2.4.3 Manual 487 / 803

Examples

-- Create dummy table with one raster column

create table dummy_rast (rid integer, rast raster);

-- Add raster with two bands, one pixel/band. In the first band, nodatavalue = pixel value ←-
= 3.
-- In the second band, nodatavalue = 13, pixel value = 4
insert into dummy_rast values(1,
(
'01' -- little endian (uint8 ndr)
||
'0000' -- version (uint16 0)
||
'0200' -- nBands (uint16 0)
||
'17263529ED684A3F' -- scaleX (float64 0.000805965234044584)
||
'F9253529ED684ABF' -- scaleY (float64 -0.00080596523404458)
||
'1C9F33CE69E352C0' -- ipX (float64 -75.5533328537098)
||
'718F0E9A27A44840' -- ipY (float64 49.2824585505576)
||
'ED50EB853EC32B3F' -- skewX (float64 0.000211812383858707)
||
'7550EB853EC32B3F' -- skewY (float64 0.000211812383858704)
||
'E6100000' -- SRID (int32 4326)
||
'0100' -- width (uint16 1)
||
'0100' -- height (uint16 1)
||
'6' -- hasnodatavalue and isnodata value set to true.
||
'2' -- first band type (4BUI)
||
'03' -- novalue==3
||
'03' -- pixel(0,0)==3 (same that nodata)
||
'0' -- hasnodatavalue set to false
||
'5' -- second band type (16BSI)
||
'0D00' -- novalue==13
||
'0400' -- pixel(0,0)==4
)::raster
);

select st_bandisnodata(rast, 1) from dummy_rast where rid = 1; -- Expected true

select st_bandisnodata(rast, 2) from dummy_rast where rid = 1; -- Expected false

See Also

ST_BandNoDataValue, ST_NumBands, ST_SetBandNoDataValue, ST_SetBandIsNoData

PostGIS 2.4.3 Manual 488 / 803

9.5.4 ST_BandPath

ST_BandPath — Returns system file path to a band stored in file system. If no bandnum specified, 1 is assumed.

Synopsis

text ST_BandPath(raster rast, integer bandnum=1);

Description

Returns system file path to a band. Throws an error if called with an in db band.

Examples

See Also

9.5.5 ST_BandPixelType

ST_BandPixelType — Returns the type of pixel for given band. If no bandnum specified, 1 is assumed.

Synopsis

text ST_BandPixelType(raster rast, integer bandnum=1);

Description

Returns the value that represents no data for the band

There are 11 pixel types. Pixel Types supported are as follows:

• 1BB - 1-bit boolean

• 2BUI - 2-bit unsigned integer

• 4BUI - 4-bit unsigned integer
• 8BSI - 8-bit signed integer
• 8BUI - 8-bit unsigned integer

• 16BSI - 16-bit signed integer

• 16BUI - 16-bit unsigned integer
• 32BSI - 32-bit signed integer

• 32BUI - 32-bit unsigned integer

• 32BF - 32-bit float
• 64BF - 64-bit float
PostGIS 2.4.3 Manual 489 / 803

Examples

SELECT ST_BandPixelType(rast,1) As btype1,

ST_BandPixelType(rast,2) As btype2, ST_BandPixelType(rast,3) As btype3
FROM dummy_rast
WHERE rid = 2;

btype1 | btype2 | btype3

--------+--------+--------
8BUI | 8BUI | 8BUI

See Also

ST_NumBands

9.5.6 ST_HasNoBand

ST_HasNoBand — Returns true if there is no band with given band number. If no band number is specified, then band number
1 is assumed.

Synopsis

boolean ST_HasNoBand(raster rast, integer bandnum=1);

Description

Returns true if there is no band with given band number. If no band number is specified, then band number 1 is assumed.
Availability: 2.0.0

Examples

SELECT rid, ST_HasNoBand(rast) As hb1, ST_HasNoBand(rast,2) as hb2,

ST_HasNoBand(rast,4) as hb4, ST_NumBands(rast) As numbands
FROM dummy_rast;

rid | hb1 | hb2 | hb4 | numbands

-----+-----+-----+-----+----------
1 | t | t | t | 0
2 | f | f | t | 3

See Also

ST_NumBands

9.6 Raster Pixel Accessors and Setters

9.6.1 ST_PixelAsPolygon

ST_PixelAsPolygon — Returns the polygon geometry that bounds the pixel for a particular row and column.
PostGIS 2.4.3 Manual 490 / 803

Synopsis

geometry ST_PixelAsPolygon(raster rast, integer columnx, integer rowy);

Description

Returns the polygon geometry that bounds the pixel for a particular row and column.
Availability: 2.0.0

Examples

-- get raster pixel polygon

SELECT i,j, ST_AsText(ST_PixelAsPolygon(foo.rast, i,j)) As b1pgeom
FROM dummy_rast As foo
CROSS JOIN generate_series(1,2) As i
CROSS JOIN generate_series(1,1) As j
WHERE rid=2;

i | j | b1pgeom
---+---+-----------------------------------------------------------------------------
1 | 1 | POLYGON((3427927.75 5793244,3427927.8 5793244,3427927.8 5793243.95,...
2 | 1 | POLYGON((3427927.8 5793244,3427927.85 5793244,3427927.85 5793243.95, ..

See Also

ST_DumpAsPolygons, ST_PixelAsPolygons, ST_PixelAsPoint, ST_PixelAsPoints, ST_PixelAsCentroid, ST_PixelAsCentroids,

ST_Intersection, ST_AsText

9.6.2 ST_PixelAsPolygons

ST_PixelAsPolygons — Returns the polygon geometry that bounds every pixel of a raster band along with the value, the X and
the Y raster coordinates of each pixel.

Synopsis

setof record ST_PixelAsPolygons(raster rast, integer band=1, boolean exclude_nodata_value=TRUE);

Description

Returns the polygon geometry that bounds every pixel of a raster band along with the value (double precision), the X and the Y
raster coordinates (integers) of each pixel.

Note
ST_PixelAsPolygons returns one polygon geometry for every pixel. This is different than ST_DumpAsPolygons where
each geometry represents one or more pixels with the same pixel value.

Note
When exclude_nodata_value = TRUE, only those pixels whose values are not NODATA are returned as polygons.
PostGIS 2.4.3 Manual 491 / 803

Availability: 2.0.0
Enhanced: 2.1.0 exclude_nodata_value optional argument was added.
Changed: 2.1.1 Changed behavior of exclude_nodata_value.

Examples

-- get raster pixel polygon

SELECT (gv).x, (gv).y, (gv).val, ST_AsText((gv).geom) geom
FROM (SELECT ST_PixelAsPolygons(
ST_SetValue(ST_SetValue(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 0.001, ←-
-0.001, 0.001, 0.001, 4269),
'8BUI'::text, 1, 0),
2, 2, 10),
1, 1, NULL)
) gv
) foo;

x | y | val | geom
---+---+-----------------------------------------------------------------------------
1 | 1 | | POLYGON((0 0,0.001 0.001,0.002 0,0.001 -0.001,0 0))
1 | 2 | 1 | POLYGON((0.001 -0.001,0.002 0,0.003 -0.001,0.002 -0.002,0.001 -0.001))
2 | 1 | 1 | POLYGON((0.001 0.001,0.002 0.002,0.003 0.001,0.002 0,0.001 0.001))
2 | 2 | 10 | POLYGON((0.002 0,0.003 0.001,0.004 0,0.003 -0.001,0.002 0))

See Also

ST_DumpAsPolygons, ST_PixelAsPolygon, ST_PixelAsPoint, ST_PixelAsPoints, ST_PixelAsCentroid, ST_PixelAsCentroids,

ST_AsText

9.6.3 ST_PixelAsPoint

ST_PixelAsPoint — Returns a point geometry of the pixel’s upper-left corner.

Synopsis

geometry ST_PixelAsPoint(raster rast, integer columnx, integer rowy);

Description

Returns a point geometry of the pixel’s upper-left corner.

Availability: 2.1.0

Examples

SELECT ST_AsText(ST_PixelAsPoint(rast, 1, 1)) FROM dummy_rast WHERE rid = 1;

st_astext
----------------
POINT(0.5 0.5)
PostGIS 2.4.3 Manual 492 / 803

See Also

ST_DumpAsPolygons, ST_PixelAsPolygon, ST_PixelAsPolygons, ST_PixelAsPoints, ST_PixelAsCentroid, ST_PixelAsCentroids

9.6.4 ST_PixelAsPoints

ST_PixelAsPoints — Returns a point geometry for each pixel of a raster band along with the value, the X and the Y raster
coordinates of each pixel. The coordinates of the point geometry are of the pixel’s upper-left corner.

Synopsis

geometry ST_PixelAsPoints(raster rast, integer band=1, boolean exclude_nodata_value=TRUE);

Description

Returns a point geometry for each pixel of a raster band along with the value, the X and the Y raster coordinates of each pixel.
The coordinates of the point geometry are of the pixel’s upper-left corner.

Note
When exclude_nodata_value = TRUE, only those pixels whose values are not NODATA are returned as points.

Availability: 2.1.0
Changed: 2.1.1 Changed behavior of exclude_nodata_value.

Examples

SELECT x, y, val, ST_AsText(geom) FROM (SELECT (ST_PixelAsPoints(rast, 1)).* FROM ←-

dummy_rast WHERE rid = 2) foo;

x | y | val | st_astext
---+---+-----+------------------------------
1 | 1 | 253 | POINT(3427927.75 5793244)
2 | 1 | 254 | POINT(3427927.8 5793244)
3 | 1 | 253 | POINT(3427927.85 5793244)
4 | 1 | 254 | POINT(3427927.9 5793244)
5 | 1 | 254 | POINT(3427927.95 5793244)
1 | 2 | 253 | POINT(3427927.75 5793243.95)
2 | 2 | 254 | POINT(3427927.8 5793243.95)
3 | 2 | 254 | POINT(3427927.85 5793243.95)
4 | 2 | 253 | POINT(3427927.9 5793243.95)
5 | 2 | 249 | POINT(3427927.95 5793243.95)
1 | 3 | 250 | POINT(3427927.75 5793243.9)
2 | 3 | 254 | POINT(3427927.8 5793243.9)
3 | 3 | 254 | POINT(3427927.85 5793243.9)
4 | 3 | 252 | POINT(3427927.9 5793243.9)
5 | 3 | 249 | POINT(3427927.95 5793243.9)
1 | 4 | 251 | POINT(3427927.75 5793243.85)
2 | 4 | 253 | POINT(3427927.8 5793243.85)
3 | 4 | 254 | POINT(3427927.85 5793243.85)
4 | 4 | 254 | POINT(3427927.9 5793243.85)
5 | 4 | 253 | POINT(3427927.95 5793243.85)
1 | 5 | 252 | POINT(3427927.75 5793243.8)
PostGIS 2.4.3 Manual 493 / 803

2 | 5 | 250 | POINT(3427927.8 5793243.8)

3 | 5 | 254 | POINT(3427927.85 5793243.8)
4 | 5 | 254 | POINT(3427927.9 5793243.8)
5 | 5 | 254 | POINT(3427927.95 5793243.8)

See Also

ST_DumpAsPolygons, ST_PixelAsPolygon, ST_PixelAsPolygons, ST_PixelAsPoint, ST_PixelAsCentroid, ST_PixelAsCentroids

9.6.5 ST_PixelAsCentroid

ST_PixelAsCentroid — Returns the centroid (point geometry) of the area represented by a pixel.

Synopsis

geometry ST_PixelAsCentroid(raster rast, integer x, integer y);

Description

Returns the centroid (point geometry) of the area represented by a pixel.

Availability: 2.1.0

Examples

SELECT ST_AsText(ST_PixelAsCentroid(rast, 1, 1)) FROM dummy_rast WHERE rid = 1;

st_astext
--------------
POINT(1.5 2)

See Also

ST_DumpAsPolygons, ST_PixelAsPolygon, ST_PixelAsPolygons, ST_PixelAsPoint, ST_PixelAsPoints, ST_PixelAsCentroids

9.6.6 ST_PixelAsCentroids

ST_PixelAsCentroids — Returns the centroid (point geometry) for each pixel of a raster band along with the value, the X and
the Y raster coordinates of each pixel. The point geometry is the centroid of the area represented by a pixel.

Synopsis

geometry ST_PixelAsCentroids(raster rast, integer band=1, boolean exclude_nodata_value=TRUE);

PostGIS 2.4.3 Manual 494 / 803

Description

Returns the centroid (point geometry) for each pixel of a raster band along with the value, the X and the Y raster coordinates of
each pixel. The point geometry is the centroid of the area represented by a pixel.

Note
When exclude_nodata_value = TRUE, only those pixels whose values are not NODATA are returned as points.

Availability: 2.1.0
Changed: 2.1.1 Changed behavior of exclude_nodata_value.

Examples

--LATERAL syntax requires PostgreSQL 9.3+

SELECT x, y, val, ST_AsText(geom)
FROM (SELECT dp.* FROM dummy_rast, LATERAL ST_PixelAsCentroids(rast, 1) AS dp WHERE rid = ←-
2) foo;
x | y | val | st_astext
---+---+-----+--------------------------------
1 | 1 | 253 | POINT(3427927.775 5793243.975)
2 | 1 | 254 | POINT(3427927.825 5793243.975)
3 | 1 | 253 | POINT(3427927.875 5793243.975)
4 | 1 | 254 | POINT(3427927.925 5793243.975)
5 | 1 | 254 | POINT(3427927.975 5793243.975)
1 | 2 | 253 | POINT(3427927.775 5793243.925)
2 | 2 | 254 | POINT(3427927.825 5793243.925)
3 | 2 | 254 | POINT(3427927.875 5793243.925)
4 | 2 | 253 | POINT(3427927.925 5793243.925)
5 | 2 | 249 | POINT(3427927.975 5793243.925)
1 | 3 | 250 | POINT(3427927.775 5793243.875)
2 | 3 | 254 | POINT(3427927.825 5793243.875)
3 | 3 | 254 | POINT(3427927.875 5793243.875)
4 | 3 | 252 | POINT(3427927.925 5793243.875)
5 | 3 | 249 | POINT(3427927.975 5793243.875)
1 | 4 | 251 | POINT(3427927.775 5793243.825)
2 | 4 | 253 | POINT(3427927.825 5793243.825)
3 | 4 | 254 | POINT(3427927.875 5793243.825)
4 | 4 | 254 | POINT(3427927.925 5793243.825)
5 | 4 | 253 | POINT(3427927.975 5793243.825)
1 | 5 | 252 | POINT(3427927.775 5793243.775)
2 | 5 | 250 | POINT(3427927.825 5793243.775)
3 | 5 | 254 | POINT(3427927.875 5793243.775)
4 | 5 | 254 | POINT(3427927.925 5793243.775)
5 | 5 | 254 | POINT(3427927.975 5793243.775)

See Also

ST_DumpAsPolygons, ST_PixelAsPolygon, ST_PixelAsPolygons, ST_PixelAsPoint, ST_PixelAsPoints, ST_PixelAsCentroid

9.6.7 ST_Value

ST_Value — Returns the value of a given band in a given columnx, rowy pixel or at a particular geometric point. Band numbers
start at 1 and assumed to be 1 if not specified. If exclude_nodata_value is set to false, then all pixels include nodata
pixels are considered to intersect and return value. If exclude_nodata_value is not passed in then reads it from metadata
of raster.
PostGIS 2.4.3 Manual 495 / 803

Synopsis

double precision ST_Value(raster rast, geometry pt, boolean exclude_nodata_value=true);

double precision ST_Value(raster rast, integer band, geometry pt, boolean exclude_nodata_value=true);
double precision ST_Value(raster rast, integer x, integer y, boolean exclude_nodata_value=true);
double precision ST_Value(raster rast, integer band, integer x, integer y, boolean exclude_nodata_value=true);

Description

Returns the value of a given band in a given columnx, rowy pixel or at a given geometry point. Band numbers start at 1 and band
is assumed to be 1 if not specified. If exclude_nodata_value is set to true, then only non nodata pixels are considered.
If exclude_nodata_value is set to false, then all pixels are considered.
Enhanced: 2.0.0 exclude_nodata_value optional argument was added.

Examples

-- get raster values at particular postgis geometry points

-- the srid of your geometry should be same as for your raster
SELECT rid, ST_Value(rast, foo.pt_geom) As b1pval, ST_Value(rast, 2, foo.pt_geom) As b2pval
FROM dummy_rast CROSS JOIN (SELECT ST_SetSRID(ST_Point(3427927.77, 5793243.76), 0) As ←-
pt_geom) As foo
WHERE rid=2;

rid | b1pval | b2pval

-----+--------+--------
2 | 252 | 79

-- general fictitious example using a real table

SELECT rid, ST_Value(rast, 3, sometable.geom) As b3pval
FROM sometable
WHERE ST_Intersects(rast,sometable.geom);

SELECT rid, ST_Value(rast, 1, 1, 1) As b1pval,

ST_Value(rast, 2, 1, 1) As b2pval, ST_Value(rast, 3, 1, 1) As b3pval
FROM dummy_rast
WHERE rid=2;

rid | b1pval | b2pval | b3pval

-----+--------+--------+--------
2 | 253 | 78 | 70

--- Get all values in bands 1,2,3 of each pixel --

SELECT x, y, ST_Value(rast, 1, x, y) As b1val,
ST_Value(rast, 2, x, y) As b2val, ST_Value(rast, 3, x, y) As b3val
FROM dummy_rast CROSS JOIN
generate_series(1, 1000) As x CROSS JOIN generate_series(1, 1000) As y
WHERE rid = 2 AND x <= ST_Width(rast) AND y <= ST_Height(rast);

x | y | b1val | b2val | b3val

---+---+-------+-------+-------
1 | 1 | 253 | 78 | 70
1 | 2 | 253 | 96 | 80
1 | 3 | 250 | 99 | 90
1 | 4 | 251 | 89 | 77
1 | 5 | 252 | 79 | 62
2 | 1 | 254 | 98 | 86
2 | 2 | 254 | 118 | 108
PostGIS 2.4.3 Manual 496 / 803

:
:

--- Get all values in bands 1,2,3 of each pixel same as above but returning the upper left ←-
point point of each pixel --
SELECT ST_AsText(ST_SetSRID(
ST_Point(ST_UpperLeftX(rast) + ST_ScaleX(rast)*x,
ST_UpperLeftY(rast) + ST_ScaleY(rast)*y),
ST_SRID(rast))) As uplpt
, ST_Value(rast, 1, x, y) As b1val,
ST_Value(rast, 2, x, y) As b2val, ST_Value(rast, 3, x, y) As b3val
FROM dummy_rast CROSS JOIN
generate_series(1,1000) As x CROSS JOIN generate_series(1,1000) As y
WHERE rid = 2 AND x <= ST_Width(rast) AND y <= ST_Height(rast);

uplpt | b1val | b2val | b3val

-----------------------------+-------+-------+-------
POINT(3427929.25 5793245.5) | 253 | 78 | 70
POINT(3427929.25 5793247) | 253 | 96 | 80
POINT(3427929.25 5793248.5) | 250 | 99 | 90
:

--- Get a polygon formed by union of all pixels

that fall in a particular value range and intersect particular polygon --
SELECT ST_AsText(ST_Union(pixpolyg)) As shadow
FROM (SELECT ST_Translate(ST_MakeEnvelope(
ST_UpperLeftX(rast), ST_UpperLeftY(rast),
ST_UpperLeftX(rast) + ST_ScaleX(rast),
ST_UpperLeftY(rast) + ST_ScaleY(rast), 0
), ST_ScaleX(rast)*x, ST_ScaleY(rast)*y
) As pixpolyg, ST_Value(rast, 2, x, y) As b2val
FROM dummy_rast CROSS JOIN
generate_series(1,1000) As x CROSS JOIN generate_series(1,1000) As y
WHERE rid = 2
AND x <= ST_Width(rast) AND y <= ST_Height(rast)) As foo
WHERE
ST_Intersects(
pixpolyg,
ST_GeomFromText('POLYGON((3427928 5793244,3427927.75 5793243.75,3427928 ←-
5793243.75,3427928 5793244))',0)
) AND b2val != 254;

shadow
------------------------------------------------------------------------------------
MULTIPOLYGON(((3427928 5793243.9,3427928 5793243.85,3427927.95 5793243.85,3427927.95 ←-
5793243.9,
3427927.95 5793243.95,3427928 5793243.95,3427928.05 5793243.95,3427928.05 ←-
5793243.9,3427928 5793243.9)),((3427927.95 5793243.9,3427927.95 579324
3.85,3427927.9 5793243.85,3427927.85 5793243.85,3427927.85 5793243.9,3427927.9 ←-
5793243.9,3427927.9 5793243.95,
3427927.95 5793243.95,3427927.95 5793243.9)),((3427927.85 5793243.75,3427927.85 ←-
5793243.7,3427927.8 5793243.7,3427927.8 5793243.75
,3427927.8 5793243.8,3427927.8 5793243.85,3427927.85 5793243.85,3427927.85 ←-
5793243.8,3427927.85 5793243.75)),
((3427928.05 5793243.75,3427928.05 5793243.7,3427928 5793243.7,3427927.95 ←-
5793243.7,3427927.95 5793243.75,3427927.95 5793243.8,3427
927.95 5793243.85,3427928 5793243.85,3427928 5793243.8,3427928.05 5793243.8,
3427928.05 5793243.75)),((3427927.95 5793243.75,3427927.95 5793243.7,3427927.9 ←-
5793243.7,3427927.85 5793243.7,
3427927.85 5793243.75,3427927.85 5793243.8,3427927.85 5793243.85,3427927.9 5793243.85,
PostGIS 2.4.3 Manual 497 / 803

3427927.95 5793243.85,3427927.95 5793243.8,3427927.95 5793243.75)))

--- Checking all the pixels of a large raster tile can take a long time.
--- You can dramatically improve speed at some lose of precision by orders of magnitude
-- by sampling pixels using the step optional parameter of generate_series.
-- This next example does the same as previous but by checking 1 for every 4 (2x2) pixels ←-
and putting in the last checked
-- putting in the checked pixel as the value for subsequent 4

SELECT ST_AsText(ST_Union(pixpolyg)) As shadow

FROM (SELECT ST_Translate(ST_MakeEnvelope(
ST_UpperLeftX(rast), ST_UpperLeftY(rast),
ST_UpperLeftX(rast) + ST_ScaleX(rast)*2,
ST_UpperLeftY(rast) + ST_ScaleY(rast)*2, 0
), ST_ScaleX(rast)*x, ST_ScaleY(rast)*y
) As pixpolyg, ST_Value(rast, 2, x, y) As b2val
FROM dummy_rast CROSS JOIN
generate_series(1,1000,2) As x CROSS JOIN generate_series(1,1000,2) As y
WHERE rid = 2
AND x <= ST_Width(rast) AND y <= ST_Height(rast) ) As foo
WHERE
ST_Intersects(
pixpolyg,
ST_GeomFromText('POLYGON((3427928 5793244,3427927.75 5793243.75,3427928 ←-
5793243.75,3427928 5793244))',0)
) AND b2val != 254;

shadow
------------------------------------------------------------------------------------
MULTIPOLYGON(((3427927.9 5793243.85,3427927.8 5793243.85,3427927.8 5793243.95,
3427927.9 5793243.95,3427928 5793243.95,3427928.1 5793243.95,3427928.1 5793243.85,3427928 ←-
5793243.85,3427927.9 5793243.85)),
((3427927.9 5793243.65,3427927.8 5793243.65,3427927.8 5793243.75,3427927.8 ←-
5793243.85,3427927.9 5793243.85,
3427928 5793243.85,3427928 5793243.75,3427928.1 5793243.75,3427928.1 5793243.65,3427928 ←-
5793243.65,3427927.9 5793243.65)))

See Also

ST_SetValue, ST_DumpAsPolygons, ST_NumBands, ST_PixelAsPolygon, ST_ScaleX, ST_ScaleY, ST_UpperLeftX, ST_UpperLeftY,

ST_SRID, ST_AsText, ST_Point, ST_MakeEnvelope, ST_Intersects, ST_Intersection

9.6.8 ST_NearestValue

ST_NearestValue — Returns the nearest non-NODATA value of a given band’s pixel specified by a columnx and rowy or a
geometric point expressed in the same spatial reference coordinate system as the raster.

Synopsis

double precision ST_NearestValue(raster rast, integer bandnum, geometry pt, boolean exclude_nodata_value=true);
double precision ST_NearestValue(raster rast, geometry pt, boolean exclude_nodata_value=true);
double precision ST_NearestValue(raster rast, integer bandnum, integer columnx, integer rowy, boolean exclude_nodata_value=true);
double precision ST_NearestValue(raster rast, integer columnx, integer rowy, boolean exclude_nodata_value=true);
PostGIS 2.4.3 Manual 498 / 803

Description

Returns the nearest non-NODATA value of a given band in a given columnx, rowy pixel or at a specific geometric point. If
the columnx, rowy pixel or the pixel at the specified geometric point is NODATA, the function will find the nearest pixel to the
columnx, rowy pixel or geometric point whose value is not NODATA.
Band numbers start at 1 and bandnum is assumed to be 1 if not specified. If exclude_nodata_value is set to false, then
all pixels include nodata pixels are considered to intersect and return value. If exclude_nodata_value is not passed in
then reads it from metadata of raster.
Availability: 2.1.0

Note
ST_NearestValue is a drop-in replacement for ST_Value.

Examples

-- pixel 2x2 has value

SELECT
ST_Value(rast, 2, 2) AS value,
ST_NearestValue(rast, 2, 2) AS nearestvalue
FROM (
SELECT
ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 0.
),
2, 3, 0.
),
3, 5, 0.
),
4, 2, 0.
),
5, 4, 0.
) AS rast
) AS foo

value | nearestvalue
-------+--------------
1 | 1

-- pixel 2x3 is NODATA

SELECT
ST_Value(rast, 2, 3) AS value,
ST_NearestValue(rast, 2, 3) AS nearestvalue
FROM (
SELECT
ST_SetValue(
ST_SetValue(
ST_SetValue(
PostGIS 2.4.3 Manual 499 / 803

ST_SetValue(
ST_SetValue(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 0.
),
2, 3, 0.
),
3, 5, 0.
),
4, 2, 0.
),
5, 4, 0.
) AS rast
) AS foo

value | nearestvalue
-------+--------------
| 1

See Also

ST_Neighborhood, ST_Value

9.6.9 ST_Neighborhood

ST_Neighborhood — Returns a 2-D double precision array of the non-NODATA values around a given band’s pixel specified by
either a columnX and rowY or a geometric point expressed in the same spatial reference coordinate system as the raster.

Synopsis

double precision[][] ST_Neighborhood(raster rast, integer bandnum, integer columnX, integer rowY, integer distanceX, integer
distanceY, boolean exclude_nodata_value=true);
double precision[][] ST_Neighborhood(raster rast, integer columnX, integer rowY, integer distanceX, integer distanceY, boolean
exclude_nodata_value=true);
double precision[][] ST_Neighborhood(raster rast, integer bandnum, geometry pt, integer distanceX, integer distanceY, boolean
exclude_nodata_value=true);
double precision[][] ST_Neighborhood(raster rast, geometry pt, integer distanceX, integer distanceY, boolean exclude_nodata_value=tru

Description

Returns a 2-D double precision array of the non-NODATA values around a given band’s pixel specified by either a columnX
and rowY or a geometric point expressed in the same spatial reference coordinate system as the raster. The distanceX and
distanceY parameters define the number of pixels around the specified pixel in the X and Y axes, e.g. I want all values within
3 pixel distance along the X axis and 2 pixel distance along the Y axis around my pixel of interest. The center value of the 2-D
array will be the value at the pixel specified by the columnX and rowY or the geometric point.
Band numbers start at 1 and bandnum is assumed to be 1 if not specified. If exclude_nodata_value is set to false, then
all pixels include nodata pixels are considered to intersect and return value. If exclude_nodata_value is not passed in
then reads it from metadata of raster.
PostGIS 2.4.3 Manual 500 / 803

Note
The number of elements along each axis of the returning 2-D array is 2 * (distanceX|distanceY) + 1. So for a
distanceX and distanceY of 1, the returning array will be 3x3.

Note
The 2-D array output can be passed to any of the raster processing builtin functions, e.g. ST_Min4ma, ST_Sum4ma,
ST_Mean4ma.

Availability: 2.1.0

Examples

-- pixel 2x2 has value

SELECT
ST_Neighborhood(rast, 2, 2, 1, 1)
FROM (
SELECT
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 1, ARRAY[
[0, 1, 1, 1, 1],
[1, 1, 1, 0, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 0],
[1, 1, 0, 1, 1]
]::double precision[],
1
) AS rast
) AS foo

st_neighborhood
---------------------------------
{{NULL,1,1},{1,1,NULL},{1,1,1}}

-- pixel 2x3 is NODATA

SELECT
ST_Neighborhood(rast, 2, 3, 1, 1)
FROM (
SELECT
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 1, ARRAY[
[0, 1, 1, 1, 1],
[1, 1, 1, 0, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 0],
[1, 1, 0, 1, 1]
]::double precision[],
1
PostGIS 2.4.3 Manual 501 / 803

) AS rast
) AS foo

st_neighborhood
------------------------------
{{1,1,1},{1,NULL,1},{1,1,1}}

-- pixel 3x3 has value

-- exclude_nodata_value = FALSE
SELECT
ST_Neighborhood(rast, 3, 3, 1, 1, false)
FROM (
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 1, ARRAY[
[0, 1, 1, 1, 1],
[1, 1, 1, 0, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 0],
[1, 1, 0, 1, 1]
]::double precision[],
1
) AS rast
) AS foo

st_neighborhood
---------------------------
{{1,0,1},{1,1,1},{0,1,1}}

See Also

ST_NearestValue, ST_Min4ma, ST_Max4ma, ST_Sum4ma, ST_Mean4ma, ST_Range4ma, ST_Distinct4ma, ST_StdDev4ma

9.6.10 ST_SetValue

ST_SetValue — Returns modified raster resulting from setting the value of a given band in a given columnx, rowy pixel or the
pixels that intersect a particular geometry. Band numbers start at 1 and assumed to be 1 if not specified.

Synopsis

raster ST_SetValue(raster rast, integer bandnum, geometry geom, double precision newvalue);
raster ST_SetValue(raster rast, geometry geom, double precision newvalue);
raster ST_SetValue(raster rast, integer bandnum, integer columnx, integer rowy, double precision newvalue);
raster ST_SetValue(raster rast, integer columnx, integer rowy, double precision newvalue);

Description

Returns modified raster resulting from setting the specified pixels’ values to new value for the designated band given the raster’s
row and column or a geometry. If no band is specified, then band 1 is assumed.
Enhanced: 2.1.0 Geometry variant of ST_SetValue() now supports any geometry type, not just point. The geometry variant is a
wrapper around the geomval[] variant of ST_SetValues()
PostGIS 2.4.3 Manual 502 / 803

Examples

-- Geometry example
SELECT (foo.geomval).val, ST_AsText(ST_Union((foo.geomval).geom))
FROM (SELECT ST_DumpAsPolygons(
ST_SetValue(rast,1,
ST_Point(3427927.75, 5793243.95),
50)
) As geomval
FROM dummy_rast
where rid = 2) As foo
WHERE (foo.geomval).val < 250
GROUP BY (foo.geomval).val;

val | st_astext
-----+-------------------------------------------------------------------
50 | POLYGON((3427927.75 5793244,3427927.75 5793243.95,3427927.8 579324 ...
249 | POLYGON((3427927.95 5793243.95,3427927.95 5793243.85,3427928 57932 ...

-- Store the changed raster --

UPDATE dummy_rast SET rast = ST_SetValue(rast,1, ST_Point(3427927.75, 5793243.95),100)
WHERE rid = 2 ;

See Also

ST_Value, ST_DumpAsPolygons

9.6.11 ST_SetValues

ST_SetValues — Returns modified raster resulting from setting the values of a given band.

Synopsis

raster ST_SetValues(raster rast, integer nband, integer columnx, integer rowy, double precision[][] newvalueset, boolean[][]
noset=NULL, boolean keepnodata=FALSE);
raster ST_SetValues(raster rast, integer nband, integer columnx, integer rowy, double precision[][] newvalueset, double precision
nosetvalue, boolean keepnodata=FALSE);
raster ST_SetValues(raster rast, integer nband, integer columnx, integer rowy, integer width, integer height, double precision
newvalue, boolean keepnodata=FALSE);
raster ST_SetValues(raster rast, integer columnx, integer rowy, integer width, integer height, double precision newvalue, boolean
keepnodata=FALSE);
raster ST_SetValues(raster rast, integer nband, geomval[] geomvalset, boolean keepnodata=FALSE);

Description

Returns modified raster resulting from setting specified pixels to new value(s) for the designated band.
If keepnodata is TRUE, those pixels whose values are NODATA will not be set with the corresponding value in newvalueset.
For Variant 1, the specific pixels to be set are determined by the columnx, rowy pixel coordinates and the dimensions of the
newvalueset array. noset can be used to prevent pixels with values present in newvalueset from being set (due to
PostgreSQL not permitting ragged/jagged arrays). See example Variant 1.
Variant 2 is like Variant 1 but with a simple double precision nosetvalue instead of a boolean noset array. Elements in
newvalueset with the nosetvalue value with be skipped. See example Variant 2.
PostGIS 2.4.3 Manual 503 / 803

For Variant 3, the specific pixels to be set are determined by the columnx, rowy pixel coordinates, width and height. See
example Variant 3.
Variant 4 is the same as Variant 3 with the exception that it assumes that the first band’s pixels of rast will be set.
For Variant 5, an array of geomval is used to determine the specific pixels to be set. If all the geometries in the array are of
type POINT or MULTIPOINT, the function uses a shortcut where the longitude and latitude of each point is used to set a pixel
directly. Otherwise, the geometries are converted to rasters and then iterated through in one pass. See example Variant 5.
Availability: 2.1.0

Examples: Variant 1

/*
The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 1 | 1 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | => | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
*/
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 2, 2, ARRAY[[9, 9], [9, 9]]::double precision[][]
)
) AS poly
) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 | 1
1 | 2 | 1
1 | 3 | 1
2 | 1 | 1
2 | 2 | 9
2 | 3 | 9
3 | 1 | 1
3 | 2 | 9
3 | 3 | 9

/*
The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 9 | 9 | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | => | 9 | | 9 |
PostGIS 2.4.3 Manual 504 / 803

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 9 | 9 | 9 |
+ - + - + - + + - + - + - +
* /
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 1, 1, ARRAY[[9, 9, 9], [9, NULL, 9], [9, 9, 9]]::double precision[][]
)
) AS poly
) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 | 9
1 | 2 | 9
1 | 3 | 9
2 | 1 | 9
2 | 2 |
2 | 3 | 9
3 | 1 | 9
3 | 2 | 9
3 | 3 | 9

/*
The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 9 | 9 | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | => | 1 | | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 9 | 9 | 9 |
+ - + - + - + + - + - + - +
*/
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 1, 1,
ARRAY[[9, 9, 9], [9, NULL, 9], [9, 9, 9]]::double precision[][],
ARRAY[[false], [true]]::boolean[][]
)
) AS poly
PostGIS 2.4.3 Manual 505 / 803

) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 | 9
1 | 2 | 1
1 | 3 | 9
2 | 1 | 9
2 | 2 |
2 | 3 | 9
3 | 1 | 9
3 | 2 | 9
3 | 3 | 9

/*
The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| | 1 | 1 | | | 9 | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | => | 1 | | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 9 | 9 | 9 |
+ - + - + - + + - + - + - +
*/
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_SetValue(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 1, 1, NULL
),
1, 1, 1,
ARRAY[[9, 9, 9], [9, NULL, 9], [9, 9, 9]]::double precision[][],
ARRAY[[false], [true]]::boolean[][],
TRUE
)
) AS poly
) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 |
1 | 2 | 1
1 | 3 | 9
2 | 1 | 9
2 | 2 |
2 | 3 | 9
3 | 1 | 9
3 | 2 | 9
3 | 3 | 9
PostGIS 2.4.3 Manual 506 / 803

Examples: Variant 2

/*
The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 1 | 1 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | => | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
*/
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 1, 1, ARRAY[[-1, -1, -1], [-1, 9, 9], [-1, 9, 9]]::double precision[][], -1
)
) AS poly
) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 | 1
1 | 2 | 1
1 | 3 | 1
2 | 1 | 1
2 | 2 | 9
2 | 3 | 9
3 | 1 | 1
3 | 2 | 9
3 | 3 | 9

/*
This example is like the previous one. Instead of nosetvalue = -1, nosetvalue = NULL

The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 1 | 1 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | => | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
*/
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
PostGIS 2.4.3 Manual 507 / 803

SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 1, 1, ARRAY[[NULL, NULL, NULL], [NULL, 9, 9], [NULL, 9, 9]]::double precision[][], ←-
NULL::double precision
)
) AS poly
) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 | 1
1 | 2 | 1
1 | 3 | 1
2 | 1 | 1
2 | 2 | 9
2 | 3 | 9
3 | 1 | 1
3 | 2 | 9
3 | 3 | 9

Examples: Variant 3

/*
The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 1 | 1 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | => | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
*/
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 2, 2, 2, 2, 9
)
) AS poly
) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 | 1
PostGIS 2.4.3 Manual 508 / 803

1 | 2 | 1
1 | 3 | 1
2 | 1 | 1
2 | 2 | 9
2 | 3 | 9
3 | 1 | 1
3 | 2 | 9
3 | 3 | 9

/*
The ST_SetValues() does the following...

+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 1 | 1 |
+ - + - + - + + - + - + - +
| 1 | | 1 | => | 1 | | 9 |
+ - + - + - + + - + - + - +
| 1 | 1 | 1 | | 1 | 9 | 9 |
+ - + - + - + + - + - + - +
*/
SELECT
(poly).x,
(poly).y,
(poly).val
FROM (
SELECT
ST_PixelAsPolygons(
ST_SetValues(
ST_SetValue(
ST_AddBand(
ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0),
1, '8BUI', 1, 0
),
1, 2, 2, NULL
),
1, 2, 2, 2, 2, 9, TRUE
)
) AS poly
) foo
ORDER BY 1, 2;

x | y | val
---+---+-----
1 | 1 | 1
1 | 2 | 1
1 | 3 | 1
2 | 1 | 1
2 | 2 |
2 | 3 | 9
3 | 1 | 1
3 | 2 | 9
3 | 3 | 9

Examples: Variant 5

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0), 1, '8BUI', 0, ←-
0) AS rast
), bar AS (
SELECT 1 AS gid, 'SRID=0;POINT(2.5 -2.5)'::geometry geom UNION ALL
PostGIS 2.4.3 Manual 509 / 803

SELECT 2 AS gid, 'SRID=0;POLYGON((1 -1, 4 -1, 4 -4, 1 -4, 1 -1))'::geometry geom UNION ←-
ALL
SELECT 3 AS gid, 'SRID=0;POLYGON((0 0, 5 0, 5 -1, 1 -1, 1 -4, 0 -4, 0 0))'::geometry geom ←-
UNION ALL
SELECT 4 AS gid, 'SRID=0;MULTIPOINT(0 0, 4 4, 4 -4)'::geometry
)
SELECT
rid, gid, ST_DumpValues(ST_SetValue(rast, 1, geom, gid))
FROM foo t1
CROSS JOIN bar t2
ORDER BY rid, gid;

rid | gid | st_dumpvalues

-----+-----+-----------------------------------------------------------------------------------------

1 | 1 | (1,"{{NULL,NULL,NULL,NULL,NULL},{NULL,NULL,NULL,NULL,NULL},{NULL,NULL,1,NULL, ←-
NULL},{NULL,NULL,NULL,NULL,NULL},{NULL,NULL,NULL,NULL,NULL}}")
1 | 2 | (1,"{{NULL,NULL,NULL,NULL,NULL},{NULL,2,2,2,NULL},{NULL,2,2,2,NULL},{NULL ←-
,2,2,2,NULL},{NULL,NULL,NULL,NULL,NULL}}")
1 | 3 | (1,"{{3,3,3,3,3},{3,NULL,NULL,NULL,NULL},{3,NULL,NULL,NULL,NULL},{3,NULL,NULL, ←-
NULL,NULL},{NULL,NULL,NULL,NULL,NULL}}")
1 | 4 | (1,"{{4,NULL,NULL,NULL,NULL},{NULL,NULL,NULL,NULL,NULL},{NULL,NULL,NULL,NULL, ←-
NULL},{NULL,NULL,NULL,NULL,NULL},{NULL,NULL,NULL,NULL,4}}")
(4 rows)

The following shows that geomvals later in the array can overwrite prior geomvals
WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0), 1, '8BUI', 0, ←-
0) AS rast
), bar AS (
SELECT 1 AS gid, 'SRID=0;POINT(2.5 -2.5)'::geometry geom UNION ALL
SELECT 2 AS gid, 'SRID=0;POLYGON((1 -1, 4 -1, 4 -4, 1 -4, 1 -1))'::geometry geom UNION ←-
ALL
SELECT 3 AS gid, 'SRID=0;POLYGON((0 0, 5 0, 5 -1, 1 -1, 1 -4, 0 -4, 0 0))'::geometry geom ←-
UNION ALL
SELECT 4 AS gid, 'SRID=0;MULTIPOINT(0 0, 4 4, 4 -4)'::geometry
)
SELECT
t1.rid, t2.gid, t3.gid, ST_DumpValues(ST_SetValues(rast, 1, ARRAY[ROW(t2.geom, t2.gid), ←-
ROW(t3.geom, t3.gid)]::geomval[]))
FROM foo t1
CROSS JOIN bar t2
CROSS JOIN bar t3
WHERE t2.gid = 1
AND t3.gid = 2
ORDER BY t1.rid, t2.gid, t3.gid;

rid | gid | gid | st_dumpvalues

-----+-----+-----+-----------------------------------------------------------------------------------

1 | 1 | 2 | (1,"{{NULL,NULL,NULL,NULL,NULL},{NULL,2,2,2,NULL},{NULL,2,2,2,NULL},{ ←-
NULL,2,2,2,NULL},{NULL,NULL,NULL,NULL,NULL}}")
(1 row)

This example is the opposite of the prior example

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0), 1, '8BUI', 0, ←-
0) AS rast
), bar AS (
SELECT 1 AS gid, 'SRID=0;POINT(2.5 -2.5)'::geometry geom UNION ALL
PostGIS 2.4.3 Manual 510 / 803

SELECT 2 AS gid, 'SRID=0;POLYGON((1 -1, 4 -1, 4 -4, 1 -4, 1 -1))'::geometry geom UNION ←-
ALL
SELECT 3 AS gid, 'SRID=0;POLYGON((0 0, 5 0, 5 -1, 1 -1, 1 -4, 0 -4, 0 0))'::geometry geom ←-
UNION ALL
SELECT 4 AS gid, 'SRID=0;MULTIPOINT(0 0, 4 4, 4 -4)'::geometry
)
SELECT
t1.rid, t2.gid, t3.gid, ST_DumpValues(ST_SetValues(rast, 1, ARRAY[ROW(t2.geom, t2.gid), ←-
ROW(t3.geom, t3.gid)]::geomval[]))
FROM foo t1
CROSS JOIN bar t2
CROSS JOIN bar t3
WHERE t2.gid = 2
AND t3.gid = 1
ORDER BY t1.rid, t2.gid, t3.gid;

rid | gid | gid | st_dumpvalues

-----+-----+-----+-----------------------------------------------------------------------------------

1 | 2 | 1 | (1,"{{NULL,NULL,NULL,NULL,NULL},{NULL,2,2,2,NULL},{NULL,2,1,2,NULL},{ ←-
NULL,2,2,2,NULL},{NULL,NULL,NULL,NULL,NULL}}")
(1 row)

See Also

ST_Value, ST_SetValue, ST_PixelAsPolygons

9.6.12 ST_DumpValues

ST_DumpValues — Get the values of the specified band as a 2-dimension array.

Synopsis

setof record ST_DumpValues( raster rast , integer[] nband=NULL , boolean exclude_nodata_value=true );

double precision[][] ST_DumpValues( raster rast , integer nband , boolean exclude_nodata_value=true );

Description

Get the values of the specified band as a 2-dimension array (first index is row, second is column). If nband is NULL or not
provided, all raster bands are processed.
Availability: 2.1.0

Examples

WITH foo AS (
SELECT ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0), ←-
1, '8BUI'::text, 1, 0), 2, '32BF'::text, 3, -9999), 3, '16BSI', 0, 0) AS rast
)
SELECT
(ST_DumpValues(rast)).*
FROM foo;

nband | valarray
-------+------------------------------------------------------
1 | {{1,1,1},{1,1,1},{1,1,1}}
PostGIS 2.4.3 Manual 511 / 803

2 | {{3,3,3},{3,3,3},{3,3,3}}
3 | {{NULL,NULL,NULL},{NULL,NULL,NULL},{NULL,NULL,NULL}}
(3 rows)

WITH foo AS (
SELECT ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0), ←-
1, '8BUI'::text, 1, 0), 2, '32BF'::text, 3, -9999), 3, '16BSI', 0, 0) AS rast
)
SELECT
(ST_DumpValues(rast, ARRAY[3, 1])).*
FROM foo;

nband | valarray
-------+------------------------------------------------------
3 | {{NULL,NULL,NULL},{NULL,NULL,NULL},{NULL,NULL,NULL}}
1 | {{1,1,1},{1,1,1},{1,1,1}}
(2 rows)

WITH foo AS (
SELECT ST_SetValue(ST_AddBand(ST_MakeEmptyRaster(3, 3, 0, 0, 1, -1, 0, 0, 0), 1, '8BUI', ←-
1, 0), 1, 2, 5) AS rast
)
SELECT
(ST_DumpValues(rast, 1))[2][1]
FROM foo;

st_dumpvalues
---------------
5
(1 row)

See Also

ST_Value, ST_SetValue, ST_SetValues

9.6.13 ST_PixelOfValue

ST_PixelOfValue — Get the columnx, rowy coordinates of the pixel whose value equals the search value.

Synopsis

setof record ST_PixelOfValue( raster rast , integer nband , double precision[] search , boolean exclude_nodata_value=true );
setof record ST_PixelOfValue( raster rast , double precision[] search , boolean exclude_nodata_value=true );
setof record ST_PixelOfValue( raster rast , integer nband , double precision search , boolean exclude_nodata_value=true );
setof record ST_PixelOfValue( raster rast , double precision search , boolean exclude_nodata_value=true );

Description

Get the columnx, rowy coordinates of the pixel whose value equals the search value. If no band is specified, then band 1 is
assumed.
Availability: 2.1.0
PostGIS 2.4.3 Manual 512 / 803

Examples

SELECT
(pixels).*
FROM (
SELECT
ST_PixelOfValue(
ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_AddBand(
ST_MakeEmptyRaster(5, 5, -2, 2, 1, -1, 0, 0, 0),
'8BUI'::text, 1, 0
),
1, 1, 0
),
2, 3, 0
),
3, 5, 0
),
4, 2, 0
),
5, 4, 255
)
, 1, ARRAY[1, 255]) AS pixels
) AS foo

val | x | y
-----+---+---
1 | 1 | 2
1 | 1 | 3
1 | 1 | 4
1 | 1 | 5
1 | 2 | 1
1 | 2 | 2
1 | 2 | 4
1 | 2 | 5
1 | 3 | 1
1 | 3 | 2
1 | 3 | 3
1 | 3 | 4
1 | 4 | 1
1 | 4 | 3
1 | 4 | 4
1 | 4 | 5
1 | 5 | 1
1 | 5 | 2
1 | 5 | 3
255 | 5 | 4
1 | 5 | 5

9.7 Raster Editors

9.7.1 ST_SetGeoReference

ST_SetGeoReference — Set Georeference 6 georeference parameters in a single call. Numbers should be separated by white
space. Accepts inputs in GDAL or ESRI format. Default is GDAL.
PostGIS 2.4.3 Manual 513 / 803

Synopsis

raster ST_SetGeoReference(raster rast, text georefcoords, text format=GDAL);

raster ST_SetGeoReference(raster rast, double precision upperleftx, double precision upperlefty, double precision scalex, double
precision scaley, double precision skewx, double precision skewy);

Description

Set Georeference 6 georeference parameters in a single call. Accepts inputs in ’GDAL’ or ’ESRI’ format. Default is GDAL. If 6
coordinates are not provided will return null.
Difference between format representations is as follows:
GDAL:
scalex skewy skewx scaley upperleftx upperlefty

ESRI:
scalex skewy skewx scaley upperleftx + scalex*0.5 upperlefty + scaley*0.5

Note
If the raster has out-db bands, changing the georeference may result in incorrect access of the band’s externally stored
data.

Enhanced: 2.1.0 Addition of ST_SetGeoReference(raster, double precision, ...) variant

Examples

WITH foo AS (
SELECT ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0) AS rast
)
SELECT
0 AS rid, (ST_Metadata(rast)).*
FROM foo
UNION ALL
SELECT
1, (ST_Metadata(ST_SetGeoReference(rast, '10 0 0 -10 0.1 0.1', 'GDAL'))).*
FROM foo
UNION ALL
SELECT
2, (ST_Metadata(ST_SetGeoReference(rast, '10 0 0 -10 5.1 -4.9', 'ESRI'))).*
FROM foo
UNION ALL
SELECT
3, (ST_Metadata(ST_SetGeoReference(rast, 1, 1, 10, -10, 0.001, 0.001))).*
FROM foo

rid | upperleftx | upperlefty | width | height | scalex | scaley | skewx | ←-

skewy | srid | numbands
-----+--------------------+--------------------+-------+--------+--------+--------+-------+-------+--

0 | 0 | 0 | 5 | 5 | 1 | -1 | 0 | ←-
0 | 0 | 0
1 | 0.1 | 0.1 | 5 | 5 | 10 | -10 | 0 | ←-
0 | 0 | 0
PostGIS 2.4.3 Manual 514 / 803

2 | 0.0999999999999996 | 0.0999999999999996 | 5 | 5 | 10 | -10 | 0 | ←-

0 | 0 | 0
3 | 1 | 1 | 5 | 5 | 10 | -10 | 0.001 | ←-
0.001 | 0 | 0

See Also

ST_GeoReference, ST_ScaleX, ST_ScaleY, ST_UpperLeftX, ST_UpperLeftY

9.7.2 ST_SetRotation

ST_SetRotation — Set the rotation of the raster in radian.

Synopsis

float8 ST_SetRotation(raster rast, float8 rotation);

Description

Uniformly rotate the raster. Rotation is in radian. Refer to World File for more details.

Examples

SELECT
ST_ScaleX(rast1), ST_ScaleY(rast1), ST_SkewX(rast1), ST_SkewY(rast1),
ST_ScaleX(rast2), ST_ScaleY(rast2), ST_SkewX(rast2), ST_SkewY(rast2)
FROM (
SELECT ST_SetRotation(rast, 15) AS rast1, rast as rast2 FROM dummy_rast
) AS foo;
st_scalex | st_scaley | st_skewx | st_skewy | ←-
st_scalex | st_scaley | st_skewx | st_skewy
---------------------+---------------------+--------------------+--------------------+-----------+---

-1.51937582571764 | -2.27906373857646 | 1.95086352047135 | 1.30057568031423 | ←-

2 | 3 | 0 | 0
-0.0379843956429411 | -0.0379843956429411 | 0.0325143920078558 | 0.0325143920078558 | ←-
0.05 | -0.05 | 0 | 0

See Also

ST_Rotation, ST_ScaleX, ST_ScaleY, ST_SkewX, ST_SkewY

9.7.3 ST_SetScale

ST_SetScale — Sets the X and Y size of pixels in units of coordinate reference system. Number units/pixel width/height.

Synopsis

raster ST_SetScale(raster rast, float8 xy);

raster ST_SetScale(raster rast, float8 x, float8 y);
PostGIS 2.4.3 Manual 515 / 803

Description

Sets the X and Y size of pixels in units of coordinate reference system. Number units/pixel width/height. If only one unit passed
in, assumed X and Y are the same number.

Note
ST_SetScale is different from ST_Rescale in that ST_SetScale do not resample the raster to match the raster extent. It
only changes the metadata (or georeference) of the raster to correct an originally mis-specified scaling. ST_Rescale re-
sults in a raster having different width and height computed to fit the geographic extent of the input raster. ST_SetScale
do not modify the width, nor the height of the raster.

Changed: 2.0.0 In WKTRaster versions this was called ST_SetPixelSize. This was changed in 2.0.0.

Examples

UPDATE dummy_rast
SET rast = ST_SetScale(rast, 1.5)
WHERE rid = 2;

SELECT ST_ScaleX(rast) As pixx, ST_ScaleY(rast) As pixy, Box3D(rast) As newbox

FROM dummy_rast
WHERE rid = 2;

pixx | pixy | newbox

------+------+----------------------------------------------
1.5 | 1.5 | BOX(3427927.75 5793244 0, 3427935.25 5793251.5 0)

UPDATE dummy_rast
SET rast = ST_SetScale(rast, 1.5, 0.55)
WHERE rid = 2;

SELECT ST_ScaleX(rast) As pixx, ST_ScaleY(rast) As pixy, Box3D(rast) As newbox

FROM dummy_rast
WHERE rid = 2;

pixx | pixy | newbox

------+------+--------------------------------------------
1.5 | 0.55 | BOX(3427927.75 5793244 0,3427935.25 5793247 0)

See Also

ST_ScaleX, ST_ScaleY, Box3D

9.7.4 ST_SetSkew

ST_SetSkew — Sets the georeference X and Y skew (or rotation parameter). If only one is passed in, sets X and Y to the same
value.

Synopsis

raster ST_SetSkew(raster rast, float8 skewxy);

raster ST_SetSkew(raster rast, float8 skewx, float8 skewy);
PostGIS 2.4.3 Manual 516 / 803

Description

Sets the georeference X and Y skew (or rotation parameter). If only one is passed in, sets X and Y to the same value. Refer to
World File for more details.

Examples

-- Example 1
UPDATE dummy_rast SET rast = ST_SetSkew(rast,1,2) WHERE rid = 1;
SELECT rid, ST_SkewX(rast) As skewx, ST_SkewY(rast) As skewy,
ST_GeoReference(rast) as georef
FROM dummy_rast WHERE rid = 1;

rid | skewx | skewy | georef

----+-------+-------+--------------
1 | 1 | 2 | 2.0000000000
: 2.0000000000
: 1.0000000000
: 3.0000000000
: 0.5000000000
: 0.5000000000

-- Example 2 set both to same number:

UPDATE dummy_rast SET rast = ST_SetSkew(rast,0) WHERE rid = 1;
SELECT rid, ST_SkewX(rast) As skewx, ST_SkewY(rast) As skewy,
ST_GeoReference(rast) as georef
FROM dummy_rast WHERE rid = 1;

rid | skewx | skewy | georef

-----+-------+-------+--------------
1 | 0 | 0 | 2.0000000000
: 0.0000000000
: 0.0000000000
: 3.0000000000
: 0.5000000000
: 0.5000000000

See Also

ST_GeoReference, ST_SetGeoReference, ST_SkewX, ST_SkewY

9.7.5 ST_SetSRID

ST_SetSRID — Sets the SRID of a raster to a particular integer srid defined in the spatial_ref_sys table.

Synopsis

raster ST_SetSRID(raster rast, integer srid);

Description

Sets the SRID on a raster to a particular integer value.

PostGIS 2.4.3 Manual 517 / 803

Note
This function does not transform the raster in any way - it simply sets meta data defining the spatial ref of the coordinate
reference system that it’s currently in. Useful for transformations later.

See Also

Section 4.3.1, ST_SRID

9.7.6 ST_SetUpperLeft

ST_SetUpperLeft — Sets the value of the upper left corner of the pixel of the raster to projected X and Y coordinates.

Synopsis

raster ST_SetUpperLeft(raster rast, double precision x, double precision y);

Description

Set the value of the upper left corner of raster to the projected X and Y coordinates

Examples

SELECT ST_SetUpperLeft(rast,-71.01,42.37)
FROM dummy_rast
WHERE rid = 2;

See Also

ST_UpperLeftX, ST_UpperLeftY

9.7.7 ST_Resample

ST_Resample — Resample a raster using a specified resampling algorithm, new dimensions, an arbitrary grid corner and a set
of raster georeferencing attributes defined or borrowed from another raster.

Synopsis

raster ST_Resample(raster rast, integer width, integer height, double precision gridx=NULL, double precision gridy=NULL,
double precision skewx=0, double precision skewy=0, text algorithm=NearestNeighbour, double precision maxerr=0.125);
raster ST_Resample(raster rast, double precision scalex=0, double precision scaley=0, double precision gridx=NULL, double
precision gridy=NULL, double precision skewx=0, double precision skewy=0, text algorithm=NearestNeighbor, double preci-
sion maxerr=0.125);
raster ST_Resample(raster rast, raster ref, text algorithm=NearestNeighbour, double precision maxerr=0.125, boolean usescale=true);
raster ST_Resample(raster rast, raster ref, boolean usescale, text algorithm=NearestNeighbour, double precision maxerr=0.125);
PostGIS 2.4.3 Manual 518 / 803

Description

Resample a raster using a specified resampling algorithm, new dimensions (width & height), a grid corner (gridx & gridy) and
a set of raster georeferencing attributes (scalex, scaley, skewx & skewy) defined or borrowed from another raster. If using a
reference raster, the two rasters must have the same SRID.
New pixel values are computed using the NearestNeighbor (English or American spelling), Bilinear, Cubic, CubicSpline or
Lanczos resampling algorithm. Default is NearestNeighbor which is the fastest but produce the worst interpolation.
A maxerror percent of 0.125 is used if no maxerr is specified.

Note
Refer to: GDAL Warp resampling methods for more details.

Availability: 2.0.0 Requires GDAL 1.6.1+

Changed: 2.1.0 Parameter srid removed. Variants with a reference raster no longer applies the reference raster’s SRID. Use
ST_Transform() to reproject raster. Works on rasters with no SRID.

Examples

SELECT
ST_Width(orig) AS orig_width,
ST_Width(reduce_100) AS new_width
FROM (
SELECT
rast AS orig,
ST_Resample(rast,100,100) AS reduce_100
FROM aerials.boston
WHERE ST_Intersects(rast,
ST_Transform(
ST_MakeEnvelope(-71.128, 42.2392,-71.1277, 42.2397, 4326),26986)
)
LIMIT 1
) AS foo;

orig_width | new_width
------------+-------------
200 | 100

See Also

ST_Rescale, ST_Resize, ST_Transform

9.7.8 ST_Rescale

ST_Rescale — Resample a raster by adjusting only its scale (or pixel size). New pixel values are computed using the Near-
estNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. Default is Nearest-
Neighbor.

Synopsis

raster ST_Rescale(raster rast, double precision scalexy, text algorithm=NearestNeighbour, double precision maxerr=0.125);
raster ST_Rescale(raster rast, double precision scalex, double precision scaley, text algorithm=NearestNeighbour, double preci-
sion maxerr=0.125);
PostGIS 2.4.3 Manual 519 / 803

Description

Resample a raster by adjusting only its scale (or pixel size). New pixel values are computed using the NearestNeighbor (english
or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. The default is NearestNeighbor which is
the fastest but results in the worst interpolation.
scalex and scaley define the new pixel size. scaley must often be negative to get well oriented raster.
When the new scalex or scaley is not a divisor of the raster width or height, the extent of the resulting raster is expanded to
encompass the extent of the provided raster. If you want to be sure to retain exact input extent see ST_Resize
A maxerror percent of 0.125 is used if no maxerr is specified.

Note
Refer to: GDAL Warp resampling methods for more details.

Note
ST_Rescale is different from ST_SetScale in that ST_SetScale do not resample the raster to match the raster extent.
ST_SetScale only changes the metadata (or georeference) of the raster to correct an originally mis-specified scaling.
ST_Rescale results in a raster having different width and height computed to fit the geographic extent of the input raster.
ST_SetScale do not modify the width, nor the height of the raster.

Availability: 2.0.0 Requires GDAL 1.6.1+

Changed: 2.1.0 Works on rasters with no SRID

Examples

A simple example rescaling a raster from a pixel size of 0.001 degree to a pixel size of 0.0015 degree.
-- the original raster pixel size
SELECT ST_PixelWidth(ST_AddBand(ST_MakeEmptyRaster(100, 100, 0, 0, 0.001, -0.001, 0, 0, ←-
4269), '8BUI'::text, 1, 0)) width

width
----------
0.001

-- the rescaled raster raster pixel size

SELECT ST_PixelWidth(ST_Rescale(ST_AddBand(ST_MakeEmptyRaster(100, 100, 0, 0, 0.001, ←-
-0.001, 0, 0, 4269), '8BUI'::text, 1, 0), 0.0015)) width

width
----------
0.0015

See Also

ST_Resize, ST_Resample, ST_SetScale, ST_ScaleX, ST_ScaleY, ST_Transform

9.7.9 ST_Reskew

ST_Reskew — Resample a raster by adjusting only its skew (or rotation parameters). New pixel values are computed using
the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. Default is
NearestNeighbor.
PostGIS 2.4.3 Manual 520 / 803

Synopsis

raster ST_Reskew(raster rast, double precision skewxy, text algorithm=NearestNeighbour, double precision maxerr=0.125);
raster ST_Reskew(raster rast, double precision skewx, double precision skewy, text algorithm=NearestNeighbour, double preci-
sion maxerr=0.125);

Description

Resample a raster by adjusting only its skew (or rotation parameters). New pixel values are computed using the NearestNeighbor
(english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. The default is NearestNeighbor
which is the fastest but results in the worst interpolation.
skewx and skewy define the new skew.
The extent of the new raster will encompass the extent of the provided raster.
A maxerror percent of 0.125 if no maxerr is specified.

Note
Refer to: GDAL Warp resampling methods for more details.

Note
ST_Reskew is different from ST_SetSkew in that ST_SetSkew do not resample the raster to match the raster extent.
ST_SetSkew only changes the metadata (or georeference) of the raster to correct an originally mis-specified skew.
ST_Reskew results in a raster having different width and height computed to fit the geographic extent of the input
raster. ST_SetSkew do not modify the width, nor the height of the raster.

Availability: 2.0.0 Requires GDAL 1.6.1+

Changed: 2.1.0 Works on rasters with no SRID

Examples

A simple example reskewing a raster from a skew of 0.0 to a skew of 0.0015.

-- the original raster non-rotated
SELECT ST_Rotation(ST_AddBand(ST_MakeEmptyRaster(100, 100, 0, 0, 0.001, -0.001, 0, 0, 4269) ←-
, '8BUI'::text, 1, 0));

-- result
0

-- the reskewed raster raster rotation

SELECT ST_Rotation(ST_Reskew(ST_AddBand(ST_MakeEmptyRaster(100, 100, 0, 0, 0.001, -0.001, ←-
0, 0, 4269), '8BUI'::text, 1, 0), 0.0015));

-- result
-0.982793723247329

See Also

ST_Resample, ST_Rescale, ST_SetSkew, ST_SetRotation, ST_SkewX, ST_SkewY, ST_Transform

PostGIS 2.4.3 Manual 521 / 803

9.7.10 ST_SnapToGrid

ST_SnapToGrid — Resample a raster by snapping it to a grid. New pixel values are computed using the NearestNeighbor
(english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. Default is NearestNeighbor.

Synopsis

raster ST_SnapToGrid(raster rast, double precision gridx, double precision gridy, text algorithm=NearestNeighbour, double
precision maxerr=0.125, double precision scalex=DEFAULT 0, double precision scaley=DEFAULT 0);
raster ST_SnapToGrid(raster rast, double precision gridx, double precision gridy, double precision scalex, double precision
scaley, text algorithm=NearestNeighbour, double precision maxerr=0.125);
raster ST_SnapToGrid(raster rast, double precision gridx, double precision gridy, double precision scalexy, text algorithm=NearestNeigh
double precision maxerr=0.125);

Description

Resample a raster by snapping it to a grid defined by an arbitrary pixel corner (gridx & gridy) and optionally a pixel size (scalex &
scaley). New pixel values are computed using the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline
or Lanczos resampling algorithm. The default is NearestNeighbor which is the fastest but results in the worst interpolation.
gridx and gridy define any arbitrary pixel corner of the new grid. This is not necessarily the upper left corner of the new
raster and it does not have to be inside or on the edge of the new raster extent.
You can optionally define the pixel size of the new grid with scalex and scaley.
The extent of the new raster will encompass the extent of the provided raster.
A maxerror percent of 0.125 if no maxerr is specified.

Note
Refer to: GDAL Warp resampling methods for more details.

Note
Use ST_Resample if you need more control over the grid parameters.

Availability: 2.0.0 Requires GDAL 1.6.1+

Changed: 2.1.0 Works on rasters with no SRID

Examples

A simple example snapping a raster to a slightly different grid.

-- the original raster upper left X
SELECT ST_UpperLeftX(ST_AddBand(ST_MakeEmptyRaster(10, 10, 0, 0, 0.001, -0.001, 0, 0, 4269) ←-
, '8BUI'::text, 1, 0));
-- result
0

-- the upper left of raster after snapping

SELECT ST_UpperLeftX(ST_SnapToGrid(ST_AddBand(ST_MakeEmptyRaster(10, 10, 0, 0, 0.001, ←-
-0.001, 0, 0, 4269), '8BUI'::text, 1, 0), 0.0002, 0.0002));

--result
-0.0008
PostGIS 2.4.3 Manual 522 / 803

See Also

ST_Resample, ST_Rescale, ST_UpperLeftX, ST_UpperLeftY

9.7.11 ST_Resize

ST_Resize — Resize a raster to a new width/height

Synopsis

raster ST_Resize(raster rast, integer width, integer height, text algorithm=NearestNeighbor, double precision maxerr=0.125);
raster ST_Resize(raster rast, double precision percentwidth, double precision percentheight, text algorithm=NearestNeighbor,
double precision maxerr=0.125);
raster ST_Resize(raster rast, text width, text height, text algorithm=NearestNeighbor, double precision maxerr=0.125);

Description

Resize a raster to a new width/height. The new width/height can be specified in exact number of pixels or a percentage of the
raster’s width/height. The extent of the the new raster will be the same as the extent of the provided raster.
New pixel values are computed using the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanc-
zos resampling algorithm. The default is NearestNeighbor which is the fastest but results in the worst interpolation.
Variant 1 expects the actual width/height of the output raster.
Variant 2 expects decimal values between zero (0) and one (1) indicating the percentage of the input raster’s width/height.
Variant 3 takes either the actual width/height of the output raster or a textual percentage ("20%") indicating the percentage of the
input raster’s width/height.
Availability: 2.1.0 Requires GDAL 1.6.1+

Examples

WITH foo AS(

SELECT
1 AS rid,
ST_Resize(
ST_AddBand(
ST_MakeEmptyRaster(1000, 1000, 0, 0, 1, -1, 0, 0, 0)
, 1, '8BUI', 255, 0
)
, '50%', '500') AS rast
UNION ALL
SELECT
2 AS rid,
ST_Resize(
ST_AddBand(
ST_MakeEmptyRaster(1000, 1000, 0, 0, 1, -1, 0, 0, 0)
, 1, '8BUI', 255, 0
)
, 500, 100) AS rast
UNION ALL
SELECT
3 AS rid,
ST_Resize(
ST_AddBand(
ST_MakeEmptyRaster(1000, 1000, 0, 0, 1, -1, 0, 0, 0)
, 1, '8BUI', 255, 0
PostGIS 2.4.3 Manual 523 / 803

)
, 0.25, 0.9) AS rast
), bar AS (
SELECT rid, ST_Metadata(rast) AS meta, rast FROM foo
)
SELECT rid, (meta).* FROM bar

rid | upperleftx | upperlefty | width | height | scalex | scaley | skewx | skewy | srid | ←-
numbands
-----+------------+------------+-------+--------+--------+--------+-------+-------+------+----------

1 | 0 | 0 | 500 | 500 | 1 | -1 | 0 | 0 | 0 | ←-
1
2 | 0 | 0 | 500 | 100 | 1 | -1 | 0 | 0 | 0 | ←-
1
3 | 0 | 0 | 250 | 900 | 1 | -1 | 0 | 0 | 0 | ←-
1
(3 rows)

See Also

ST_Resample, ST_Rescale, ST_Reskew, ST_SnapToGrid

9.7.12 ST_Transform

ST_Transform — Reprojects a raster in a known spatial reference system to another known spatial reference system using spec-
ified resampling algorithm. Options are NearestNeighbor, Bilinear, Cubic, CubicSpline, Lanczos defaulting to NearestNeighbor.

Synopsis

raster ST_Transform(raster rast, integer srid, text algorithm=NearestNeighbor, double precision maxerr=0.125, double precision
scalex, double precision scaley);
raster ST_Transform(raster rast, integer srid, double precision scalex, double precision scaley, text algorithm=NearestNeighbor,
double precision maxerr=0.125);
raster ST_Transform(raster rast, raster alignto, text algorithm=NearestNeighbor, double precision maxerr=0.125);

Description

Reprojects a raster in a known spatial reference system to another known spatial reference system using specified pixel warping
algorithm. Uses ’NearestNeighbor’ if no algorithm is specified and maxerror percent of 0.125 if no maxerr is specified.
Algorithm options are: ’NearestNeighbor’, ’Bilinear’, ’Cubic’, ’CubicSpline’, and ’Lanczos’. Refer to: GDAL Warp resampling
methods for more details.
ST_Transform is often confused with ST_SetSRID(). ST_Transform actually changes the coordinates of a raster (and resamples
the pixel values) from one spatial reference system to another, while ST_SetSRID() simply changes the SRID identifier of the
raster.
Unlike the other variants, Variant 3 requires a reference raster as alignto. The transformed raster will be transformed to the
spatial reference system (SRID) of the reference raster and be aligned (ST_SameAlignment = TRUE) to the reference raster.

Note
If you find your transformation support is not working right, you may need to set the environment variable PROJSO to
the .so or .dll projection library your PostGIS is using. This just needs to have the name of the file. So for example on
windows, you would in Control Panel -> System -> Environment Variables add a system variable called PROJSO and
set it to libproj.dll (if you are using proj 4.6.1). You’ll have to restart your PostgreSQL service/daemon after this
change.
PostGIS 2.4.3 Manual 524 / 803

Availability: 2.0.0 Requires GDAL 1.6.1+

Enhanced: 2.1.0 Addition of ST_Transform(rast, alignto) variant

Examples

SELECT ST_Width(mass_stm) As w_before, ST_Width(wgs_84) As w_after,

ST_Height(mass_stm) As h_before, ST_Height(wgs_84) As h_after
FROM
( SELECT rast As mass_stm, ST_Transform(rast,4326) As wgs_84
, ST_Transform(rast,4326, 'Bilinear') AS wgs_84_bilin
FROM aerials.o_2_boston
WHERE ST_Intersects(rast,
ST_Transform(ST_MakeEnvelope(-71.128, 42.2392,-71.1277, 42.2397, 4326),26986) )
LIMIT 1) As foo;

w_before | w_after | h_before | h_after

----------+---------+----------+---------
200 | 228 | 200 | 170

After transform to wgs 84 long lat

After transform to wgs 84 long lat
with bilinear algorithm instead of NN
(wgs_84)
original mass state plane meters default (wgs_84_bilin)
(mass_stm)

Examples: Variant 3

The following shows the difference between using ST_Transform(raster, srid) and ST_Transform(raster, alignto)
WITH foo AS (
SELECT 0 AS rid, ST_AddBand(ST_MakeEmptyRaster(2, 2, -500000, 600000, 100, -100, 0, 0, ←-
2163), 1, '16BUI', 1, 0) AS rast UNION ALL
SELECT 1, ST_AddBand(ST_MakeEmptyRaster(2, 2, -499800, 600000, 100, -100, 0, 0, 2163), 1, ←-
'16BUI', 2, 0) AS rast UNION ALL
SELECT 2, ST_AddBand(ST_MakeEmptyRaster(2, 2, -499600, 600000, 100, -100, 0, 0, 2163), 1, ←-
'16BUI', 3, 0) AS rast UNION ALL

SELECT 3, ST_AddBand(ST_MakeEmptyRaster(2, 2, -500000, 599800, 100, -100, 0, 0, 2163), 1, ←-

'16BUI', 10, 0) AS rast UNION ALL
SELECT 4, ST_AddBand(ST_MakeEmptyRaster(2, 2, -499800, 599800, 100, -100, 0, 0, 2163), 1, ←-
'16BUI', 20, 0) AS rast UNION ALL
SELECT 5, ST_AddBand(ST_MakeEmptyRaster(2, 2, -499600, 599800, 100, -100, 0, 0, 2163), 1, ←-
'16BUI', 30, 0) AS rast UNION ALL
PostGIS 2.4.3 Manual 525 / 803

SELECT 6, ST_AddBand(ST_MakeEmptyRaster(2, 2, -500000, 599600, 100, -100, 0, 0, 2163), 1, ←-

'16BUI', 100, 0) AS rast UNION ALL
SELECT 7, ST_AddBand(ST_MakeEmptyRaster(2, 2, -499800, 599600, 100, -100, 0, 0, 2163), 1, ←-
'16BUI', 200, 0) AS rast UNION ALL
SELECT 8, ST_AddBand(ST_MakeEmptyRaster(2, 2, -499600, 599600, 100, -100, 0, 0, 2163), 1, ←-
'16BUI', 300, 0) AS rast
), bar AS (
SELECT
ST_Transform(rast, 4269) AS alignto
FROM foo
LIMIT 1
), baz AS (
SELECT
rid,
rast,
ST_Transform(rast, 4269) AS not_aligned,
ST_Transform(rast, alignto) AS aligned
FROM foo
CROSS JOIN bar
)
SELECT
ST_SameAlignment(rast) AS rast,
ST_SameAlignment(not_aligned) AS not_aligned,
ST_SameAlignment(aligned) AS aligned
FROM baz

rast | not_aligned | aligned

------+-------------+---------
t | f | t

See Also

ST_Transform, ST_SetSRID

9.8 Raster Band Editors

9.8.1 ST_SetBandNoDataValue

ST_SetBandNoDataValue — Sets the value for the given band that represents no data. Band 1 is assumed if no band is specified.
To mark a band as having no nodata value, set the nodata value = NULL.

Synopsis

raster ST_SetBandNoDataValue(raster rast, double precision nodatavalue);

raster ST_SetBandNoDataValue(raster rast, integer band, double precision nodatavalue, boolean forcechecking=false);

Description

Sets the value that represents no data for the band. Band 1 is assumed if not specified. This will affect results from ST_Polygon,
ST_DumpAsPolygons, and the ST_PixelAs...() functions.
PostGIS 2.4.3 Manual 526 / 803

Examples

-- change just first band no data value

UPDATE dummy_rast
SET rast = ST_SetBandNoDataValue(rast,1, 254)
WHERE rid = 2;

-- change no data band value of bands 1,2,3

UPDATE dummy_rast
SET rast =
ST_SetBandNoDataValue(
ST_SetBandNoDataValue(
ST_SetBandNoDataValue(
rast,1, 254)
,2,99),
3,108)
WHERE rid = 2;

-- wipe out the nodata value this will ensure all pixels are considered for all processing ←-
functions
UPDATE dummy_rast
SET rast = ST_SetBandNoDataValue(rast,1, NULL)
WHERE rid = 2;

See Also

ST_BandNoDataValue, ST_NumBands

9.8.2 ST_SetBandIsNoData

ST_SetBandIsNoData — Sets the isnodata flag of the band to TRUE.

Synopsis

raster ST_SetBandIsNoData(raster rast, integer band=1);

Description

Sets the isnodata flag for the band to true. Band 1 is assumed if not specified. This function should be called only when the flag is
considered dirty. That is, when the result calling ST_BandIsNoData is different using TRUE as last argument and without using
it
Availability: 2.0.0

Examples

-- Create dummy table with one raster column

create table dummy_rast (rid integer, rast raster);

-- Add raster with two bands, one pixel/band. In the first band, nodatavalue = pixel value ←-
= 3.
-- In the second band, nodatavalue = 13, pixel value = 4
insert into dummy_rast values(1,
(
'01' -- little endian (uint8 ndr)
PostGIS 2.4.3 Manual 527 / 803

||
'0000' -- version (uint16 0)
||
'0200' -- nBands (uint16 0)
||
'17263529ED684A3F' -- scaleX (float64 0.000805965234044584)
||
'F9253529ED684ABF' -- scaleY (float64 -0.00080596523404458)
||
'1C9F33CE69E352C0' -- ipX (float64 -75.5533328537098)
||
'718F0E9A27A44840' -- ipY (float64 49.2824585505576)
||
'ED50EB853EC32B3F' -- skewX (float64 0.000211812383858707)
||
'7550EB853EC32B3F' -- skewY (float64 0.000211812383858704)
||
'E6100000' -- SRID (int32 4326)
||
'0100' -- width (uint16 1)
||
'0100' -- height (uint16 1)
||
'4' -- hasnodatavalue set to true, isnodata value set to false (when it should be true)
||
'2' -- first band type (4BUI)
||
'03' -- novalue==3
||
'03' -- pixel(0,0)==3 (same that nodata)
||
'0' -- hasnodatavalue set to false
||
'5' -- second band type (16BSI)
||
'0D00' -- novalue==13
||
'0400' -- pixel(0,0)==4
)::raster
);

select st_bandisnodata(rast, 1) from dummy_rast where rid = 1; -- Expected false

select st_bandisnodata(rast, 1, TRUE) from dummy_rast where rid = 1; -- Expected true

-- The isnodata flag is dirty. We are going to set it to true

update dummy_rast set rast = st_setbandisnodata(rast, 1) where rid = 1;

select st_bandisnodata(rast, 1) from dummy_rast where rid = 1; -- Expected true

See Also

ST_BandNoDataValue, ST_NumBands, ST_SetBandNoDataValue, ST_BandIsNoData

PostGIS 2.4.3 Manual 528 / 803

9.9 Raster Band Statistics and Analytics

9.9.1 ST_Count

ST_Count — Returns the number of pixels in a given band of a raster or raster coverage. If no band is specified defaults to band
1. If exclude_nodata_value is set to true, will only count pixels that are not equal to the nodata value.

Synopsis

bigint ST_Count(raster rast, integer nband=1, boolean exclude_nodata_value=true);

bigint ST_Count(raster rast, boolean exclude_nodata_value);
bigint ST_Count(text rastertable, text rastercolumn, integer nband=1, boolean exclude_nodata_value=true);
bigint ST_Count(text rastertable, text rastercolumn, boolean exclude_nodata_value);

Description

Returns the number of pixels in a given band of a raster or raster coverage. If no band is specified nband defaults to 1.

Note
If exclude_nodata_value is set to true, will only count pixels with value not equal to the nodata value of the
raster. Set exclude_nodata_value to false to get count all pixels

Availability: 2.0.0

Warning
The ST_Count(rastertable, rastercolumn, ...) variants are deprecated as of 2.2.0. Use ST_CountAgg instead.

Examples

--example will count all pixels not 249 and one will count all pixels. --
SELECT rid, ST_Count(ST_SetBandNoDataValue(rast,249)) As exclude_nodata,
ST_Count(ST_SetBandNoDataValue(rast,249),false) As include_nodata
FROM dummy_rast WHERE rid=2;

rid | exclude_nodata | include_nodata

-----+----------------+----------------
2 | 23 | 25

See Also

ST_CountAgg, ST_SummaryStats, ST_SetBandNoDataValue

9.9.2 ST_CountAgg

ST_CountAgg — Aggregate. Returns the number of pixels in a given band of a set of rasters. If no band is specified defaults to
band 1. If exclude_nodata_value is set to true, will only count pixels that are not equal to the NODATA value.
PostGIS 2.4.3 Manual 529 / 803

Synopsis

bigint ST_CountAgg(raster rast, integer nband, boolean exclude_nodata_value, double precision sample_percent);
bigint ST_CountAgg(raster rast, integer nband, boolean exclude_nodata_value);
bigint ST_CountAgg(raster rast, boolean exclude_nodata_value);

Description

Returns the number of pixels in a given band of a set of rasters. If no band is specified nband defaults to 1.
If exclude_nodata_value is set to true, will only count pixels with value not equal to the NODATA value of the raster. Set
exclude_nodata_value to false to get count all pixels
By default will sample all pixels. To get faster response, set sample_percent to value between zero (0) and one (1)
Availability: 2.2.0

Examples

WITH foo AS (
SELECT
rast.rast
FROM (
SELECT ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_AddBand(
ST_MakeEmptyRaster(10, 10, 10, 10, 2, 2, 0, 0,0)
, 1, '64BF', 0, 0
)
, 1, 1, 1, -10
)
, 1, 5, 4, 0
)
, 1, 5, 5, 3.14159
) AS rast
) AS rast
FULL JOIN (
SELECT generate_series(1, 10) AS id
) AS id
ON 1 = 1
)
SELECT
ST_CountAgg(rast, 1, TRUE)
FROM foo;

st_countagg
-------------
20
(1 row)

See Also

ST_Count, ST_SummaryStats, ST_SetBandNoDataValue

9.9.3 ST_Histogram

ST_Histogram — Returns a set of record summarizing a raster or raster coverage data distribution separate bin ranges. Number
of bins are autocomputed if not specified.
PostGIS 2.4.3 Manual 530 / 803

Synopsis

SETOF record ST_Histogram(raster rast, integer nband=1, boolean exclude_nodata_value=true, integer bins=autocomputed,
double precision[] width=NULL, boolean right=false);
SETOF record ST_Histogram(raster rast, integer nband, integer bins, double precision[] width=NULL, boolean right=false);
SETOF record ST_Histogram(raster rast, integer nband, boolean exclude_nodata_value, integer bins, boolean right);
SETOF record ST_Histogram(raster rast, integer nband, integer bins, boolean right);
SETOF record ST_Histogram(text rastertable, text rastercolumn, integer nband, integer bins, boolean right);
SETOF record ST_Histogram(text rastertable, text rastercolumn, integer nband, boolean exclude_nodata_value, integer bins,
boolean right);
SETOF record ST_Histogram(text rastertable, text rastercolumn, integer nband=1, boolean exclude_nodata_value=true, integer
bins=autocomputed, double precision[] width=NULL, boolean right=false);
SETOF record ST_Histogram(text rastertable, text rastercolumn, integer nband=1, integer bins, double precision[] width=NULL,
boolean right=false);

Description

Returns set of records consisting of min, max, count, percent for a given raster band for each bin. If no band is specified nband
defaults to 1.

Note
By default only considers pixel values not equal to the nodata value . Set exclude_nodata_value to false to
get count all pixels.

width double precision[] width: an array indicating the width of each category/bin. If the number of bins is greater than the
number of widths, the widths are repeated.
Example: 9 bins, widths are [a, b, c] will have the output be [a, b, c, a, b, c, a, b, c]
bins integer Number of breakouts -- this is the number of records you’ll get back from the function if specified. If not specified
then the number of breakouts is autocomputed.
right boolean compute the histogram from the right rather than from the left (default). This changes the criteria for evaluating
a value x from [a, b) to (a, b]

Availability: 2.0.0

Example: Single raster tile - compute histograms for bands 1, 2, 3 and autocompute bins

SELECT band, (stats).*

FROM (SELECT rid, band, ST_Histogram(rast, band) As stats
FROM dummy_rast CROSS JOIN generate_series(1,3) As band
WHERE rid=2) As foo;

band | min | max | count | percent

------+-------+-------+-------+---------
1 | 249 | 250 | 2 | 0.08
1 | 250 | 251 | 2 | 0.08
1 | 251 | 252 | 1 | 0.04
1 | 252 | 253 | 2 | 0.08
1 | 253 | 254 | 18 | 0.72
2 | 78 | 113.2 | 11 | 0.44
2 | 113.2 | 148.4 | 4 | 0.16
2 | 148.4 | 183.6 | 4 | 0.16
2 | 183.6 | 218.8 | 1 | 0.04
PostGIS 2.4.3 Manual 531 / 803

2 | 218.8 | 254 | 5 | 0.2

3 | 62 | 100.4 | 11 | 0.44
3 | 100.4 | 138.8 | 5 | 0.2
3 | 138.8 | 177.2 | 4 | 0.16
3 | 177.2 | 215.6 | 1 | 0.04
3 | 215.6 | 254 | 4 | 0.16

Example: Just band 2 but for 6 bins

SELECT (stats).*
FROM (SELECT rid, ST_Histogram(rast, 2,6) As stats
FROM dummy_rast
WHERE rid=2) As foo;

min | max | count | percent

------------+------------+-------+---------
78 | 107.333333 | 9 | 0.36
107.333333 | 136.666667 | 6 | 0.24
136.666667 | 166 | 0 | 0
166 | 195.333333 | 4 | 0.16
195.333333 | 224.666667 | 1 | 0.04
224.666667 | 254 | 5 | 0.2
(6 rows)

-- Same as previous but we explicitly control the pixel value range of each bin.
SELECT (stats).*
FROM (SELECT rid, ST_Histogram(rast, 2,6,ARRAY[0.5,1,4,100,5]) As stats
FROM dummy_rast
WHERE rid=2) As foo;

min | max | count | percent

-------+-------+-------+----------
78 | 78.5 | 1 | 0.08
78.5 | 79.5 | 1 | 0.04
79.5 | 83.5 | 0 | 0
83.5 | 183.5 | 17 | 0.0068
183.5 | 188.5 | 0 | 0
188.5 | 254 | 6 | 0.003664
(6 rows)

See Also

ST_Count, ST_SummaryStats, ST_SummaryStatsAgg

9.9.4 ST_Quantile

ST_Quantile — Compute quantiles for a raster or raster table coverage in the context of the sample or population. Thus, a value
could be examined to be at the raster’s 25%, 50%, 75% percentile.

Synopsis

SETOF record ST_Quantile(raster rast, integer nband=1, boolean exclude_nodata_value=true, double precision[] quantiles=NULL);
SETOF record ST_Quantile(raster rast, double precision[] quantiles);
SETOF record ST_Quantile(raster rast, integer nband, double precision[] quantiles);
double precision ST_Quantile(raster rast, double precision quantile);
PostGIS 2.4.3 Manual 532 / 803

double precision ST_Quantile(raster rast, boolean exclude_nodata_value, double precision quantile=NULL);

double precision ST_Quantile(raster rast, integer nband, double precision quantile);
double precision ST_Quantile(raster rast, integer nband, boolean exclude_nodata_value, double precision quantile);
double precision ST_Quantile(raster rast, integer nband, double precision quantile);
SETOF record ST_Quantile(text rastertable, text rastercolumn, integer nband=1, boolean exclude_nodata_value=true, double
precision[] quantiles=NULL);
SETOF record ST_Quantile(text rastertable, text rastercolumn, integer nband, double precision[] quantiles);

Description

Compute quantiles for a raster or raster table coverage in the context of the sample or population. Thus, a value could be examined
to be at the raster’s 25%, 50%, 75% percentile.

Note
If exclude_nodata_value is set to false, will also count pixels with no data.

Availability: 2.0.0

Examples

UPDATE dummy_rast SET rast = ST_SetBandNoDataValue(rast,249) WHERE rid=2;

--Example will consider only pixels of band 1 that are not 249 and in named quantiles --

SELECT (pvq).*
FROM (SELECT ST_Quantile(rast, ARRAY[0.25,0.75]) As pvq
FROM dummy_rast WHERE rid=2) As foo
ORDER BY (pvq).quantile;

quantile | value
----------+-------
0.25 | 253
0.75 | 254

SELECT ST_Quantile(rast, 0.75) As value

FROM dummy_rast WHERE rid=2;

value
------
254

--real live example. Quantile of all pixels in band 2 intersecting a geometry

SELECT rid, (ST_Quantile(rast,2)).* As pvc
FROM o_4_boston
WHERE ST_Intersects(rast,
ST_GeomFromText('POLYGON((224486 892151,224486 892200,224706 892200,224706 ←-
892151,224486 892151))',26986)
)
ORDER BY value, quantile,rid
;

rid | quantile | value

-----+----------+-------
1 | 0 | 0
2 | 0 | 0
PostGIS 2.4.3 Manual 533 / 803

14 | 0 | 1
15 | 0 | 2
14 | 0.25 | 37
1 | 0.25 | 42
15 | 0.25 | 47
2 | 0.25 | 50
14 | 0.5 | 56
1 | 0.5 | 64
15 | 0.5 | 66
2 | 0.5 | 77
14 | 0.75 | 81
15 | 0.75 | 87
1 | 0.75 | 94
2 | 0.75 | 106
14 | 1 | 199
1 | 1 | 244
2 | 1 | 255
15 | 1 | 255

See Also

ST_Count, ST_SummaryStats, ST_SummaryStatsAgg, ST_SetBandNoDataValue

9.9.5 ST_SummaryStats

ST_SummaryStats — Returns summarystats consisting of count, sum, mean, stddev, min, max for a given raster band of a raster
or raster coverage. Band 1 is assumed is no band is specified.

Synopsis

summarystats ST_SummaryStats(raster rast, boolean exclude_nodata_value);

summarystats ST_SummaryStats(raster rast, integer nband, boolean exclude_nodata_value);
summarystats ST_SummaryStats(text rastertable, text rastercolumn, boolean exclude_nodata_value);
summarystats ST_SummaryStats(text rastertable, text rastercolumn, integer nband=1, boolean exclude_nodata_value=true);

Description

Returns summarystats consisting of count, sum, mean, stddev, min, max for a given raster band of a raster or raster coverage. If
no band is specified nband defaults to 1.

Note
By default only considers pixel values not equal to the nodata value. Set exclude_nodata_value to false to get
count of all pixels.

Note
By default will sample all pixels. To get faster response, set sample_percent to lower than 1

Availability: 2.0.0
PostGIS 2.4.3 Manual 534 / 803

Warning
The ST_SummaryStats(rastertable, rastercolumn, ...) variants are deprecated as of 2.2.0. Use ST_SummaryStatsAgg
instead.

Example: Single raster tile

SELECT rid, band, (stats).*

FROM (SELECT rid, band, ST_SummaryStats(rast, band) As stats
FROM dummy_rast CROSS JOIN generate_series(1,3) As band
WHERE rid=2) As foo;

rid | band | count | sum | mean | stddev | min | max

-----+------+-------+------+------------+-----------+-----+-----
2 | 1 | 23 | 5821 | 253.086957 | 1.248061 | 250 | 254
2 | 2 | 25 | 3682 | 147.28 | 59.862188 | 78 | 254
2 | 3 | 25 | 3290 | 131.6 | 61.647384 | 62 | 254

Example: Summarize pixels that intersect buildings of interest

This example took 574ms on PostGIS windows 64-bit with all of Boston Buildings and aerial Tiles (tiles each 150x150 pixels ~
134,000 tiles), ~102,000 building records
WITH
-- our features of interest
feat AS (SELECT gid As building_id, geom_26986 As geom FROM buildings AS b
WHERE gid IN(100, 103,150)
),
-- clip band 2 of raster tiles to boundaries of builds
-- then get stats for these clipped regions
b_stats AS
(SELECT building_id, (stats).*
FROM (SELECT building_id, ST_SummaryStats(ST_Clip(rast,2,geom)) As stats
FROM aerials.boston
INNER JOIN feat
ON ST_Intersects(feat.geom,rast)
) As foo
)
-- finally summarize stats
SELECT building_id, SUM(count) As num_pixels
, MIN(min) As min_pval
, MAX(max) As max_pval
, SUM(mean*count)/SUM(count) As avg_pval
FROM b_stats
WHERE count > 0
GROUP BY building_id
ORDER BY building_id;
building_id | num_pixels | min_pval | max_pval | avg_pval
-------------+------------+----------+----------+------------------
100 | 1090 | 1 | 255 | 61.0697247706422
103 | 655 | 7 | 182 | 70.5038167938931
150 | 895 | 2 | 252 | 185.642458100559

Example: Raster coverage

PostGIS 2.4.3 Manual 535 / 803

-- stats for each band --

SELECT band, (stats).*
FROM (SELECT band, ST_SummaryStats('o_4_boston','rast', band) As stats
FROM generate_series(1,3) As band) As foo;

band | count | sum | mean | stddev | min | max

------+---------+--------+------------------+------------------+-----+-----
1 | 8450000 | 725799 | 82.7064349112426 | 45.6800222638537 | 0 | 255
2 | 8450000 | 700487 | 81.4197705325444 | 44.2161184161765 | 0 | 255
3 | 8450000 | 575943 | 74.682739408284 | 44.2143885481407 | 0 | 255

-- For a table -- will get better speed if set sampling to less than 100%
-- Here we set to 25% and get a much faster answer
SELECT band, (stats).*
FROM (SELECT band, ST_SummaryStats('o_4_boston','rast', band,true,0.25) As stats
FROM generate_series(1,3) As band) As foo;

band | count | sum | mean | stddev | min | max

------+---------+--------+------------------+------------------+-----+-----
1 | 2112500 | 180686 | 82.6890480473373 | 45.6961043857248 | 0 | 255
2 | 2112500 | 174571 | 81.448503668639 | 44.2252623171821 | 0 | 255
3 | 2112500 | 144364 | 74.6765884023669 | 44.2014869384578 | 0 | 255

See Also

summarystats, ST_SummaryStatsAgg, ST_Count, ST_Clip

9.9.6 ST_SummaryStatsAgg

ST_SummaryStatsAgg — Aggregate. Returns summarystats consisting of count, sum, mean, stddev, min, max for a given raster
band of a set of raster. Band 1 is assumed is no band is specified.

Synopsis

summarystats ST_SummaryStatsAgg(raster rast, integer nband, boolean exclude_nodata_value, double precision sample_percent);
summarystats ST_SummaryStatsAgg(raster rast, boolean exclude_nodata_value, double precision sample_percent);
summarystats ST_SummaryStatsAgg(raster rast, integer nband, boolean exclude_nodata_value);

Description

Returns summarystats consisting of count, sum, mean, stddev, min, max for a given raster band of a raster or raster coverage. If
no band is specified nband defaults to 1.

Note
By default only considers pixel values not equal to the NODATA value. Set exclude_nodata_value to False to
get count of all pixels.

Note
By default will sample all pixels. To get faster response, set sample_percent to value between 0 and 1

Availability: 2.2.0
PostGIS 2.4.3 Manual 536 / 803

Examples

WITH foo AS (
SELECT
rast.rast
FROM (
SELECT ST_SetValue(
ST_SetValue(
ST_SetValue(
ST_AddBand(
ST_MakeEmptyRaster(10, 10, 10, 10, 2, 2, 0, 0,0)
, 1, '64BF', 0, 0
)
, 1, 1, 1, -10
)
, 1, 5, 4, 0
)
, 1, 5, 5, 3.14159
) AS rast
) AS rast
FULL JOIN (
SELECT generate_series(1, 10) AS id
) AS id
ON 1 = 1
)
SELECT
(stats).count,
round((stats).sum::numeric, 3),
round((stats).mean::numeric, 3),
round((stats).stddev::numeric, 3),
round((stats).min::numeric, 3),
round((stats).max::numeric, 3)
FROM (
SELECT
ST_SummaryStatsAgg(rast, 1, TRUE, 1) AS stats
FROM foo
) bar;

count | round | round | round | round | round

-------+---------+--------+-------+---------+-------
20 | -68.584 | -3.429 | 6.571 | -10.000 | 3.142
(1 row)

See Also

summarystats, ST_SummaryStats, ST_Count, ST_Clip

9.9.7 ST_ValueCount

ST_ValueCount — Returns a set of records containing a pixel band value and count of the number of pixels in a given band of
a raster (or a raster coverage) that have a given set of values. If no band is specified defaults to band 1. By default nodata value
pixels are not counted. and all other values in the pixel are output and pixel band values are rounded to the nearest integer.

Synopsis

SETOF record ST_ValueCount(raster rast, integer nband=1, boolean exclude_nodata_value=true, double precision[] searchval-
ues=NULL, double precision roundto=0, double precision OUT value, integer OUT count);
PostGIS 2.4.3 Manual 537 / 803

SETOF record ST_ValueCount(raster rast, integer nband, double precision[] searchvalues, double precision roundto=0, double
precision OUT value, integer OUT count);
SETOF record ST_ValueCount(raster rast, double precision[] searchvalues, double precision roundto=0, double precision OUT
value, integer OUT count);
bigint ST_ValueCount(raster rast, double precision searchvalue, double precision roundto=0);
bigint ST_ValueCount(raster rast, integer nband, boolean exclude_nodata_value, double precision searchvalue, double precision
roundto=0);
bigint ST_ValueCount(raster rast, integer nband, double precision searchvalue, double precision roundto=0);
SETOF record ST_ValueCount(text rastertable, text rastercolumn, integer nband=1, boolean exclude_nodata_value=true, dou-
ble precision[] searchvalues=NULL, double precision roundto=0, double precision OUT value, integer OUT count);
SETOF record ST_ValueCount(text rastertable, text rastercolumn, double precision[] searchvalues, double precision roundto=0,
double precision OUT value, integer OUT count);
SETOF record ST_ValueCount(text rastertable, text rastercolumn, integer nband, double precision[] searchvalues, double pre-
cision roundto=0, double precision OUT value, integer OUT count);
bigintST_ValueCount(text rastertable, text rastercolumn, integer nband, boolean exclude_nodata_value, double precision search-
value, double precision roundto=0);
bigint ST_ValueCount(text rastertable, text rastercolumn, double precision searchvalue, double precision roundto=0);
bigint ST_ValueCount(text rastertable, text rastercolumn, integer nband, double precision searchvalue, double precision roundto=0);

Description

Returns a set of records with columns value count which contain the pixel band value and count of pixels in the raster tile or
raster coverage of selected band.
If no band is specified nband defaults to 1. If no searchvalues are specified, will return all pixel values found in the raster
or raster coverage. If one searchvalue is given, will return an integer instead of records denoting the count of pixels having that
pixel band value

Note
If exclude_nodata_value is set to false, will also count pixels with no data.

Availability: 2.0.0

Examples

UPDATE dummy_rast SET rast = ST_SetBandNoDataValue(rast,249) WHERE rid=2;

--Example will count only pixels of band 1 that are not 249. --

SELECT (pvc).*
FROM (SELECT ST_ValueCount(rast) As pvc
FROM dummy_rast WHERE rid=2) As foo
ORDER BY (pvc).value;

value | count
-------+-------
250 | 2
251 | 1
252 | 2
253 | 6
254 | 12

-- Example will coount all pixels of band 1 including 249 --

SELECT (pvc).*
FROM (SELECT ST_ValueCount(rast,1,false) As pvc
FROM dummy_rast WHERE rid=2) As foo
PostGIS 2.4.3 Manual 538 / 803

ORDER BY (pvc).value;

value | count
-------+-------
249 | 2
250 | 2
251 | 1
252 | 2
253 | 6
254 | 12

-- Example will count only non-nodata value pixels of band 2

SELECT (pvc).*
FROM (SELECT ST_ValueCount(rast,2) As pvc
FROM dummy_rast WHERE rid=2) As foo
ORDER BY (pvc).value;
value | count
-------+-------
78 | 1
79 | 1
88 | 1
89 | 1
96 | 1
97 | 1
98 | 1
99 | 2
112 | 2
:

--real live example. Count all the pixels in an aerial raster tile band 2 intersecting a ←-
geometry
-- and return only the pixel band values that have a count > 500
SELECT (pvc).value, SUM((pvc).count) As total
FROM (SELECT ST_ValueCount(rast,2) As pvc
FROM o_4_boston
WHERE ST_Intersects(rast,
ST_GeomFromText('POLYGON((224486 892151,224486 892200,224706 892200,224706 ←-
892151,224486 892151))',26986)
)
) As foo
GROUP BY (pvc).value
HAVING SUM((pvc).count) > 500
ORDER BY (pvc).value;

value | total
-------+-----
51 | 502
54 | 521

-- Just return count of pixels in each raster tile that have value of 100 of tiles that ←-
intersect a specific geometry --
SELECT rid, ST_ValueCount(rast,2,100) As count
FROM o_4_boston
WHERE ST_Intersects(rast,
ST_GeomFromText('POLYGON((224486 892151,224486 892200,224706 892200,224706 ←-
892151,224486 892151))',26986)
) ;

rid | count
-----+-------
PostGIS 2.4.3 Manual 539 / 803

1 | 56
2 | 95
14 | 37
15 | 64

See Also

ST_Count, ST_SetBandNoDataValue

9.10 Raster Outputs

9.10.1 ST_AsBinary

ST_AsBinary — Return the Well-Known Binary (WKB) representation of the raster.

Synopsis

bytea ST_AsBinary(raster rast, boolean outasin=FALSE);

Description

Returns the Binary representation of the raster. If outasin is TRUE, out-db bands are treated as in-db. Refer to raster/doc/RFC2-
WellKnownBinaryFormat located in the PostGIS source folder for details of the representation.
This is useful in binary cursors to pull data out of the database without converting it to a string representation.

Note
By default, WKB output contains the external file path for out-db bands. If the client does not have access to the raster
file underlying an out-db band, set outasin to TRUE.

Enhanced: 2.1.0 Addition of outasin

Examples

SELECT ST_AsBinary(rast) As rastbin FROM dummy_rast WHERE rid=1;

rastbin
---------------------------------------------------------------------------------
\001\000\000\000\000\000\000\000\000\000\000\000@\000\000\000\000\000\000\010@\
000\000\000\000\000\000\340?\000\000\000\000\000\000\340?\000\000\000\000\000\00
0\000\000\000\000\000\000\000\000\000\000\012\000\000\000\012\000\024\000

9.10.2 ST_AsGDALRaster

ST_AsGDALRaster — Return the raster tile in the designated GDAL Raster format. Raster formats are one of those supported
by your compiled library. Use ST_GDALDrivers() to get a list of formats supported by your library.
PostGIS 2.4.3 Manual 540 / 803

Synopsis

bytea ST_AsGDALRaster(raster rast, text format, text[] options=NULL, integer srid=sameassource);

Description

Returns the raster tile in the designated format. Arguments are itemized below:

• format format to output. This is dependent on the drivers compiled in your libgdal library. Generally available are ’JPEG’,
’GTIff’, ’PNG’. Use ST_GDALDrivers to get a list of formats supported by your library.
• options text array of GDAL options. Valid options are dependent on the format. Refer to GDAL Raster format options for
more details.
• srs The proj4text or srtext (from spatial_ref_sys) to embed in the image

Availability: 2.0.0 - requires GDAL >= 1.6.0.

JPEG Output Example, multiple tiles as single raster

SELECT ST_AsGDALRaster(ST_Union(rast), 'JPEG', ARRAY['QUALITY=50']) As rastjpg

FROM dummy_rast
WHERE rast && ST_MakeEnvelope(10, 10, 11, 11);

Using PostgreSQL Large Object Support to export raster

One way to export raster into another format is using PostgreSQL large object export functions. We’lll repeat the prior example
but also exporting. Note for this you’ll need to have super user access to db since it uses server side lo functions. It will also
export to path on server network. If you need export locally, use the psql equivalent lo_ functions which export to the local file
system instead of the server file system.
DROP TABLE IF EXISTS tmp_out ;

CREATE TABLE tmp_out AS

SELECT lo_from_bytea(0,
ST_AsGDALRaster(ST_Union(rast), 'JPEG', ARRAY['QUALITY=50'])
) AS loid
FROM dummy_rast
WHERE rast && ST_MakeEnvelope(10, 10, 11, 11);

SELECT lo_export(loid, '/tmp/dummy.jpg')

FROM tmp_out;

SELECT lo_unlink(loid)
FROM tmp_out;

GTIFF Output Examples

SELECT ST_AsGDALRaster(rast, 'GTiff') As rastjpg

FROM dummy_rast WHERE rid=2;

-- Out GeoTiff with jpeg compression, 90% quality

SELECT ST_AsGDALRaster(rast, 'GTiff',
ARRAY['COMPRESS=JPEG', 'JPEG_QUALITY=90'],
4269) As rasttiff
FROM dummy_rast WHERE rid=2;
PostGIS 2.4.3 Manual 541 / 803

See Also

Section 5.3, ST_GDALDrivers, ST_SRID

9.10.3 ST_AsJPEG

ST_AsJPEG — Return the raster tile selected bands as a single Joint Photographic Exports Group (JPEG) image (byte array). If
no band is specified and 1 or more than 3 bands, then only the first band is used. If only 3 bands then all 3 bands are used and
mapped to RGB.

Synopsis

bytea ST_AsJPEG(raster rast, text[] options=NULL);

bytea ST_AsJPEG(raster rast, integer nband, integer quality);
bytea ST_AsJPEG(raster rast, integer nband, text[] options=NULL);
bytea ST_AsJPEG(raster rast, integer[] nbands, text[] options=NULL);
bytea ST_AsJPEG(raster rast, integer[] nbands, integer quality);

Description

Returns the selected bands of the raster as a single Joint Photographic Exports Group Image (JPEG). Use ST_AsGDALRaster if
you need to export as less common raster types. If no band is specified and 1 or more than 3 bands, then only the first band is
used. If 3 bands then all 3 bands are used. There are many variants of the function with many options. These are itemized below:

• nband is for single band exports.

• nbands is an array of bands to export (note that max is 3 for JPEG) and the order of the bands is RGB. e.g ARRAY[3,2,1]
means map band 3 to Red, band 2 to green and band 1 to blue
• quality number from 0 to 100. The higher the number the crisper the image.
• options text Array of GDAL options as defined for JPEG (look at create_options for JPEG ST_GDALDrivers). For JPEG
valid ones are PROGRESSIVE ON or OFF and QUALITY a range from 0 to 100 and default to 75. Refer to GDAL Raster
format options for more details.

Availability: 2.0.0 - requires GDAL >= 1.6.0.

Examples: Output

-- output first 3 bands 75% quality

SELECT ST_AsJPEG(rast) As rastjpg
FROM dummy_rast WHERE rid=2;

-- output only first band as 90% quality

SELECT ST_AsJPEG(rast,1,90) As rastjpg
FROM dummy_rast WHERE rid=2;

-- output first 3 bands (but make band 2 Red, band 1 green, and band 3 blue, progressive ←-
and 90% quality
SELECT ST_AsJPEG(rast,ARRAY[2,1,3],ARRAY['QUALITY=90','PROGRESSIVE=ON']) As rastjpg
FROM dummy_rast WHERE rid=2;

See Also

Section 5.3, ST_GDALDrivers, ST_AsGDALRaster, ST_AsPNG, ST_AsTIFF

PostGIS 2.4.3 Manual 542 / 803

9.10.4 ST_AsPNG

ST_AsPNG — Return the raster tile selected bands as a single portable network graphics (PNG) image (byte array). If 1, 3, or 4
bands in raster and no bands are specified, then all bands are used. If more 2 or more than 4 bands and no bands specified, then
only band 1 is used. Bands are mapped to RGB or RGBA space.

Synopsis

bytea ST_AsPNG(raster rast, text[] options=NULL);

bytea ST_AsPNG(raster rast, integer nband, integer compression);
bytea ST_AsPNG(raster rast, integer nband, text[] options=NULL);
bytea ST_AsPNG(raster rast, integer[] nbands, integer compression);
bytea ST_AsPNG(raster rast, integer[] nbands, text[] options=NULL);

Description

Returns the selected bands of the raster as a single Portable Network Graphics Image (PNG). Use ST_AsGDALRaster if you
need to export as less common raster types. If no band is specified, then the first 3 bands are exported. There are many variants
of the function with many options. If no srid is specified then then srid of the raster is used. These are itemized below:

• nband is for single band exports.

• nbands is an array of bands to export (note that max is 4 for PNG) and the order of the bands is RGBA. e.g ARRAY[3,2,1]
means map band 3 to Red, band 2 to green and band 1 to blue
• compression number from 1 to 9. The higher the number the greater the compression.

• options text Array of GDAL options as defined for PNG (look at create_options for PNG of ST_GDALDrivers). For PNG
valid one is only ZLEVEL (amount of time to spend on compression -- default 6) e.g. ARRAY[’ZLEVEL=9’]. WORLDFILE
is not allowed since the function would have to output two outputs. Refer to GDAL Raster format options for more details.

Availability: 2.0.0 - requires GDAL >= 1.6.0.

Examples

SELECT ST_AsPNG(rast) As rastpng

FROM dummy_rast WHERE rid=2;

-- export the first 3 bands and map band 3 to Red, band 1 to Green, band 2 to blue
SELECT ST_AsPNG(rast, ARRAY[3,1,2]) As rastpng
FROM dummy_rast WHERE rid=2;

See Also

ST_AsGDALRaster, ST_ColorMap, ST_GDALDrivers, Section 5.3

9.10.5 ST_AsTIFF

ST_AsTIFF — Return the raster selected bands as a single TIFF image (byte array). If no band is specified, then will try to use
all bands.
PostGIS 2.4.3 Manual 543 / 803

Synopsis

bytea ST_AsTIFF(raster rast, text[] options=”, integer srid=sameassource);

bytea ST_AsTIFF(raster rast, text compression=”, integer srid=sameassource);
bytea ST_AsTIFF(raster rast, integer[] nbands, text compression=”, integer srid=sameassource);
bytea ST_AsTIFF(raster rast, integer[] nbands, text[] options, integer srid=sameassource);

Description

Returns the selected bands of the raster as a single Tagged Image File Format (TIFF). If no band is specified, will try to use all
bands. This is a wrapper around ST_AsGDALRaster. Use ST_AsGDALRaster if you need to export as less common raster types.
There are many variants of the function with many options. If no spatial reference SRS text is present, the spatial reference of
the raster is used. These are itemized below:

• nbands is an array of bands to export (note that max is 3 for PNG) and the order of the bands is RGB. e.g ARRAY[3,2,1]
means map band 3 to Red, band 2 to green and band 1 to blue
• compression Compression expression -- JPEG90 (or some other percent), LZW, JPEG, DEFLATE9.
• options text Array of GDAL create options as defined for GTiff (look at create_options for GTiff of ST_GDALDrivers). or
refer to GDAL Raster format options for more details.
• srid srid of spatial_ref_sys of the raster. This is used to populate the georeference information

Availability: 2.0.0 - requires GDAL >= 1.6.0.

Examples: Use jpeg compression 90%

SELECT ST_AsTIFF(rast, 'JPEG90') As rasttiff

FROM dummy_rast WHERE rid=2;

See Also

ST_GDALDrivers, ST_AsGDALRaster, ST_SRID

9.11 Raster Processing

9.11.1 Map Algebra

9.11.1.1 ST_Clip

ST_Clip — Returns the raster clipped by the input geometry. If band number not is specified, all bands are processed. If crop
is not specified or TRUE, the output raster is cropped.

Synopsis

raster ST_Clip(raster rast, integer[] nband, geometry geom, double precision[] nodataval=NULL, boolean crop=TRUE);
raster ST_Clip(raster rast, integer nband, geometry geom, double precision nodataval, boolean crop=TRUE);
raster ST_Clip(raster rast, integer nband, geometry geom, boolean crop);
raster ST_Clip(raster rast, geometry geom, double precision[] nodataval=NULL, boolean crop=TRUE);
raster ST_Clip(raster rast, geometry geom, double precision nodataval, boolean crop=TRUE);
raster ST_Clip(raster rast, geometry geom, boolean crop);
PostGIS 2.4.3 Manual 544 / 803

Description

Returns a raster that is clipped by the input geometry geom. If band index is not specified, all bands are processed.
Rasters resulting from ST_Clip must have a nodata value assigned for areas clipped, one for each band. If none are provided and
the input raster do not have a nodata value defined, nodata values of the resulting raster are set to ST_MinPossibleValue(ST_BandPixelTyp
band)). When the number of nodata value in the array is smaller than the number of band, the last one in the array is used for
the remaining bands. If the number of nodata value is greater than the number of band, the extra nodata values are ignored. All
variants accepting an array of nodata values also accept a single value which will be assigned to each band.
If crop is not specified, true is assumed meaning the output raster is cropped to the intersection of the geomand rast extents.
If crop is set to false, the new raster gets the same extent as rast.
Availability: 2.0.0
Enhanced: 2.1.0 Rewritten in C
Examples here use Massachusetts aerial data available on MassGIS site MassGIS Aerial Orthos. Coordinates are in Mas-
sachusetts State Plane Meters.

Examples: 1 band clipping

-- Clip the first band of an aerial tile by a 20 meter buffer.

SELECT ST_Clip(rast, 1,
ST_Buffer(ST_Centroid(ST_Envelope(rast)),20)
) from aerials.boston
WHERE rid = 4;

-- Demonstrate effect of crop on final dimensions of raster

-- Note how final extent is clipped to that of the geometry
-- if crop = true
SELECT ST_XMax(ST_Envelope(ST_Clip(rast, 1, clipper, true))) As xmax_w_trim,
ST_XMax(clipper) As xmax_clipper,
ST_XMax(ST_Envelope(ST_Clip(rast, 1, clipper, false))) As xmax_wo_trim,
ST_XMax(ST_Envelope(rast)) As xmax_rast_orig
FROM (SELECT rast, ST_Buffer(ST_Centroid(ST_Envelope(rast)),6) As clipper
FROM aerials.boston
WHERE rid = 6) As foo;

xmax_w_trim | xmax_clipper | xmax_wo_trim | xmax_rast_orig

------------------+------------------+------------------+------------------
230657.436173996 | 230657.436173996 | 230666.436173996 | 230666.436173996
PostGIS 2.4.3 Manual 545 / 803

Full raster tile before clipping After Clipping

Examples: 1 band clipping with no crop and add back other bands unchanged

-- Same example as before, but we need to set crop to false to be able to use ST_AddBand
-- because ST_AddBand requires all bands be the same Width and height
SELECT ST_AddBand(ST_Clip(rast, 1,
ST_Buffer(ST_Centroid(ST_Envelope(rast)),20),false
), ARRAY[ST_Band(rast,2),ST_Band(rast,3)] ) from aerials.boston
WHERE rid = 6;

Full raster tile before clipping After Clipping - surreal

Examples: Clip all bands

-- Clip all bands of an aerial tile by a 20 meter buffer.

-- Only difference is we don't specify a specific band to clip
-- so all bands are clipped
SELECT ST_Clip(rast,
ST_Buffer(ST_Centroid(ST_Envelope(rast)), 20),
PostGIS 2.4.3 Manual 546 / 803

false
) from aerials.boston
WHERE rid = 4;

Full raster tile before clipping After Clipping

See Also

ST_AddBand, ST_MapAlgebra, ST_Intersection

9.11.1.2 ST_ColorMap

ST_ColorMap — Creates a new raster of up to four 8BUI bands (grayscale, RGB, RGBA) from the source raster and a specified
band. Band 1 is assumed if not specified.

Synopsis

raster ST_ColorMap(raster rast, integer nband=1, text colormap=grayscale, text method=INTERPOLATE);

raster ST_ColorMap(raster rast, text colormap, text method=INTERPOLATE);

Description

Apply a colormap to the band at nband of rast resulting a new raster comprised of up to four 8BUI bands. The number of
8BUI bands in the new raster is determined by the number of color components defined in colormap.
If nband is not specified, then band 1 is assumed.
colormap can be a keyword of a pre-defined colormap or a set of lines defining the value and the color components.
Valid pre-defined colormap keyword:

• grayscale or greyscale for a one 8BUI band raster of shades of gray.

• pseudocolor for a four 8BUI (RGBA) band raster with colors going from blue to green to red.
• fire for a four 8BUI (RGBA) band raster with colors going from black to red to pale yellow.
PostGIS 2.4.3 Manual 547 / 803

• bluered for a four 8BUI (RGBA) band raster with colors going from blue to pale white to red.

Users can pass a set of entries (one per line) to colormap to specify custom colormaps. Each entry generally consists of five
values: the pixel value and corresponding Red, Green, Blue, Alpha components (color components between 0 and 255). Percent
values can be used instead of pixel values where 0% and 100% are the minimum and maximum values found in the raster band.
Values can be separated with commas (’,’), tabs, colons (’:’) and/or spaces. The pixel value can be set to nv, null or nodata for
the NODATA value. An example is provided below.
5 0 0 0 255
4 100:50 55 255
1 150,100 150 255
0% 255 255 255 255
nv 0 0 0 0

The syntax of colormap is similar to that of the color-relief mode of GDAL gdaldem.
Valid keywords for method:

• INTERPOLATE to use linear interpolation to smoothly blend the colors between the given pixel values
• EXACT to strictly match only those pixels values found in the colormap. Pixels whose value does not match a colormap entry
will be set to 0 0 0 0 (RGBA)
• NEAREST to use the colormap entry whose value is closest to the pixel value

Note
A great reference for colormaps is ColorBrewer.

Warning
The resulting bands of new raster will have no NODATA value set. Use ST_SetBandNoDataValue to set a NODATA
value if one is needed.

Availability: 2.1.0

Examples

This is a junk table to play with

-- setup test raster table --
DROP TABLE IF EXISTS funky_shapes;
CREATE TABLE funky_shapes(rast raster);

INSERT INTO funky_shapes(rast)

WITH ref AS (
SELECT ST_MakeEmptyRaster( 200, 200, 0, 200, 1, -1, 0, 0) AS rast
)
SELECT
ST_Union(rast)
FROM (
SELECT
ST_AsRaster(
ST_Rotate(
ST_Buffer(
ST_GeomFromText('LINESTRING(0 2,50 50,150 150,125 50)'),
PostGIS 2.4.3 Manual 548 / 803

i*2
),
pi() * i * 0.125, ST_Point(50,50)
),
ref.rast, '8BUI'::text, i * 5
) AS rast
FROM ref
CROSS JOIN generate_series(1, 10, 3) AS i
) AS shapes;

SELECT
ST_NumBands(rast) As n_orig,
ST_NumBands(ST_ColorMap(rast,1, 'greyscale')) As ngrey,
ST_NumBands(ST_ColorMap(rast,1, 'pseudocolor')) As npseudo,
ST_NumBands(ST_ColorMap(rast,1, 'fire')) As nfire,
ST_NumBands(ST_ColorMap(rast,1, 'bluered')) As nbluered,
ST_NumBands(ST_ColorMap(rast,1, '
100% 255 0 0
80% 160 0 0
50% 130 0 0
30% 30 0 0
20% 60 0 0
0% 0 0 0
nv 255 255 255
')) As nred
FROM funky_shapes;

n_orig | ngrey | npseudo | nfire | nbluered | nred

--------+-------+---------+-------+----------+------
1 | 1 | 4 | 4 | 4 | 3

Examples: Compare different color map looks using ST_AsPNG

SELECT
ST_AsPNG(rast) As orig_png,
ST_AsPNG(ST_ColorMap(rast,1,'greyscale')) As grey_png,
ST_AsPNG(ST_ColorMap(rast,1, 'pseudocolor')) As pseudo_png,
ST_AsPNG(ST_ColorMap(rast,1, 'nfire')) As fire_png,
ST_AsPNG(ST_ColorMap(rast,1, 'bluered')) As bluered_png,
ST_AsPNG(ST_ColorMap(rast,1, '
100% 255 0 0
80% 160 0 0
50% 130 0 0
30% 30 0 0
20% 60 0 0
0% 0 0 0
nv 255 255 255
')) As red_png
FROM funky_shapes;
PostGIS 2.4.3 Manual 549 / 803

orig_png grey_png pseudo_png

fire_png bluered_png red_png

See Also

ST_AsPNG, ST_AsRaster ST_MapAlgebra, ST_NumBands, ST_Reclass, ST_SetBandNoDataValue, ST_Union

9.11.1.3 ST_Intersection

ST_Intersection — Returns a raster or a set of geometry-pixelvalue pairs representing the shared portion of two rasters or the
geometrical intersection of a vectorization of the raster and a geometry.
PostGIS 2.4.3 Manual 550 / 803

Synopsis

setof geomval ST_Intersection(geometry geom, raster rast, integer band_num=1);

setof geomval ST_Intersection(raster rast, geometry geom);
setof geomval ST_Intersection(raster rast, integer band, geometry geomin);
raster ST_Intersection(raster rast1, raster rast2, double precision[] nodataval);
raster ST_Intersection(raster rast1, raster rast2, text returnband, double precision[] nodataval);
raster ST_Intersection(raster rast1, integer band1, raster rast2, integer band2, double precision[] nodataval);
raster ST_Intersection(raster rast1, integer band1, raster rast2, integer band2, text returnband, double precision[] nodataval);

Description

Returns a raster or a set of geometry-pixelvalue pairs representing the shared portion of two rasters or the geometrical intersection
of a vectorization of the raster and a geometry.
The first three variants, returning a setof geomval, works in vector space. The raster is first vectorized (using ST_DumpAsPolygon)
into a set of geomval rows and those rows are then intersected with the geometry using the ST_Intersection(geometry, geome-
try) PostGIS function. Geometries intersecting only with a nodata value area of a raster returns an empty geometry. They are
normally excluded from the results by the proper usage of ST_Intersect in the WHERE clause.
You can access the geometry and the value parts of the resulting set of geomval by surrounding them with parenthesis and adding
’.geom’ or ’.val’ at the end of the expression. e.g. (ST_Intersection(rast, geom)).geom
The other variants, returning a raster, works in raster space. They are using the two rasters version of ST_MapAlgebraExpr to
perform the intersection.
The extent of the resulting raster corresponds to the geometrical intersection of the two raster extents. The resulting raster
includes ’BAND1’, ’BAND2’ or ’BOTH’ bands, following what is passed as the returnband parameter. Nodata value areas
present in any band results in nodata value areas in every bands of the result. In other words, any pixel intersecting with a nodata
value pixel becomes a nodata value pixel in the result.
Rasters resulting from ST_Intersection must have a nodata value assigned for areas not intersecting. You can define or replace the
nodata value for any resulting band by providing a nodataval[] array of one or two nodata values depending if you request
’BAND1’, ’BAND2’ or ’BOTH’ bands. The first value in the array replace the nodata value in the first band and the second value
replace the nodata value in the second band. If one input band do not have a nodata value defined and none are provided as an
array, one is chosen using the ST_MinPossibleValue function. All variant accepting an array of nodata value can also accept a
single value which will be assigned to each requested band.
In all variants, if no band number is specified band 1 is assumed. If you need an intersection between a raster and geometry that
returns a raster, refer to ST_Clip.

Note
To get more control on the resulting extent or on what to return when encountering a nodata value, use the two rasters
version of ST_MapAlgebraExpr.

Note
To compute the intersection of a raster band with a geometry in raster space, use ST_Clip. ST_Clip works on multiple
bands rasters and does not return a band corresponding to the rasterized geometry.

Note
ST_Intersection should be used in conjunction with ST_Intersects and an index on the raster column and/or the geom-
etry column.

Enhanced: 2.0.0 - Intersection in the raster space was introduced. In earlier pre-2.0.0 versions, only intersection performed in
vector space were supported.
PostGIS 2.4.3 Manual 551 / 803

Examples: Geometry, Raster -- resulting in geometry vals

SELECT
foo.rid,
foo.gid,
ST_AsText((foo.geomval).geom) As geomwkt,
(foo.geomval).val
FROM (
SELECT
A.rid,
g.gid,
ST_Intersection(A.rast, g.geom) As geomval
FROM dummy_rast AS A
CROSS JOIN (
VALUES
(1, ST_Point(3427928, 5793243.85) ),
(2, ST_GeomFromText('LINESTRING(3427927.85 5793243.75,3427927.8 5793243.75,3427927.8 ←-
5793243.8)')),
(3, ST_GeomFromText('LINESTRING(1 2, 3 4)'))
) As g(gid,geom)
WHERE A.rid = 2
) As foo;

rid | gid | geomwkt | val

-----+-----+-----------------------------------------------------------------------------------------

2 | 1 | POINT(3427928 5793243.85) | 249

2 | 1 | POINT(3427928 5793243.85) | 253
2 | 2 | POINT(3427927.85 5793243.75) | 254
2 | 2 | POINT(3427927.8 5793243.8) | 251
2 | 2 | POINT(3427927.8 5793243.8) | 253
2 | 2 | LINESTRING(3427927.8 5793243.75,3427927.8 5793243.8) | 252
2 | 2 | MULTILINESTRING((3427927.8 5793243.8,3427927.8 5793243.75),...) | 250
2 | 3 | GEOMETRYCOLLECTION EMPTY

See Also

geomval, ST_Intersects, ST_MapAlgebraExpr, ST_Clip, ST_AsText

9.11.1.4 ST_MapAlgebra

ST_MapAlgebra — Callback function version - Returns a one-band raster given one or more input rasters, band indexes and one
user-specified callback function.

Synopsis

raster ST_MapAlgebra(rastbandarg[] rastbandargset, regprocedure callbackfunc, text pixeltype=NULL, text extenttype=INTERSECTIO

raster customextent=NULL, integer distancex=0, integer distancey=0, text[] VARIADIC userargs=NULL);
raster ST_MapAlgebra(raster rast, integer[] nband, regprocedure callbackfunc, text pixeltype=NULL, text extenttype=FIRST,
raster customextent=NULL, integer distancex=0, integer distancey=0, text[] VARIADIC userargs=NULL);
raster ST_MapAlgebra(raster rast, integer nband, regprocedure callbackfunc, text pixeltype=NULL, text extenttype=FIRST,
raster customextent=NULL, integer distancex=0, integer distancey=0, text[] VARIADIC userargs=NULL);
raster ST_MapAlgebra(raster rast1, integer nband1, raster rast2, integer nband2, regprocedure callbackfunc, text pixeltype=NULL,
text extenttype=INTERSECTION, raster customextent=NULL, integer distancex=0, integer distancey=0, text[] VARIADIC user-
args=NULL);
raster ST_MapAlgebra(nband integer, regprocedure callbackfunc, float8[] mask, boolean weighted, text pixeltype=NULL, text
extenttype=INTERSECTION, raster customextent=NULL, text[] VARIADIC userargs=NULL);
PostGIS 2.4.3 Manual 552 / 803

Description

Returns a one-band raster given one or more input rasters, band indexes and one user-specified callback function.

rast,rast1,rast2, rastbandargset Rasters on which the map algebra process is evaluated.

rastbandargset allows the use of a map algebra operation on many rasters and/or many bands. See example Variant
1.
nband, nband1, nband2 Band numbers of the raster to be evaluated. nband can be an integer or integer[] denoting the bands.
nband1 is band on rast1 and nband2 is band on rast2 for hte 2 raster/2band case.
callbackfunc The callbackfunc parameter must be the name and signature of an SQL or PL/pgSQL function, cast to a
regprocedure. An example PL/pgSQL function example is:
CREATE OR REPLACE FUNCTION sample_callbackfunc(value double precision[][][], position ←-
integer[][], VARIADIC userargs text[])
RETURNS double precision
AS $$
BEGIN
RETURN 0;
END;
$$ LANGUAGE 'plpgsql' IMMUTABLE;

The callbackfunc must have three arguments: a 3-dimension double precision array, a 2-dimension integer array and a
variadic 1-dimension text array. The first argument value is the set of values (as double precision) from all input rasters.
The three dimensions (where indexes are 1-based) are: raster #, row y, column x. The second argument position is
the set of pixel positions from the output raster and input rasters. The outer dimension (where indexes are 0-based) is the
raster #. The position at outer dimension index 0 is the output raster’s pixel position. For each outer dimension, there are
two elements in the inner dimension for X and Y. The third argument userargs is for passing through any user-specified
arguments.
Passing a regprocedure argument to a SQL function requires the full function signature to be passed, then cast to a regpro-
cedure type. To pass the above example PL/pgSQL function as an argument, the SQL for the argument is:
'sample_callbackfunc(double precision[], integer[], text[])'::regprocedure

Note that the argument contains the name of the function, the types of the function arguments, quotes around the name and
argument types, and a cast to a regprocedure.
mask An n-dimensional array (matrix) of numbers used to filter what cells get passed to map algebra call-back function. 0
means a neighbor cell value should be treated as no-data and 1 means value should be treated as data. If weight is set to
true, then the values, are used as multipliers to multiple the pixel value of that value in the neighborhood position.
weighted boolean (true/false) to denote if a mask value should be weighted (multiplied by original value) or not (only applies to
proto that takes a mask).
pixeltype If pixeltype is passed in, the one band of the new raster will be of that pixeltype. If pixeltype is passed NULL
or left out, the new raster band will have the same pixeltype as the specified band of the first raster (for extent types:
INTERSECTION, UNION, FIRST, CUSTOM) or the specified band of the appropriate raster (for extent types: SECOND,
LAST). If in doubt, always specify pixeltype.
The resulting pixel type of the output raster must be one listed in ST_BandPixelType or left out or set to NULL.
extenttype Possible values are INTERSECTION (default), UNION, FIRST (default for one raster variants), SECOND, LAST,
CUSTOM.
customextent If extentype is CUSTOM, a raster must be provided for customextent. See example 4 of Variant 1.
distancex The distance in pixels from the reference cell in x direction. So width of resulting matrix would be 2*distancex
+ 1.If not specified only the reference cell is considered (neighborhood of 0).
distancey The distance in pixels from reference cell in y direction. Height of resulting matrix would be 2*distancey + 1
.If not specified only the reference cell is considered (neighborhood of 0).
PostGIS 2.4.3 Manual 553 / 803

userargs The third argument to the callbackfunc is a variadic text array. All trailing text arguments are passed through to
the specified callbackfunc, and are contained in the userargs argument.

Note
For more information about the VARIADIC keyword, please refer to the PostgreSQL documentation and the "SQL
Functions with Variable Numbers of Arguments" section of Query Language (SQL) Functions.

Note
The text[] argument to the callbackfunc is required, regardless of whether you choose to pass any arguments to
the callback function for processing or not.

Variant 1 accepts an array of rastbandarg allowing the use of a map algebra operation on many rasters and/or many bands.
See example Variant 1.
Variants 2 and 3 operate upon one or more bands of one raster. See example Variant 2 and 3.
Variant 4 operate upon two rasters with one band per raster. See example Variant 4.
Availability: 2.2.0: Ability to add a mask
Availability: 2.1.0

Examples: Variant 1

One raster, one band

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', ←-
1, 0) AS rast
)
SELECT
ST_MapAlgebra(
ARRAY[ROW(rast, 1)]::rastbandarg[],
'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
) AS rast
FROM foo

One raster, several bands

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, ←-
0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast
)
SELECT
ST_MapAlgebra(
ARRAY[ROW(rast, 3), ROW(rast, 1), ROW(rast, 3), ROW(rast, 2)]::rastbandarg[],
'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
) AS rast
FROM foo

Several rasters, several bands

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, ←-
0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast UNION ALL
SELECT 2 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 1, 1, -1, ←-
0, 0, 0), 1, '16BUI', 2, 0), 2, '8BUI', 20, 0), 3, '32BUI', 300, 0) AS rast
PostGIS 2.4.3 Manual 554 / 803

)
SELECT
ST_MapAlgebra(
ARRAY[ROW(t1.rast, 3), ROW(t2.rast, 1), ROW(t2.rast, 3), ROW(t1.rast, 2)]::rastbandarg ←-
[],
'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
) AS rast
FROM foo t1
CROSS JOIN foo t2
WHERE t1.rid = 1
AND t2.rid = 2

Complete example of tiles of a coverage with neighborhood. This query only works with PostgreSQL 9.1 or higher.
WITH foo AS (
SELECT 0 AS rid, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', ←-
1, 0) AS rast UNION ALL
SELECT 1, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, 0, 1, -1, 0, 0, 0), 1, '16BUI', 2, 0) AS ←-
rast UNION ALL
SELECT 2, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, 0, 1, -1, 0, 0, 0), 1, '16BUI', 3, 0) AS ←-
rast UNION ALL

SELECT 3, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -2, 1, -1, 0, 0, 0), 1, '16BUI', 10, 0) ←-

AS rast UNION ALL
SELECT 4, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -2, 1, -1, 0, 0, 0), 1, '16BUI', 20, 0) ←-
AS rast UNION ALL
SELECT 5, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -2, 1, -1, 0, 0, 0), 1, '16BUI', 30, 0) ←-
AS rast UNION ALL

SELECT 6, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -4, 1, -1, 0, 0, 0), 1, '16BUI', 100, 0) ←-

AS rast UNION ALL
SELECT 7, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -4, 1, -1, 0, 0, 0), 1, '16BUI', 200, 0) ←-
AS rast UNION ALL
SELECT 8, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -4, 1, -1, 0, 0, 0), 1, '16BUI', 300, 0) ←-
AS rast
)
SELECT
t1.rid,
ST_MapAlgebra(
ARRAY[ROW(ST_Union(t2.rast), 1)]::rastbandarg[],
'sample_callbackfunc(double precision[], int[], text[])'::regprocedure,
'32BUI',
'CUSTOM', t1.rast,
1, 1
) AS rast
FROM foo t1
CROSS JOIN foo t2
WHERE t1.rid = 4
AND t2.rid BETWEEN 0 AND 8
AND ST_Intersects(t1.rast, t2.rast)
GROUP BY t1.rid, t1.rast

Example like the prior one for tiles of a coverage with neighborhood but works with PostgreSQL 9.0.
WITH src AS (
SELECT 0 AS rid, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, 0, 0, 0), 1, '16BUI', ←-
1, 0) AS rast UNION ALL
SELECT 1, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, 0, 1, -1, 0, 0, 0), 1, '16BUI', 2, 0) AS ←-
rast UNION ALL
SELECT 2, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, 0, 1, -1, 0, 0, 0), 1, '16BUI', 3, 0) AS ←-
rast UNION ALL
PostGIS 2.4.3 Manual 555 / 803

SELECT 3, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -2, 1, -1, 0, 0, 0), 1, '16BUI', 10, 0) ←-

AS rast UNION ALL
SELECT 4, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -2, 1, -1, 0, 0, 0), 1, '16BUI', 20, 0) ←-
AS rast UNION ALL
SELECT 5, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -2, 1, -1, 0, 0, 0), 1, '16BUI', 30, 0) ←-
AS rast UNION ALL

SELECT 6, ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, -4, 1, -1, 0, 0, 0), 1, '16BUI', 100, 0) ←-

AS rast UNION ALL
SELECT 7, ST_AddBand(ST_MakeEmptyRaster(2, 2, 2, -4, 1, -1, 0, 0, 0), 1, '16BUI', 200, 0) ←-
AS rast UNION ALL
SELECT 8, ST_AddBand(ST_MakeEmptyRaster(2, 2, 4, -4, 1, -1, 0, 0, 0), 1, '16BUI', 300, 0) ←-
AS rast
)
WITH foo AS (
SELECT
t1.rid,
ST_Union(t2.rast) AS rast
FROM src t1
JOIN src t2
ON ST_Intersects(t1.rast, t2.rast)
AND t2.rid BETWEEN 0 AND 8
WHERE t1.rid = 4
GROUP BY t1.rid
), bar AS (
SELECT
t1.rid,
ST_MapAlgebra(
ARRAY[ROW(t2.rast, 1)]::rastbandarg[],
'raster_nmapalgebra_test(double precision[], int[], text[])'::regprocedure,
'32BUI',
'CUSTOM', t1.rast,
1, 1
) AS rast
FROM src t1
JOIN foo t2
ON t1.rid = t2.rid
)
SELECT
rid,
(ST_Metadata(rast)),
(ST_BandMetadata(rast, 1)),
ST_Value(rast, 1, 1, 1)
FROM bar;

Examples: Variants 2 and 3

One raster, several bands

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, ←-
0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast
)
SELECT
ST_MapAlgebra(
rast, ARRAY[3, 1, 3, 2]::integer[],
'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
) AS rast
FROM foo

One raster, one band

PostGIS 2.4.3 Manual 556 / 803

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, ←-
0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast
)
SELECT
ST_MapAlgebra(
rast, 2,
'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
) AS rast
FROM foo

Examples: Variant 4

Two rasters, two bands

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, ←-
0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI', 100, 0) AS rast UNION ALL
SELECT 2 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 1, 1, -1, ←-
0, 0, 0), 1, '16BUI', 2, 0), 2, '8BUI', 20, 0), 3, '32BUI', 300, 0) AS rast
)
SELECT
ST_MapAlgebra(
t1.rast, 2,
t2.rast, 1,
'sample_callbackfunc(double precision[], int[], text[])'::regprocedure
) AS rast
FROM foo t1
CROSS JOIN foo t2
WHERE t1.rid = 1
AND t2.rid = 2

Examples: Using Masks

WITH foo AS (SELECT

ST_SetBandNoDataValue(
ST_SetValue(ST_SetValue(ST_AsRaster(
ST_Buffer(
ST_GeomFromText('LINESTRING(50 50,100 90,100 50)'), 5,'join=bevel'),
200,200,ARRAY['8BUI'], ARRAY[100], ARRAY[0]), ST_Buffer('POINT(70 70)'::geometry,10,' ←-
quad_segs=1') ,50),
'LINESTRING(20 20, 100 100, 150 98)'::geometry,1),0) AS rast )
SELECT 'original' AS title, rast
FROM foo
UNION ALL
SELECT 'no mask mean value' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], ←-
int[], text[])'::regprocedure) AS rast
FROM foo
UNION ALL
SELECT 'mask only consider neighbors, exclude center' AS title, ST_MapAlgebra(rast,1,' ←-
ST_mean4ma(double precision[], int[], text[])'::regprocedure,
'{{1,1,1}, {1,0,1}, {1,1,1}}'::double precision[], false) As rast
FROM foo

UNION ALL
SELECT 'mask weighted only consider neighbors, exclude center multi otehr pixel values by ←-
2' AS title, ST_MapAlgebra(rast,1,'ST_mean4ma(double precision[], int[], text[])':: ←-
regprocedure,
PostGIS 2.4.3 Manual 557 / 803

'{{2,2,2}, {2,0,2}, {2,2,2}}'::double precision[], true) As rast

FROM foo;

original no mask mean value (same as having all 1s in mask matrix)

mask weighted only consider neighbors, exclude center

mask only consider neighbors, exclude center
multi other pixel values by 2

See Also

rastbandarg, ST_Union, ST_MapAlgebra

9.11.1.5 ST_MapAlgebra

ST_MapAlgebra — Expression version - Returns a one-band raster given one or two input rasters, band indexes and one or more
user-specified SQL expressions.
PostGIS 2.4.3 Manual 558 / 803

Synopsis

raster ST_MapAlgebra(raster rast, integer nband, text pixeltype, text expression, double precision nodataval=NULL);
raster ST_MapAlgebra(raster rast, text pixeltype, text expression, double precision nodataval=NULL);
raster ST_MapAlgebra(raster rast1, integer nband1, raster rast2, integer nband2, text expression, text pixeltype=NULL, text
extenttype=INTERSECTION, text nodata1expr=NULL, text nodata2expr=NULL, double precision nodatanodataval=NULL);
raster ST_MapAlgebra(raster rast1, raster rast2, text expression, text pixeltype=NULL, text extenttype=INTERSECTION, text
nodata1expr=NULL, text nodata2expr=NULL, double precision nodatanodataval=NULL);

Description

Expression version - Returns a one-band raster given one or two input rasters, band indexes and one or more user-specified SQL
expressions.
Availability: 2.1.0

Description: Variants 1 and 2 (one raster)

Creates a new one band raster formed by applying a valid PostgreSQL algebraic operation defined by the expression on the
input raster (rast). If nband is not provided, band 1 is assumed. The new raster will have the same georeference, width, and
height as the original raster but will only have one band.
If pixeltype is passed in, then the new raster will have a band of that pixeltype. If pixeltype is passed NULL, then the new
raster band will have the same pixeltype as the input rast band.

• Keywords permitted for expression

1. [rast] - Pixel value of the pixel of interest
2. [rast.val] - Pixel value of the pixel of interest
3. [rast.x] - 1-based pixel column of the pixel of interest
4. [rast.y] - 1-based pixel row of the pixel of interest

Description: Variants 3 and 4 (two raster)

Creates a new one band raster formed by applying a valid PostgreSQL algebraic operation to the two bands defined by the
expression on the two input raster bands rast1, (rast2). If no band1, band2 is specified band 1 is assumed. The
resulting raster will be aligned (scale, skew and pixel corners) on the grid defined by the first raster. The resulting raster will have
the extent defined by the extenttype parameter.

expression A PostgreSQL algebraic expression involving the two rasters and PostgreSQL defined functions/operators that will
define the pixel value when pixels intersect. e.g. (([rast1] + [rast2])/2.0)::integer
pixeltype The resulting pixel type of the output raster. Must be one listed in ST_BandPixelType, left out or set to NULL. If not
passed in or set to NULL, will default to the pixeltype of the first raster.
extenttype Controls the extent of resulting raster

1. INTERSECTION - The extent of the new raster is the intersection of the two rasters. This is the default.
2. UNION - The extent of the new raster is the union of the two rasters.
3. FIRST - The extent of the new raster is the same as the one of the first raster.
4. SECOND - The extent of the new raster is the same as the one of the second raster.

nodata1expr An algebraic expression involving only rast2 or a constant that defines what to return when pixels of rast1
are nodata values and spatially corresponding rast2 pixels have values.
nodata2expr An algebraic expression involving only rast1 or a constant that defines what to return when pixels of rast2
are nodata values and spatially corresponding rast1 pixels have values.
PostGIS 2.4.3 Manual 559 / 803

nodatanodataval A numeric constant to return when spatially corresponding rast1 and rast2 pixels are both nodata values.

• Keywords permitted in expression, nodata1expr and nodata2expr

1. [rast1] - Pixel value of the pixel of interest from rast1

2. [rast1.val] - Pixel value of the pixel of interest from rast1
3. [rast1.x] - 1-based pixel column of the pixel of interest from rast1
4. [rast1.y] - 1-based pixel row of the pixel of interest from rast1
5. [rast2] - Pixel value of the pixel of interest from rast2
6. [rast2.val] - Pixel value of the pixel of interest from rast2
7. [rast2.x] - 1-based pixel column of the pixel of interest from rast2
8. [rast2.y] - 1-based pixel row of the pixel of interest from rast2

Examples: Variants 1 and 2

WITH foo AS (
SELECT ST_AddBand(ST_MakeEmptyRaster(10, 10, 0, 0, 1, 1, 0, 0, 0), '32BF'::text, 1, -1) ←-
AS rast
)
SELECT
ST_MapAlgebra(rast, 1, NULL, 'ceil([rast]*[rast.x]/[rast.y]+[rast.val])')
FROM foo;

Examples: Variant 3 and 4

WITH foo AS (
SELECT 1 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 0, 1, -1, ←-
0, 0, 0), 1, '16BUI', 1, 0), 2, '8BUI', 10, 0), 3, '32BUI'::text, 100, 0) AS rast ←-
UNION ALL
SELECT 2 AS rid, ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(2, 2, 0, 1, 1, -1, ←-
0, 0, 0), 1, '16BUI', 2, 0), 2, '8BUI', 20, 0), 3, '32BUI'::text, 300, 0) AS rast
)
SELECT
ST_MapAlgebra(
t1.rast, 2,
t2.rast, 1,
'([rast2] + [rast1.val]) / 2'
) AS rast
FROM foo t1
CROSS JOIN foo t2
WHERE t1.rid = 1
AND t2.rid = 2;

See Also

rastbandarg, ST_Union, ST_MapAlgebra

9.11.1.6 ST_MapAlgebraExpr

ST_MapAlgebraExpr — 1 raster band version: Creates a new one band raster formed by applying a valid PostgreSQL algebraic
operation on the input raster band and of pixeltype provided. Band 1 is assumed if no band is specified.
PostGIS 2.4.3 Manual 560 / 803

Synopsis

raster ST_MapAlgebraExpr(raster rast, integer band, text pixeltype, text expression, double precision nodataval=NULL);
raster ST_MapAlgebraExpr(raster rast, text pixeltype, text expression, double precision nodataval=NULL);

Description

Warning
ST_MapAlgebraExpr is deprecated as of 2.1.0. Use ST_MapAlgebra instead.

Creates a new one band raster formed by applying a valid PostgreSQL algebraic operation defined by the expression on the
input raster (rast). If no band is specified band 1 is assumed. The new raster will have the same georeference, width, and
height as the original raster but will only have one band.
If pixeltype is passed in, then the new raster will have a band of that pixeltype. If pixeltype is passed NULL, then the new
raster band will have the same pixeltype as the input rast band.
In the expression you can use the term [rast] to refer to the pixel value of the original band, [rast.x] to refer to the 1-based
pixel column index, [rast.y] to refer to the 1-based pixel row index.
Availability: 2.0.0

Examples

Create a new 1 band raster from our original that is a function of modulo 2 of the original raster band.
ALTER TABLE dummy_rast ADD COLUMN map_rast raster;
UPDATE dummy_rast SET map_rast = ST_MapAlgebraExpr(rast,NULL,'mod([rast]::numeric,2)') ←-
WHERE rid = 2;

SELECT
ST_Value(rast,1,i,j) As origval,
ST_Value(map_rast, 1, i, j) As mapval
FROM dummy_rast
CROSS JOIN generate_series(1, 3) AS i
CROSS JOIN generate_series(1,3) AS j
WHERE rid = 2;

origval | mapval
---------+--------
253 | 1
254 | 0
253 | 1
253 | 1
254 | 0
254 | 0
250 | 0
254 | 0
254 | 0

Create a new 1 band raster of pixel-type 2BUI from our original that is reclassified and set the nodata value to be 0.
ALTER TABLE dummy_rast ADD COLUMN map_rast2 raster;
UPDATE dummy_rast SET
map_rast2 = ST_MapAlgebraExpr(rast,'2BUI'::text,'CASE WHEN [rast] BETWEEN 100 and 250 ←-
THEN 1 WHEN [rast] = 252 THEN 2 WHEN [rast] BETWEEN 253 and 254 THEN 3 ELSE 0 END':: ←-
text, '0')
PostGIS 2.4.3 Manual 561 / 803

WHERE rid = 2;

SELECT DISTINCT
ST_Value(rast,1,i,j) As origval,
ST_Value(map_rast2, 1, i, j) As mapval
FROM dummy_rast
CROSS JOIN generate_series(1, 5) AS i
CROSS JOIN generate_series(1,5) AS j
WHERE rid = 2;

origval | mapval
---------+--------
249 | 1
250 | 1
251 |
252 | 2
253 | 3
254 | 3

SELECT
ST_BandPixelType(map_rast2) As b1pixtyp
FROM dummy_rast
WHERE rid = 2;

b1pixtyp
----------
2BUI

original (column rast_view) rast_view_ma

Create a new 3 band raster same pixel type from our original 3 band raster with first band altered by map algebra and remaining
2 bands unaltered.
SELECT
ST_AddBand(
ST_AddBand(
ST_AddBand(
ST_MakeEmptyRaster(rast_view),
ST_MapAlgebraExpr(rast_view,1,NULL,'tan([rast])*[rast]')
PostGIS 2.4.3 Manual 562 / 803

),
ST_Band(rast_view,2)
),
ST_Band(rast_view, 3)
) As rast_view_ma
FROM wind
WHERE rid=167;

See Also

ST_MapAlgebraExpr, ST_MapAlgebraFct, ST_BandPixelType, ST_GeoReference, ST_Value

9.11.1.7 ST_MapAlgebraExpr

ST_MapAlgebraExpr — 2 raster band version: Creates a new one band raster formed by applying a valid PostgreSQL algebraic
operation on the two input raster bands and of pixeltype provided. band 1 of each raster is assumed if no band numbers are
specified. The resulting raster will be aligned (scale, skew and pixel corners) on the grid defined by the first raster and have its
extent defined by the "extenttype" parameter. Values for "extenttype" can be: INTERSECTION, UNION, FIRST, SECOND.

Synopsis

raster ST_MapAlgebraExpr(raster rast1, raster rast2, text expression, text pixeltype=same_as_rast1_band, text extenttype=INTERSECT
text nodata1expr=NULL, text nodata2expr=NULL, double precision nodatanodataval=NULL);
raster ST_MapAlgebraExpr(raster rast1, integer band1, raster rast2, integer band2, text expression, text pixeltype=same_as_rast1_band,
text extenttype=INTERSECTION, text nodata1expr=NULL, text nodata2expr=NULL, double precision nodatanodataval=NULL);

Description

Warning
ST_MapAlgebraExpr is deprecated as of 2.1.0. Use ST_MapAlgebra instead.

Creates a new one band raster formed by applying a valid PostgreSQL algebraic operation to the two bands defined by the
expression on the two input raster bands rast1, (rast2). If no band1, band2 is specified band 1 is assumed. The
resulting raster will be aligned (scale, skew and pixel corners) on the grid defined by the first raster. The resulting raster will have
the extent defined by the extenttype parameter.

expression A PostgreSQL algebraic expression involving the two rasters and PostgreSQL defined functions/operators that will
define the pixel value when pixels intersect. e.g. (([rast1] + [rast2])/2.0)::integer
pixeltype The resulting pixel type of the output raster. Must be one listed in ST_BandPixelType, left out or set to NULL. If not
passed in or set to NULL, will default to the pixeltype of the first raster.
extenttype Controls the extent of resulting raster

1. INTERSECTION - The extent of the new raster is the intersection of the two rasters. This is the default.
2. UNION - The extent of the new raster is the union of the two rasters.
3. FIRST - The extent of the new raster is the same as the one of the first raster.
4. SECOND - The extent of the new raster is the same as the one of the second raster.

nodata1expr An algebraic expression involving only rast2 or a constant that defines what to return when pixels of rast1
are nodata values and spatially corresponding rast2 pixels have values.
PostGIS 2.4.3 Manual 563 / 803

nodata2expr An algebraic expression involving only rast1 or a constant that defines what to return when pixels of rast2
are nodata values and spatially corresponding rast1 pixels have values.
nodatanodataval A numeric constant to return when spatially corresponding rast1 and rast2 pixels are both nodata values.

If pixeltype is passed in, then the new raster will have a band of that pixeltype. If pixeltype is passed NULL or no pixel type
specified, then the new raster band will have the same pixeltype as the input rast1 band.
Use the term [rast1.val] [rast2.val] to refer to the pixel value of the original raster bands and [rast1.x], [rast1.y]
etc. to refer to the column / row positions of the pixels.
Availability: 2.0.0

Example: 2 Band Intersection and Union

Create a new 1 band raster from our original that is a function of modulo 2 of the original raster band.
--Create a cool set of rasters --
DROP TABLE IF EXISTS fun_shapes;
CREATE TABLE fun_shapes(rid serial PRIMARY KEY, fun_name text, rast raster);

-- Insert some cool shapes around Boston in Massachusetts state plane meters --
INSERT INTO fun_shapes(fun_name, rast)
VALUES ('ref', ST_AsRaster(ST_MakeEnvelope(235229, 899970, 237229, 901930,26986),200,200,'8 ←-
BUI',0,0));

INSERT INTO fun_shapes(fun_name,rast)

WITH ref(rast) AS (SELECT rast FROM fun_shapes WHERE fun_name = 'ref' )
SELECT 'area' AS fun_name, ST_AsRaster(ST_Buffer(ST_SetSRID(ST_Point(236229, 900930),26986) ←-
, 1000),
ref.rast,'8BUI', 10, 0) As rast
FROM ref
UNION ALL
SELECT 'rand bubbles',
ST_AsRaster(
(SELECT ST_Collect(geom)
FROM (SELECT ST_Buffer(ST_SetSRID(ST_Point(236229 + i*random()*100, 900930 + j*random() ←-
*100),26986), random()*20) As geom
FROM generate_series(1,10) As i, generate_series(1,10) As j
) As foo ), ref.rast,'8BUI', 200, 0)
FROM ref;

--map them -
SELECT ST_MapAlgebraExpr(
area.rast, bub.rast, '[rast2.val]', '8BUI', 'INTERSECTION', '[rast2.val]', '[rast1.val ←-
]') As interrast,
ST_MapAlgebraExpr(
area.rast, bub.rast, '[rast2.val]', '8BUI', 'UNION', '[rast2.val]', '[rast1.val]') As ←-
unionrast
FROM
(SELECT rast FROM fun_shapes WHERE
fun_name = 'area') As area
CROSS JOIN (SELECT rast
FROM fun_shapes WHERE
fun_name = 'rand bubbles') As bub
PostGIS 2.4.3 Manual 564 / 803

mapalgebra intersection

map algebra union

Example: Overlaying rasters on a canvas as separate bands

-- we use ST_AsPNG to render the image so all single band ones look grey --
WITH mygeoms
AS ( SELECT 2 As bnum, ST_Buffer(ST_Point(1,5),10) As geom
UNION ALL
SELECT 3 AS bnum,
ST_Buffer(ST_GeomFromText('LINESTRING(50 50,150 150,150 50)'), 10,'join= ←-
bevel') As geom
UNION ALL
SELECT 1 As bnum,
ST_Buffer(ST_GeomFromText('LINESTRING(60 50,150 150,150 50)'), 5,'join= ←-
bevel') As geom
),
-- define our canvas to be 1 to 1 pixel to geometry
canvas
AS (SELECT ST_AddBand(ST_MakeEmptyRaster(200,
200,
ST_XMin(e)::integer, ST_YMax(e)::integer, 1, -1, 0, 0) , '8BUI'::text,0) As rast
FROM (SELECT ST_Extent(geom) As e,
Max(ST_SRID(geom)) As srid
from mygeoms
) As foo
),
rbands AS (SELECT ARRAY(SELECT ST_MapAlgebraExpr(canvas.rast, ST_AsRaster(m.geom, canvas ←-
.rast, '8BUI', 100),
'[rast2.val]', '8BUI', 'FIRST', '[rast2.val]', '[rast1.val]') As rast
FROM mygeoms AS m CROSS JOIN canvas
ORDER BY m.bnum) As rasts
)
SELECT rasts[1] As rast1 , rasts[2] As rast2, rasts[3] As rast3, ST_AddBand(
ST_AddBand(rasts[1],rasts[2]), rasts[3]) As final_rast
FROM rbands;
PostGIS 2.4.3 Manual 565 / 803

rast1 rast2

rast3 final_rast

Example: Overlay 2 meter boundary of select parcels over an aerial imagery

-- Create new 3 band raster composed of first 2 clipped bands, and overlay of 3rd band with ←-
our geometry
-- This query took 3.6 seconds on PostGIS windows 64-bit install
WITH pr AS
-- Note the order of operation: we clip all the rasters to dimensions of our region
(SELECT ST_Clip(rast,ST_Expand(geom,50) ) As rast, g.geom
FROM aerials.o_2_boston AS r INNER JOIN
-- union our parcels of interest so they form a single geometry we can later intersect with
(SELECT ST_Union(ST_Transform(the_geom,26986)) AS geom
FROM landparcels WHERE pid IN('0303890000', '0303900000')) As g
ON ST_Intersects(rast::geometry, ST_Expand(g.geom,50))
),
-- we then union the raster shards together
PostGIS 2.4.3 Manual 566 / 803

-- ST_Union on raster is kinda of slow but much faster the smaller you can get the rasters
-- therefore we want to clip first and then union
prunion AS
(SELECT ST_AddBand(NULL, ARRAY[ST_Union(rast,1),ST_Union(rast,2),ST_Union(rast,3)] ) As ←-
clipped,geom
FROM pr
GROUP BY geom)
-- return our final raster which is the unioned shard with
-- with the overlay of our parcel boundaries
-- add first 2 bands, then mapalgebra of 3rd band + geometry
SELECT ST_AddBand(ST_Band(clipped,ARRAY[1,2])
, ST_MapAlgebraExpr(ST_Band(clipped,3), ST_AsRaster(ST_Buffer(ST_Boundary(geom),2), ←-
clipped, '8BUI',250),
'[rast2.val]', '8BUI', 'FIRST', '[rast2.val]', '[rast1.val]') ) As rast
FROM prunion;

The blue lines are the boundaries of select parcels

See Also

ST_MapAlgebraExpr, ST_AddBand, ST_AsPNG, ST_AsRaster, ST_MapAlgebraFct, ST_BandPixelType, ST_GeoReference,

ST_Value, ST_Union, ST_Union

9.11.1.8 ST_MapAlgebraFct

ST_MapAlgebraFct — 1 band version - Creates a new one band raster formed by applying a valid PostgreSQL function on the
input raster band and of pixeltype prodived. Band 1 is assumed if no band is specified.

Synopsis

raster ST_MapAlgebraFct(raster rast, regprocedure onerasteruserfunc);

raster ST_MapAlgebraFct(raster rast, regprocedure onerasteruserfunc, text[] VARIADIC args);
PostGIS 2.4.3 Manual 567 / 803

raster ST_MapAlgebraFct(raster rast, text pixeltype, regprocedure onerasteruserfunc);

raster ST_MapAlgebraFct(raster rast, text pixeltype, regprocedure onerasteruserfunc, text[] VARIADIC args);
raster ST_MapAlgebraFct(raster rast, integer band, regprocedure onerasteruserfunc);
raster ST_MapAlgebraFct(raster rast, integer band, regprocedure onerasteruserfunc, text[] VARIADIC args);
raster ST_MapAlgebraFct(raster rast, integer band, text pixeltype, regprocedure onerasteruserfunc);
raster ST_MapAlgebraFct(raster rast, integer band, text pixeltype, regprocedure onerasteruserfunc, text[] VARIADIC args);

Description

Warning
ST_MapAlgebraFct is deprecated as of 2.1.0. Use ST_MapAlgebra instead.

Creates a new one band raster formed by applying a valid PostgreSQL function specified by the onerasteruserfunc on the
input raster (rast). If no band is specified, band 1 is assumed. The new raster will have the same georeference, width, and
height as the original raster but will only have one band.
If pixeltype is passed in, then the new raster will have a band of that pixeltype. If pixeltype is passed NULL, then the new
raster band will have the same pixeltype as the input rast band.
The onerasteruserfunc parameter must be the name and signature of a SQL or PL/pgSQL function, cast to a regprocedure.
A very simple and quite useless PL/pgSQL function example is:
CREATE OR REPLACE FUNCTION simple_function(pixel FLOAT, pos INTEGER[], VARIADIC args TEXT ←-
[])
RETURNS FLOAT
AS $$ BEGIN
RETURN 0.0;
END; $$
LANGUAGE 'plpgsql' IMMUTABLE;

The userfunction may accept two or three arguments: a float value, an optional integer array, and a variadic text array. The
first argument is the value of an individual raster cell (regardless of the raster datatype). The second argument is the position of
the current processing cell in the form ’{x,y}’. The third argument indicates that all remaining parameters to ST_MapAlgebraFct
shall be passed through to the userfunction.
Passing a regprodedure argument to a SQL function requires the full function signature to be passed, then cast to a regprocedure
type. To pass the above example PL/pgSQL function as an argument, the SQL for the argument is:
'simple_function(float,integer[],text[])'::regprocedure

Note that the argument contains the name of the function, the types of the function arguments, quotes around the name and
argument types, and a cast to a regprocedure.
The third argument to the userfunction is a variadic text array. All trailing text arguments to any ST_MapAlgebraFct call
are passed through to the specified userfunction, and are contained in the args argument.

Note
For more information about the VARIADIC keyword, please refer to the PostgreSQL documentation and the "SQL
Functions with Variable Numbers of Arguments" section of Query Language (SQL) Functions.

Note
The text[] argument to the userfunction is required, regardless of whether you choose to pass any arguments to
your user function for processing or not.

Availability: 2.0.0
PostGIS 2.4.3 Manual 568 / 803

Examples

Create a new 1 band raster from our original that is a function of modulo 2 of the original raster band.
ALTER TABLE dummy_rast ADD COLUMN map_rast raster;
CREATE FUNCTION mod_fct(pixel float, pos integer[], variadic args text[])
RETURNS float
AS $$
BEGIN
RETURN pixel::integer % 2;
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE;

UPDATE dummy_rast SET map_rast = ST_MapAlgebraFct(rast,NULL,'mod_fct(float,integer[],text ←-

[])'::regprocedure) WHERE rid = 2;

SELECT ST_Value(rast,1,i,j) As origval, ST_Value(map_rast, 1, i, j) As mapval

FROM dummy_rast CROSS JOIN generate_series(1, 3) AS i CROSS JOIN generate_series(1,3) AS j
WHERE rid = 2;

origval | mapval
---------+--------
253 | 1
254 | 0
253 | 1
253 | 1
254 | 0
254 | 0
250 | 0
254 | 0
254 | 0

Create a new 1 band raster of pixel-type 2BUI from our original that is reclassified and set the nodata value to a passed parameter
to the user function (0).
ALTER TABLE dummy_rast ADD COLUMN map_rast2 raster;
CREATE FUNCTION classify_fct(pixel float, pos integer[], variadic args text[])
RETURNS float
AS
$$
DECLARE
nodata float := 0;
BEGIN
IF NOT args[1] IS NULL THEN
nodata := args[1];
END IF;
IF pixel < 251 THEN
RETURN 1;
ELSIF pixel = 252 THEN
RETURN 2;
ELSIF pixel > 252 THEN
RETURN 3;
ELSE
RETURN nodata;
END IF;
END;
$$
LANGUAGE 'plpgsql';
UPDATE dummy_rast SET map_rast2 = ST_MapAlgebraFct(rast,'2BUI','classify_fct(float,integer ←-
[],text[])'::regprocedure, '0') WHERE rid = 2;
PostGIS 2.4.3 Manual 569 / 803

SELECT DISTINCT ST_Value(rast,1,i,j) As origval, ST_Value(map_rast2, 1, i, j) As mapval

FROM dummy_rast CROSS JOIN generate_series(1, 5) AS i CROSS JOIN generate_series(1,5) AS j
WHERE rid = 2;

origval | mapval
---------+--------
249 | 1
250 | 1
251 |
252 | 2
253 | 3
254 | 3

SELECT ST_BandPixelType(map_rast2) As b1pixtyp

FROM dummy_rast WHERE rid = 2;

b1pixtyp
----------
2BUI

original (column rast-view) rast_view_ma

Create a new 3 band raster same pixel type from our original 3 band raster with first band altered by map algebra and remaining
2 bands unaltered.
CREATE FUNCTION rast_plus_tan(pixel float, pos integer[], variadic args text[])
RETURNS float
AS
$$
BEGIN
RETURN tan(pixel) * pixel;
END;
$$
LANGUAGE 'plpgsql';

SELECT ST_AddBand(
ST_AddBand(
ST_AddBand(
ST_MakeEmptyRaster(rast_view),
PostGIS 2.4.3 Manual 570 / 803

ST_MapAlgebraFct(rast_view,1,NULL,'rast_plus_tan(float,integer[],text[])':: ←-
regprocedure)
),
ST_Band(rast_view,2)
),
ST_Band(rast_view, 3) As rast_view_ma
)
FROM wind
WHERE rid=167;

See Also

ST_MapAlgebraExpr, ST_BandPixelType, ST_GeoReference, ST_SetValue

9.11.1.9 ST_MapAlgebraFct

ST_MapAlgebraFct — 2 band version - Creates a new one band raster formed by applying a valid PostgreSQL function on the 2
input raster bands and of pixeltype prodived. Band 1 is assumed if no band is specified. Extent type defaults to INTERSECTION
if not specified.

Synopsis

raster ST_MapAlgebraFct(raster rast1, raster rast2, regprocedure tworastuserfunc, text pixeltype=same_as_rast1, text extent-
type=INTERSECTION, text[] VARIADIC userargs);
raster ST_MapAlgebraFct(raster rast1, integer band1, raster rast2, integer band2, regprocedure tworastuserfunc, text pixel-
type=same_as_rast1, text extenttype=INTERSECTION, text[] VARIADIC userargs);

Description

Warning
ST_MapAlgebraFct is deprecated as of 2.1.0. Use ST_MapAlgebra instead.

Creates a new one band raster formed by applying a valid PostgreSQL function specified by the tworastuserfunc on the
input raster rast1, rast2. If no band1 or band2 is specified, band 1 is assumed. The new raster will have the same
georeference, width, and height as the original rasters but will only have one band.
If pixeltype is passed in, then the new raster will have a band of that pixeltype. If pixeltype is passed NULL or left out, then
the new raster band will have the same pixeltype as the input rast1 band.
The tworastuserfunc parameter must be the name and signature of an SQL or PL/pgSQL function, cast to a regprocedure.
An example PL/pgSQL function example is:
CREATE OR REPLACE FUNCTION simple_function_for_two_rasters(pixel1 FLOAT, pixel2 FLOAT, pos ←-
INTEGER[], VARIADIC args TEXT[])
RETURNS FLOAT
AS $$ BEGIN
RETURN 0.0;
END; $$
LANGUAGE 'plpgsql' IMMUTABLE;

The tworastuserfunc may accept three or four arguments: a double precision value, a double precision value, an optional
integer array, and a variadic text array. The first argument is the value of an individual raster cell in rast1 (regardless of the
raster datatype). The second argument is an individual raster cell value in rast2. The third argument is the position of the
PostGIS 2.4.3 Manual 571 / 803

current processing cell in the form ’{x,y}’. The fourth argument indicates that all remaining parameters to ST_MapAlgebraFct
shall be passed through to the tworastuserfunc.
Passing a regprodedure argument to a SQL function requires the full function signature to be passed, then cast to a regprocedure
type. To pass the above example PL/pgSQL function as an argument, the SQL for the argument is:
'simple_function(double precision, double precision, integer[], text[])'::regprocedure

Note that the argument contains the name of the function, the types of the function arguments, quotes around the name and
argument types, and a cast to a regprocedure.
The fourth argument to the tworastuserfunc is a variadic text array. All trailing text arguments to any ST_MapAlgebraFct
call are passed through to the specified tworastuserfunc, and are contained in the userargs argument.

Note
For more information about the VARIADIC keyword, please refer to the PostgreSQL documentation and the "SQL
Functions with Variable Numbers of Arguments" section of Query Language (SQL) Functions.

Note
The text[] argument to the tworastuserfunc is required, regardless of whether you choose to pass any arguments
to your user function for processing or not.

Availability: 2.0.0

Example: Overlaying rasters on a canvas as separate bands

-- define our user defined function --

CREATE OR REPLACE FUNCTION raster_mapalgebra_union(
rast1 double precision,
rast2 double precision,
pos integer[],
VARIADIC userargs text[]
)
RETURNS double precision
AS $$
DECLARE
BEGIN
CASE
WHEN rast1 IS NOT NULL AND rast2 IS NOT NULL THEN
RETURN ((rast1 + rast2)/2.);
WHEN rast1 IS NULL AND rast2 IS NULL THEN
RETURN NULL;
WHEN rast1 IS NULL THEN
RETURN rast2;
ELSE
RETURN rast1;
END CASE;

RETURN NULL;
END;
$$ LANGUAGE 'plpgsql' IMMUTABLE COST 1000;

-- prep our test table of rasters

DROP TABLE IF EXISTS map_shapes;
CREATE TABLE map_shapes(rid serial PRIMARY KEY, rast raster, bnum integer, descrip text);
INSERT INTO map_shapes(rast,bnum, descrip)
PostGIS 2.4.3 Manual 572 / 803

WITH mygeoms
AS ( SELECT 2 As bnum, ST_Buffer(ST_Point(90,90),30) As geom, 'circle' As descrip
UNION ALL
SELECT 3 AS bnum,
ST_Buffer(ST_GeomFromText('LINESTRING(50 50,150 150,150 50)'), 15) As geom, ←-
'big road' As descrip
UNION ALL
SELECT 1 As bnum,
ST_Translate(ST_Buffer(ST_GeomFromText('LINESTRING(60 50,150 150,150 50)'), ←-
8,'join=bevel'), 10,-6) As geom, 'small road' As descrip
),
-- define our canvas to be 1 to 1 pixel to geometry
canvas
AS ( SELECT ST_AddBand(ST_MakeEmptyRaster(250,
250,
ST_XMin(e)::integer, ST_YMax(e)::integer, 1, -1, 0, 0 ) , '8BUI'::text,0) As rast
FROM (SELECT ST_Extent(geom) As e,
Max(ST_SRID(geom)) As srid
from mygeoms
) As foo
)
-- return our rasters aligned with our canvas
SELECT ST_AsRaster(m.geom, canvas.rast, '8BUI', 240) As rast, bnum, descrip
FROM mygeoms AS m CROSS JOIN canvas
UNION ALL
SELECT canvas.rast, 4, 'canvas'
FROM canvas;

-- Map algebra on single band rasters and then collect with ST_AddBand
INSERT INTO map_shapes(rast,bnum,descrip)
SELECT ST_AddBand(ST_AddBand(rasts[1], rasts[2]),rasts[3]), 4, 'map bands overlay fct union ←-
(canvas)'
FROM (SELECT ARRAY(SELECT ST_MapAlgebraFct(m1.rast, m2.rast,
'raster_mapalgebra_union(double precision, double precision, integer[], text[])':: ←-
regprocedure, '8BUI', 'FIRST')
FROM map_shapes As m1 CROSS JOIN map_shapes As m2
WHERE m1.descrip = 'canvas' AND m2.descrip <> 'canvas' ORDER BY m2.bnum) As rasts) As foo ←-
;
PostGIS 2.4.3 Manual 573 / 803

map bands overlay (canvas) (R: small road, G: circle, B: big road)

User Defined function that takes extra args

CREATE OR REPLACE FUNCTION raster_mapalgebra_userargs(

rast1 double precision,
rast2 double precision,
pos integer[],
VARIADIC userargs text[]
)
RETURNS double precision
AS $$
DECLARE
BEGIN
CASE
WHEN rast1 IS NOT NULL AND rast2 IS NOT NULL THEN
RETURN least(userargs[1]::integer,(rast1 + rast2)/2.);
WHEN rast1 IS NULL AND rast2 IS NULL THEN
RETURN userargs[2]::integer;
WHEN rast1 IS NULL THEN
RETURN greatest(rast2,random()*userargs[3]::integer)::integer;
ELSE
RETURN greatest(rast1, random()*userargs[4]::integer)::integer;
END CASE;

RETURN NULL;
END;
$$ LANGUAGE 'plpgsql' VOLATILE COST 1000;

SELECT ST_MapAlgebraFct(m1.rast, 1, m1.rast, 3,

'raster_mapalgebra_userargs(double precision, double precision, integer[], text[])':: ←-
regprocedure,
'8BUI', 'INTERSECT', '100','200','200','0')
FROM map_shapes As m1
PostGIS 2.4.3 Manual 574 / 803

WHERE m1.descrip = 'map bands overlay fct union (canvas)';

user defined with extra args and different bands from same raster

See Also

ST_MapAlgebraExpr, ST_BandPixelType, ST_GeoReference, ST_SetValue

9.11.1.10 ST_MapAlgebraFctNgb

ST_MapAlgebraFctNgb — 1-band version: Map Algebra Nearest Neighbor using user-defined PostgreSQL function. Return a
raster which values are the result of a PLPGSQL user function involving a neighborhood of values from the input raster band.

Synopsis

raster ST_MapAlgebraFctNgb(raster rast, integer band, text pixeltype, integer ngbwidth, integer ngbheight, regprocedure on-
erastngbuserfunc, text nodatamode, text[] VARIADIC args);

Description

Warning
ST_MapAlgebraFctNgb is deprecated as of 2.1.0. Use ST_MapAlgebra instead.

(one raster version) Return a raster which values are the result of a PLPGSQL user function involving a neighborhood of values
from the input raster band. The user function takes the neighborhood of pixel values as an array of numbers, for each pixel,
returns the result from the user function, replacing pixel value of currently inspected pixel with the function result.

rast Raster on which the user function is evaluated.

PostGIS 2.4.3 Manual 575 / 803

band Band number of the raster to be evaluated. Default to 1.

pixeltype The resulting pixel type of the output raster. Must be one listed in ST_BandPixelType or left out or set to NULL. If
not passed in or set to NULL, will default to the pixeltype of the rast. Results are truncated if they are larger than what
is allowed for the pixeltype.
ngbwidth The width of the neighborhood, in cells.
ngbheight The height of the neighborhood, in cells.
onerastngbuserfunc PLPGSQL/psql user function to apply to neighborhood pixels of a single band of a raster. The first element
is a 2-dimensional array of numbers representing the rectangular pixel neighborhood
nodatamode Defines what value to pass to the function for a neighborhood pixel that is nodata or NULL
’ignore’: any NODATA values encountered in the neighborhood are ignored by the computation -- this flag must be sent
to the user callback function, and the user function decides how to ignore it.
’NULL’: any NODATA values encountered in the neighborhood will cause the resulting pixel to be NULL -- the user
callback function is skipped in this case.
’value’: any NODATA values encountered in the neighborhood are replaced by the reference pixel (the one in the center of
the neighborhood). Note that if this value is NODATA, the behavior is the same as ’NULL’ (for the affected neighborhood)
args Arguments to pass into the user function.

Availability: 2.0.0

Examples

Examples utilize the katrina raster loaded as a single tile described in http://trac.osgeo.org/gdal/wiki/frmts_wtkraster.html and
then prepared in the ST_Rescale examples
--
-- A simple 'callback' user function that averages up all the values in a neighborhood.
--
CREATE OR REPLACE FUNCTION rast_avg(matrix float[][], nodatamode text, variadic args text ←-
[])
RETURNS float AS
$$
DECLARE
_matrix float[][];
x1 integer;
x2 integer;
y1 integer;
y2 integer;
sum float;
BEGIN
_matrix := matrix;
sum := 0;
FOR x in array_lower(matrix, 1)..array_upper(matrix, 1) LOOP
FOR y in array_lower(matrix, 2)..array_upper(matrix, 2) LOOP
sum := sum + _matrix[x][y];
END LOOP;
END LOOP;
RETURN (sum*1.0/(array_upper(matrix,1)*array_upper(matrix,2) ))::integer ;
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE COST 1000;

-- now we apply to our raster averaging pixels within 2 pixels of each other in X and Y ←-
direction --
SELECT ST_MapAlgebraFctNgb(rast, 1, '8BUI', 4,4,
PostGIS 2.4.3 Manual 576 / 803

'rast_avg(float[][], text, text[])'::regprocedure, 'NULL', NULL) As nn_with_border

FROM katrinas_rescaled
limit 1;

new raster after averaging pixels withing 4x4 pixels of each

First band of our raster
other

See Also

ST_MapAlgebraFct, ST_MapAlgebraExpr, ST_Rescale

9.11.1.11 ST_Reclass

ST_Reclass — Creates a new raster composed of band types reclassified from original. The nband is the band to be changed. If
nband is not specified assumed to be 1. All other bands are returned unchanged. Use case: convert a 16BUI band to a 8BUI and
so forth for simpler rendering as viewable formats.

Synopsis

raster ST_Reclass(raster rast, integer nband, text reclassexpr, text pixeltype, double precision nodataval=NULL);
raster ST_Reclass(raster rast, reclassarg[] VARIADIC reclassargset);
raster ST_Reclass(raster rast, text reclassexpr, text pixeltype);

Description

Creates a new raster formed by applying a valid PostgreSQL algebraic operation defined by the reclassexpr on the input
raster (rast). If no band is specified band 1 is assumed. The new raster will have the same georeference, width, and height as
the original raster. Bands not designated will come back unchanged. Refer to reclassarg for description of valid reclassification
expressions.
The bands of the new raster will have pixel type of pixeltype. If reclassargset is passed in then each reclassarg defines
behavior of each band generated.
Availability: 2.0.0
PostGIS 2.4.3 Manual 577 / 803

Examples Basic

Create a new raster from the original where band 2 is converted from 8BUI to 4BUI and all values from 101-254 are set to nodata
value.
ALTER TABLE dummy_rast ADD COLUMN reclass_rast raster;
UPDATE dummy_rast SET reclass_rast = ST_Reclass(rast,2,'0-87:1-10, 88-100:11-15, ←-
101-254:0-0', '4BUI',0) WHERE rid = 2;

SELECT i as col, j as row, ST_Value(rast,2,i,j) As origval,

ST_Value(reclass_rast, 2, i, j) As reclassval,
ST_Value(reclass_rast, 2, i, j, false) As reclassval_include_nodata
FROM dummy_rast CROSS JOIN generate_series(1, 3) AS i CROSS JOIN generate_series(1,3) AS j
WHERE rid = 2;

col | row | origval | reclassval | reclassval_include_nodata

-----+-----+---------+------------+---------------------------
1 | 1 | 78 | 9 | 9
2 | 1 | 98 | 14 | 14
3 | 1 | 122 | | 0
1 | 2 | 96 | 14 | 14
2 | 2 | 118 | | 0
3 | 2 | 180 | | 0
1 | 3 | 99 | 15 | 15
2 | 3 | 112 | | 0
3 | 3 | 169 | | 0

Example: Advanced using multiple reclassargs

Create a new raster from the original where band 1,2,3 is converted to 1BB,4BUI, 4BUI respectively and reclassified. Note this
uses the variadic reclassarg argument which can take as input an indefinite number of reclassargs (theoretically as many
bands as you have)
UPDATE dummy_rast SET reclass_rast =
ST_Reclass(rast,
ROW(2,'0-87]:1-10, (87-100]:11-15, (101-254]:0-0', '4BUI',NULL)::reclassarg,
ROW(1,'0-253]:1, 254:0', '1BB', NULL)::reclassarg,
ROW(3,'0-70]:1, (70-86:2, [86-150):3, [150-255:4', '4BUI', NULL)::reclassarg
) WHERE rid = 2;

SELECT i as col, j as row,ST_Value(rast,1,i,j) As ov1, ST_Value(reclass_rast, 1, i, j) As ←-

rv1,
ST_Value(rast,2,i,j) As ov2, ST_Value(reclass_rast, 2, i, j) As rv2,
ST_Value(rast,3,i,j) As ov3, ST_Value(reclass_rast, 3, i, j) As rv3
FROM dummy_rast CROSS JOIN generate_series(1, 3) AS i CROSS JOIN generate_series(1,3) AS j
WHERE rid = 2;

col | row | ov1 | rv1 | ov2 | rv2 | ov3 | rv3

----+-----+-----+-----+-----+-----+-----+-----
1 | 1 | 253 | 1 | 78 | 9 | 70 | 1
2 | 1 | 254 | 0 | 98 | 14 | 86 | 3
3 | 1 | 253 | 1 | 122 | 0 | 100 | 3
1 | 2 | 253 | 1 | 96 | 14 | 80 | 2
2 | 2 | 254 | 0 | 118 | 0 | 108 | 3
3 | 2 | 254 | 0 | 180 | 0 | 162 | 4
1 | 3 | 250 | 1 | 99 | 15 | 90 | 3
2 | 3 | 254 | 0 | 112 | 0 | 108 | 3
3 | 3 | 254 | 0 | 169 | 0 | 175 | 4
PostGIS 2.4.3 Manual 578 / 803

Example: Advanced Map a single band 32BF raster to multiple viewable bands

Create a new 3 band (8BUI,8BUI,8BUI viewable raster) from a raster that has only one 32bf band
ALTER TABLE wind ADD COLUMN rast_view raster;
UPDATE wind
set rast_view = ST_AddBand( NULL,
ARRAY[
ST_Reclass(rast, 1,'0.1-10]:1-10,9-10]:11,(11-33:0'::text, '8BUI'::text,0),
ST_Reclass(rast,1, '11-33):0-255,[0-32:0,(34-1000:0'::text, '8BUI'::text,0),
ST_Reclass(rast,1,'0-32]:0,(32-100:100-255'::text, '8BUI'::text,0)
]
);

See Also

ST_AddBand, ST_Band, ST_BandPixelType, ST_MakeEmptyRaster, reclassarg, ST_Value

9.11.1.12 ST_Union

ST_Union — Returns the union of a set of raster tiles into a single raster composed of 1 or more bands.

Synopsis

raster ST_Union(setof raster rast);

raster ST_Union(setof raster rast, unionarg[] unionargset);
raster ST_Union(setof raster rast, integer nband);
raster ST_Union(setof raster rast, text uniontype);
raster ST_Union(setof raster rast, integer nband, text uniontype);

Description

Returns the union of a set of raster tiles into a single raster composed of at least one band. The resulting raster’s extent is the
extent of the whole set. In the case of intersection, the resulting value is defined by uniontype which is one of the following:
LAST (default), FIRST, MIN, MAX, COUNT, SUM, MEAN, RANGE.

Note
In order for rasters to be unioned, they must all have the same alignment. Use ST_SameAlignment and
ST_NotSameAlignmentReason for more details and help. One way to fix alignment issues is to use ST_Resample
and use the same reference raster for alignment.

Availability: 2.0.0
Enhanced: 2.1.0 Improved Speed (fully C-Based).
Availability: 2.1.0 ST_Union(rast, unionarg) variant was introduced.
Enhanced: 2.1.0 ST_Union(rast) (variant 1) unions all bands of all input rasters. Prior versions of PostGIS assumed the first
band.
Enhanced: 2.1.0 ST_Union(rast, uniontype) (variant 4) unions all bands of all input rasters.
PostGIS 2.4.3 Manual 579 / 803

Examples: Reconstitute a single band chunked raster tile

-- this creates a single band from first band of raster tiles

-- that form the original file system tile
SELECT filename, ST_Union(rast,1) As file_rast
FROM sometable WHERE filename IN('dem01', 'dem02') GROUP BY filename;

Examples: Return a multi-band raster that is the union of tiles intersecting geometry

-- this creates a multi band raster collecting all the tiles that intersect a line
-- Note: In 2.0, this would have just returned a single band raster
-- , new union works on all bands by default
-- this is equivalent to unionarg: ARRAY[ROW(1, 'LAST'), ROW(2, 'LAST'), ROW(3, 'LAST')]:: ←-
unionarg[]
SELECT ST_Union(rast)
FROM aerials.boston
WHERE ST_Intersects(rast, ST_GeomFromText('LINESTRING(230486 887771, 230500 88772)',26986) ←-
);

Examples: Return a multi-band raster that is the union of tiles intersecting geometry

Here we use the longer syntax if we only wanted a subset of bands or we want to change order of bands
-- this creates a multi band raster collecting all the tiles that intersect a line
SELECT ST_Union(rast,ARRAY[ROW(2, 'LAST'), ROW(1, 'LAST'), ROW(3, 'LAST')]::unionarg[])
FROM aerials.boston
WHERE ST_Intersects(rast, ST_GeomFromText('LINESTRING(230486 887771, 230500 88772)',26986) ←-
);

See Also

unionarg, ST_Envelope, ST_ConvexHull, ST_Clip, ST_Union

9.11.2 Built-in Map Algebra Callback Functions

9.11.2.1 ST_Distinct4ma

ST_Distinct4ma — Raster processing function that calculates the number of unique pixel values in a neighborhood.

Synopsis

float8 ST_Distinct4ma(float8[][] matrix, text nodatamode, text[] VARIADIC args);

double precision ST_Distinct4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate the number of unique pixel values in a neighborhood of pixels.

Note
Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb.
PostGIS 2.4.3 Manual 580 / 803

Note
Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Warning
Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0.

Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2

Examples

SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, NULL, 1, 1, 'st_distinct4ma(float[][],text,text[])':: ←-
regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+----------
2 | 3
(1 row)

See Also

ST_MapAlgebraFctNgb, ST_MapAlgebra, ST_Min4ma, ST_Max4ma, ST_Sum4ma, ST_Mean4ma, ST_Distinct4ma, ST_StdDev4ma

9.11.2.2 ST_InvDistWeight4ma

ST_InvDistWeight4ma — Raster processing function that interpolates a pixel’s value from the pixel’s neighborhood.

Synopsis

double precision ST_InvDistWeight4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate an interpolated value for a pixel using the Inverse Distance Weighted method.
There are two optional parameters that can be passed through userargs. The first parameter is the power factor (variable k in
the equation below) between 0 and 1 used in the Inverse Distance Weighted equation. If not specified, default value is 1. The
second parameter is the weight percentage applied only when the value of the pixel of interest is included with the interpolated
value from the neighborhood. If not specified and the pixel of interest has a value, that value is returned.
The basic inverse distance weight equation is:
PostGIS 2.4.3 Manual 581 / 803

k = power factor, a real number between 0 and 1

Note
This function is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Availability: 2.1.0

Examples

-- NEEDS EXAMPLE

See Also

ST_MapAlgebra, ST_MinDist4ma

9.11.2.3 ST_Max4ma

ST_Max4ma — Raster processing function that calculates the maximum pixel value in a neighborhood.

Synopsis

float8 ST_Max4ma(float8[][] matrix, text nodatamode, text[] VARIADIC args);

double precision ST_Max4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate the maximum pixel value in a neighborhood of pixels.

For Variant 2, a substitution value for NODATA pixels can be specified by passing that value to userargs.

Note
Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb.

Note
Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Warning
Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0.

Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2
PostGIS 2.4.3 Manual 582 / 803

Examples

SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, NULL, 1, 1, 'st_max4ma(float[][],text,text[])':: ←-
regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+----------
2 | 254
(1 row)

See Also

ST_MapAlgebraFctNgb, ST_MapAlgebra, ST_Min4ma, ST_Sum4ma, ST_Mean4ma, ST_Range4ma, ST_Distinct4ma, ST_StdDev4ma

9.11.2.4 ST_Mean4ma

ST_Mean4ma — Raster processing function that calculates the mean pixel value in a neighborhood.

Synopsis

float8 ST_Mean4ma(float8[][] matrix, text nodatamode, text[] VARIADIC args);

double precision ST_Mean4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate the mean pixel value in a neighborhood of pixels.

For Variant 2, a substitution value for NODATA pixels can be specified by passing that value to userargs.

Note
Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb.

Note
Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Warning
Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0.

Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2
PostGIS 2.4.3 Manual 583 / 803

Examples: Variant 1

SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, '32BF', 1, 1, 'st_mean4ma(float[][],text,text[])':: ←-
regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+------------------
2 | 253.222229003906
(1 row)

Examples: Variant 2

SELECT
rid,
st_value(
ST_MapAlgebra(rast, 1, 'st_mean4ma(double precision[][][], integer[][], text ←-
[])'::regprocedure,'32BF', 'FIRST', NULL, 1, 1)
, 2, 2)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+------------------
2 | 253.222229003906
(1 row)

See Also

ST_MapAlgebraFctNgb, ST_MapAlgebra, ST_Min4ma, ST_Max4ma, ST_Sum4ma, ST_Range4ma, ST_StdDev4ma

9.11.2.5 ST_Min4ma

ST_Min4ma — Raster processing function that calculates the minimum pixel value in a neighborhood.

Synopsis

float8 ST_Min4ma(float8[][] matrix, text nodatamode, text[] VARIADIC args);

double precision ST_Min4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate the minimum pixel value in a neighborhood of pixels.

For Variant 2, a substitution value for NODATA pixels can be specified by passing that value to userargs.

Note
Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb.
PostGIS 2.4.3 Manual 584 / 803

Note
Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Warning
Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0.

Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2

Examples

SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, NULL, 1, 1, 'st_min4ma(float[][],text,text[])':: ←-
regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+----------
2 | 250
(1 row)

See Also

ST_MapAlgebraFctNgb, ST_MapAlgebra, ST_Max4ma, ST_Sum4ma, ST_Mean4ma, ST_Range4ma, ST_Distinct4ma, ST_StdDev4m

9.11.2.6 ST_MinDist4ma

ST_MinDist4ma — Raster processing function that returns the minimum distance (in number of pixels) between the pixel of
interest and a neighboring pixel with value.

Synopsis

double precision ST_MinDist4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Return the shortest distance (in number of pixels) between the pixel of interest and the closest pixel with value in the neighbor-
hood.

Note
The intent of this function is to provide an informative data point that helps infer the usefulness of the pixel of interest’s
interpolated value from ST_InvDistWeight4ma. This function is particularly useful when the neighborhood is sparsely
populated.
PostGIS 2.4.3 Manual 585 / 803

Note
This function is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Availability: 2.1.0

Examples

-- NEEDS EXAMPLE

See Also

ST_MapAlgebra, ST_InvDistWeight4ma

9.11.2.7 ST_Range4ma

ST_Range4ma — Raster processing function that calculates the range of pixel values in a neighborhood.

Synopsis

float8 ST_Range4ma(float8[][] matrix, text nodatamode, text[] VARIADIC args);

double precision ST_Range4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate the range of pixel values in a neighborhood of pixels.

For Variant 2, a substitution value for NODATA pixels can be specified by passing that value to userargs.

Note
Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb.

Note
Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Warning
Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0.

Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2
PostGIS 2.4.3 Manual 586 / 803

Examples

SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, NULL, 1, 1, 'st_range4ma(float[][],text,text[])':: ←-
regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+----------
2 | 4
(1 row)

See Also

ST_MapAlgebraFctNgb, ST_MapAlgebra, ST_Min4ma, ST_Max4ma, ST_Sum4ma, ST_Mean4ma, ST_Distinct4ma, ST_StdDev4ma

9.11.2.8 ST_StdDev4ma

ST_StdDev4ma — Raster processing function that calculates the standard deviation of pixel values in a neighborhood.

Synopsis

float8 ST_StdDev4ma(float8[][] matrix, text nodatamode, text[] VARIADIC args);

double precision ST_StdDev4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate the standard deviation of pixel values in a neighborhood of pixels.

Note
Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb.

Note
Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Warning
Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0.

Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2
PostGIS 2.4.3 Manual 587 / 803

Examples

SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, '32BF', 1, 1, 'st_stddev4ma(float[][],text,text[])':: ←-
regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+------------------
2 | 1.30170822143555
(1 row)

See Also

ST_MapAlgebraFctNgb, ST_MapAlgebra, ST_Min4ma, ST_Max4ma, ST_Sum4ma, ST_Mean4ma, ST_Distinct4ma, ST_StdDev4ma

9.11.2.9 ST_Sum4ma

ST_Sum4ma — Raster processing function that calculates the sum of all pixel values in a neighborhood.

Synopsis

float8 ST_Sum4ma(float8[][] matrix, text nodatamode, text[] VARIADIC args);

double precision ST_Sum4ma(double precision[][][] value, integer[][] pos, text[] VARIADIC userargs);

Description

Calculate the sum of all pixel values in a neighborhood of pixels.

For Variant 2, a substitution value for NODATA pixels can be specified by passing that value to userargs.

Note
Variant 1 is a specialized callback function for use as a callback parameter to ST_MapAlgebraFctNgb.

Note
Variant 2 is a specialized callback function for use as a callback parameter to ST_MapAlgebra.

Warning
Use of Variant 1 is discouraged since ST_MapAlgebraFctNgb has been deprecated as of 2.1.0.

Availability: 2.0.0
Enhanced: 2.1.0 Addition of Variant 2
PostGIS 2.4.3 Manual 588 / 803

Examples

SELECT
rid,
st_value(
st_mapalgebrafctngb(rast, 1, '32BF', 1, 1, 'st_sum4ma(float[][],text,text[])':: ←-
regprocedure, 'ignore', NULL), 2, 2
)
FROM dummy_rast
WHERE rid = 2;
rid | st_value
-----+----------
2 | 2279
(1 row)

See Also

ST_MapAlgebraFctNgb, ST_MapAlgebra, ST_Min4ma, ST_Max4ma, ST_Mean4ma, ST_Range4ma, ST_Distinct4ma, ST_StdDev4ma

9.11.3 DEM (Elevation)

9.11.3.1 ST_Aspect

ST_Aspect — Returns the aspect (in degrees by default) of an elevation raster band. Useful for analyzing terrain.

Synopsis

raster ST_Aspect(raster rast, integer band=1, text pixeltype=32BF, text units=DEGREES, boolean interpolate_nodata=FALSE);
raster ST_Aspect(raster rast, integer band, raster customextent, text pixeltype=32BF, text units=DEGREES, boolean interpo-
late_nodata=FALSE);

Description

Returns the aspect (in degrees by default) of an elevation raster band. Utilizes map algebra and applies the aspect equation to
neighboring pixels.
units indicates the units of the aspect. Possible values are: RADIANS, DEGREES (default).
When units = RADIANS, values are between 0 and 2 * pi radians measured clockwise from North.
When units = DEGREES, values are between 0 and 360 degrees measured clockwise from North.
If slope of pixel is zero, aspect of pixel is -1.

Note
For more information about Slope, Aspect and Hillshade, please refer to ESRI - How hillshade works and ERDAS Field
Guide - Aspect Images.

Availability: 2.0.0
Enhanced: 2.1.0 Uses ST_MapAlgebra() and added optional interpolate_nodata function parameter
Changed: 2.1.0 In prior versions, return values were in radians. Now, return values default to degrees
PostGIS 2.4.3 Manual 589 / 803

Examples: Variant 1

WITH foo AS (
SELECT ST_SetValues(
ST_AddBand(ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0), 1, '32BF', 0, -9999),
1, 1, 1, ARRAY[
[1, 1, 1, 1, 1],
[1, 2, 2, 2, 1],
[1, 2, 3, 2, 1],
[1, 2, 2, 2, 1],
[1, 1, 1, 1, 1]
]::double precision[][]
) AS rast
)
SELECT
ST_DumpValues(ST_Aspect(rast, 1, '32BF'))
FROM foo

-----------------------------------------------------------------------------------------------------

----------------------------------
(1,"{{315,341.565063476562,0,18.4349479675293,45},{288.434936523438,315,0,45,71.5650482177734},{270,

2227,180,161.565048217773,135}}")
(1 row)

Examples: Variant 2

Complete example of tiles of a coverage. This query only works with PostgreSQL 9.1 or higher.
WITH foo AS (
SELECT ST_Tile(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(6, 6, 0, 0, 1, -1, 0, 0, 0),
1, '32BF', 0, -9999
),
1, 1, 1, ARRAY[
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 2, 1],
[1, 2, 2, 3, 3, 1],
[1, 1, 3, 2, 1, 1],
[1, 2, 2, 1, 2, 1],
[1, 1, 1, 1, 1, 1]
]::double precision[]
),
2, 2
) AS rast
)
SELECT
t1.rast,
ST_Aspect(ST_Union(t2.rast), 1, t1.rast)
FROM foo t1
CROSS JOIN foo t2
WHERE ST_Intersects(t1.rast, t2.rast)
GROUP BY t1.rast;
PostGIS 2.4.3 Manual 590 / 803

See Also

ST_MapAlgebra, ST_TRI, ST_TPI, ST_Roughness, ST_HillShade, ST_Slope

9.11.3.2 ST_HillShade

ST_HillShade — Returns the hypothetical illumination of an elevation raster band using provided azimuth, altitude, brightness
and scale inputs.

Synopsis

raster ST_HillShade(raster rast, integer band=1, text pixeltype=32BF, double precision azimuth=315, double precision alti-
tude=45, double precision max_bright=255, double precision scale=1.0, boolean interpolate_nodata=FALSE);
raster ST_HillShade(raster rast, integer band, raster customextent, text pixeltype=32BF, double precision azimuth=315, double
precision altitude=45, double precision max_bright=255, double precision scale=1.0, boolean interpolate_nodata=FALSE);

Description

Returns the hypothetical illumination of an elevation raster band using the azimuth, altitude, brightness, and scale inputs. Utilizes
map algebra and applies the hill shade equation to neighboring pixels. Return pixel values are between 0 and 255.
azimuth is a value between 0 and 360 degrees measured clockwise from North.
altitude is a value between 0 and 90 degrees where 0 degrees is at the horizon and 90 degrees is directly overhead.
max_bright is a value between 0 and 255 with 0 as no brightness and 255 as max brightness.
scale is the ratio of vertical units to horizontal. For Feet:LatLon use scale=370400, for Meters:LatLon use scale=111120.
If interpolate_nodata is TRUE, values for NODATA pixels from the input raster will be interpolated using ST_InvDistWeight4ma
before computing the hillshade illumination.

Note
For more information about Hillshade, please refer to How hillshade works.

Availability: 2.0.0
Enhanced: 2.1.0 Uses ST_MapAlgebra() and added optional interpolate_nodata function parameter
Changed: 2.1.0 In prior versions, azimuth and altitude were expressed in radians. Now, azimuth and altitude are expressed in
degrees

Examples: Variant 1

WITH foo AS (
SELECT ST_SetValues(
ST_AddBand(ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0), 1, '32BF', 0, -9999),
1, 1, 1, ARRAY[
[1, 1, 1, 1, 1],
[1, 2, 2, 2, 1],
[1, 2, 3, 2, 1],
[1, 2, 2, 2, 1],
[1, 1, 1, 1, 1]
]::double precision[][]
) AS rast
)
PostGIS 2.4.3 Manual 591 / 803

SELECT
ST_DumpValues(ST_Hillshade(rast, 1, '32BF'))
FROM foo

-----------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------
(1,"{{NULL,NULL,NULL,NULL,NULL},{NULL,251.32763671875,220.749786376953,147.224319458008, ←-
NULL},{NULL,220.749786376953,180.312225341797,67.7497863769531,NULL},{NULL ←-
,147.224319458008
,67.7497863769531,43.1210060119629,NULL},{NULL,NULL,NULL,NULL,NULL}}")
(1 row)

Examples: Variant 2

Complete example of tiles of a coverage. This query only works with PostgreSQL 9.1 or higher.
WITH foo AS (
SELECT ST_Tile(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(6, 6, 0, 0, 1, -1, 0, 0, 0),
1, '32BF', 0, -9999
),
1, 1, 1, ARRAY[
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 2, 1],
[1, 2, 2, 3, 3, 1],
[1, 1, 3, 2, 1, 1],
[1, 2, 2, 1, 2, 1],
[1, 1, 1, 1, 1, 1]
]::double precision[]
),
2, 2
) AS rast
)
SELECT
t1.rast,
ST_Hillshade(ST_Union(t2.rast), 1, t1.rast)
FROM foo t1
CROSS JOIN foo t2
WHERE ST_Intersects(t1.rast, t2.rast)
GROUP BY t1.rast;

See Also

ST_MapAlgebra, ST_TRI, ST_TPI, ST_Roughness, ST_Aspect, ST_Slope

9.11.3.3 ST_Roughness

ST_Roughness — Returns a raster with the calculated "roughness" of a DEM.

Synopsis

raster ST_Roughness(raster rast, integer nband, raster customextent, text pixeltype="32BF" , boolean interpolate_nodata=FALSE
);
PostGIS 2.4.3 Manual 592 / 803

Description

Calculates the "roughness" of a DEM, by subtracting the maximum from the minimum for a given area.
Availability: 2.1.0

Examples

-- needs examples

See Also

ST_MapAlgebra, ST_TRI, ST_TPI, ST_Slope, ST_HillShade, ST_Aspect

9.11.3.4 ST_Slope

ST_Slope — Returns the slope (in degrees by default) of an elevation raster band. Useful for analyzing terrain.

Synopsis

raster ST_Slope(raster rast, integer nband=1, text pixeltype=32BF, text units=DEGREES, double precision scale=1.0, boolean
interpolate_nodata=FALSE);
raster ST_Slope(raster rast, integer nband, raster customextent, text pixeltype=32BF, text units=DEGREES, double precision
scale=1.0, boolean interpolate_nodata=FALSE);

Description

Returns the slope (in degrees by default) of an elevation raster band. Utilizes map algebra and applies the slope equation to
neighboring pixels.
units indicates the units of the slope. Possible values are: RADIANS, DEGREES (default), PERCENT.
scale is the ratio of vertical units to horizontal. For Feet:LatLon use scale=370400, for Meters:LatLon use scale=111120.
If interpolate_nodata is TRUE, values for NODATA pixels from the input raster will be interpolated using ST_InvDistWeight4ma
before computing the surface slope.

Note
For more information about Slope, Aspect and Hillshade, please refer to ESRI - How hillshade works and ERDAS Field
Guide - Slope Images.

Availability: 2.0.0
Enhanced: 2.1.0 Uses ST_MapAlgebra() and added optional units, scale, interpolate_nodata function parameters
Changed: 2.1.0 In prior versions, return values were in radians. Now, return values default to degrees
PostGIS 2.4.3 Manual 593 / 803

Examples: Variant 1

WITH foo AS (
SELECT ST_SetValues(
ST_AddBand(ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0), 1, '32BF', 0, -9999),
1, 1, 1, ARRAY[
[1, 1, 1, 1, 1],
[1, 2, 2, 2, 1],
[1, 2, 3, 2, 1],
[1, 2, 2, 2, 1],
[1, 1, 1, 1, 1]
]::double precision[][]
) AS rast
)
SELECT
ST_DumpValues(ST_Slope(rast, 1, '32BF'))
FROM foo

st_dumpvalues

-----------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------

---------------------------------------------------------------------
(1,"{{10.0249881744385,21.5681285858154,26.5650520324707,21.5681285858154,10.0249881744385},{21.5681

{26.5650520324707,36.8698959350586,0,36.8698959350586,26.5650520324707},{21.5681285858154,35.26438903

5681285858154,26.5650520324707,21.5681285858154,10.0249881744385}}")
(1 row)

Examples: Variant 2

Complete example of tiles of a coverage. This query only works with PostgreSQL 9.1 or higher.
WITH foo AS (
SELECT ST_Tile(
ST_SetValues(
ST_AddBand(
ST_MakeEmptyRaster(6, 6, 0, 0, 1, -1, 0, 0, 0),
1, '32BF', 0, -9999
),
1, 1, 1, ARRAY[
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 2, 1],
[1, 2, 2, 3, 3, 1],
[1, 1, 3, 2, 1, 1],
[1, 2, 2, 1, 2, 1],
[1, 1, 1, 1, 1, 1]
]::double precision[]
),
2, 2
) AS rast
)
SELECT
t1.rast,
ST_Slope(ST_Union(t2.rast), 1, t1.rast)
FROM foo t1
CROSS JOIN foo t2
WHERE ST_Intersects(t1.rast, t2.rast)
PostGIS 2.4.3 Manual 594 / 803

GROUP BY t1.rast;

See Also

ST_MapAlgebra, ST_TRI, ST_TPI, ST_Roughness, ST_HillShade, ST_Aspect

9.11.3.5 ST_TPI

ST_TPI — Returns a raster with the calculated Topographic Position Index.

Synopsis

raster ST_TPI(raster rast, integer nband, raster customextent, text pixeltype="32BF" , boolean interpolate_nodata=FALSE );

Description

Calculates the Topographic Position Index, which is defined as the focal mean with radius of one minus the center cell.

Note
This function only supports a focalmean radius of one.

Availability: 2.1.0

Examples

-- needs examples

See Also

ST_MapAlgebra, ST_TRI, ST_Roughness, ST_Slope, ST_HillShade, ST_Aspect

9.11.3.6 ST_TRI

ST_TRI — Returns a raster with the calculated Terrain Ruggedness Index.

Synopsis

raster ST_TRI(raster rast, integer nband, raster customextent, text pixeltype="32BF" , boolean interpolate_nodata=FALSE );

Description

Terrain Ruggedness Index is calculated by comparing a central pixel with its neighbors, taking the absolute values of the differ-
ences, and averaging the result.

Note
This function only supports a focalmean radius of one.

Availability: 2.1.0
PostGIS 2.4.3 Manual 595 / 803

Examples

-- needs examples

See Also

ST_MapAlgebra, ST_Roughness, ST_TPI, ST_Slope, ST_HillShade, ST_Aspect

9.11.4 Raster to Geometry

9.11.4.1 Box3D

Box3D — Returns the box 3d representation of the enclosing box of the raster.

Synopsis

box3d Box3D(raster rast);

Description

Returns the box representing the extent of the raster.

The polygon is defined by the corner points of the bounding box ((MINX, MINY), (MAXX, MAXY))
Changed: 2.0.0 In pre-2.0 versions, there used to be a box2d instead of box3d. Since box2d is a deprecated type, this was changed
to box3d.

Examples

SELECT
rid,
Box3D(rast) AS rastbox
FROM dummy_rast;

rid | rastbox
----+-------------------------------------------------
1 | BOX3D(0.5 0.5 0,20.5 60.5 0)
2 | BOX3D(3427927.75 5793243.5 0,3427928 5793244 0)

See Also

ST_Envelope

9.11.4.2 ST_ConvexHull

ST_ConvexHull — Return the convex hull geometry of the raster including pixel values equal to BandNoDataValue. For regular
shaped and non-skewed rasters, this gives the same result as ST_Envelope so only useful for irregularly shaped or skewed rasters.

Synopsis

geometry ST_ConvexHull(raster rast);

PostGIS 2.4.3 Manual 596 / 803

Description

Return the convex hull geometry of the raster including the NoDataBandValue band pixels. For regular shaped and non-skewed
rasters, this gives more or less the same result as ST_Envelope so only useful for irregularly shaped or skewed rasters.

Note
ST_Envelope floors the coordinates and hence add a little buffer around the raster so the answer is subtly different from
ST_ConvexHull which does not floor.

Examples

Refer to PostGIS Raster Specification for a diagram of this.

-- Note envelope and convexhull are more or less the same
SELECT ST_AsText(ST_ConvexHull(rast)) As convhull,
ST_AsText(ST_Envelope(rast)) As env
FROM dummy_rast WHERE rid=1;

convhull | env
--------------------------------------------------------+------------------------------------ ←-

POLYGON((0.5 0.5,20.5 0.5,20.5 60.5,0.5 60.5,0.5 0.5)) | POLYGON((0 0,20 0,20 60,0 60,0 0) ←-
)

-- now we skew the raster

-- note how the convex hull and envelope are now different
SELECT ST_AsText(ST_ConvexHull(rast)) As convhull,
ST_AsText(ST_Envelope(rast)) As env
FROM (SELECT ST_SetRotation(rast, 0.1, 0.1) As rast
FROM dummy_rast WHERE rid=1) As foo;

convhull | env
--------------------------------------------------------+------------------------------------ ←-

POLYGON((0.5 0.5,20.5 1.5,22.5 61.5,2.5 60.5,0.5 0.5)) | POLYGON((0 0,22 0,22 61,0 61,0 0) ←-
)

See Also

ST_Envelope, ST_MinConvexHull, ST_ConvexHull, ST_AsText

9.11.4.3 ST_DumpAsPolygons

ST_DumpAsPolygons — Returns a set of geomval (geom,val) rows, from a given raster band. If no band number is specified,
band num defaults to 1.

Synopsis

setof geomval ST_DumpAsPolygons(raster rast, integer band_num=1, boolean exclude_nodata_value=TRUE);

PostGIS 2.4.3 Manual 597 / 803

Description

This is a set-returning function (SRF). It returns a set of geomval rows, formed by a geometry (geom) and a pixel band value
(val). Each polygon is the union of all pixels for that band that have the same pixel value denoted by val.
ST_DumpAsPolygon is useful for polygonizing rasters. It is the reverse of a GROUP BY in that it creates new rows. For example
it can be used to expand a single raster into multiple POLYGONS/MULTIPOLYGONS.
Availability: Requires GDAL 1.7 or higher.

Note
If there is a no data value set for a band, pixels with that value will not be returned except in the case of ex-
clude_nodata_value=false.

Note
If you only care about count of pixels with a given value in a raster, it is faster to use ST_ValueCount.

Note
This is different than ST_PixelAsPolygons where one geometry is returned for each pixel regardless of pixel value.

Examples

-- this syntax requires PostgreSQL 9.3+

SELECT val, ST_AsText(geom) As geomwkt
FROM (
SELECT dp.*
FROM dummy_rast, LATERAL ST_DumpAsPolygons(rast) AS dp
WHERE rid = 2
) As foo
WHERE val BETWEEN 249 and 251
ORDER BY val;

val | geomwkt
-----+--------------------------------------------------------------------------
249 | POLYGON((3427927.95 5793243.95,3427927.95 5793243.85,3427928 5793243.85,
3427928 5793243.95,3427927.95 5793243.95))
250 | POLYGON((3427927.75 5793243.9,3427927.75 5793243.85,3427927.8 5793243.85,
3427927.8 5793243.9,3427927.75 5793243.9))
250 | POLYGON((3427927.8 5793243.8,3427927.8 5793243.75,3427927.85 5793243.75,
3427927.85 5793243.8, 3427927.8 5793243.8))
251 | POLYGON((3427927.75 5793243.85,3427927.75 5793243.8,3427927.8 5793243.8,
3427927.8 5793243.85,3427927.75 5793243.85))

See Also

geomval, ST_Value, ST_Polygon, ST_ValueCount

9.11.4.4 ST_Envelope

ST_Envelope — Returns the polygon representation of the extent of the raster.

PostGIS 2.4.3 Manual 598 / 803

Synopsis

geometry ST_Envelope(raster rast);

Description

Returns the polygon representation of the extent of the raster in spatial coordinate units defined by srid. It is a float8 minimum
bounding box represented as a polygon.
The polygon is defined by the corner points of the bounding box ((MINX, MINY), (MINX, MAXY), (MAXX, MAXY), (MAXX, MINY),
(MINX, MINY))

Examples

SELECT rid, ST_AsText(ST_Envelope(rast)) As envgeomwkt

FROM dummy_rast;

rid | envgeomwkt
-----+--------------------------------------------------------------------
1 | POLYGON((0 0,20 0,20 60,0 60,0 0))
2 | POLYGON((3427927 5793243,3427928 5793243,
3427928 5793244,3427927 5793244, 3427927 5793243))

See Also

ST_Envelope, ST_AsText, ST_SRID

9.11.4.5 ST_MinConvexHull

ST_MinConvexHull — Return the convex hull geometry of the raster excluding NODATA pixels.

Synopsis

geometry ST_MinConvexHull(raster rast, integer nband=NULL);

Description

Return the convex hull geometry of the raster excluding NODATA pixels. If nband is NULL, all bands of the raster are
considered.
Availability: 2.1.0

Examples

WITH foo AS (
SELECT
ST_SetValues(
ST_SetValues(
ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(9, 9, 0, 0, 1, -1, 0, 0, 0), 1, '8BUI', 0, ←-
0), 2, '8BUI', 1, 0),
1, 1, 1,
ARRAY[
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
PostGIS 2.4.3 Manual 599 / 803

[0, 0, 0, 1, 0, 0, 0, 0, 1],
[0, 0, 0, 1, 1, 0, 0, 0, 0],
[0, 0, 0, 1, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0]
]::double precision[][]
),
2, 1, 1,
ARRAY[
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[1, 0, 0, 0, 0, 1, 0, 0, 0],
[0, 0, 0, 0, 1, 1, 0, 0, 0],
[0, 0, 0, 0, 0, 1, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0],
[0, 0, 1, 0, 0, 0, 0, 0, 0]
]::double precision[][]
) AS rast
)
SELECT
ST_AsText(ST_ConvexHull(rast)) AS hull,
ST_AsText(ST_MinConvexHull(rast)) AS mhull,
ST_AsText(ST_MinConvexHull(rast, 1)) AS mhull_1,
ST_AsText(ST_MinConvexHull(rast, 2)) AS mhull_2
FROM foo

hull | mhull | ←-
mhull_1 | mhull_2
----------------------------------+-------------------------------------+----------------------------

POLYGON((0 0,9 0,9 -9,0 -9,0 0)) | POLYGON((0 -3,9 -3,9 -9,0 -9,0 -3)) | POLYGON((3 -3,9 ←-
-3,9 -6,3 -6,3 -3)) | POLYGON((0 -3,6 -3,6 -9,0 -9,0 -3))

See Also

ST_Envelope, ST_ConvexHull, ST_ConvexHull, ST_AsText

9.11.4.6 ST_Polygon

ST_Polygon — Returns a multipolygon geometry formed by the union of pixels that have a pixel value that is not no data value.
If no band number is specified, band num defaults to 1.

Synopsis

geometry ST_Polygon(raster rast, integer band_num=1);

Description

Availability: 0.1.6 Requires GDAL 1.7 or higher.

Enhanced: 2.1.0 Improved Speed (fully C-Based) and the returning multipolygon is ensured to be valid.
Changed: 2.1.0 In prior versions would sometimes return a polygon, changed to always return multipolygon.
PostGIS 2.4.3 Manual 600 / 803

Examples

-- by default no data band value is 0 or not set, so polygon will return a square polygon
SELECT ST_AsText(ST_Polygon(rast)) As geomwkt
FROM dummy_rast
WHERE rid = 2;

geomwkt
--------------------------------------------
MULTIPOLYGON(((3427927.75 5793244,3427928 5793244,3427928 5793243.75,3427927.75 ←-
5793243.75,3427927.75 5793244)))

-- now we change the no data value of first band

UPDATE dummy_rast SET rast = ST_SetBandNoDataValue(rast,1,254)
WHERE rid = 2;
SELECt rid, ST_BandNoDataValue(rast)
from dummy_rast where rid = 2;

-- ST_Polygon excludes the pixel value 254 and returns a multipolygon

SELECT ST_AsText(ST_Polygon(rast)) As geomwkt
FROM dummy_rast
WHERE rid = 2;

geomwkt
---------------------------------------------------------
MULTIPOLYGON(((3427927.9 5793243.95,3427927.85 5793243.95,3427927.85 5793244,3427927.9 ←-
5793244,3427927.9 5793243.95)),((3427928 5793243.85,3427928 5793243.8,3427927.95 ←-
5793243.8,3427927.95 5793243.85,3427927.9 5793243.85,3427927.9 5793243.9,3427927.9 ←-
5793243.95,3427927.95 5793243.95,3427928 5793243.95,3427928 5793243.85)),((3427927.8 ←-
5793243.75,3427927.75 5793243.75,3427927.75 5793243.8,3427927.75 5793243.85,3427927.75 ←-
5793243.9,3427927.75 5793244,3427927.8 5793244,3427927.8 5793243.9,3427927.8 ←-
5793243.85,3427927.85 5793243.85,3427927.85 5793243.8,3427927.85 5793243.75,3427927.8 ←-
5793243.75)))

-- Or if you want the no data value different for just one time

SELECT ST_AsText(
ST_Polygon(
ST_SetBandNoDataValue(rast,1,252)
)
) As geomwkt
FROM dummy_rast
WHERE rid =2;

geomwkt
---------------------------------
MULTIPOLYGON(((3427928 5793243.85,3427928 5793243.8,3427928 5793243.75,3427927.85 ←-
5793243.75,3427927.8 5793243.75,3427927.8 5793243.8,3427927.75 5793243.8,3427927.75 ←-
5793243.85,3427927.75 5793243.9,3427927.75 5793244,3427927.8 5793244,3427927.85 ←-
5793244,3427927.9 5793244,3427928 5793244,3427928 5793243.95,3427928 5793243.85) ←-
,(3427927.9 5793243.9,3427927.9 5793243.85,3427927.95 5793243.85,3427927.95 ←-
5793243.9,3427927.9 5793243.9)))

See Also

ST_Value, ST_DumpAsPolygons
PostGIS 2.4.3 Manual 601 / 803

9.12 Raster Operators

9.12.1 &&

&& — Returns TRUE if A’s bounding box intersects B’s bounding box.

Synopsis

boolean &&( raster A , raster B );

boolean &&( raster A , geometry B );
boolean &&( geometry B , raster A );

Description

The && operator returns TRUE if the bounding box of raster/geometr A intersects the bounding box of raster/geometr B.

Note
This operand will make use of any indexes that may be available on the rasters.

Availability: 2.0.0

Examples

SELECT A.rid As a_rid, B.rid As b_rid, A.rast && B.rast As intersect

FROM dummy_rast AS A CROSS JOIN dummy_rast AS B LIMIT 3;

a_rid | b_rid | intersect

-------+-------+---------
2 | 2 | t
2 | 3 | f
2 | 1 | f

9.12.2 &<

&< — Returns TRUE if A’s bounding box is to the left of B’s.

Synopsis

boolean &<( raster A , raster B );

Description

The &< operator returns TRUE if the bounding box of raster A overlaps or is to the left of the bounding box of raster B, or more
accurately, overlaps or is NOT to the right of the bounding box of raster B.

Note
This operand will make use of any indexes that may be available on the rasters.
PostGIS 2.4.3 Manual 602 / 803

Examples

SELECT A.rid As a_rid, B.rid As b_rid, A.rast &< B.rast As overleft

FROM dummy_rast AS A CROSS JOIN dummy_rast AS B;

a_rid | b_rid | overleft

------+-------+----------
2 | 2 | t
2 | 3 | f
2 | 1 | f
3 | 2 | t
3 | 3 | t
3 | 1 | f
1 | 2 | t
1 | 3 | t
1 | 1 | t

9.12.3 &>

&> — Returns TRUE if A’s bounding box is to the right of B’s.

Synopsis

boolean &>( raster A , raster B );

Description

The &> operator returns TRUE if the bounding box of raster A overlaps or is to the right of the bounding box of raster B, or more
accurately, overlaps or is NOT to the left of the bounding box of raster B.

Note
This operand will make use of any indexes that may be available on the geometries.

Examples

SELECT A.rid As a_rid, B.rid As b_rid, A.rast &> B.rast As overright

FROM dummy_rast AS A CROSS JOIN dummy_rast AS B;

a_rid | b_rid | overright

-------+-------+----------
2 | 2 | t
2 | 3 | t
2 | 1 | t
3 | 2 | f
3 | 3 | t
3 | 1 | f
1 | 2 | f
1 | 3 | t
1 | 1 | t
PostGIS 2.4.3 Manual 603 / 803

9.12.4 =

= — Returns TRUE if A’s bounding box is the same as B’s. Uses double precision bounding box.

Synopsis

boolean =( raster A , raster B );

Description

The = operator returns TRUE if the bounding box of raster A is the same as the bounding box of raster B. PostgreSQL uses the
=, <, and > operators defined for rasters to perform internal orderings and comparison of rasters (ie. in a GROUP BY or ORDER
BY clause).

Caution
This operand will NOT make use of any indexes that may be available on the rasters. Use ~= instead. This operator
exists mostly so one can group by the raster column.

Availability: 2.1.0

See Also

~=

9.12.5 @

@ — Returns TRUE if A’s bounding box is contained by B’s. Uses double precision bounding box.

Synopsis

boolean @( raster A , raster B );

boolean @( geometry A , raster B );
boolean @( raster B , geometry A );

Description

The @ operator returns TRUE if the bounding box of raster/geometry A is contained by bounding box of raster/geometr B.

Note
This operand will use spatial indexes on the rasters.

Availability: 2.0.0 raster @ raster, raster @ geometry introduced

Availability: 2.0.5 geometry @ raster introduced

See Also

~
PostGIS 2.4.3 Manual 604 / 803

9.12.6 ~=

~= — Returns TRUE if A’s bounding box is the same as B’s.

Synopsis

boolean ~=( raster A , raster B );

Description

The ~= operator returns TRUE if the bounding box of raster A is the same as the bounding box of raster B.

Note
This operand will make use of any indexes that may be available on the rasters.

Availability: 2.0.0

Examples

Very useful usecase is for taking two sets of single band rasters that are of the same chunk but represent different themes and
creating a multi-band raster
SELECT ST_AddBand(prec.rast, alt.rast) As new_rast
FROM prec INNER JOIN alt ON (prec.rast ~= alt.rast);

See Also

ST_AddBand, =

9.12.7 ~

~ — Returns TRUE if A’s bounding box is contains B’s. Uses double precision bounding box.

Synopsis

boolean ~( raster A , raster B );

boolean ~( geometry A , raster B );
boolean ~( raster B , geometry A );

Description

The ~ operator returns TRUE if the bounding box of raster/geometry A is contains bounding box of raster/geometr B.

Note
This operand will use spatial indexes on the rasters.

Availability: 2.0.0
PostGIS 2.4.3 Manual 605 / 803

See Also

9.13 Raster and Raster Band Spatial Relationships

9.13.1 ST_Contains

ST_Contains — Return true if no points of raster rastB lie in the exterior of raster rastA and at least one point of the interior of
rastB lies in the interior of rastA.

Synopsis

boolean ST_Contains( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_Contains( raster rastA , raster rastB );

Description

Raster rastA contains rastB if and only if no points of rastB lie in the exterior of rastA and at least one point of the interior of
rastB lies in the interior of rastA. If the band number is not provided (or set to NULL), only the convex hull of the raster is
considered in the test. If the band number is provided, only those pixels with value (not NODATA) are considered in the test.

Note
This function will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_Contains(ST_Polygon(raster), geometry) or ST_Contains(geometry, ST_Polygon(raster)).

Note
ST_Contains() is the inverse of ST_Within(). So, ST_Contains(rastA, rastB) implies ST_Within(rastB, rastA).

Availability: 2.1.0

Examples

-- specified band numbers

SELECT r1.rid, r2.rid, ST_Contains(r1.rast, 1, r2.rast, 1) FROM dummy_rast r1 CROSS JOIN ←-
dummy_rast r2 WHERE r1.rid = 1;

NOTICE: The first raster provided has no bands

rid | rid | st_contains
-----+-----+-------------
1 | 1 |
1 | 2 | f
PostGIS 2.4.3 Manual 606 / 803

-- no band numbers specified

SELECT r1.rid, r2.rid, ST_Contains(r1.rast, r2.rast) FROM dummy_rast r1 CROSS JOIN ←-
dummy_rast r2 WHERE r1.rid = 1;
rid | rid | st_contains
-----+-----+-------------
1 | 1 | t
1 | 2 | f

See Also

ST_Intersects, ST_Within

9.13.2 ST_ContainsProperly

ST_ContainsProperly — Return true if rastB intersects the interior of rastA but not the boundary or exterior of rastA.

Synopsis

boolean ST_ContainsProperly( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_ContainsProperly( raster rastA , raster rastB );

Description

Raster rastA contains properly rastB if rastB intersects the interior of rastA but not the boundary or exterior of rastA. If the band
number is not provided (or set to NULL), only the convex hull of the raster is considered in the test. If the band number is
provided, only those pixels with value (not NODATA) are considered in the test.
Raster rastA does not contain properly itself but does contain itself.

Note
This function will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_ContainsProperly(ST_Polygon(raster), geometry) or ST_ContainsProperly(geometry, ST_Polygon(raster)).

Availability: 2.1.0

Examples

SELECT r1.rid, r2.rid, ST_ContainsProperly(r1.rast, 1, r2.rast, 1) FROM dummy_rast r1 CROSS ←-

JOIN dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_containsproperly

-----+-----+---------------------
2 | 1 | f
2 | 2 | f
PostGIS 2.4.3 Manual 607 / 803

See Also

ST_Intersects, ST_Contains

9.13.3 ST_Covers

ST_Covers — Return true if no points of raster rastB lie outside raster rastA.

Synopsis

boolean ST_Covers( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_Covers( raster rastA , raster rastB );

Description

Raster rastA covers rastB if and only if no points of rastB lie in the exterior of rastA. If the band number is not provided (or set to
NULL), only the convex hull of the raster is considered in the test. If the band number is provided, only those pixels with value
(not NODATA) are considered in the test.

Note
This function will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_Covers(ST_Polygon(raster), geometry) or ST_Covers(geometry, ST_Polygon(raster)).

Availability: 2.1.0

Examples

SELECT r1.rid, r2.rid, ST_Covers(r1.rast, 1, r2.rast, 1) FROM dummy_rast r1 CROSS JOIN ←-

dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_covers

-----+-----+-----------
2 | 1 | f
2 | 2 | t

See Also

ST_Intersects, ST_CoveredBy

9.13.4 ST_CoveredBy

ST_CoveredBy — Return true if no points of raster rastA lie outside raster rastB.
PostGIS 2.4.3 Manual 608 / 803

Synopsis

boolean ST_CoveredBy( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_CoveredBy( raster rastA , raster rastB );

Description

Raster rastA is covered by rastB if and only if no points of rastA lie in the exterior of rastB. If the band number is not provided
(or set to NULL), only the convex hull of the raster is considered in the test. If the band number is provided, only those pixels
with value (not NODATA) are considered in the test.

Note
This function will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_CoveredBy(ST_Polygon(raster), geometry) or ST_CoveredBy(geometry, ST_Polygon(raster)).

Availability: 2.1.0

Examples

SELECT r1.rid, r2.rid, ST_CoveredBy(r1.rast, 1, r2.rast, 1) FROM dummy_rast r1 CROSS JOIN ←-

dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_coveredby

-----+-----+--------------
2 | 1 | f
2 | 2 | t

See Also

ST_Intersects, ST_Covers

9.13.5 ST_Disjoint

ST_Disjoint — Return true if raster rastA does not spatially intersect rastB.

Synopsis

boolean ST_Disjoint( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_Disjoint( raster rastA , raster rastB );
PostGIS 2.4.3 Manual 609 / 803

Description

Raster rastA and rastB are disjointed if they do not share any space together. If the band number is not provided (or set to
NULL), only the convex hull of the raster is considered in the test. If the band number is provided, only those pixels with value
(not NODATA) are considered in the test.

Note
This function does NOT use any indexes.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_Disjoint(ST_Polygon(raster), geometry).

Availability: 2.1.0

Examples

-- rid = 1 has no bands, hence the NOTICE and the NULL value for st_disjoint
SELECT r1.rid, r2.rid, ST_Disjoint(r1.rast, 1, r2.rast, 1) FROM dummy_rast r1 CROSS JOIN ←-
dummy_rast r2 WHERE r1.rid = 2;

NOTICE: The second raster provided has no bands

rid | rid | st_disjoint
-----+-----+-------------
2 | 1 |
2 | 2 | f

-- this time, without specifying band numbers

SELECT r1.rid, r2.rid, ST_Disjoint(r1.rast, r2.rast) FROM dummy_rast r1 CROSS JOIN ←-
dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_disjoint

-----+-----+-------------
2 | 1 | t
2 | 2 | f

See Also

ST_Intersects

9.13.6 ST_Intersects

ST_Intersects — Return true if raster rastA spatially intersects raster rastB.

Synopsis

boolean ST_Intersects( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_Intersects( raster rastA , raster rastB );
boolean ST_Intersects( raster rast , integer nband , geometry geommin );
boolean ST_Intersects( raster rast , geometry geommin , integer nband=NULL );
boolean ST_Intersects( geometry geommin , raster rast , integer nband=NULL );
PostGIS 2.4.3 Manual 610 / 803

Description

Return true if raster rastA spatially intersects raster rastB. If the band number is not provided (or set to NULL), only the convex
hull of the raster is considered in the test. If the band number is provided, only those pixels with value (not NODATA) are
considered in the test.

Note
This function will make use of any indexes that may be available on the rasters.

Enhanced: 2.0.0 support raster/raster intersects was introduced.

Warning
Changed: 2.1.0 The behavior of the ST_Intersects(raster, geometry) variants changed to match that of
ST_Intersects(geometry, raster).

Examples

-- different bands of same raster

SELECT ST_Intersects(rast, 2, rast, 3) FROM dummy_rast WHERE rid = 2;

st_intersects
---------------
t

See Also

ST_Intersection, ST_Disjoint

9.13.7 ST_Overlaps

ST_Overlaps — Return true if raster rastA and rastB intersect but one does not completely contain the other.

Synopsis

boolean ST_Overlaps( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_Overlaps( raster rastA , raster rastB );

Description

Return true if raster rastA spatially overlaps raster rastB. This means that rastA and rastB intersect but one does not completely
contain the other. If the band number is not provided (or set to NULL), only the convex hull of the raster is considered in the test.
If the band number is provided, only those pixels with value (not NODATA) are considered in the test.

Note
This function will make use of any indexes that may be available on the rasters.
PostGIS 2.4.3 Manual 611 / 803

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_Overlaps(ST_Polygon(raster), geometry).

Availability: 2.1.0

Examples

-- comparing different bands of same raster

SELECT ST_Overlaps(rast, 1, rast, 2) FROM dummy_rast WHERE rid = 2;

st_overlaps
-------------
f

See Also

ST_Intersects

9.13.8 ST_Touches

ST_Touches — Return true if raster rastA and rastB have at least one point in common but their interiors do not intersect.

Synopsis

boolean ST_Touches( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_Touches( raster rastA , raster rastB );

Description

Return true if raster rastA spatially touches raster rastB. This means that rastA and rastB have at least one point in common
but their interiors do not intersect. If the band number is not provided (or set to NULL), only the convex hull of the raster is
considered in the test. If the band number is provided, only those pixels with value (not NODATA) are considered in the test.

Note
This function will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_Touches(ST_Polygon(raster), geometry).

Availability: 2.1.0
PostGIS 2.4.3 Manual 612 / 803

Examples

SELECT r1.rid, r2.rid, ST_Touches(r1.rast, 1, r2.rast, 1) FROM dummy_rast r1 CROSS JOIN ←-

dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_touches

-----+-----+------------
2 | 1 | f
2 | 2 | f

See Also

ST_Intersects

9.13.9 ST_SameAlignment

ST_SameAlignment — Returns true if rasters have same skew, scale, spatial ref, and offset (pixels can be put on same grid
without cutting into pixels) and false if they don’t with notice detailing issue.

Synopsis

boolean ST_SameAlignment( raster rastA , raster rastB );

boolean ST_SameAlignment( double precision ulx1 , double precision uly1 , double precision scalex1 , double precision scaley1
, double precision skewx1 , double precision skewy1 , double precision ulx2 , double precision uly2 , double precision scalex2 ,
double precision scaley2 , double precision skewx2 , double precision skewy2 );
boolean ST_SameAlignment( raster set rastfield );

Description

Non-Aggregate version (Variants 1 and 2): Returns true if the two rasters (either provided directly or made using the values for
upperleft, scale, skew and srid) have the same scale, skew, srid and at least one of any of the four corners of any pixel of one
raster falls on any corner of the grid of the other raster. Returns false if they don’t and a NOTICE detailing the alignment issue.
Aggregate version (Variant 3): From a set of rasters, returns true if all rasters in the set are aligned. The ST_SameAlignment()
function is an "aggregate" function in the terminology of PostgreSQL. That means that it operates on rows of data, in the same
way the SUM() and AVG() functions do.
Availability: 2.0.0
Enhanced: 2.1.0 addition of Aggegrate variant

Examples: Rasters

SELECT ST_SameAlignment(
ST_MakeEmptyRaster(1, 1, 0, 0, 1, 1, 0, 0),
ST_MakeEmptyRaster(1, 1, 0, 0, 1, 1, 0, 0)
) as sm;

sm
----
t
PostGIS 2.4.3 Manual 613 / 803

SELECT ST_SameAlignment(A.rast,b.rast)
FROM dummy_rast AS A CROSS JOIN dummy_rast AS B;

NOTICE: The two rasters provided have different SRIDs

NOTICE: The two rasters provided have different SRIDs
st_samealignment
------------------
t
f
f
f

See Also

Section 5.1, ST_NotSameAlignmentReason, ST_MakeEmptyRaster

9.13.10 ST_NotSameAlignmentReason

ST_NotSameAlignmentReason — Returns text stating if rasters are aligned and if not aligned, a reason why.

Synopsis

text ST_NotSameAlignmentReason(raster rastA, raster rastB);

Description

Returns text stating if rasters are aligned and if not aligned, a reason why.

Note
If there are several reasons why the rasters are not aligned, only one reason (the first test to fail) will be returned.

Availability: 2.1.0

Examples

SELECT
ST_SameAlignment(
ST_MakeEmptyRaster(1, 1, 0, 0, 1, 1, 0, 0),
ST_MakeEmptyRaster(1, 1, 0, 0, 1.1, 1.1, 0, 0)
),
ST_NotSameAlignmentReason(
ST_MakeEmptyRaster(1, 1, 0, 0, 1, 1, 0, 0),
ST_MakeEmptyRaster(1, 1, 0, 0, 1.1, 1.1, 0, 0)
)
;

st_samealignment | st_notsamealignmentreason
------------------+-------------------------------------------------
f | The rasters have different scales on the X axis
(1 row)
PostGIS 2.4.3 Manual 614 / 803

See Also

Section 5.1, ST_SameAlignment

9.13.11 ST_Within

ST_Within — Return true if no points of raster rastA lie in the exterior of raster rastB and at least one point of the interior of
rastA lies in the interior of rastB.

Synopsis

boolean ST_Within( raster rastA , integer nbandA , raster rastB , integer nbandB );
boolean ST_Within( raster rastA , raster rastB );

Description

Raster rastA is within rastB if and only if no points of rastA lie in the exterior of rastB and at least one point of the interior
of rastA lies in the interior of rastB. If the band number is not provided (or set to NULL), only the convex hull of the raster is
considered in the test. If the band number is provided, only those pixels with value (not NODATA) are considered in the test.

Note
This operand will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_Within(ST_Polygon(raster), geometry) or ST_Within(geometry, ST_Polygon(raster)).

Note
ST_Within() is the inverse of ST_Contains(). So, ST_Within(rastA, rastB) implies ST_Contains(rastB, rastA).

Availability: 2.1.0

Examples

SELECT r1.rid, r2.rid, ST_Within(r1.rast, 1, r2.rast, 1) FROM dummy_rast r1 CROSS JOIN ←-

dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_within

-----+-----+-----------
2 | 1 | f
2 | 2 | t

See Also

ST_Intersects, ST_Contains, ST_DWithin, ST_DFullyWithin

PostGIS 2.4.3 Manual 615 / 803

9.13.12 ST_DWithin

ST_DWithin — Return true if rasters rastA and rastB are within the specified distance of each other.

Synopsis

boolean ST_DWithin( raster rastA , integer nbandA , raster rastB , integer nbandB , double precision distance_of_srid );
boolean ST_DWithin( raster rastA , raster rastB , double precision distance_of_srid );

Description

Return true if rasters rastA and rastB are within the specified distance of each other. If the band number is not provided (or set to
NULL), only the convex hull of the raster is considered in the test. If the band number is provided, only those pixels with value
(not NODATA) are considered in the test.
The distance is specified in units defined by the spatial reference system of the rasters. For this function to make sense, the source
rasters must both be of the same coordinate projection, having the same SRID.

Note
This operand will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_DWithin(ST_Polygon(raster), geometry).

Availability: 2.1.0

Examples

SELECT r1.rid, r2.rid, ST_DWithin(r1.rast, 1, r2.rast, 1, 3.14) FROM dummy_rast r1 CROSS ←-

JOIN dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_dwithin

-----+-----+------------
2 | 1 | f
2 | 2 | t

See Also

ST_Within, ST_DFullyWithin

9.13.13 ST_DFullyWithin

ST_DFullyWithin — Return true if rasters rastA and rastB are fully within the specified distance of each other.

Synopsis

boolean ST_DFullyWithin( raster rastA , integer nbandA , raster rastB , integer nbandB , double precision distance_of_srid );
boolean ST_DFullyWithin( raster rastA , raster rastB , double precision distance_of_srid );
PostGIS 2.4.3 Manual 616 / 803

Description

Return true if rasters rastA and rastB are fully within the specified distance of each other. If the band number is not provided (or
set to NULL), only the convex hull of the raster is considered in the test. If the band number is provided, only those pixels with
value (not NODATA) are considered in the test.
The distance is specified in units defined by the spatial reference system of the rasters. For this function to make sense, the source
rasters must both be of the same coordinate projection, having the same SRID.

Note
This operand will make use of any indexes that may be available on the rasters.

Note
To test the spatial relationship of a raster and a geometry, use ST_Polygon on the raster, e.g.
ST_DFullyWithin(ST_Polygon(raster), geometry).

Availability: 2.1.0

Examples

SELECT r1.rid, r2.rid, ST_DFullyWithin(r1.rast, 1, r2.rast, 1, 3.14) FROM dummy_rast r1 ←-

CROSS JOIN dummy_rast r2 WHERE r1.rid = 2;

rid | rid | st_dfullywithin

-----+-----+-----------------
2 | 1 | f
2 | 2 | t

See Also

ST_Within, ST_DWithin
PostGIS 2.4.3 Manual 617 / 803

Chapter 10

PostGIS Raster Frequently Asked Questions

1. I’m getting error ERROR: RASTER_fromGDALRaster: Could not open bytea with GDAL. Check that
the bytea is of a GDAL supported format. when using ST_FromGDALRaster or ERROR: rt_raster_to_g
Could not load the output GDAL driver when trying to use ST_AsPNG or other raster input functions.
As of PostGIS 2.1.3 and 2.0.5, a security change was made to by default disable all GDAL drivers and out of db rasters.
The release notes are at PostGIS 2.0.6, 2.1.3 security release. In order to reenable specific drivers or all drivers and reenable
out of database support, refer to Section 2.1.

2. Where can I find out more about the PostGIS Raster Project?
Refer to the PostGIS Raster home page.
3. Are there any books or tutorials to get me started with this wonderful invention?
There is a full length beginner tutorial Intersecting vector buffers with large raster coverage using PostGIS Raster. Jorge
has a series of blog articles on PostGIS Raster that demonstrate how to load raster data as well as cross compare to same
tasks in Oracle GeoRaster. Check out Jorge’s PostGIS Raster / Oracle GeoRaster Series. There is a whole chapter (more
than 35 pages of content) dedicated to PostGIS Raster with free code and data downloads at PostGIS in Action - Raster
chapter. You can buy PostGIS in Action now from Manning in hard-copy (significant discounts for bulk purchases) or just
the E-book format. You can also buy from Amazon and various other book distributors. All hard-copy books come with a
free coupon to download the E-book version. Here is a review from a PostGIS Raster user PostGIS raster applied to land
classification urban forestry
4. How do I install Raster support in my PostGIS database?
The easiest is to download binaries for PostGIS and Raster which are currently available for windows and latest versions of
Mac OSX. First you need a working PostGIS 2.0.0 or above and be running PostgreSQL 8.4, 9.0, or 9.1. Note in PostGIS
2.0 PostGIS Raster is fully integrated, so it will be compiled when you compile PostGIS.Instructions for installing and run-
ning under windows are available at How to Install and Configure PostGIS raster on windows If you are on windows, you
can compile yourself, or use the pre-compiled PostGIS Raster windows binaries. If you are on Mac OSX Leopard or Snow
Leopard, there are binaries available at Kyng Chaos Mac OSX PostgreSQL/GIS binaries. Then to enable raster support in
your database, run the rtpostgis.sql file in your database. To upgrade an existing install use rtpostgis_upgrade_minor..sql
instead of rtpostgis.sqlFor other platforms, you generally need to compile yourself. Dependencies are PostGIS and GDAL.
For more details about compiling from source, please refer to Installing PostGIS Raster from source (in prior versions of
PostGIS)
5. I get error could not load library "C:/Program Files/PostgreSQL/8.4/lib/rtpostgis.dll": The specified module could not be
found. or could not load library on Linux when trying to run rtpostgis.sql
rtpostgis.so/dll is built with dependency on libgdal.dll/so. Make sure for Windows you have libgdal-1.dll in the bin folder
of your PostgreSQL install. For Linux libgdal has to be in your path or bin folder. You may also run into different errors
if you don’t have PostGIS installed in your database. Make sure to install PostGIS first in your database before trying to
install the raster support.
PostGIS 2.4.3 Manual 618 / 803

6. How do I load Raster data into PostGIS?

The latest version of PostGIS comes packaged with a raster2pgsql raster loader executable capable of loading many
kinds of rasters and also generating lower resolution overviews without any additional software. Please refer to Sec-
tion 5.1.1 for more details. Pre-2.0 versions came with a raster2pgsql.py that required python with numpy and
GDAL. This is no longer needed.
7. What kind of raster file formats can I load into my database?
Any that your GDAL library supports. GDAL supported formats are documented GDAL File Formats.Your particular
GDAL install may not support all formats. To verify the ones supported by your particular GDAL install, you can use
raster2pgsql -G

8. Can I export my PostGIS raster data to other raster formats?

YesGDAL 1.7+ has a PostGIS raster driver, but is only compiled in if you choose to compile with PostgreSQL support. The
driver currently doesn’t support irregularly blocked rasters, although you can store irregularly blocked rasters in PostGIS
raster data type.If you are compiling from source, you need to include in your configure
--with-pg=path/to/pg_config

to enable the driver. Refer to GDAL Build Hints for tips on building GDAL against in various OS platforms. If your
version of GDAL is compiled with the PostGIS Raster driver you should see PostGIS Raster in list when you do
gdalinfo --formats

To get a summary about your raster via GDAL use gdalinfo:

gdalinfo "PG:host=localhost port=5432 dbname='mygisdb' user='postgres' password=' ←-
whatever' schema='someschema' table=sometable"

To export data to other raster formats, use gdal_translate the below will export all data from a table to a PNG file at 10%
size.Depending on your pixel band types, some translations may not work if the export format does not support that Pixel
type. For example floating point band types and 32 bit unsigned ints will not translate easily to JPG or some others.Here is
an example simple translation
gdal_translate -of PNG -outsize 10% 10% "PG:host=localhost port=5432 dbname='mygisdb' ←-
user='postgres' password='whatever' schema='someschema' table=sometable" C:\ ←-
somefile.png

You can also use SQL where clauses in your export using the where=... in your driver connection string. Below are some
using a where clause
gdal_translate -of PNG -outsize 10% 10% "PG:host=localhost port=5432 dbname='mygisdb' ←-
user='postgres' password='whatever' schema='someschema' table=sometable where=' ←-
filename=\'abcd.sid\''" " C:\somefile.png

gdal_translate -of PNG -outsize 10% 10% "PG:host=localhost port=5432 dbname='mygisdb' ←-

user='postgres' password='whatever' schema='someschema' table=sometable where=' ←-
ST_Intersects(rast, ST_SetSRID(ST_Point(-71.032,42.3793),4326) )' " C:\ ←-
intersectregion.png

To see more examples and syntax refer to Reading Raster Data of PostGIS Raster section
9. Are their binaries of GDAL available already compiled with PostGIS Raster suppport?
Yes. Check out the page GDAL Binaries page. Any compiled with PostgreSQL support should have PostGIS Raster
in them. PostGIS Raster is undergoing many changes. If you want to get the latest nightly build for Windows -- then
check out the Tamas Szekeres nightly builds built with Visual Studio which contain GDAL trunk, Python Bindings and
MapServer executables and PostGIS Raster driver built-in. Just click the SDK bat and run your commands from there.
http://www.gisinternals.com. Also available are VS project files.FWTools latest stable version for Windows is compiled
with Raster support.
PostGIS 2.4.3 Manual 619 / 803

10. What tools can I use to view PostGIS raster data?

You can use MapServer compiled with GDAL 1.7+ and PostGIS Raster driver support to view Raster data. QuantumGIS
(QGIS) now supports viewing of PostGIS Raster if you have PostGIS raster driver installed.In theory any tool that renders
data using GDAL can support PostGIS raster data or support it with fairly minimal effort. Again for Windows, Tamas’
binaries http://www.gisinternals.com are a good choice if you don’t want the hassle of having to setup to compile your
own.
11. How can I add a PostGIS raster layer to my MapServer map?
First you need GDAL 1.7 or higher compiled with PostGIS raster support. GDAL 1.8 or above is preferred since many
issues have been fixed in 1.8 and more PostGIS raster issues fixed in trunk version.You can much like you can with
any other raster. Refer to MapServer Raster processing options for list of various processing functions you can use with
MapServer raster layers.What makes PostGIS raster data particularly interesting, is that since each tile can have various
standard database columns, you can segment it in your data sourceBelow is an example of how you would define a PostGIS
raster layer in MapServer.

Note
The mode=2 is required for tiled rasters and was added in PostGIS 2.0 and GDAL 1.8 drivers. This does not exist
in GDAL 1.7 drivers.

-- displaying raster with standard raster options

LAYER
NAME coolwktraster
TYPE raster
STATUS ON
DATA "PG:host=localhost port=5432 dbname='somedb' user='someuser' password='whatever'
schema='someschema' table='cooltable' mode='2'"
PROCESSING "NODATA=0"
PROCESSING "SCALE=AUTO"
#... other standard raster processing functions here
#... classes are optional but useful for 1 band data
CLASS
NAME "boring"
EXPRESSION ([pixel] < 20)
COLOR 250 250 250
END
CLASS
NAME "mildly interesting"
EXPRESSION ([pixel] > 20 AND [pixel] < 1000)
COLOR 255 0 0
END
CLASS
NAME "very interesting"
EXPRESSION ([pixel] >= 1000)
COLOR 0 255 0
END
END

-- displaying raster with standard raster options and a where clause

LAYER
NAME soil_survey2009
TYPE raster
STATUS ON
DATA "PG:host=localhost port=5432 dbname='somedb' user='someuser' password='whatever'
schema='someschema' table='cooltable' where='survey_year=2009' mode='2'"
PROCESSING "NODATA=0"
#... other standard raster processing functions here
#... classes are optional but useful for 1 band data
END
PostGIS 2.4.3 Manual 620 / 803

12. What functions can I currently use with my raster data?

Refer to the list of Chapter 9. There are more, but this is still a work in progress.Refer to the PostGIS Raster roadmap page
for details of what you can expect in the future.

13. I am getting error ERROR: function st_intersects(raster, unknown) is not unique or st_union(geometry,text) is not unique.
How do I fix?
The function is not unique error happens if one of your arguments is a textual representation of a geometry instead of a
geometry. In these cases, PostgreSQL marks the textual representation as an unknown type, which means it can fall into the
st_intersects(raster, geometry) or st_intersects(raster,raster) thus resulting in a non-unique case since both functions can in
theory support your request. To prevent this, you need to cast the textual representation of the geometry to a geometry.For
example if your code looks like this:
SELECT rast
FROM my_raster
WHERE ST_Intersects(rast, 'SRID=4326;POINT(-10 10)');

Cast the textual geometry representation to a geometry by changing your code to this:
SELECT rast
FROM my_raster
WHERE ST_Intersects(rast, 'SRID=4326;POINT(-10 10)'::geometry);

14. How is PostGIS Raster different from Oracle GeoRaster (SDO_GEORASTER) and SDO_RASTER types?
For a more extensive discussion on this topic, check out Jorge Arévalo Oracle GeoRaster and PostGIS Raster: First
impressions The major advantage of one-georeference-by-raster over one-georeference-by-layer is to allow:* coverages
to be not necessarily rectangular (which is often the case of raster coverage covering large extents. See the possible
raster arrangements in the documentation)* rasters to overlaps (which is necessary to implement lossless vector to raster
conversion) These arrangements are possible in Oracle as well, but they imply the storage of multiple SDO_GEORASTER
objects linked to as many SDO_RASTER tables. A complex coverage can lead to hundreds of tables in the database. With
PostGIS Raster you can store a similar raster arrangement into a unique table.It’s a bit like if PostGIS would force you to
store only full rectangular vector coverage without gaps or overlaps (a perfect rectangular topological layer). This is very
practical in some applications but practice has shown that it is not realistic or desirable for most geographical coverages.
Vector structures needs the flexibility to store discontinuous and non-rectangular coverages. We think it is a big advantage
that raster structure should benefit as well.
15. raster2pgsql load of large file fails with String of N bytes is too long for encoding conversion?
raster2pgsql doesn’t make any connections to your database when generating the file to load. If your database has set an
explicit client encoding different from your database encoding, then when loading large raster files (above 30 MB in size),
you may run into a bytes is too long for encoding conversion.This generally happens if for example
you have your database in UTF8, but to support windows apps, you have the client encoding set to WIN1252.To work
around this make sure the client encoding is the same as your database encoding during load. You can do this by explicitly
setting the encoding in your load script. Example, if you are on windows:
set PGCLIENTENCODING=UTF8

If you are on Unix/Linux

export PGCLIENTENCODING=UTF8

Gory details of this issue are detailed in http://trac.osgeo.org/postgis/ticket/2209

PostGIS 2.4.3 Manual 621 / 803

Chapter 11

Topology

The PostGIS Topology types and functions are used to manage topological objects such as faces, edges and nodes.
Sandro Santilli’s presentation at PostGIS Day Paris 2011 conference gives a good synopsis of PostGIS Topology and where it is
headed Topology with PostGIS 2.0 slide deck.
Vincent Picavet provides a good synopsis and overview of what is Topology, how is it used, and various FOSS4G tools that
support it in PostGIS Topology PGConf EU 2012.
An example of a topologically based GIS database is the US Census Topologically Integrated Geographic Encoding and Ref-
erencing System (TIGER) database. If you want to experiment with PostGIS topology and need some data, check out Topol-
ogy_Load_Tiger.
The PostGIS topology module has existed in prior versions of PostGIS but was never part of the Official PostGIS documentation.
In PostGIS 2.0.0 major cleanup is going on to remove use of all deprecated functions in it, fix known usability issues, better
document the features and functions, add new functions, and enhance to closer conform to SQL-MM standards.
Details of this project can be found at PostGIS Topology Wiki
All functions and tables associated with this module are installed in a schema called topology.
Functions that are defined in SQL/MM standard are prefixed with ST_ and functions specific to PostGIS are not prefixed.
Topolgy support is build by default starting with PostGIS 2.0, and can be disabled specifying --without-topology configure option
at build time as described in Chapter 2

11.1 Topology Types

11.1.1 getfaceedges_returntype

getfaceedges_returntype — A composite type that consists of a sequence number and edge number. This is the return type for
ST_GetFaceEdges

Description

A composite type that consists of a sequence number and edge number. This is the return type for ST_GetFaceEdges function.

1. sequence is an integer: Refers to a topology defined in the topology.topology table which defines the topology schema
and srid.
2. edge is an integer: The identifier of an edge.
PostGIS 2.4.3 Manual 622 / 803

11.1.2 TopoGeometry

TopoGeometry — A composite type representing a topologically defined geometry

Description

A composite type that refers to a topology geometry in a specific topology layer, having a specific type and a specific id. The
elements of a TopoGeometry are the properties: topology_id, layer_id, id integer, type integer.

1. topology_id is an integer: Refers to a topology defined in the topology.topology table which defines the topology
schema and srid.
2. layer_id is an integer: The layer_id in the layers table that the TopoGeometry belongs to. The combination of topol-
ogy_id, layer_id provides a unique reference in the topology.layers table.

3. id is an integer: The id is the autogenerated sequence number that uniquely defines the topogeometry in the respective
topology layer.
4. type integer between 1 - 4 that defines the geometry type: 1:[multi]point, 2:[multi]line, 3:[multi]poly, 4:collection

Casting Behavior

This section lists the automatic as well as explicit casts allowed for this data type

Cast To Behavior
geometry automatic

See Also

CreateTopoGeom

11.1.3 validatetopology_returntype

validatetopology_returntype — A composite type that consists of an error message and id1 and id2 to denote location of error.
This is the return type for ValidateTopology

Description

A composite type that consists of an error message and two integers. The ValidateTopology function returns a set of these to
denote validation errors and the id1 and id2 to denote the ids of the topology objects involved in the error.

1. error is varchar: Denotes type of error.

Current error descriptors are: coincident nodes, edge crosses node, edge not simple, edge end node geometry mis-match,
edge start node geometry mismatch, face overlaps face,face within face,
2. id1 is an integer: Denotes identifier of edge / face / nodes in error.

3. id2 is an integer: For errors that involve 2 objects denotes the secondary edge / or node

See Also

ValidateTopology
PostGIS 2.4.3 Manual 623 / 803

11.2 Topology Domains

11.2.1 TopoElement

TopoElement — An array of 2 integers generally used to identify a TopoGeometry component.

Description

An array of 2 integers used to represent one component of a simple or hierarchical TopoGeometry.

In the case of a simple TopoGeometry the first element of the array represents the identifier of a topological primitive and the
second element represents its type (1:node, 2:edge, 3:face). In the case of a hierarchical TopoGeometry the first element of the
array represents the identifier of a child TopoGeometry and the second element represents its layer identifier.

Note
For any given hierarchical TopoGeometry all child TopoGeometry elements will come from the same child layer, as
specified in the topology.layer record for the layer of the TopoGeometry being defined.

Examples

SELECT te[1] AS id, te[2] AS type FROM

( SELECT ARRAY[1,2]::topology.topoelement AS te ) f;
id | type
----+------
1 | 2

SELECT ARRAY[1,2]::topology.topoelement;
te
-------
{1,2}

--Example of what happens when you try to case a 3 element array to topoelement
-- NOTE: topoement has to be a 2 element array so fails dimension check
SELECT ARRAY[1,2,3]::topology.topoelement;
ERROR: value for domain topology.topoelement violates check constraint "dimensions"

See Also

GetTopoGeomElements, TopoElementArray, TopoGeometry, TopoGeom_addElement, TopoGeom_remElement

11.2.2 TopoElementArray

TopoElementArray — An array of TopoElement objects

Description

An array of 1 or more TopoElement objects, generally used to pass around components of TopoGeometry objects.
PostGIS 2.4.3 Manual 624 / 803

Examples

SELECT '{{1,2},{4,3}}'::topology.topoelementarray As tea;

tea
-------
{{1,2},{4,3}}

-- more verbose equivalent --

SELECT ARRAY[ARRAY[1,2], ARRAY[4,3]]::topology.topoelementarray As tea;

tea
-------
{{1,2},{4,3}}

--using the array agg function packaged with topology --

SELECT topology.TopoElementArray_Agg(ARRAY[e,t]) As tea
FROM generate_series(1,4) As e CROSS JOIN generate_series(1,3) As t;
tea
--------------------------------------------------------------------------
{{1,1},{1,2},{1,3},{2,1},{2,2},{2,3},{3,1},{3,2},{3,3},{4,1},{4,2},{4,3}}

SELECT '{{1,2,4},{3,4,5}}'::topology.topoelementarray As tea;

ERROR: value for domain topology.topoelementarray violates check constraint "dimensions"

See Also

TopoElement, GetTopoGeomElementArray, TopoElementArray_Agg

11.3 Topology and TopoGeometry Management

11.3.1 AddTopoGeometryColumn

AddTopoGeometryColumn — Adds a topogeometry column to an existing table, registers this new column as a layer in topol-
ogy.layer and returns the new layer_id.

Synopsis

integer AddTopoGeometryColumn(varchar topology_name, varchar schema_name, varchar table_name, varchar column_name,

varchar feature_type);
integer AddTopoGeometryColumn(varchar topology_name, varchar schema_name, varchar table_name, varchar column_name,
varchar feature_type, integer child_layer);

Description

Each TopoGeometry object belongs to a specific Layer of a specific Topology. Before creating a TopoGeometry object you need
to create its TopologyLayer. A Topology Layer is an association of a feature-table with the topology. It also contain type and
hierarchy information. We create a layer using the AddTopoGeometryColumn() function:
This function will both add the requested column to the table and add a record to the topology.layer table with all the given info.
If you don’t specify [child_layer] (or set it to NULL) this layer would contain Basic TopoGeometries (composed by primitive
topology elements). Otherwise this layer will contain hierarchical TopoGeometries (composed by TopoGeometries from the
child_layer).
Once the layer is created (its id is returned by the AddTopoGeometryColumn function) you’re ready to construct TopoGeometry
objects in it
PostGIS 2.4.3 Manual 625 / 803

Valid feature_types are: POINT, LINE, POLYGON, COLLECTION

Availability: 1.?

Examples

-- Note for this example we created our new table in the ma_topo schema
-- though we could have created it in a different schema -- in which case topology_name and ←-
schema_name would be different
CREATE SCHEMA ma;
CREATE TABLE ma.parcels(gid serial, parcel_id varchar(20) PRIMARY KEY, address text);
SELECT topology.AddTopoGeometryColumn('ma_topo', 'ma', 'parcels', 'topo', 'POLYGON');

CREATE SCHEMA ri;

CREATE TABLE ri.roads(gid serial PRIMARY KEY, road_name text);
SELECT topology.AddTopoGeometryColumn('ri_topo', 'ri', 'roads', 'topo', 'LINE');

See Also

CreateTopology, CreateTopoGeom

11.3.2 DropTopology

DropTopology — Use with caution: Drops a topology schema and deletes its reference from topology.topology table and refer-
ences to tables in that schema from the geometry_columns table.

Synopsis

integer DropTopology(varchar topology_schema_name);

Description

Drops a topology schema and deletes its reference from topology.topology table and references to tables in that schema from
the geometry_columns table. This function should be USED WITH CAUTION, as it could destroy data you care about. If the
schema does not exist, it just removes reference entries the named schema.
Availability: 1.?

Examples

Cascade drops the ma_topo schema and removes all references to it in topology.topology and geometry_columns.
SELECT topology.DropTopology('ma_topo');

See Also

11.3.3 DropTopoGeometryColumn

DropTopoGeometryColumn — Drops the topogeometry column from the table named table_name in schema schema_name
and unregisters the columns from topology.layer table.
PostGIS 2.4.3 Manual 626 / 803

Synopsis

text DropTopoGeometryColumn(varchar schema_name, varchar table_name, varchar column_name);

Description

Drops the topogeometry column from the table named table_name in schema schema_name and unregisters the columns
from topology.layer table. Returns summary of drop status. NOTE: it first sets all values to NULL before dropping to bypass
referential integrity checks.
Availability: 1.?

Examples

SELECT topology.DropTopoGeometryColumn('ma_topo', 'parcel_topo', 'topo');

See Also

AddTopoGeometryColumn

11.3.4 Populate_Topology_Layer

Populate_Topology_Layer — Adds missing entries to topology.layer table by reading metadata from topo tables.

Synopsis

setof record Populate_Topology_Layer();

Description

Adds missing entries to the topology.layer table by inspecting topology constraints on tables. This function is useful for
fixing up entries in topology catalog after restores of schemas with topo data.
It returns the list of entries created. Returned columns are schema_name, table_name, feature_column.
Availability: 2.3.0

Examples

SELECT CreateTopology('strk_topo');
CREATE SCHEMA strk;
CREATE TABLE strk.parcels(gid serial, parcel_id varchar(20) PRIMARY KEY, address text);
SELECT topology.AddTopoGeometryColumn('strk_topo', 'strk', 'parcels', 'topo', 'POLYGON');
-- this will return no records because this feature is already registered
SELECT *
FROM topology.Populate_Topology_Layer();

-- let's rebuild
TRUNCATE TABLE topology.layer;

SELECT *
FROM topology.Populate_Topology_Layer();

SELECT topology_id,layer_id, schema_name As sn, table_name As tn, feature_column As fc

FROM topology.layer;
PostGIS 2.4.3 Manual 627 / 803

schema_name | table_name | feature_column

-------------+------------+----------------
strk | parcels | topo
(1 row)

topology_id | layer_id | sn | tn | fc
-------------+----------+------+---------+------
2 | 2 | strk | parcels | topo
(1 row)

See Also

AddTopoGeometryColumn

11.3.5 TopologySummary

TopologySummary — Takes a topology name and provides summary totals of types of objects in topology

Synopsis

text TopologySummary(varchar topology_schema_name);

Description

Takes a topology name and provides summary totals of types of objects in topology.
Availability: 2.0.0

Examples

SELECT topology.topologysummary('city_data');
topologysummary
--------------------------------------------------------
Topology city_data (329), SRID 4326, precision: 0
22 nodes, 24 edges, 10 faces, 29 topogeoms in 5 layers
Layer 1, type Polygonal (3), 9 topogeoms
Deploy: features.land_parcels.feature
Layer 2, type Puntal (1), 8 topogeoms
Deploy: features.traffic_signs.feature
Layer 3, type Lineal (2), 8 topogeoms
Deploy: features.city_streets.feature
Layer 4, type Polygonal (3), 3 topogeoms
Hierarchy level 1, child layer 1
Deploy: features.big_parcels.feature
Layer 5, type Puntal (1), 1 topogeoms
Hierarchy level 1, child layer 2
Deploy: features.big_signs.feature

See Also

Topology_Load_Tiger
PostGIS 2.4.3 Manual 628 / 803

11.3.6 ValidateTopology

ValidateTopology — Returns a set of validatetopology_returntype objects detailing issues with topology

Synopsis

setof validatetopology_returntype ValidateTopology(varchar topology_schema_name);

Description

Returns a set of validatetopology_returntype objects detailing issues with topology. List of possible errors and what the returned
ids represent are displayed below:

Error id1 id2

edge crosses node edge_id node_id
invalid edge edge_id null
edge not simple edge_id null
edge crosses edge edge_id edge_id
edge start node geometry mis-match edge_id node_id
edge end node geometry mis-match edge_id node_id
face without edges face_id null
face has no rings face_id null
face overlaps face face_id face_id
face within face inner face_id outer face_id

Availability: 1.0.0
Enhanced: 2.0.0 more efficient edge crossing detection and fixes for false positives that were existent in prior versions.
Changed: 2.2.0 values for id1 and id2 were swapped for ’edge crosses node’ to be consistent with error description.

Examples

SELECT * FROM topology.ValidateTopology('ma_topo');

error | id1 | id2
-------------------+-----+-----
face without edges | 0 |

See Also

validatetopology_returntype, Topology_Load_Tiger

11.4 Topology Constructors

11.4.1 CreateTopology

CreateTopology — Creates a new topology schema and registers this new schema in the topology.topology table.
PostGIS 2.4.3 Manual 629 / 803

Synopsis

integer CreateTopology(varchar topology_schema_name);

integer CreateTopology(varchar topology_schema_name, integer srid);
integer CreateTopology(varchar topology_schema_name, integer srid, double precision prec);
integer CreateTopology(varchar topology_schema_name, integer srid, double precision prec, boolean hasz);

Description

Creates a new schema with name topology_name consisting of tables (edge_data,face,node, relation and registers
this new topology in the topology.topology table. It returns the id of the topology in the topology table. The srid is the spatial
reference identified as defined in spatial_ref_sys table for that topology. Topologies must be uniquely named. The tolerance is
measured in the units of the spatial reference system. If the tolerance (prec) is not specified defaults to 0.
This is similar to the SQL/MM ST_InitTopoGeo but a bit more functional. hasz defaults to false if not specified.
Availability: 1.?

Examples

This example creates a new schema called ma_topo that will store edges, faces, and relations in Massachusetts State Plane meters.
The tolerance represents 1/2 meter since the spatial reference system is a meter based spatial reference system
SELECT topology.CreateTopology('ma_topo',26986, 0.5);

Create Rhode Island topology in State Plane ft

SELECT topology.CreateTopology('ri_topo',3438) As topoid;
topoid
------
2

See Also

Section 4.3.1, ST_InitTopoGeo, Topology_Load_Tiger

11.4.2 CopyTopology

CopyTopology — Makes a copy of a topology structure (nodes, edges, faces, layers and TopoGeometries).

Synopsis

integer CopyTopology(varchar existing_topology_name, varchar new_name);

Description

Creates a new topology with name new_topology_name and SRID and precision taken from existing_topology_name,
copies all nodes, edges and faces in there, copies layers and their TopoGeometries too.

Note
The new rows in topology.layer will contain synthesized values for schema_name, table_name and feature_column.
This is because the TopoGeometry will only exist as a definition but won’t be available in any user-level table yet.

Availability: 2.0.0
PostGIS 2.4.3 Manual 630 / 803

Examples

This example makes a backup of a topology called ma_topo

SELECT topology.CopyTopology('ma_topo', 'ma_topo_bakup');

See Also

Section 4.3.1, CreateTopology

11.4.3 ST_InitTopoGeo

ST_InitTopoGeo — Creates a new topology schema and registers this new schema in the topology.topology table and details
summary of process.

Synopsis

text ST_InitTopoGeo(varchar topology_schema_name);

Description

This is an SQL-MM equivalent of CreateTopology but lacks the spatial reference and tolerance options of CreateTopology and
outputs a text description of creation instead of topology id.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM 3 Topo-Geo and Topo-Net 3: Routine Details: X.3.17

Examples

SELECT topology.ST_InitTopoGeo('topo_schema_to_create') AS topocreation;

astopocreation
------------------------------------------------------------
Topology-Geometry 'topo_schema_to_create' (id:7) created.

See Also

CreateTopology

11.4.4 ST_CreateTopoGeo

ST_CreateTopoGeo — Adds a collection of geometries to a given empty topology and returns a message detailing success.

Synopsis

text ST_CreateTopoGeo(varchar atopology, geometry acollection);

PostGIS 2.4.3 Manual 631 / 803

Description

Adds a collection of geometries to a given empty topology and returns a message detailing success.
Useful for populating an empty topology.
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details -- X.3.18

Examples

-- Populate topology --
SELECT topology.ST_CreateTopoGeo('ri_topo',
ST_GeomFromText('MULTILINESTRING((384744 236928,384750 236923,384769 236911,384799 ←-
236895,384811 236890,384833 236884,
384844 236882,384866 236881,384879 236883,384954 236898,385087 236932,385117 236938,
385167 236938,385203 236941,385224 236946,385233 236950,385241 236956,385254 236971,
385260 236979,385268 236999,385273 237018,385273 237037,385271 237047,385267 237057,
385225 237125,385210 237144,385192 237161,385167 237192,385162 237202,385159 237214,
385159 237227,385162 237241,385166 237256,385196 237324,385209 237345,385234 237375,
385237 237383,385238 237399,385236 237407,385227 237419,385213 237430,385193 237439,
385174 237451,385170 237455,385169 237460,385171 237475,385181 237503,385190 237521,
385200 237533,385206 237538,385213 237541,385221 237542,385235 237540,385242 237541,
385249 237544,385260 237555,385270 237570,385289 237584,385292 237589,385291 ←-
237596,385284 237630))',3438)
);

st_createtopogeo
----------------------------
Topology ri_topo populated

-- create tables and topo geometries --

CREATE TABLE ri.roads(gid serial PRIMARY KEY, road_name text);

SELECT topology.AddTopoGeometryColumn('ri_topo', 'ri', 'roads', 'topo', 'LINE');

See Also

AddTopoGeometryColumn, CreateTopology, DropTopology

11.4.5 TopoGeo_AddPoint

TopoGeo_AddPoint — Adds a point to an existing topology using a tolerance and possibly splitting an existing edge.

Synopsis

integer TopoGeo_AddPoint(varchar toponame, geometry apoint, float8 tolerance);

Description

Adds a point to an existing topology and return its identifier. The given point will snap to existing nodes or edges within given
tolerance. An existing edge may be split by the snapped point.
Availability: 2.0.0
PostGIS 2.4.3 Manual 632 / 803

See Also

TopoGeo_AddLineString, TopoGeo_AddPolygon, AddNode, CreateTopology

11.4.6 TopoGeo_AddLineString

TopoGeo_AddLineString — Adds a linestring to an existing topology using a tolerance and possibly splitting existing edges/-
faces. Returns edge identifiers

Synopsis

SETOF integer TopoGeo_AddLineString(varchar toponame, geometry aline, float8 tolerance);

Description

Adds a linestring to an existing topology and return a set of edge identifiers forming it up. The given line will snap to existing
nodes or edges within given tolerance. Existing edges and faces may be split by the line.
Availability: 2.0.0

See Also

TopoGeo_AddPoint, TopoGeo_AddPolygon, AddEdge, CreateTopology

11.4.7 TopoGeo_AddPolygon

TopoGeo_AddPolygon — Adds a polygon to an existing topology using a tolerance and possibly splitting existing edges/faces.

Synopsis

integer TopoGeo_AddPolygon(varchar atopology, geometry apoly, float8 atolerance);

Description

Adds a polygon to an existing topology and return a set of face identifiers forming it up. The boundary of the given polygon
will snap to existing nodes or edges within given tolerance. Existing edges and faces may be split by the boundary of the new
polygon.
Availability: 2.0.0

See Also

TopoGeo_AddPoint, TopoGeo_AddLineString, AddFace, CreateTopology

11.5 Topology Editors

11.5.1 ST_AddIsoNode

ST_AddIsoNode — Adds an isolated node to a face in a topology and returns the nodeid of the new node. If face is null, the
node is still created.
PostGIS 2.4.3 Manual 633 / 803

Synopsis

integer ST_AddIsoNode(varchar atopology, integer aface, geometry apoint);

Description

Adds an isolated node with point location apoint to an existing face with faceid aface to a topology atopology and returns
the nodeid of the new node.
If the spatial reference system (srid) of the point geometry is not the same as the topology, the apoint is not a point geometry,
the point is null, or the point intersects an existing edge (even at the boundaries) then an exception is thrown. If the point already
exists as a node, an exception is thrown.
If aface is not null and the apoint is not within the face, then an exception is thrown.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM: Topo-Net Routines: X+1.3.1

Examples

See Also

AddNode, CreateTopology, DropTopology, ST_Intersects

11.5.2 ST_AddIsoEdge

ST_AddIsoEdge — Adds an isolated edge defined by geometry alinestring to a topology connecting two existing isolated
nodes anode and anothernode and returns the edge id of the new edge.

Synopsis

integer ST_AddIsoEdge(varchar atopology, integer anode, integer anothernode, geometry alinestring);

Description

Adds an isolated edge defined by geometry alinestring to a topology connecting two existing isolated nodes anode and
anothernode and returns the edge id of the new edge.
If the spatial reference system (srid) of the alinestring geometry is not the same as the topology, any of the input arguments
are null, or the nodes are contained in more than one face, or the nodes are start or end nodes of an existing edge, then an
exception is thrown.
If the alinestring is not within the face of the face the anode and anothernode belong to, then an exception is thrown.
If the anode and anothernode are not the start and end points of the alinestring then an exception is thrown.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.4

Examples

See Also

ST_AddIsoNode, ST_IsSimple, ST_Within

PostGIS 2.4.3 Manual 634 / 803

11.5.3 ST_AddEdgeNewFaces

ST_AddEdgeNewFaces — Add a new edge and, if in doing so it splits a face, delete the original face and replace it with two new
faces.

Synopsis

integer ST_AddEdgeNewFaces(varchar atopology, integer anode, integer anothernode, geometry acurve);

Description

Add a new edge and, if in doing so it splits a face, delete the original face and replace it with two new faces. Returns the id of
the newly added edge.
Updates all existing joined edges and relationships accordingly.
If any arguments are null, the given nodes are unknown (must already exist in the node table of the topology schema) , the
acurve is not a LINESTRING, the anode and anothernode are not the start and endpoints of acurve then an error is
thrown.
If the spatial reference system (srid) of the acurve geometry is not the same as the topology an exception is thrown.
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.12

Examples

See Also

ST_RemEdgeNewFace
ST_AddEdgeModFace

11.5.4 ST_AddEdgeModFace

ST_AddEdgeModFace — Add a new edge and, if in doing so it splits a face, modify the original face and add a new face.

Synopsis

integer ST_AddEdgeModFace(varchar atopology, integer anode, integer anothernode, geometry acurve);

Description

Add a new edge and, if doing so splits a face, modify the original face and add a new one.

Note
If possible, the new face will be created on left side of the new edge. This will not be possible if the face on the left side
will need to be the Universe face (unbounded).
PostGIS 2.4.3 Manual 635 / 803

Returns the id of the newly added edge.

Updates all existing joined edges and relationships accordingly.
If any arguments are null, the given nodes are unknown (must already exist in the node table of the topology schema) , the
acurve is not a LINESTRING, the anode and anothernode are not the start and endpoints of acurve then an error is
thrown.
If the spatial reference system (srid) of the acurve geometry is not the same as the topology an exception is thrown.
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.13

Examples

See Also

ST_RemEdgeModFace
ST_AddEdgeNewFaces

11.5.5 ST_RemEdgeNewFace

ST_RemEdgeNewFace — Removes an edge and, if the removed edge separated two faces, delete the original faces and replace
them with a new face.

Synopsis

integer ST_RemEdgeNewFace(varchar atopology, integer anedge);

Description

Removes an edge and, if the removed edge separated two faces, delete the original faces and replace them with a new face.
Returns the id of a newly created face or NULL, if no new face is created. No new face is created when the removed edge is
dangling or isolated or confined with the universe face (possibly making the universe flood into the face on the other side).
Updates all existing joined edges and relationships accordingly.
Refuses to remove an edge participating in the definition of an existing TopoGeometry. Refuses to heal two faces if any TopoGe-
ometry is defined by only one of them (and not the other).
If any arguments are null, the given edge is unknown (must already exist in the edge table of the topology schema), the topology
name is invalid then an error is thrown.
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.14

Examples

See Also

ST_RemEdgeModFace
ST_AddEdgeNewFaces
PostGIS 2.4.3 Manual 636 / 803

11.5.6 ST_RemEdgeModFace

ST_RemEdgeModFace — Removes an edge and, if the removed edge separated two faces, delete one of the them and modify
the other to take the space of both.

Synopsis

integer ST_RemEdgeModFace(varchar atopology, integer anedge);

Description

Removes an edge and, if the removed edge separated two faces, delete one of the them and modify the other to take the space of
both. Preferentially keeps the face on the right, to be symmetric with ST_AddEdgeModFace also keeping it. Returns the id of
the face remaining in place of the removed edge.
Updates all existing joined edges and relationships accordingly.
Refuses to remove an edge partecipating in the definition of an existing TopoGeometry. Refuses to heal two faces if any Topo-
Geometry is defined by only one of them (and not the other).
If any arguments are null, the given edge is unknown (must already exist in the edge table of the topology schema), the topology
name is invalid then an error is thrown.
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.15

Examples

See Also

ST_AddEdgeModFace
ST_RemEdgeNewFace

11.5.7 ST_ChangeEdgeGeom

ST_ChangeEdgeGeom — Changes the shape of an edge without affecting the topology structure.

Synopsis

integer ST_ChangeEdgeGeom(varchar atopology, integer anedge, geometry acurve);

Description

Changes the shape of an edge without affecting the topology structure.

If any arguments are null, the given edge does not exist in the edge table of the topology schema, the acurve is not a
LINESTRING, the anode and anothernode are not the start and endpoints of acurve or the modification would change
the underlying topology then an error is thrown.
If the spatial reference system (srid) of the acurve geometry is not the same as the topology an exception is thrown.
If the new acurve is not simple, then an error is thrown.
If moving the edge from old to new position would hit an obstacle then an error is thrown.
PostGIS 2.4.3 Manual 637 / 803

Availability: 1.1.0
Enhanced: 2.0.0 adds topological consistency enforcement

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details X.3.6

Examples

SELECT topology.ST_ChangeEdgeGeom('ma_topo', 1,
ST_GeomFromText('LINESTRING(227591.9 893900.4,227622.6 893844.3,227641.6 893816.6, ←-
227704.5 893778.5)', 26986) );
----
Edge 1 changed

See Also

ST_AddEdgeModFace
ST_RemEdgeModFace
ST_ModEdgeSplit

11.5.8 ST_ModEdgeSplit

ST_ModEdgeSplit — Split an edge by creating a new node along an existing edge, modifying the original edge and adding a
new edge.

Synopsis

integer ST_ModEdgeSplit(varchar atopology, integer anedge, geometry apoint);

Description

Split an edge by creating a new node along an existing edge, modifying the original edge and adding a new edge. Updates all
existing joined edges and relationships accordingly. Returns the identifier of the newly added node.
Availability: 1.?
Changed: 2.0 - In prior versions, this was misnamed ST_ModEdgesSplit

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.9

Examples

-- Add an edge --
SELECT topology.AddEdge('ma_topo', ST_GeomFromText('LINESTRING(227592 893910, 227600 ←-
893910)', 26986) ) As edgeid;

-- edgeid-
3

-- Split the edge --

SELECT topology.ST_ModEdgeSplit('ma_topo', 3, ST_SetSRID(ST_Point(227594,893910),26986) ) ←-
As node_id;
PostGIS 2.4.3 Manual 638 / 803

node_id
-------------------------
7

See Also

ST_NewEdgesSplit, ST_ModEdgeHeal, ST_NewEdgeHeal, AddEdge

11.5.9 ST_ModEdgeHeal

ST_ModEdgeHeal — Heal two edges by deleting the node connecting them, modifying the first edge and deleting the second
edge. Returns the id of the deleted node.

Synopsis

int ST_ModEdgeHeal(varchar atopology, integer anedge, integer anotheredge);

Description

Heal two edges by deleting the node connecting them, modifying the first edge and deleting the second edge. Returns the id of
the deleted node. Updates all existing joined edges and relationships accordingly.
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.9

See Also

ST_ModEdgeSplit ST_NewEdgesSplit

11.5.10 ST_NewEdgeHeal

ST_NewEdgeHeal — Heal two edges by deleting the node connecting them, deleting both edges, and replacing them with an
edge whose direction is the same as the first edge provided.

Synopsis

int ST_NewEdgeHeal(varchar atopology, integer anedge, integer anotheredge);

Description

Heal two edges by deleting the node connecting them, deleting both edges, and replacing them with an edge whose direction is
the same as the first edge provided. Returns the id of the new edge replacing the healed ones. Updates all existing joined edges
and relationships accordingly.
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.9
PostGIS 2.4.3 Manual 639 / 803

See Also

ST_ModEdgeHeal ST_ModEdgeSplit ST_NewEdgesSplit

11.5.11 ST_MoveIsoNode

ST_MoveIsoNode — Moves an isolated node in a topology from one point to another. If new apoint geometry exists as a node
an error is thrown. Returns description of move.

Synopsis

text ST_MoveIsoNode(varchar atopology, integer anedge, geometry apoint);

Description

Moves an isolated node in a topology from one point to another. If new apoint geometry exists as a node an error is thrown.
If any arguments are null, the apoint is not a point, the existing node is not isolated (is a start or end point of an existing edge),
new node location intersects an existing edge (even at the end points) then an exception is thrown.
If the spatial reference system (srid) of the point geometry is not the same as the topology an exception is thrown.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM: Topo-Net Routines: X.3.2

Examples

-- Add an isolated node with no face --

SELECT topology.ST_AddIsoNode('ma_topo', NULL, ST_GeomFromText('POINT(227579 893916)', ←-
26986) ) As nodeid;
nodeid
--------
7
-- Move the new node --
SELECT topology.ST_MoveIsoNode('ma_topo', 7, ST_GeomFromText('POINT(227579.5 893916.5)', ←-
26986) ) As descrip;
descrip
----------------------------------------------------
Isolated Node 7 moved to location 227579.5,893916.5

See Also

ST_AddIsoNode

11.5.12 ST_NewEdgesSplit

ST_NewEdgesSplit — Split an edge by creating a new node along an existing edge, deleting the original edge and replacing it
with two new edges. Returns the id of the new node created that joins the new edges.

Synopsis

integer ST_NewEdgesSplit(varchar atopology, integer anedge, geometry apoint);

PostGIS 2.4.3 Manual 640 / 803

Description

Split an edge with edge id anedge by creating a new node with point location apoint along current edge, deleting the original
edge and replacing it with two new edges. Returns the id of the new node created that joins the new edges. Updates all existing
joined edges and relationships accordingly.
If the spatial reference system (srid) of the point geometry is not the same as the topology, the apoint is not a point geometry,
the point is null, the point already exists as a node, the edge does not correspond to an existing edge or the point is not within the
edge then an exception is thrown.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM: Topo-Net Routines: X.3.8

Examples

-- Add an edge --
SELECT topology.AddEdge('ma_topo', ST_GeomFromText('LINESTRING(227575 893917,227592 893900) ←-
', 26986) ) As edgeid;
-- result-
edgeid
------
2
-- Split the new edge --
SELECT topology.ST_NewEdgesSplit('ma_topo', 2, ST_GeomFromText('POINT(227578.5 893913.5)', ←-
26986) ) As newnodeid;
newnodeid
---------
6

See Also

ST_ModEdgeSplit ST_ModEdgeHeal ST_NewEdgeHeal AddEdge

11.5.13 ST_RemoveIsoNode

ST_RemoveIsoNode — Removes an isolated node and returns description of action. If the node is not isolated (is start or end of
an edge), then an exception is thrown.

Synopsis

text ST_RemoveIsoNode(varchar atopology, integer anode);

Description

Removes an isolated node and returns description of action. If the node is not isolated (is start or end of an edge), then an
exception is thrown.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X+1.3.3
PostGIS 2.4.3 Manual 641 / 803

Examples

-- Remove an isolated node with no face --

SELECT topology.ST_RemoveIsoNode('ma_topo', 7 ) As result;
result
-------------------------
Isolated node 7 removed

See Also

ST_AddIsoNode

11.5.14 ST_RemoveIsoEdge

ST_RemoveIsoEdge — Removes an isolated edge and returns description of action. If the edge is not isolated, then an exception
is thrown.

Synopsis

text ST_RemoveIsoEdge(varchar atopology, integer anedge);

Description

Removes an isolated edge and returns description of action. If the edge is not isolated, then an exception is thrown.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X+1.3.3

Examples

-- Remove an isolated node with no face --

SELECT topology.ST_RemoveIsoNode('ma_topo', 7 ) As result;
result
-------------------------
Isolated node 7 removed

See Also

ST_AddIsoNode

11.6 Topology Accessors

11.6.1 GetEdgeByPoint

GetEdgeByPoint — Find the edge-id of an edge that intersects a given point

Synopsis

integer GetEdgeByPoint(varchar atopology, geometry apoint, float8 tol);

PostGIS 2.4.3 Manual 642 / 803

Retrieve the id of an edge that intersects a Point

The function returns an integer (id-edge) given a topology, a POINT and a tolerance. If tolerance = 0 then the point has to
intersect the edge.
If the point doesn’t intersect an edge, returns 0 (zero).
If use tolerance > 0 and there is more than one edge near the point then an exception is thrown.

Note
If tolerance = 0, the function use ST_Intersects otherwise uses ST_DWithin.

Availability: 2.0.0 - requires GEOS >= 3.3.0.

Examples

These examples use edges we created in AddEdge

SELECT topology.GetEdgeByPoint('ma_topo',geom, 1) As with1mtol, topology.GetEdgeByPoint(' ←-
ma_topo',geom,0) As withnotol
FROM ST_GeomFromEWKT('SRID=26986;POINT(227622.6 893843)') As geom;
with1mtol | withnotol
-----------+-----------
2 | 0

SELECT topology.GetEdgeByPoint('ma_topo',geom, 1) As nearnode

FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;

-- get error --
ERROR: Two or more edges found

See Also

AddEdge, GetNodeByPoint, GetFaceByPoint

11.6.2 GetFaceByPoint

GetFaceByPoint — Find the face-id of a face that intersects a given point

Synopsis

integer GetFaceByPoint(varchar atopology, geometry apoint, float8 tol);

Description

Retrieve the id of a face that intersects a Point.

The function returns an integer (id-face) given a topology, a POINT and a tolerance. If tolerance = 0 then the point has to intersect
the face.
If the point doesn’t intersect a face, returns 0 (zero).
If use tolerance > 0 and there is more than one face near the point then an exception is thrown.
PostGIS 2.4.3 Manual 643 / 803

Note
If tolerance = 0, the function uses ST_Intersects otherwise uses ST_DWithin.

Availability: 2.0.0 - requires GEOS >= 3.3.0.

Examples

These examples use edges faces created in AddFace

SELECT topology.GetFaceByPoint('ma_topo',geom, 10) As with1mtol, topology.GetFaceByPoint(' ←-
ma_topo',geom,0) As withnotol
FROM ST_GeomFromEWKT('POINT(234604.6 899382.0)') As geom;

with1mtol | withnotol
-----------+-----------
1 | 0

SELECT topology.GetFaceByPoint('ma_topo',geom, 1) As nearnode

FROM ST_GeomFromEWKT('POINT(227591.9 893900.4)') As geom;

-- get error --
ERROR: Two or more faces found

See Also

AddFace, GetNodeByPoint, GetEdgeByPoint

11.6.3 GetNodeByPoint

GetNodeByPoint — Find the id of a node at a point location

Synopsis

integer GetNodeByPoint(varchar atopology, geometry point, float8 tol);

Retrieve the id of a node at a point location

The function return an integer (id-node) given a topology, a POINT and a tolerance. If tolerance = 0 mean exactly intersection
otherwise retrieve the node from an interval.
If there isn’t a node at the point, it return 0 (zero).
If use tolerance > 0 and near the point there are more than one node it throw an exception.

Note
If tolerance = 0, the function use ST_Intersects otherwise will use ST_DWithin.

Availability: 2.0.0 - requires GEOS >= 3.3.0.

PostGIS 2.4.3 Manual 644 / 803

Examples

These examples use edges we created in AddEdge

SELECT topology.GetNodeByPoint('ma_topo',geom, 1) As nearnode
FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;
nearnode
----------
2

SELECT topology.GetNodeByPoint('ma_topo',geom, 1000) As too_much_tolerance

FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;

----get error--
ERROR: Two or more nodes found

See Also

AddEdge, GetEdgeByPoint, GetFaceByPoint

11.6.4 GetTopologyID

GetTopologyID — Returns the id of a topology in the topology.topology table given the name of the topology.

Synopsis

integer GetTopologyID(varchar toponame);

Description

Returns the id of a topology in the topology.topology table given the name of the topology.
Availability: 1.?

Examples

SELECT topology.GetTopologyID('ma_topo') As topo_id;

topo_id
---------
1

See Also

CreateTopology, DropTopology, GetTopologyName, GetTopologySRID

11.6.5 GetTopologySRID

GetTopologySRID — Returns the SRID of a topology in the topology.topology table given the name of the topology.

Synopsis

integer GetTopologyID(varchar toponame);

PostGIS 2.4.3 Manual 645 / 803

Description

Returns the spatial reference id of a topology in the topology.topology table given the name of the topology.
Availability: 2.0.0

Examples

SELECT topology.GetTopologySRID('ma_topo') As SRID;

SRID
-------
4326

See Also

CreateTopology, DropTopology, GetTopologyName, GetTopologyID

11.6.6 GetTopologyName

GetTopologyName — Returns the name of a topology (schema) given the id of the topology.

Synopsis

varchar GetTopologyName(integer topology_id);

Description

Returns the topology name (schema) of a topology from the topology.topology table given the topology id of the topology.
Availability: 1.?

Examples

SELECT topology.GetTopologyName(1) As topo_name;

topo_name
-----------
ma_topo

See Also

CreateTopology, DropTopology, GetTopologyID, GetTopologySRID

11.6.7 ST_GetFaceEdges

ST_GetFaceEdges — Returns a set of ordered edges that bound aface.

Synopsis

getfaceedges_returntype ST_GetFaceEdges(varchar atopology, integer aface);

PostGIS 2.4.3 Manual 646 / 803

Description

Returns a set of ordered edges that bound aface. Each output consists of a sequence and edgeid. Sequence numbers start with
value 1.
Enumeration of each ring edges start from the edge with smallest identifier. Order of edges follows a left-hand-rule (bound face
is on the left of each directed edge).
Availability: 2.0

This method implements the SQL/MM specification. SQL-MM 3 Topo-Geo and Topo-Net 3: Routine Details: X.3.5

Examples

-- Returns the edges bounding face 1

SELECT (topology.ST_GetFaceEdges('tt', 1)).*;
-- result --
sequence | edge
----------+------
1 | -4
2 | 5
3 | 7
4 | -6
5 | 1
6 | 2
7 | 3
(7 rows)

-- Returns the sequence, edge id

-- and geometry of the edges that bound face 1
-- If you just need geom and seq, can use ST_GetFaceGeometry
SELECT t.seq, t.edge, geom
FROM topology.ST_GetFaceEdges('tt',1) As t(seq,edge)
INNER JOIN tt.edge AS e ON abs(t.edge) = e.edge_id;

See Also

GetRingEdges, AddFace, ST_GetFaceGeometry

11.6.8 ST_GetFaceGeometry

ST_GetFaceGeometry — Returns the polygon in the given topology with the specified face id.

Synopsis

geometry ST_GetFaceGeometry(varchar atopology, integer aface);

Description

Returns the polygon in the given topology with the specified face id. Builds the polygon from the edges making up the face.
Availability: 1.?

This method implements the SQL/MM specification. SQL-MM 3 Topo-Geo and Topo-Net 3: Routine Details: X.3.16
PostGIS 2.4.3 Manual 647 / 803

Examples

-- Returns the wkt of the polygon added with AddFace

SELECT ST_AsText(topology.ST_GetFaceGeometry('ma_topo', 1)) As facegeomwkt;
-- result --
facegeomwkt

--------------------------------------------------------------------------------
POLYGON((234776.9 899563.7,234896.5 899456.7,234914 899436.4,234946.6 899356.9,
234872.5 899328.7,234891 899285.4,234992.5 899145,234890.6 899069,
234755.2 899255.4,234612.7 899379.4,234776.9 899563.7))

See Also

AddFace

11.6.9 GetRingEdges

GetRingEdges — Returns the ordered set of signed edge identifiers met by walking on an a given edge side.

Synopsis

getfaceedges_returntype GetRingEdges(varchar atopology, integer aring, integer max_edges=null);

Description

Returns the ordered set of signed edge identifiers met by walking on an a given edge side. Each output consists of a sequence
and a signed edge id. Sequence numbers start with value 1.
If you pass a positive edge id, the walk starts on the left side of the corresponding edge and follows the edge direction. If you
pass a negative edge id, the walk starts on the right side of it and goes backward.
If max_edges is not null no more than those records are returned by that function. This is meant to be a safety parameter when
dealing with possibly invalid topologies.

Note
This function uses edge ring linking metadata.

Availability: 2.0.0

See Also

ST_GetFaceEdges, GetNodeEdges

11.6.10 GetNodeEdges

GetNodeEdges — Returns an ordered set of edges incident to the given node.

Synopsis

getfaceedges_returntype GetNodeEdges(varchar atopology, integer anode);

PostGIS 2.4.3 Manual 648 / 803

Description

Returns an ordered set of edges incident to the given node. Each output consists of a sequence and a signed edge id. Sequence
numbers start with value 1. A positive edge starts at the given node. A negative edge ends into the given node. Closed edges will
appear twice (with both signs). Order is clockwise starting from northbound.

Note
This function computes ordering rather than deriving from metadata and is thus usable to build edge ring linking.

Availability: 2.0

See Also

GetRingEdges, ST_Azimuth

11.7 Topology Processing

11.7.1 Polygonize

Polygonize — Find and register all faces defined by topology edges

Synopsis

text Polygonize(varchar toponame);

Description

Register all faces that can be built out a topology edge primitives.
The target topology is assumed to contain no self-intersecting edges.

Note
Already known faces are recognized, so it is safe to call Polygonize multiple times on the same topology.

Note
This function does not use nor set the next_left_edge and next_right_edge fields of the edge table.

Availability: 2.0.0

See Also

AddFace, ST_Polygonize
PostGIS 2.4.3 Manual 649 / 803

11.7.2 AddNode

AddNode — Adds a point node to the node table in the specified topology schema and returns the nodeid of new node. If point
already exists as node, the existing nodeid is returned.

Synopsis

integer AddNode(varchar toponame, geometry apoint, boolean allowEdgeSplitting=false, boolean computeContainingFace=false);

Description

Adds a point node to the node table in the specified topology schema. The AddEdge function automatically adds start and end
points of an edge when called so not necessary to explicitly add nodes of an edge.
If any edge crossing the node is found either an exception is raised or the edge is split, depending on the allowEdgeSplitting
parameter value.
If computeContainingFace is true a newly added node would get the correct containing face computed.

Note
If the apoint geometry already exists as a node, the node is not added but the existing nodeid is returned.

Availability: 2.0.0

Examples

SELECT topology.AddNode('ma_topo', ST_GeomFromText('POINT(227641.6 893816.5)', 26986) ) As ←-

nodeid;
-- result --
nodeid
--------
4

See Also

AddEdge, CreateTopology

11.7.3 AddEdge

AddEdge — Adds a linestring edge to the edge table and associated start and end points to the point nodes table of the specified
topology schema using the specified linestring geometry and returns the edgeid of the new (or existing) edge.

Synopsis

integer AddEdge(varchar toponame, geometry aline);

PostGIS 2.4.3 Manual 650 / 803

Description

Adds an edge to the edge table and associated nodes to the nodes table of the specified toponame schema using the specified
linestring geometry and returns the edgeid of the new or existing record. The newly added edge has "universe" face on both sides
and links to itself.

Note
If the aline geometry crosses, overlaps, contains or is contained by an existing linestring edge, then an error is thrown
and the edge is not added.

Note
The geometry of aline must have the same srid as defined for the topology otherwise an invalid spatial reference
sys error will be thrown.

Availability: 2.0.0 requires GEOS >= 3.3.0.

Examples

SELECT topology.AddEdge('ma_topo', ST_GeomFromText('LINESTRING(227575.8 893917.2,227591.9 ←-

893900.4)', 26986) ) As edgeid;
-- result-
edgeid
--------
1

SELECT topology.AddEdge('ma_topo', ST_GeomFromText('LINESTRING(227591.9 893900.4,227622.6 ←-

893844.2,227641.6 893816.5,
227704.5 893778.5)', 26986) ) As edgeid;
-- result --
edgeid
--------
2

SELECT topology.AddEdge('ma_topo', ST_GeomFromText('LINESTRING(227591.2 893900, 227591.9 ←-

893900.4,
227704.5 893778.5)', 26986) ) As edgeid;
-- gives error --
ERROR: Edge intersects (not on endpoints) with existing edge 1

See Also

TopoGeo_AddLineString, CreateTopology, Section 4.3.1

11.7.4 AddFace

AddFace — Registers a face primitive to a topology and gets its identifier.

Synopsis

integer AddFace(varchar toponame, geometry apolygon, boolean force_new=false);

PostGIS 2.4.3 Manual 651 / 803

Description

Registers a face primitive to a topology and gets its identifier.

For a newly added face, the edges forming its boundaries and the ones contained in the face will be updated to have correct values
in the left_face and right_face fields. Isolated nodes contained in the face will also be updated to have a correct containing_face
field value.

Note
This function does not use nor set the next_left_edge and next_right_edge fields of the edge table.

The target topology is assumed to be valid (containing no self-intersecting edges). An exception is raised if: The polygon
boundary is not fully defined by existing edges or the polygon overlaps an existing face.
If the apolygon geometry already exists as a face, then: if force_new is false (the default) the face id of the existing face is
returned; if force_new is true a new id will be assigned to the newly registered face.

Note
When a new registration of an existing face is performed (force_new=true), no action will be taken to resolve dangling
references to the existing face in the edge, node an relation tables, nor will the MBR field of the existing face record be
updated. It is up to the caller to deal with that.

Note
The apolygon geometry must have the same srid as defined for the topology otherwise an invalid spatial reference
sys error will be thrown.

Availability: 2.0.0

Examples

-- first add the edges we use generate_series as an iterator (the below

-- will only work for polygons with < 10000 points because of our max in gs)
SELECT topology.AddEdge('ma_topo', ST_MakeLine(ST_PointN(geom,i), ST_PointN(geom, i + 1) )) ←-
As edgeid
FROM (SELECT ST_NPoints(geom) AS npt, geom
FROM
(SELECT ST_Boundary(ST_GeomFromText('POLYGON((234896.5 899456.7,234914 ←-
899436.4,234946.6 899356.9,234872.5 899328.7,
234891 899285.4,234992.5 899145, 234890.6 899069,234755.2 899255.4,
234612.7 899379.4,234776.9 899563.7,234896.5 899456.7))', 26986) ) As geom
) As geoms) As facen CROSS JOIN generate_series(1,10000) As i
WHERE i < npt;
-- result --
edgeid
--------
3
4
5
6
7
8
9
PostGIS 2.4.3 Manual 652 / 803

10
11
12
(10 rows)
-- then add the face -

SELECT topology.AddFace('ma_topo',
ST_GeomFromText('POLYGON((234896.5 899456.7,234914 899436.4,234946.6 899356.9,234872.5 ←-
899328.7,
234891 899285.4,234992.5 899145, 234890.6 899069,234755.2 899255.4,
234612.7 899379.4,234776.9 899563.7,234896.5 899456.7))', 26986) ) As faceid;
-- result --
faceid
--------
1

See Also

AddEdge, CreateTopology, Section 4.3.1

11.7.5 ST_Simplify

ST_Simplify — Returns a "simplified" geometry version of the given TopoGeometry using the Douglas-Peucker algorithm.

Synopsis

geometry ST_Simplify(TopoGeometry geomA, float tolerance);

Description

Returns a "simplified" geometry version of the given TopoGeometry using the Douglas-Peucker algorithm on each component
edge.

Note
The returned geometry may be non-simple or non-valid.
Splitting component edges may help retaining simplicity/validity.

Performed by the GEOS module.

Availability: 2.1.0

See Also

Geometry ST_Simplify, ST_IsSimple, ST_IsValid, ST_ModEdgeSplit

11.8 TopoGeometry Constructors

11.8.1 CreateTopoGeom

CreateTopoGeom — Creates a new topo geometry object from topo element array - tg_type: 1:[multi]point, 2:[multi]line,
3:[multi]poly, 4:collection
PostGIS 2.4.3 Manual 653 / 803

Synopsis

topogeometry CreateTopoGeom(varchar toponame, integer tg_type, integer layer_id, topoelementarray tg_objs);

topogeometry CreateTopoGeom(varchar toponame, integer tg_type, integer layer_id);

Description

Creates a topogeometry object for layer denoted by layer_id and registers it in the relations table in the toponame schema.
tg_type is an integer: 1:[multi]point (punctal), 2:[multi]line (lineal), 3:[multi]poly (areal), 4:collection. layer_id is the layer id in
the topology.layer table.
punctal layers are formed from set of nodes, lineal layers are formed from a set of edges, areal layers are formed from a set of
faces, and collections can be formed from a mixture of nodes, edges, and faces.
Omitting the array of components generates an empty TopoGeometry object.
Availability: 1.?

Examples: Form from existing edges

Create a topogeom in ri_topo schema for layer 2 (our ri_roads), of type (2) LINE, for the first edge (we loaded in ST_CreateTopoGeo).
INSERT INTO ri.ri_roads(road_name, topo) VALUES('Unknown', topology.CreateTopoGeom('ri_topo ←-
',2,2,'{{1,2}}'::topology.topoelementarray);

Examples: Convert an areal geometry to best guess topogeometry

Lets say we have geometries that should be formed from a collection of faces. We have for example blockgroups table and want
to know the topo geometry of each block group. If our data was perfectly aligned, we could do this:
-- create our topo geometry column --
SELECT topology.AddTopoGeometryColumn(
'topo_boston',
'boston', 'blockgroups', 'topo', 'POLYGON');

-- addtopgeometrycolumn --
1

-- update our column assuming

-- everything is perfectly aligned with our edges
UPDATE boston.blockgroups AS bg
SET topo = topology.CreateTopoGeom('topo_boston'
,3,1
, foo.bfaces)
FROM (SELECT b.gid, topology.TopoElementArray_Agg(ARRAY[f.face_id,3]) As bfaces
FROM boston.blockgroups As b
INNER JOIN topo_boston.face As f ON b.geom && f.mbr
WHERE ST_Covers(b.geom, topology.ST_GetFaceGeometry('topo_boston', f.face_id))
GROUP BY b.gid) As foo
WHERE foo.gid = bg.gid;

--the world is rarely perfect allow for some error

--count the face if 50% of it falls
-- within what we think is our blockgroup boundary
UPDATE boston.blockgroups AS bg
SET topo = topology.CreateTopoGeom('topo_boston'
,3,1
, foo.bfaces)
PostGIS 2.4.3 Manual 654 / 803

FROM (SELECT b.gid, topology.TopoElementArray_Agg(ARRAY[f.face_id,3]) As bfaces

FROM boston.blockgroups As b
INNER JOIN topo_boston.face As f ON b.geom && f.mbr
WHERE ST_Covers(b.geom, topology.ST_GetFaceGeometry('topo_boston', f.face_id))
OR
( ST_Intersects(b.geom, topology.ST_GetFaceGeometry('topo_boston', f.face_id))
AND ST_Area(ST_Intersection(b.geom, topology.ST_GetFaceGeometry('topo_boston', ←-
f.face_id) ) ) >
ST_Area(topology.ST_GetFaceGeometry('topo_boston', f.face_id))*0.5
)
GROUP BY b.gid) As foo
WHERE foo.gid = bg.gid;

-- and if we wanted to convert our topogeometry back

-- to a denomalized geometry aligned with our faces and edges
-- cast the topo to a geometry
-- The really cool thing is my new geometries
-- are now aligned with my tiger street centerlines
UPDATE boston.blockgroups SET new_geom = topo::geometry;

See Also

AddTopoGeometryColumn, toTopoGeom ST_CreateTopoGeo, ST_GetFaceGeometry, TopoElementArray, TopoElementArray_Agg

11.8.2 toTopoGeom

toTopoGeom — Converts a simple Geometry into a topo geometry

Synopsis

topogeometry toTopoGeom(geometry geom, varchar toponame, integer layer_id, float8 tolerance);

topogeometry toTopoGeom(geometry geom, topogeometry topogeom, float8 tolerance);

Description

Converts a simple Geometry into a TopoGeometry.

Topological primitives required to represent the input geometry will be added to the underlying topology, possibly splitting
existing ones, and they will be associated with the output TopoGeometry in the relation table.
Existing TopoGeometry objects (with the possible exception of topogeom, if given) will retain their shapes.
When tolerance is given it will be used to snap the input geometry to existing primitives.
In the first form a new TopoGeometry will be created for the given layer (layer_id) of the given topology (toponame).
In the second form the primitives resulting from the conversion will be added to the pre-existing TopoGeometry (topogeom),
possibly adding space to its final shape. To have the new shape completely replace the old one see clearTopoGeom.
Availability: 2.0
Enhanced: 2.1.0 adds the version taking an existing TopoGeometry.

Examples

This is a full self-contained workflow

PostGIS 2.4.3 Manual 655 / 803

-- do this if you don't have a topology setup already

-- creates topology not allowing any tolerance
SELECT topology.CreateTopology('topo_boston_test', 2249);
-- create a new table
CREATE TABLE nei_topo(gid serial primary key, nei varchar(30));
--add a topogeometry column to it
SELECT topology.AddTopoGeometryColumn('topo_boston_test', 'public', 'nei_topo', 'topo', ' ←-
MULTIPOLYGON') As new_layer_id;
new_layer_id
-----------
1

--use new layer id in populating the new topogeometry column

-- we add the topogeoms to the new layer with 0 tolerance
INSERT INTO nei_topo(nei, topo)
SELECT nei, topology.toTopoGeom(geom, 'topo_boston_test', 1)
FROM neighborhoods
WHERE gid BETWEEN 1 and 15;

--use to verify what has happened --

SELECT * FROM
topology.TopologySummary('topo_boston_test');

-- summary--
Topology topo_boston_test (5), SRID 2249, precision 0
61 nodes, 87 edges, 35 faces, 15 topogeoms in 1 layers
Layer 1, type Polygonal (3), 15 topogeoms
Deploy: public.nei_topo.topo

-- Shrink all TopoGeometry polygons by 10 meters

UPDATE nei_topo SET topo = ST_Buffer(clearTopoGeom(topo), -10);

-- Get the no-one-lands left by the above operation

-- I think GRASS calls this "polygon0 layer"
SELECT ST_GetFaceGeometry('topo_boston_test', f.face_id)
FROM topo_boston_test.face f
WHERE f.face_id > 0 -- don't consider the universe face
AND NOT EXISTS ( -- check that no TopoGeometry references the face
SELECT * FROM topo_boston_test.relation
WHERE layer_id = 1 AND element_id = f.face_id
);

See Also

CreateTopology, AddTopoGeometryColumn, CreateTopoGeom, TopologySummary, clearTopoGeom

11.8.3 TopoElementArray_Agg

TopoElementArray_Agg — Returns a topoelementarray for a set of element_id, type arrays (topoelements)

Synopsis

topoelementarray TopoElementArray_Agg(topoelement set tefield);

PostGIS 2.4.3 Manual 656 / 803

Description

Used to create a TopoElementArray from a set of TopoElement.

Availability: 2.0.0

Examples

SELECT topology.TopoElementArray_Agg(ARRAY[e,t]) As tea

FROM generate_series(1,3) As e CROSS JOIN generate_series(1,4) As t;
tea
--------------------------------------------------------------------------
{{1,1},{1,2},{1,3},{1,4},{2,1},{2,2},{2,3},{2,4},{3,1},{3,2},{3,3},{3,4}}

See Also

TopoElement, TopoElementArray

11.9 TopoGeometry Editors

11.9.1 clearTopoGeom

clearTopoGeom — Clears the content of a topo geometry

Synopsis

topogeometry clearTopoGeom(topogeometry topogeom);

Description

Clears the content a TopoGeometry turning it into an empty one. Mostly useful in conjunction with toTopoGeom to replace the
shape of existing objects and any dependent object in higher hierarchical levels.
Availability: 2.1

Examples

-- Shrink all TopoGeometry polygons by 10 meters

UPDATE nei_topo SET topo = ST_Buffer(clearTopoGeom(topo), -10);

See Also

toTopoGeom

11.9.2 TopoGeom_addElement

TopoGeom_addElement — Add an element to the definition of a TopoGeometry

Synopsis

topogeometry TopoGeom_addElement(topogeometry tg, topoelement el);

PostGIS 2.4.3 Manual 657 / 803

Description

Adds a TopoElement to the definition of a TopoGeometry object. Does not error out if the element is already part of the definition.
Availability: 2.3

Examples

-- Add edge 5 to TopoGeometry tg

UPDATE mylayer SET tg = TopoGeom_addElement(tg, '{5,2}');

See Also

TopoGeom_remElement, CreateTopoGeom

11.9.3 TopoGeom_remElement

TopoGeom_remElement — Remove an element from the definition of a TopoGeometry

Synopsis

topogeometry TopoGeom_remElement(topogeometry tg, topoelement el);

Description

Removes a TopoElement from the definition of a TopoGeometry object.

Availability: 2.3

Examples

-- Remove face 43 from TopoGeometry tg

UPDATE mylayer SET tg = TopoGeom_remElement(tg, '{43,3}');

See Also

TopoGeom_addElement, CreateTopoGeom

11.9.4 toTopoGeom

toTopoGeom — Adds a geometry shape to an existing topo geometry

Description

Refer to toTopoGeom
PostGIS 2.4.3 Manual 658 / 803

11.10 TopoGeometry Accessors

11.10.1 GetTopoGeomElementArray

GetTopoGeomElementArray — Returns a topoelementarray (an array of topoelements) containing the topological ele-
ments and type of the given TopoGeometry (primitive elements)

Synopsis

topoelementarray GetTopoGeomElementArray(varchar toponame, integer layer_id, integer tg_id);

topoelementarray topoelement GetTopoGeomElementArray(topogeometry tg);

Description

Returns a TopoElementArray containing the topological elements and type of the given TopoGeometry (primitive elements).
This is similar to GetTopoGeomElements except it returns the elements as an array rather than as a dataset.
tg_id is the topogeometry id of the topogeometry object in the topology in the layer denoted by layer_id in the topology.layer
table.
Availability: 1.?

Examples

See Also

GetTopoGeomElements, TopoElementArray

11.10.2 GetTopoGeomElements

GetTopoGeomElements — Returns a set of topoelement objects containing the topological element_id,element_type of the
given TopoGeometry (primitive elements)

Synopsis

setof topoelement GetTopoGeomElements(varchar toponame, integer layer_id, integer tg_id);

setof topoelement GetTopoGeomElements(topogeometry tg);

Description

Returns a set of element_id,element_type (topoelements) for a given topogeometry object in toponame schema.
tg_id is the topogeometry id of the topogeometry object in the topology in the layer denoted by layer_id in the topology.layer
table.
Availability: 2.0.0

Examples

See Also

GetTopoGeomElementArray, TopoElement, TopoGeom_addElement, TopoGeom_remElement

PostGIS 2.4.3 Manual 659 / 803

11.11 TopoGeometry Outputs

11.11.1 AsGML

AsGML — Returns the GML representation of a topogeometry.

Synopsis

text AsGML(topogeometry tg);

text AsGML(topogeometry tg, text nsprefix_in);
text AsGML(topogeometry tg, regclass visitedTable);
text AsGML(topogeometry tg, regclass visitedTable, text nsprefix);
text AsGML(topogeometry tg, text nsprefix_in, integer precision, integer options);
text AsGML(topogeometry tg, text nsprefix_in, integer precision, integer options, regclass visitedTable);
text AsGML(topogeometry tg, text nsprefix_in, integer precision, integer options, regclass visitedTable, text idprefix);
text AsGML(topogeometry tg, text nsprefix_in, integer precision, integer options, regclass visitedTable, text idprefix, int gm-
lversion);

Description

Returns the GML representation of a topogeometry in version GML3 format. If no nsprefix_in is specified then gml is
used. Pass in an empty string for nsprefix to get a non-qualified name space. The precision (default: 15) and options (default 1)
parameters, if given, are passed untouched to the underlying call to ST_AsGML.
The visitedTable parameter, if given, is used for keeping track of the visited Node and Edge elements so to use cross-
references (xlink:xref) rather than duplicating definitions. The table is expected to have (at least) two integer fields: ’ele-
ment_type’ and ’element_id’. The calling user must have both read and write privileges on the given table. For best performance,
an index should be defined on element_type and element_id, in that order. Such index would be created automatically
by adding a unique constraint to the fields. Example:
CREATE TABLE visited (
element_type integer, element_id integer,
unique(element_type, element_id)
);

The idprefix parameter, if given, will be prepended to Edge and Node tag identifiers.
The gmlver parameter, if given, will be passed to the underlying ST_AsGML. Defaults to 3.
Availability: 2.0.0

Examples

This uses the topo geometry we created in CreateTopoGeom

SELECT topology.AsGML(topo) As rdgml
FROM ri.roads
WHERE road_name = 'Unknown';

-- rdgml--
<gml:TopoCurve>
<gml:directedEdge>
<gml:Edge gml:id="E1">
<gml:directedNode orientation="-">
<gml:Node gml:id="N1"/>
</gml:directedNode>
<gml:directedNode></gml:directedNode>
<gml:curveProperty>
PostGIS 2.4.3 Manual 660 / 803

<gml:Curve srsName="urn:ogc:def:crs:EPSG::3438">
<gml:segments>
<gml:LineStringSegment>
<gml:posList srsDimension="2">384744 236928 384750 236923 ←-
384769 236911 384799 236895 384811 236890
384833 236884 384844 236882 384866 236881 384879 236883 384954 ←-
236898 385087 236932 385117 236938
385167 236938 385203 236941 385224 236946 385233 236950 385241 ←-
236956 385254 236971
385260 236979 385268 236999 385273 237018 385273 237037 385271 ←-
237047 385267 237057 385225 237125
385210 237144 385192 237161 385167 237192 385162 237202 385159 ←-
237214 385159 237227 385162 237241
385166 237256 385196 237324 385209 237345 385234 237375 385237 ←-
237383 385238 237399 385236 237407
385227 237419 385213 237430 385193 237439 385174 237451 385170 ←-
237455 385169 237460 385171 237475
385181 237503 385190 237521 385200 237533 385206 237538 385213 ←-
237541 385221 237542 385235 237540 385242 237541
385249 237544 385260 237555 385270 237570 385289 237584 385292 ←-
237589 385291 237596 385284 237630</gml:posList>
</gml:LineStringSegment>
</gml:segments>
</gml:Curve>
</gml:curveProperty>
</gml:Edge>
</gml:directedEdge>
</gml:TopoCurve>

Same exercise as previous without namespace

SELECT topology.AsGML(topo,'') As rdgml
FROM ri.roads
WHERE road_name = 'Unknown';

-- rdgml--
<TopoCurve>
<directedEdge>
<Edge id="E1">
<directedNode orientation="-">
<Node id="N1"/>
</directedNode>
<directedNode></directedNode>
<curveProperty>
<Curve srsName="urn:ogc:def:crs:EPSG::3438">
<segments>
<LineStringSegment>
<posList srsDimension="2">384744 236928 384750 236923 384769 ←-
236911 384799 236895 384811 236890
384833 236884 384844 236882 384866 236881 384879 236883 384954 ←-
236898 385087 236932 385117 236938
385167 236938 385203 236941 385224 236946 385233 236950 385241 ←-
236956 385254 236971
385260 236979 385268 236999 385273 237018 385273 237037 385271 ←-
237047 385267 237057 385225 237125
385210 237144 385192 237161 385167 237192 385162 237202 385159 ←-
237214 385159 237227 385162 237241
385166 237256 385196 237324 385209 237345 385234 237375 385237 ←-
237383 385238 237399 385236 237407
385227 237419 385213 237430 385193 237439 385174 237451 385170 ←-
237455 385169 237460 385171 237475
385181 237503 385190 237521 385200 237533 385206 237538 385213 ←-
PostGIS 2.4.3 Manual 661 / 803

237541 385221 237542 385235 237540 385242 237541

385249 237544 385260 237555 385270 237570 385289 237584 385292 ←-
237589 385291 237596 385284 237630</posList>
</LineStringSegment>
</segments>
</Curve>
</curveProperty>
</Edge>
</directedEdge>
</TopoCurve>

See Also

CreateTopoGeom, ST_CreateTopoGeo

11.11.2 AsTopoJSON

AsTopoJSON — Returns the TopoJSON representation of a topogeometry.

Synopsis

text AsTopoJSON(topogeometry tg, regclass edgeMapTable);

Description

Returns the TopoJSON representation of a topogeometry. If edgeMapTable is not null, it will be used as a lookup/storage
mapping of edge identifiers to arc indices. This is to be able to allow for a compact "arcs" array in the final document.
The table, if given, is expected to have an "arc_id" field of type "serial" and an "edge_id" of type integer; the code will query the
table for "edge_id" so it is recommended to add an index on that field.

Note
Arc indices in the TopoJSON output are 0-based but they are 1-based in the "edgeMapTable" table.

A full TopoJSON document will be need to contain, in addition to the snippets returned by this function, the actual arcs plus
some headers. See the TopoJSON specification.
Availability: 2.1.0
Enhanced: 2.2.1 added support for puntal inputs

See Also

ST_AsGeoJSON
PostGIS 2.4.3 Manual 662 / 803

Examples

CREATE TEMP TABLE edgemap(arc_id serial, edge_id int unique);

-- header
SELECT '{ "type": "Topology", "transform": { "scale": [1,1], "translate": [0,0] }, "objects ←-
": {'

-- objects
UNION ALL SELECT '"' || feature_name || '": ' || AsTopoJSON(feature, 'edgemap')
FROM features.big_parcels WHERE feature_name = 'P3P4';

-- arcs
WITH edges AS (
SELECT m.arc_id, e.geom FROM edgemap m, city_data.edge e
WHERE e.edge_id = m.edge_id
), points AS (
SELECT arc_id, (st_dumppoints(geom)).* FROM edges
), compare AS (
SELECT p2.arc_id,
CASE WHEN p1.path IS NULL THEN p2.geom
ELSE ST_Translate(p2.geom, -ST_X(p1.geom), -ST_Y(p1.geom))
END AS geom
FROM points p2 LEFT OUTER JOIN points p1
ON ( p1.arc_id = p2.arc_id AND p2.path[1] = p1.path[1]+1 )
ORDER BY arc_id, p2.path
), arcsdump AS (
SELECT arc_id, (regexp_matches( ST_AsGeoJSON(geom), '\[.*\]'))[1] as t
FROM compare
), arcs AS (
SELECT arc_id, '[' || array_to_string(array_agg(t), ',') || ']' as a FROM arcsdump
GROUP BY arc_id
ORDER BY arc_id
)
SELECT '}, "arcs": [' UNION ALL
SELECT array_to_string(array_agg(a), E',\n') from arcs

-- footer
UNION ALL SELECT ']}'::text as t;

-- Result:
{ "type": "Topology", "transform": { "scale": [1,1], "translate": [0,0] }, "objects": {
"P3P4": { "type": "MultiPolygon", "arcs": [[[-1]],[[6,5,-5,-4,-3,1]]]}
}, "arcs": [
[[25,30],[6,0],[0,10],[-14,0],[0,-10],[8,0]],
[[35,6],[0,8]],
[[35,6],[12,0]],
[[47,6],[0,8]],
[[47,14],[0,8]],
[[35,22],[12,0]],
[[35,14],[0,8]]
]}

11.12 Topology Spatial Relationships

11.12.1 Equals

Equals — Returns true if two topogeometries are composed of the same topology primitives.
PostGIS 2.4.3 Manual 663 / 803

Synopsis

boolean Equals(topogeometry tg1, topogeometry tg2);

Description

Returns true if two topogeometries are composed of the same topology primitives: faces, edges, nodes.

Note
This function not supported for topogeometries that are geometry collections. It also can not compare topogeometries
from different topologies.

Availability: 1.1.0

This function supports 3d and will not drop the z-index.

Examples

See Also

GetTopoGeomElements, ST_Equals

11.12.2 Intersects

Intersects — Returns true if any pair of primitives from the two topogeometries intersect.

Synopsis

boolean Intersects(topogeometry tg1, topogeometry tg2);

Description

Returns true if any pair of primitives from the two topogeometries intersect.

Note
This function not supported for topogeometries that are geometry collections. It also can not compare topogeometries
from different topologies. Also not currently supported for hierarchichal topogeometries (topogeometries composed of
other topogeometries).

Availability: 1.1.0

This function supports 3d and will not drop the z-index.

PostGIS 2.4.3 Manual 664 / 803

Examples

See Also

ST_Intersects
PostGIS 2.4.3 Manual 665 / 803

Chapter 12

Address Standardizer

This is a fork of the PAGC standardizer (original code for this portion was PAGC PostgreSQL Address Standardizer).
The address standardizer is a single line address parser that takes an input address and normalizes it based on a set of rules stored
in a table and helper lex and gaz tables.
The code is built into a single postgresql extension library called address_standardizer which can be installed with
CREATE EXTENSION address_standardizer;. In addition to the address_standardizer extension, a sample data ex-
tension called address_standardizer_data_us extensions is built, which contains gaz, lex, and rules tables for US data.
This extensions can be installed via: CREATE EXTENSION address_standardizer_data_us;
The code for this extension can be found in the PostGIS extensions/address_standardizer and is currently self-
contained.
For installation instructions refer to: Section 2.7.

12.1 How the Parser Works

The parser works from right to left looking first at the macro elements for postcode, state/province, city, and then looks micro
elements to determine if we are dealing with a house number street or intersection or landmark. It currently does not look for a
country code or name, but that could be introduced in the future.

Country code Assumed to be US or CA based on: postcode as US or Canada state/province as US or Canada else US
Postcode/zipcode These are recognized using Perl compatible regular expressions. These regexs are currently in the parseaddress-
api.c and are relatively simple to make changes to if needed.
State/province These are recognized using Perl compatible regular expressions. These regexs are currently in the parseaddress-
api.c but could get moved into includes in the future for easier maintenance.

12.2 Address Standardizer Types

12.2.1 stdaddr

stdaddr — A composite type that consists of the elements of an address. This is the return type for standardize_address
function.
PostGIS 2.4.3 Manual 666 / 803

Description

A composite type that consists of elements of an address. This is the return type for standardize_address function. Some
descriptions for elements are borrowed from PAGC Postal Attributes.
The token numbers denote the output reference number in the rules table.

This method needs address_standardizer extension.

building is text (token number 0): Refers to building number or name. Unparsed building identifiers and types. Generally blank
for most addresses.
house_num is a text (token number 1): This is the street number on a street. Example 75 in 75 State Street.

predir is text (token number 2): STREET NAME PRE-DIRECTIONAL such as North, South, East, West etc.
qual is text (token number 3): STREET NAME PRE-MODIFIER Example OLD in 3715 OLD HIGHWAY 99.
pretype is text (token number 4): STREET PREFIX TYPE

name is text (token number 5): STREET NAME

suftype is text (token number 6): STREET POST TYPE e.g. St, Ave, Cir. A street type following the root street name. Example
STREET in 75 State Street.
sufdir is text (token number 7): STREET POST-DIRECTIONAL A directional modifier that follows the street name.. Example
WEST in 3715 TENTH AVENUE WEST.

ruralroute is text (token number 8): RURAL ROUTE . Example 7 in RR 7.

extra is text: Extra information like Floor number.
city is text (token number 10): Example Boston.

state is text (token number 11): Example MASSACHUSETTS

country is text (token number 12): Example USA
postcode is text POSTAL CODE (ZIP CODE) (token number 13): Example 02109
box is text POSTAL BOX NUMBER (token number 14 and 15): Example 02109

unit is text Apartment number or Suite Number (token number 17): Example 3B in APT 3B.

12.3 Address Standardizer Tables

12.3.1 rules table

rules table — The rules table contains a set of rules that maps address input sequence tokens to standardized output sequence. A
rule is defined as a set of input tokens followed by -1 (terminator) followed by set of output tokens followed by -1 followed by
number denoting kind of rule followed by ranking of rule.
PostGIS 2.4.3 Manual 667 / 803

Description

A rules table must have at least the following columns, though you are allowed to add more for your own uses.

id Primary key of table

rule text field denoting the rule. Details at PAGC Address Standardizer Rule records.
A rule consists of a set of non-negative integers representing input tokens, terminated by a -1, followed by an equal number
of non-negative integers representing postal attributes, terminated by a -1, followed by an integer representing a rule type,
followed by an integer representing the rank of the rule. The rules are ranked from 0 (lowest) to 17 (highest).
So for example the rule 2 0 2 22 3 -1 5 5 6 7 3 -1 2 6 maps to sequence of output tokens TYPE NUMBER
TYPE DIRECT QUALIF to the output sequence STREET STREET SUFTYP SUFDIR QUALIF. The rule is an ARC_C rule
of rank 6.
Numbers for corresponding output tokens are listed in stdaddr.

Input Tokens

Each rule starts with a set of input tokens followed by a terminator -1. Valid input tokens excerpted from PAGC Input Tokens
are as follows:
Form-Based Input Tokens

AMPERS (13). The ampersand (&) is frequently used to abbreviate the word "and".
DASH (9). A punctuation character.

DOUBLE (21). A sequence of two letters. Often used as identifiers.

FRACT (25). Fractions are sometimes used in civic numbers or unit numbers.
MIXED (23). An alphanumeric string that contains both letters and digits. Used for identifiers.
NUMBER (0). A string of digits.

ORD (15). Representations such as First or 1st. Often used in street names.
ORD (18). A single letter.
WORD (1). A word is a string of letters of arbitrary length. A single letter can be both a SINGLE and a WORD.

Function-based Input Tokens

BOXH (14). Words used to denote post office boxes. For example Box or PO Box.
BUILDH (19). Words used to denote buildings or building complexes, usually as a prefix. For example: Tower in Tower 7A.

BUILDT (24). Words and abbreviations used to denote buildings or building complexes, usually as a suffix. For example:
Shopping Centre.
DIRECT (22). Words used to denote directions, for example North.
MILE (20). Words used to denote milepost addresses.

ROAD (6). Words and abbreviations used to denote highways and roads. For example: the Interstate in Interstate 5
RR (8). Words and abbreviations used to denote rural routes. RR.
TYPE (2). Words and abbreviation used to denote street typess. For example: ST or AVE.
UNITH (16). Words and abbreviation used to denote internal subaddresses. For example, APT or UNIT.
PostGIS 2.4.3 Manual 668 / 803

Postal Type Input Tokens

QUINT (28). A 5 digit number. Identifies a Zip Code

QUAD (29). A 4 digit number. Identifies ZIP4.
PCH (27). A 3 character sequence of letter number letter. Identifies an FSA, the first 3 characters of a Canadian postal code.
PCT (26). A 3 character sequence of number letter number. Identifies an LDU, the last 3 characters of a Canadian postal code.

Stopwords
STOPWORDS combine with WORDS. In rules a string of multiple WORDs and STOPWORDs will be represented by a single
WORD token.

STOPWORD (7). A word with low lexical significance, that can be omitted in parsing. For example: THE.

Output Tokens

After the first -1 (terminator), follows the output tokens and their order, followed by a terminator -1. Numbers for corresponding
output tokens are listed in stdaddr. What are allowed is dependent on kind of rule. Output tokens valid for each rule type are
listed in the section called “Rule Types and Rank”.

Rule Types and Rank

The final part of the rule is the rule type which is denoted by one of the following, followed by a rule rank. The rules are ranked
from 0 (lowest) to 17 (highest).
MACRO_C
(token number = "0"). The class of rules for parsing MACRO clauses such as PLACE STATE ZIP
MACRO_C output tokens (excerpted from http://www.pagcgeo.org/docs/html/pagc-12.html#--r-typ--.

CITY (token number "10"). Example "Albany"

STATE (token number "11"). Example "NY"
NATION (token number "12"). This attribute is not used in most reference files. Example "USA"
POSTAL (token number "13"). (SADS elements "ZIP CODE" , "PLUS 4" ). This attribute is used for both the US Zip and the
Canadian Postal Codes.

MICRO_C
(token number = "1"). The class of rules for parsing full MICRO clauses (such as House, street, sufdir, predir, pretyp, suftype,
qualif) (ie ARC_C plus CIVIC_C). These rules are not used in the build phase.
MICRO_C output tokens (excerpted from http://www.pagcgeo.org/docs/html/pagc-12.html#--r-typ--.

HOUSE is a text (token number 1): This is the street number on a street. Example 75 in 75 State Street.
predir is text (token number 2): STREET NAME PRE-DIRECTIONAL such as North, South, East, West etc.
qual is text (token number 3): STREET NAME PRE-MODIFIER Example OLD in 3715 OLD HIGHWAY 99.
pretype is text (token number 4): STREET PREFIX TYPE
street is text (token number 5): STREET NAME
suftype is text (token number 6): STREET POST TYPE e.g. St, Ave, Cir. A street type following the root street name. Example
STREET in 75 State Street.
PostGIS 2.4.3 Manual 669 / 803

sufdir is text (token number 7): STREET POST-DIRECTIONAL A directional modifier that follows the street name.. Example
WEST in 3715 TENTH AVENUE WEST.

ARC_C
(token number = "2"). The class of rules for parsing MICRO clauses, excluding the HOUSE attribute. As such uses same set of
output tokens as MICRO_C minus the HOUSE token.
CIVIC_C
(token number = "3"). The class of rules for parsing the HOUSE attribute.
EXTRA_C
(token number = "4"). The class of rules for parsing EXTRA attributes - attributes excluded from geocoding. These rules are not
used in the build phase.
EXTRA_C output tokens (excerpted from http://www.pagcgeo.org/docs/html/pagc-12.html#--r-typ--.

BLDNG (token number 0): Unparsed building identifiers and types.

BOXH (token number 14): The BOX in BOX 3B
BOXT (token number 15): The 3B in BOX 3B

RR (token number 8): The RR in RR 7

UNITH (token number 16): The APT in APT 3B
UNITT (token number 17): The 3B in APT 3B
UNKNWN (token number 9): An otherwise unclassified output.

12.3.2 lex table

lex table — A lex table is used to classify alphanumeric input and associate that input with (a) input tokens ( See the section
called “Input Tokens”) and (b) standardized representations.

Description

A lex (short for lexicon) table is used to classify alphanumeric input and associate that input with the section called “Input
Tokens” and (b) standardized representations. Things you will find in these tables are ONE mapped to stdword: 1.
A lex has at least the following columns in the table. You may add

id Primary key of table

seq integer: definition number?
word text: the input word

stdword text: the standardized replacement word

token integer: the kind of word it is. Only if it is used in this context will it be replaced. Refer to PAGC Tokens.

12.3.3 gaz table

gaz table — A gaz table is used to standardize place names and associate that input with (a) input tokens ( See the section called
“Input Tokens”) and (b) standardized representations.
PostGIS 2.4.3 Manual 670 / 803

Description

A gaz (short for gazeteer) table is used to standardize place names and associate that input with the section called “Input Tokens”
and (b) standardized representations. For example if you are in US, you may load these with State Names and associated
abbreviations.
A gaz table has at least the following columns in the table. You may add more columns if you wish for your own purposes.

id Primary key of table

seq integer: definition number? - identifer used for that instance of the word
word text: the input word
stdword text: the standardized replacement word
token integer: the kind of word it is. Only if it is used in this context will it be replaced. Refer to PAGC Tokens.

12.4 Address Standardizer Functions

12.4.1 parse_address

parse_address — Takes a 1 line address and breaks into parts

Synopsis

record parse_address(text address);

Description

Returns takes an address as input, and returns a record output consisting of fields num, street, street2, address1, city, state, zip,
zipplus, country.
Availability: 2.2.0

This method needs address_standardizer extension.

Examples

Single Addresss
SELECT num, street, city, zip, zipplus
FROM parse_address('1 Devonshire Place, Boston, MA 02109-1234') AS a;

num | street | city | zip | zipplus

-----+------------------+--------+-------+---------
1 | Devonshire Place | Boston | 02109 | 1234

Table of addresses
-- basic table
CREATE TABLE places(addid serial PRIMARY KEY, address text);

INSERT INTO places(address)

VALUES ('529 Main Street, Boston MA, 02129'),
('77 Massachusetts Avenue, Cambridge, MA 02139'),
PostGIS 2.4.3 Manual 671 / 803

('25 Wizard of Oz, Walaford, KS 99912323'),

('26 Capen Street, Medford, MA'),
('124 Mount Auburn St, Cambridge, Massachusetts 02138'),
('950 Main Street, Worcester, MA 01610');

-- parse the addresses

-- if you want all fields you can use (a).*
SELECT addid, (a).num, (a).street, (a).city, (a).state, (a).zip, (a).zipplus
FROM (SELECT addid, parse_address(address) As a
FROM places) AS p;

addid | num | street | city | state | zip | zipplus

-------+-----+----------------------+-----------+-------+-------+---------
1 | 529 | Main Street | Boston | MA | 02129 |
2 | 77 | Massachusetts Avenue | Cambridge | MA | 02139 |
3 | 25 | Wizard of Oz | Walaford | KS | 99912 | 323
4 | 26 | Capen Street | Medford | MA | |
5 | 124 | Mount Auburn St | Cambridge | MA | 02138 |
6 | 950 | Main Street | Worcester | MA | 01610 |
(6 rows)

See Also

12.4.2 standardize_address

standardize_address — Returns an stdaddr form of an input address utilizing lex, gaz, and rule tables.

Synopsis

stdaddr standardize_address(text lextab, text gaztab, text rultab, text address);

stdaddr standardize_address(text lextab, text gaztab, text rultab, text micro, text macro);

Description

Returns an stdaddr form of an input address utilizing lex table table name, gaz table, and rules table table names and an address.
Variant 1: Takes an address as a single line.
Variant 2: Takes an address as 2 parts. A micro consisting of standard first line of postal address e.g. house_num street,
and a macro consisting of standard postal second line of an address e.g city, state postal_code country.
Availability: 2.2.0

This method needs address_standardizer extension.

Examples

Using address_standardizer_data_us extension

CREATE EXTENSION address_standardizer_data_us; -- only needs to be done once

Variant 1: Single line address. This doesn’t work well with non-US addresses
SELECT house_num, name, suftype, city, country, state, unit FROM standardize_address(' ←-
us_lex',
'us_gaz', 'us_rules', 'One Devonshire Place, PH 301, Boston, MA 02109');
PostGIS 2.4.3 Manual 672 / 803

house_num | name | suftype | city | country | state | unit

----------+------------+---------+--------+---------+---------------+-----------------
1 | DEVONSHIRE | PLACE | BOSTON | USA | MASSACHUSETTS | # PENTHOUSE 301

Using tables packaged with tiger geocoder. This example only works if you installed postgis_tiger_geocoder.
SELECT * FROM standardize_address('tiger.pagc_lex',
'tiger.pagc_gaz', 'tiger.pagc_rules', 'One Devonshire Place, PH 301, Boston, MA ←-
02109-1234');

Make easier to read we’ll dump output using hstore extension CREATE EXTENSION hstore; you need to install
SELECT (each(hstore(p))).*
FROM standardize_address('tiger.pagc_lex', 'tiger.pagc_gaz',
'tiger.pagc_rules', 'One Devonshire Place, PH 301, Boston, MA 02109') As p;

key | value
------------+-----------------
box |
city | BOSTON
name | DEVONSHIRE
qual |
unit | # PENTHOUSE 301
extra |
state | MA
predir |
sufdir |
country | USA
pretype |
suftype | PL
building |
postcode | 02109
house_num | 1
ruralroute |
(16 rows)

Variant 2: As a two part Address

SELECT (each(hstore(p))).*
FROM standardize_address('tiger.pagc_lex', 'tiger.pagc_gaz',
'tiger.pagc_rules', 'One Devonshire Place, PH 301', 'Boston, MA 02109, US') As p;

key | value
------------+-----------------
box |
city | BOSTON
name | DEVONSHIRE
qual |
unit | # PENTHOUSE 301
extra |
state | MA
predir |
sufdir |
country | USA
pretype |
suftype | PL
building |
postcode | 02109
house_num | 1
ruralroute |
(16 rows)
PostGIS 2.4.3 Manual 673 / 803

See Also

stdaddr, rules table, lex table, gaz table, Pagc_Normalize_Address

PostGIS 2.4.3 Manual 674 / 803

Chapter 13

PostGIS Extras

This chapter documents features found in the extras folder of the PostGIS source tarballs and source repository. These are not
always packaged with PostGIS binary releases, but are usually plpgsql based or standard shell scripts that can be run as is.

13.1 Tiger Geocoder

There are a couple other open source geocoders for PostGIS, that unlike tiger geocoder have the advantage of multi-country
geocoding support

• Nominatim uses OpenStreetMap gazeteer formatted data. It requires osm2pgsql for loading the data, PostgreSQL 8.4+ and
PostGIS 1.5+ to function. It is packaged as a webservice interface and seems designed to be called as a webservice. Just like
the tiger geocoder, it has both a geocoder and a reverse geocoder component. From the documentation, it is unclear if it has a
pure SQL interface like the tiger geocoder, or if a good deal of the logic is implemented in the web interface.
• GIS Graphy also utilizes PostGIS and like Nominatim works with OpenStreetMap (OSM) data. It comes with a loader to load
OSM data and similar to Nominatim is capable of geocoding not just US. Much like Nominatim, it runs as a webservice and
relies on Java 1.5, Servlet apps, Solr. GisGraphy is cross-platform and also has a reverse geocoder among some other neat
features.

13.1.1 Drop_Indexes_Generate_Script

Drop_Indexes_Generate_Script — Generates a script that drops all non-primary key and non-unique indexes on tiger schema
and user specified schema. Defaults schema to tiger_data if no schema is specified.

Synopsis

text Drop_Indexes_Generate_Script(text param_schema=tiger_data);

Description

Generates a script that drops all non-primary key and non-unique indexes on tiger schema and user specified schema. Defaults
schema to tiger_data if no schema is specified.
This is useful for minimizing index bloat that may confuse the query planner or take up unnecessary space. Use in combination
with Install_Missing_Indexes to add just the indexes used by the geocoder.
Availability: 2.0.0
PostGIS 2.4.3 Manual 675 / 803

Examples

SELECT drop_indexes_generate_script() As actionsql;

actionsql
---------------------------------------------------------
DROP INDEX tiger.idx_tiger_countysub_lookup_lower_name;
DROP INDEX tiger.idx_tiger_edges_countyfp;
DROP INDEX tiger.idx_tiger_faces_countyfp;
DROP INDEX tiger.tiger_place_the_geom_gist;
DROP INDEX tiger.tiger_edges_the_geom_gist;
DROP INDEX tiger.tiger_state_the_geom_gist;
DROP INDEX tiger.idx_tiger_addr_least_address;
DROP INDEX tiger.idx_tiger_addr_tlid;
DROP INDEX tiger.idx_tiger_addr_zip;
DROP INDEX tiger.idx_tiger_county_countyfp;
DROP INDEX tiger.idx_tiger_county_lookup_lower_name;
DROP INDEX tiger.idx_tiger_county_lookup_snd_name;
DROP INDEX tiger.idx_tiger_county_lower_name;
DROP INDEX tiger.idx_tiger_county_snd_name;
DROP INDEX tiger.idx_tiger_county_the_geom_gist;
DROP INDEX tiger.idx_tiger_countysub_lookup_snd_name;
DROP INDEX tiger.idx_tiger_cousub_countyfp;
DROP INDEX tiger.idx_tiger_cousub_cousubfp;
DROP INDEX tiger.idx_tiger_cousub_lower_name;
DROP INDEX tiger.idx_tiger_cousub_snd_name;
DROP INDEX tiger.idx_tiger_cousub_the_geom_gist;
DROP INDEX tiger_data.idx_tiger_data_ma_addr_least_address;
DROP INDEX tiger_data.idx_tiger_data_ma_addr_tlid;
DROP INDEX tiger_data.idx_tiger_data_ma_addr_zip;
DROP INDEX tiger_data.idx_tiger_data_ma_county_countyfp;
DROP INDEX tiger_data.idx_tiger_data_ma_county_lookup_lower_name;
DROP INDEX tiger_data.idx_tiger_data_ma_county_lookup_snd_name;
DROP INDEX tiger_data.idx_tiger_data_ma_county_lower_name;
DROP INDEX tiger_data.idx_tiger_data_ma_county_snd_name;
:
:

See Also

Install_Missing_Indexes, Missing_Indexes_Generate_Script

13.1.2 Drop_Nation_Tables_Generate_Script

Drop_Nation_Tables_Generate_Script — Generates a script that drops all tables in the specified schema that start with county_all,
state_all or state code followed by county or state.

Synopsis

text Drop_Nation_Tables_Generate_Script(text param_schema=tiger_data);

Description

Generates a script that drops all tables in the specified schema that start with county_all, state_all or stae code followed
by county or state. This is needed if you are upgrading from tiger_2010 to tiger_2011 data.
Availability: 2.1.0
PostGIS 2.4.3 Manual 676 / 803

Examples

SELECT drop_nation_tables_generate_script();
DROP TABLE tiger_data.county_all;
DROP TABLE tiger_data.county_all_lookup;
DROP TABLE tiger_data.state_all;
DROP TABLE tiger_data.ma_county;
DROP TABLE tiger_data.ma_state;

See Also

Loader_Generate_Nation_Script

13.1.3 Drop_State_Tables_Generate_Script

Drop_State_Tables_Generate_Script — Generates a script that drops all tables in the specified schema that are prefixed with the
state abbreviation. Defaults schema to tiger_data if no schema is specified.

Synopsis

text Drop_State_Tables_Generate_Script(text param_state, text param_schema=tiger_data);

Description

Generates a script that drops all tables in the specified schema that are prefixed with the state abbreviation. Defaults schema to
tiger_data if no schema is specified. This function is useful for dropping tables of a state just before you reload a state in
case something went wrong during your previous load.
Availability: 2.0.0

Examples

SELECT drop_state_tables_generate_script('PA');
DROP TABLE tiger_data.pa_addr;
DROP TABLE tiger_data.pa_county;
DROP TABLE tiger_data.pa_county_lookup;
DROP TABLE tiger_data.pa_cousub;
DROP TABLE tiger_data.pa_edges;
DROP TABLE tiger_data.pa_faces;
DROP TABLE tiger_data.pa_featnames;
DROP TABLE tiger_data.pa_place;
DROP TABLE tiger_data.pa_state;
DROP TABLE tiger_data.pa_zip_lookup_base;
DROP TABLE tiger_data.pa_zip_state;
DROP TABLE tiger_data.pa_zip_state_loc;

See Also

Loader_Generate_Script
PostGIS 2.4.3 Manual 677 / 803

13.1.4 Geocode

Geocode — Takes in an address as a string (or other normalized address) and outputs a set of possible locations which include a
point geometry in NAD 83 long lat, a normalized address for each, and the rating. The lower the rating the more likely the match.
Results are sorted by lowest rating first. Can optionally pass in maximum results, defaults to 10, and restrict_region (defaults to
NULL)

Synopsis

setof record geocode(varchar address, integer max_results=10, geometry restrict_region=NULL, norm_addy OUT addy, geom-
etry OUT geomout, integer OUT rating);
setof record geocode(norm_addy in_addy, integer max_results=10, geometry restrict_region=NULL, norm_addy OUT addy,
geometry OUT geomout, integer OUT rating);

Description

Takes in an address as a string (or already normalized address) and outputs a set of possible locations which include a point
geometry in NAD 83 long lat, a normalized_address (addy) for each, and the rating. The lower the rating the more
likely the match. Results are sorted by lowest rating first. Uses Tiger data (edges,faces,addr), PostgreSQL fuzzy string matching
(soundex,levenshtein) and PostGIS line interpolation functions to interpolate address along the Tiger edges. The higher the rating
the less likely the geocode is right. The geocoded point is defaulted to offset 10 meters from center-line off to side (L/R) of street
address is located on.
Enhanced: 2.0.0 to support Tiger 2010 structured data and revised some logic to improve speed, accuracy of geocoding, and
to offset point from centerline to side of street address is located on. The new parameter max_results useful for specifying
number of best results or just returning the best result.

Examples: Basic

The below examples timings are on a 3.0 GHZ single processor Windows 7 machine with 2GB ram running PostgreSQL
9.1rc1/PostGIS 2.0 loaded with all of MA,MN,CA, RI state Tiger data loaded.
Exact matches are faster to compute (61ms)
SELECT g.rating, ST_X(g.geomout) As lon, ST_Y(g.geomout) As lat,
(addy).address As stno, (addy).streetname As street,
(addy).streettypeabbrev As styp, (addy).location As city, (addy).stateabbrev As st,( ←-
addy).zip
FROM geocode('75 State Street, Boston MA 02109', 1) As g;
rating | lon | lat | stno | street | styp | city | st | zip
--------+-------------------+----------------+------+--------+------+--------+----+-------
0 | -71.0557505845646 | 42.35897920691 | 75 | State | St | Boston | MA | 02109

Even if zip is not passed in the geocoder can guess (took about 122-150 ms)
SELECT g.rating, ST_AsText(ST_SnapToGrid(g.geomout,0.00001)) As wktlonlat,
(addy).address As stno, (addy).streetname As street,
(addy).streettypeabbrev As styp, (addy).location As city, (addy).stateabbrev As st,( ←-
addy).zip
FROM geocode('226 Hanover Street, Boston, MA',1) As g;
rating | wktlonlat | stno | street | styp | city | st | zip
--------+---------------------------+------+---------+------+--------+----+-------
1 | POINT(-71.05528 42.36316) | 226 | Hanover | St | Boston | MA | 02113

Can handle misspellings and provides more than one possible solution with ratings and takes longer (500ms).
PostGIS 2.4.3 Manual 678 / 803

SELECT g.rating, ST_AsText(ST_SnapToGrid(g.geomout,0.00001)) As wktlonlat,

(addy).address As stno, (addy).streetname As street,
(addy).streettypeabbrev As styp, (addy).location As city, (addy).stateabbrev As st,( ←-
addy).zip
FROM geocode('31 - 37 Stewart Street, Boston, MA 02116',1) As g;
rating | wktlonlat | stno | street | styp | city | st | zip
--------+---------------------------+------+--------+------+--------+----+-------
70 | POINT(-71.06466 42.35114) | 31 | Stuart | St | Boston | MA | 02116

Using to do a batch geocode of addresses. Easiest is to set max_results=1. Only process those not yet geocoded (have no
rating).
CREATE TABLE addresses_to_geocode(addid serial PRIMARY KEY, address text,
lon numeric, lat numeric, new_address text, rating integer);

INSERT INTO addresses_to_geocode(address)

VALUES ('529 Main Street, Boston MA, 02129'),
('77 Massachusetts Avenue, Cambridge, MA 02139'),
('25 Wizard of Oz, Walaford, KS 99912323'),
('26 Capen Street, Medford, MA'),
('124 Mount Auburn St, Cambridge, Massachusetts 02138'),
('950 Main Street, Worcester, MA 01610');

-- only update the first 3 addresses (323-704 ms - there are caching and shared memory ←-
effects so first geocode you do is always slower) --
-- for large numbers of addresses you don't want to update all at once
-- since the whole geocode must commit at once
-- For this example we rejoin with LEFT JOIN
-- and set to rating to -1 rating if no match
-- to ensure we don't regeocode a bad address
UPDATE addresses_to_geocode
SET (rating, new_address, lon, lat)
= ( COALESCE(g.rating,-1), pprint_addy(g.addy),
ST_X(g.geomout)::numeric(8,5), ST_Y(g.geomout)::numeric(8,5) )
FROM (SELECT addid, address
FROM addresses_to_geocode
WHERE rating IS NULL ORDER BY addid LIMIT 3) As a
LEFT JOIN LATERAL geocode(a.address,1) As g ON true
WHERE a.addid = addresses_to_geocode.addid;

result
-----
Query returned successfully: 3 rows affected, 480 ms execution time.

SELECT * FROM addresses_to_geocode WHERE rating is not null;

addid | address | lon | lat | ←-

new_address | rating
-------+----------------------------------------------+-----------+----------+-----------------------

1 | 529 Main Street, Boston MA, 02129 | -71.07177 | 42.38357 | 529 Main St, ←-
Boston, MA 02129 | 0
2 | 77 Massachusetts Avenue, Cambridge, MA 02139 | -71.09396 | 42.35961 | 77 ←-
Massachusetts Ave, Cambridge, MA 02139 | 0
3 | 25 Wizard of Oz, Walaford, KS 99912323 | -97.92913 | 38.12717 | Willowbrook, ←-
KS 67502 | 108
(3 rows)

Examples: Using Geometry filter

PostGIS 2.4.3 Manual 679 / 803

SELECT g.rating, ST_AsText(ST_SnapToGrid(g.geomout,0.00001)) As wktlonlat,

(addy).address As stno, (addy).streetname As street,
(addy).streettypeabbrev As styp,
(addy).location As city, (addy).stateabbrev As st,(addy).zip
FROM geocode('100 Federal Street, MA',
3,
(SELECT ST_Union(the_geom)
FROM place WHERE statefp = '25' AND name = 'Lynn')::geometry
) As g;

rating | wktlonlat | stno | street | styp | city | st | zip

--------+---------------------------+------+---------+------+------+----+-------
7 | POINT(-70.96796 42.4659) | 100 | Federal | St | Lynn | MA | 01905
16 | POINT(-70.96786 42.46853) | NULL | Federal | St | Lynn | MA | 01905
(2 rows)

Time: 622.939 ms

See Also

Normalize_Address, Pprint_Addy, ST_AsText, ST_SnapToGrid, ST_X, ST_Y

13.1.5 Geocode_Intersection

Geocode_Intersection — Takes in 2 streets that intersect and a state, city, zip, and outputs a set of possible locations on the first
cross street that is at the intersection, also includes a geomout as the point location in NAD 83 long lat, a normalized_address
(addy) for each location, and the rating. The lower the rating the more likely the match. Results are sorted by lowest rating first.
Can optionally pass in maximum results, defaults to 10. Uses Tiger data (edges, faces, addr), PostgreSQL fuzzy string matching
(soundex, levenshtein).

Synopsis

setof record geocode_intersection(text roadway1, text roadway2, text in_state, text in_city, text in_zip, integer max_results=10,
norm_addy OUT addy, geometry OUT geomout, integer OUT rating);

Description

Takes in 2 streets that intersect and a state, city, zip, and outputs a set of possible locations on the first cross street that is at the
intersection, also includes a point geometry in NAD 83 long lat, a normalized address for each location, and the rating. The lower
the rating the more likely the match. Results are sorted by lowest rating first. Can optionally pass in maximum results, defaults
to 10. Returns normalized_address (addy) for each, geomout as the point location in nad 83 long lat, and the rating.
The lower the rating the more likely the match. Results are sorted by lowest rating first. Uses Tiger data (edges,faces,addr),
PostgreSQL fuzzy string matching (soundex,levenshtein)
Availability: 2.0.0

Examples: Basic

The below examples timings are on a 3.0 GHZ single processor Windows 7 machine with 2GB ram running PostgreSQL 9.0/Post-
GIS 1.5 loaded with all of MA state Tiger data loaded. Currently a bit slow (3000 ms)
Testing on Windows 2003 64-bit 8GB on PostGIS 2.0 PostgreSQL 64-bit Tiger 2011 data loaded -- (41ms)
PostGIS 2.4.3 Manual 680 / 803

SELECT pprint_addy(addy), st_astext(geomout),rating

FROM geocode_intersection( 'Haverford St','Germania St', 'MA', 'Boston', ←-
'02130',1);
pprint_addy | st_astext | rating
----------------------------------+----------------------------+--------
98 Haverford St, Boston, MA 02130 | POINT(-71.101375 42.31376) | 0

Even if zip is not passed in the geocoder can guess (took about 3500 ms on the windows 7 box), on the windows 2003 64-bit 741
ms
SELECT pprint_addy(addy), st_astext(geomout),rating
FROM geocode_intersection('Weld', 'School', 'MA', 'Boston');
pprint_addy | st_astext | rating
-------------------------------+--------------------------+--------
98 Weld Ave, Boston, MA 02119 | POINT(-71.099 42.314234) | 3
99 Weld Ave, Boston, MA 02119 | POINT(-71.099 42.314234) | 3

See Also

Geocode, Pprint_Addy, ST_AsText

13.1.6 Get_Geocode_Setting

Get_Geocode_Setting — Returns value of specific setting stored in tiger.geocode_settings table.

Synopsis

text Get_Geocode_Setting(text setting_name);

Description

Returns value of specific setting stored in tiger.geocode_settings table. Settings allow you to toggle debugging of functions. Later
plans will be to control rating with settings. Current list of settings are as follows:
name | setting | unit | category | ←-
short_desc
--------------------------------+---------+---------+-----------+------------------------------------

debug_geocode_address | false | boolean | debug | outputs debug information ←-

in notice log such as queries when geocode_address is called if true
debug_geocode_intersection | false | boolean | debug | outputs debug information ←-
in notice log such as queries when geocode_intersection is called if true
debug_normalize_address | false | boolean | debug | outputs debug information ←-
in notice log such as queries and intermediate expressions when normalize_address is ←-
called if true
debug_reverse_geocode | false | boolean | debug | if true, outputs debug ←-
information in notice log such as queries and intermediate expressions when ←-
reverse_geocode
reverse_geocode_numbered_roads | 0 | integer | rating | For state and county ←-
highways, 0 - no preference in name,
1 - prefer the numbered ←-
highway name, 2 - ←-
prefer local state/ ←-
county name
use_pagc_address_parser | false | boolean | normalize | If set to true, will try ←-
to use the address_standardizer extension (via pagc_normalize_address)
PostGIS 2.4.3 Manual 681 / 803

instead of tiger ←-
normalize_address built ←-
one

Changed: 2.2.0 : default settings are now kept in a table called geocode_settings_default. Use customized settingsa are in
geocode_settings and only contain those that have been set by user.
Availability: 2.1.0

Example return debugging setting

SELECT get_geocode_setting('debug_geocode_address) As result;

result
---------
false

See Also

Set_Geocode_Setting

13.1.7 Get_Tract

Get_Tract — Returns census tract or field from tract table of where the geometry is located. Default to returning short name of
tract.

Synopsis

text get_tract(geometry loc_geom, text output_field=name);

Description

Given a geometry will return the census tract location of that geometry. NAD 83 long lat is assumed if no spatial ref sys is
specified.

Note
This function uses the census tract whic is not loaded by default. If you have already loaded your state table, you
can load tract as well as bg, and tabblock using the Loader_Generate_Census_Script script.
If you have not loaded your state data yet and want these additional tables loaded, do the following
UPDATE tiger.loader_lookuptables SET load = true WHERE load = false AND lookup_name ←-
IN('tract', 'bg', 'tabblock');

then they will be included by the Loader_Generate_Script.

Availability: 2.0.0

Examples: Basic

SELECT get_tract(ST_Point(-71.101375, 42.31376) ) As tract_name;

tract_name
---------
1203.01
PostGIS 2.4.3 Manual 682 / 803

--this one returns the tiger geoid

SELECT get_tract(ST_Point(-71.101375, 42.31376), 'tract_id' ) As tract_id;
tract_id
---------
25025120301

See Also

Geocode>

13.1.8 Install_Missing_Indexes

Install_Missing_Indexes — Finds all tables with key columns used in geocoder joins and filter conditions that are missing used
indexes on those columns and will add them.

Synopsis

boolean Install_Missing_Indexes();

Description

Finds all tables in tiger and tiger_data schemas with key columns used in geocoder joins and filters that are missing
indexes on those columns and will output the SQL DDL to define the index for those tables and then execute the generated
script. This is a helper function that adds new indexes needed to make queries faster that may have been missing during the load
process. This function is a companion to Missing_Indexes_Generate_Script that in addition to generating the create index script,
also executes it. It is called as part of the update_geocode.sql upgrade script.
Availability: 2.0.0

Examples

SELECT install_missing_indexes();
install_missing_indexes
-------------------------
t

See Also

Loader_Generate_Script, Missing_Indexes_Generate_Script

13.1.9 Loader_Generate_Census_Script

Loader_Generate_Census_Script — Generates a shell script for the specified platform for the specified states that will download
Tiger census state tract, bg, and tabblocks data tables, stage and load into tiger_data schema. Each state script is returned as
a separate record.

Synopsis

setof text loader_generate_census_script(text[] param_states, text os);

PostGIS 2.4.3 Manual 683 / 803

Description

Generates a shell script for the specified platform for the specified states that will download Tiger data census state tract, block
groups bg, and tabblocks data tables, stage and load into tiger_data schema. Each state script is returned as a separate
record.
It uses unzip on Linux (7-zip on Windows by default) and wget to do the downloading. It uses Section 4.4.2 to load in the data.
Note the smallest unit it does is a whole state. It will only process the files in the staging and temp folders.
It uses the following control tables to control the process and different OS shell syntax variations.

1. loader_variables keeps track of various variables such as census site, year, data and staging schemas
2. loader_platform profiles of various platforms and where the various executables are located. Comes with windows
and linux. More can be added.
3. loader_lookuptables each record defines a kind of table (state, county), whether to process records in it and how
to load them in. Defines the steps to import data, stage data, add, removes columns, indexes, and constraints for each.
Each table is prefixed with the state and inherits from a table in the tiger schema. e.g. creates tiger_data.ma_faces
which inherits from tiger.faces

Availability: 2.0.0

Note
Loader_Generate_Script includes this logic, but if you installed tiger geocoder prior to PostGIS 2.0.0 alpha5, you’ll need
to run this on the states you have already done to get these additional tables.

Examples

Generate script to load up data for select states in Windows shell script format.
SELECT loader_generate_census_script(ARRAY['MA'], 'windows');
-- result --
set STATEDIR="\gisdata\www2.census.gov\geo\pvs\tiger2010st\25_Massachusetts"
set TMPDIR=\gisdata\temp\
set UNZIPTOOL="C:\Program Files\7-Zip\7z.exe"
set WGETTOOL="C:\wget\wget.exe"
set PGBIN=C:\projects\pg\pg91win\bin\
set PGPORT=5432
set PGHOST=localhost
set PGUSER=postgres
set PGPASSWORD=yourpasswordhere
set PGDATABASE=tiger_postgis20
set PSQL="%PGBIN%psql"
set SHP2PGSQL="%PGBIN%shp2pgsql"
cd \gisdata

%WGETTOOL% http://www2.census.gov/geo/pvs/tiger2010st/25_Massachusetts/25/ --no-parent -- ←-

relative --accept=*bg10.zip,*tract10.zip,*tabblock10.zip --mirror --reject=html
del %TMPDIR%\*.* /Q
%PSQL% -c "DROP SCHEMA tiger_staging CASCADE;"
%PSQL% -c "CREATE SCHEMA tiger_staging;"
cd %STATEDIR%
for /r %%z in (*.zip) do %UNZIPTOOL% e %%z -o%TMPDIR%
cd %TMPDIR%
%PSQL% -c "CREATE TABLE tiger_data.MA_tract(CONSTRAINT pk_MA_tract PRIMARY KEY (tract_id) ) ←-
INHERITS(tiger.tract); "
%SHP2PGSQL% -c -s 4269 -g the_geom -W "latin1" tl_2010_25_tract10.dbf tiger_staging. ←-
ma_tract10 | %PSQL%
PostGIS 2.4.3 Manual 684 / 803

%PSQL% -c "ALTER TABLE tiger_staging.MA_tract10 RENAME geoid10 TO tract_id; SELECT ←-

loader_load_staged_data(lower('MA_tract10'), lower('MA_tract')); "
%PSQL% -c "CREATE INDEX tiger_data_MA_tract_the_geom_gist ON tiger_data.MA_tract USING gist ←-
(the_geom);"
%PSQL% -c "VACUUM ANALYZE tiger_data.MA_tract;"
%PSQL% -c "ALTER TABLE tiger_data.MA_tract ADD CONSTRAINT chk_statefp CHECK (statefp = ←-
'25');"
:

Generate sh script
STATEDIR="/gisdata/www2.census.gov/geo/pvs/tiger2010st/25_Massachusetts"
TMPDIR="/gisdata/temp/"
UNZIPTOOL=unzip
WGETTOOL="/usr/bin/wget"
export PGBIN=/usr/pgsql-9.0/bin
export PGPORT=5432
export PGHOST=localhost
export PGUSER=postgres
export PGPASSWORD=yourpasswordhere
export PGDATABASE=geocoder
PSQL=${PGBIN}/psql
SHP2PGSQL=${PGBIN}/shp2pgsql
cd /gisdata

wget http://www2.census.gov/geo/pvs/tiger2010st/25_Massachusetts/25/ --no-parent --relative ←-

--accept=*bg10.zip,*tract10.zip,*tabblock10.zip --mirror --reject=html
rm -f ${TMPDIR}/*.*
${PSQL} -c "DROP SCHEMA tiger_staging CASCADE;"
${PSQL} -c "CREATE SCHEMA tiger_staging;"
cd $STATEDIR
for z in *.zip; do $UNZIPTOOL -o -d $TMPDIR $z; done
:
:

See Also

Loader_Generate_Script

13.1.10 Loader_Generate_Script

Loader_Generate_Script — Generates a shell script for the specified platform for the specified states that will download Tiger
data, stage and load into tiger_data schema. Each state script is returned as a separate record. Latest version supports Tiger
2010 structural changes and also loads census tract, block groups, and blocks tables.

Synopsis

setof text loader_generate_script(text[] param_states, text os);

Description

Generates a shell script for the specified platform for the specified states that will download Tiger data, stage and load into
tiger_data schema. Each state script is returned as a separate record.
It uses unzip on Linux (7-zip on Windows by default) and wget to do the downloading. It uses Section 4.4.2 to load in the data.
Note the smallest unit it does is a whole state, but you can overwrite this by downloading the files yourself. It will only process
the files in the staging and temp folders.
It uses the following control tables to control the process and different OS shell syntax variations.
PostGIS 2.4.3 Manual 685 / 803

1. loader_variables keeps track of various variables such as census site, year, data and staging schemas
2. loader_platform profiles of various platforms and where the various executables are located. Comes with windows
and linux. More can be added.

3. loader_lookuptables each record defines a kind of table (state, county), whether to process records in it and how
to load them in. Defines the steps to import data, stage data, add, removes columns, indexes, and constraints for each.
Each table is prefixed with the state and inherits from a table in the tiger schema. e.g. creates tiger_data.ma_faces
which inherits from tiger.faces

Availability: 2.0.0 to support Tiger 2010 structured data and load census tract (tract), block groups (bg), and blocks (tabblocks)
tables .

Note
If you are using pgAdmin 3, be warned that by default pgAdmin 3 truncates long text. To fix, change File -> Options ->
Query Tool -> Query Editor - > Max. characters per column to larger than 50000 characters.

Examples

Using psql where gistest is your database and /gisdata/data_load.sh is the file to create with the shell commands to run.
psql -U postgres -h localhost -d gistest -A -t \
-c "SELECT Loader_Generate_Script(ARRAY['MA'], 'gistest')" > /gisdata/data_load.sh;

Generate script to load up data for 2 states in Windows shell script format.
SELECT loader_generate_script(ARRAY['MA','RI'], 'windows') AS result;
-- result --
set TMPDIR=\gisdata\temp\
set UNZIPTOOL="C:\Program Files\7-Zip\7z.exe"
set WGETTOOL="C:\wget\wget.exe"
set PGBIN=C:\Program Files\PostgreSQL\9.4\bin\
set PGPORT=5432
set PGHOST=localhost
set PGUSER=postgres
set PGPASSWORD=yourpasswordhere
set PGDATABASE=geocoder
set PSQL="%PGBIN%psql"
set SHP2PGSQL="%PGBIN%shp2pgsql"
cd \gisdata

cd \gisdata
%WGETTOOL% ftp://ftp2.census.gov/geo/tiger/TIGER2015/PLACE/tl_*_25_* --no-parent --relative ←-
--recursive --level=2 --accept=zip --mirror --reject=html
cd \gisdata/ftp2.census.gov/geo/tiger/TIGER2015/PLACE
:
:

Generate sh script
SELECT loader_generate_script(ARRAY['MA','RI'], 'sh') AS result;
-- result --
TMPDIR="/gisdata/temp/"
UNZIPTOOL=unzip
WGETTOOL="/usr/bin/wget"
export PGBIN=/usr/lib/postgresql/9.4/bin
export PGPORT=5432
export PGHOST=localhost
PostGIS 2.4.3 Manual 686 / 803

export PGUSER=postgres
export PGPASSWORD=yourpasswordhere
export PGDATABASE=geocoder
PSQL=${PGBIN}/psql
SHP2PGSQL=${PGBIN}/shp2pgsql
cd /gisdata

cd /gisdata
wget ftp://ftp2.census.gov/geo/tiger/TIGER2015/PLACE/tl_*_25_* --no-parent --relative -- ←-
recursive --level=2 --accept=zip --mirror --reject=html
cd /gisdata/ftp2.census.gov/geo/tiger/TIGER2015/PLACE
rm -f ${TMPDIR}/*.*
:
:

See Also

Section 2.8.1, Loader_Generate_Nation_Script

13.1.11 Loader_Generate_Nation_Script

Loader_Generate_Nation_Script — Generates a shell script for the specified platform that loads in the county and state lookup
tables.

Synopsis

text loader_generate_nation_script(text os);

Description

Generates a shell script for the specified platform that loads in the county_all, county_all_lookup, state_all tables
into tiger_data schema. These inherit respectively from the county, county_lookup, state tables in tiger schema.
It uses unzip on Linux (7-zip on Windows by default) and wget to do the downloading. It uses Section 4.4.2 to load in the data.
It uses the following control tables tiger.loader_platform, tiger.loader_variables, and tiger.loader_lookupt
to control the process and different OS shell syntax variations.

1. loader_variables keeps track of various variables such as census site, year, data and staging schemas
2. loader_platform profiles of various platforms and where the various executables are located. Comes with windows
and linux/unix. More can be added.
3. loader_lookuptables each record defines a kind of table (state, county), whether to process records in it and how
to load them in. Defines the steps to import data, stage data, add, removes columns, indexes, and constraints for each.
Each table is prefixed with the state and inherits from a table in the tiger schema. e.g. creates tiger_data.ma_faces
which inherits from tiger.faces

Enhanced: 2.4.1 zip code 5 tabulation area (zcta5) load step was fixed and when enabled, zcta5 data is loaded as a single table
called zcta5_all as part of the nation script load.
Availability: 2.1.0

Note
If you want zip code 5 tabulation area (zcta5) to be included in your nation script load, do the following:
UPDATE tiger.loader_lookuptables SET load = true WHERE table_name = 'zcta510';
PostGIS 2.4.3 Manual 687 / 803

Note
If you were running tiger_2010 version and you want to reload as state with newer tiger data, you’ll need to for the
very first load generate and run drop statements Drop_Nation_Tables_Generate_Script before you run this script.

Examples

Generate script script to load nation data Windows.

SELECT loader_generate_nation_script('windows');

Generate script to load up data for Linux/Unix systems.

SELECT loader_generate_nation_script('sh');

See Also

Loader_Generate_Script

13.1.12 Missing_Indexes_Generate_Script

Missing_Indexes_Generate_Script — Finds all tables with key columns used in geocoder joins that are missing indexes on those
columns and will output the SQL DDL to define the index for those tables.

Synopsis

text Missing_Indexes_Generate_Script();

Description

Finds all tables in tiger and tiger_data schemas with key columns used in geocoder joins that are missing indexes on
those columns and will output the SQL DDL to define the index for those tables. This is a helper function that adds new indexes
needed to make queries faster that may have been missing during the load process. As the geocoder is improved, this function
will be updated to accommodate new indexes being used. If this function outputs nothing, it means all your tables have what we
think are the key indexes already in place.
Availability: 2.0.0

Examples

SELECT missing_indexes_generate_script();
-- output: This was run on a database that was created before many corrections were made to ←-
the loading script ---
CREATE INDEX idx_tiger_county_countyfp ON tiger.county USING btree(countyfp);
CREATE INDEX idx_tiger_cousub_countyfp ON tiger.cousub USING btree(countyfp);
CREATE INDEX idx_tiger_edges_tfidr ON tiger.edges USING btree(tfidr);
CREATE INDEX idx_tiger_edges_tfidl ON tiger.edges USING btree(tfidl);
CREATE INDEX idx_tiger_zip_lookup_all_zip ON tiger.zip_lookup_all USING btree(zip);
CREATE INDEX idx_tiger_data_ma_county_countyfp ON tiger_data.ma_county USING btree(countyfp ←-
);
CREATE INDEX idx_tiger_data_ma_cousub_countyfp ON tiger_data.ma_cousub USING btree(countyfp ←-
);
CREATE INDEX idx_tiger_data_ma_edges_countyfp ON tiger_data.ma_edges USING btree(countyfp);
CREATE INDEX idx_tiger_data_ma_faces_countyfp ON tiger_data.ma_faces USING btree(countyfp);
PostGIS 2.4.3 Manual 688 / 803

See Also

Loader_Generate_Script, Install_Missing_Indexes

13.1.13 Normalize_Address

Normalize_Address — Given a textual street address, returns a composite norm_addy type that has road suffix, prefix and type
standardized, street, streetname etc. broken into separate fields. This function will work with just the lookup data packaged with
the tiger_geocoder (no need for tiger census data).

Synopsis

norm_addy normalize_address(varchar in_address);

Description

Given a textual street address, returns a composite norm_addy type that has road suffix, prefix and type standardized, street,
streetname etc. broken into separate fields. This is the first step in the geocoding process to get all addresses into normalized
postal form. No other data is required aside from what is packaged with the geocoder.
This function just uses the various direction/state/suffix lookup tables preloaded with the tiger_geocoder and located in the
tiger schema, so it doesn’t need you to download tiger census data or any other additional data to make use of it. You may find
the need to add more abbreviations or alternative namings to the various lookup tables in the tiger schema.
It uses various control lookup tables located in tiger schema to normalize the input address.
Fields in the norm_addy type object returned by this function in this order where () indicates a field required by the geocoder,
[] indicates an optional field:
(address) [predirAbbrev] (streetName) [streetTypeAbbrev] [postdirAbbrev] [internal] [location] [stateAbbrev] [zip] [parsed]
[zip4] [address_alphanumeric]
Enhanced: 2.4.0 norm_addy object includes additional fields zip4 and address_alphanumeric.

1. address is an integer: The street number

2. predirAbbrev is varchar: Directional prefix of road such as N, S, E, W etc. These are controlled using the direction_looku
table.
3. streetName varchar
4. streetTypeAbbrev varchar abbreviated version of street type: e.g. St, Ave, Cir. These are controlled using the
street_type_lookup table.
5. postdirAbbrev varchar abbreviated directional suffice of road N, S, E, W etc. These are controlled using the direction_loo
table.
6. internal varchar internal address such as an apartment or suite number.
7. location varchar usually a city or governing province.
8. stateAbbrev varchar two character US State. e.g MA, NY, MI. These are controlled by the state_lookup table.
9. zip varchar 5-digit zipcode. e.g. 02109.
10. parsed boolean - denotes if addess was formed from normalize process. The normalize_address function sets this to true
before returning the address.
11. zip4 last 4 digits of a 9 digit zip code. Availability: PostGIS 2.4.0.
12. address_alphanumeric Full street number even if it has alpha characters like 17R. Parsing of this is better using
Pagc_Normalize_Address function. Availability: PostGIS 2.4.0.
PostGIS 2.4.3 Manual 689 / 803

Examples

Output select fields. Use Pprint_Addy if you want a pretty textual output.
SELECT address As orig, (g.na).streetname, (g.na).streettypeabbrev
FROM (SELECT address, normalize_address(address) As na
FROM addresses_to_geocode) As g;

orig | streetname | streettypeabbrev

-----------------------------------------------------+---------------+------------------
28 Capen Street, Medford, MA | Capen | St
124 Mount Auburn St, Cambridge, Massachusetts 02138 | Mount Auburn | St
950 Main Street, Worcester, MA 01610 | Main | St
529 Main Street, Boston MA, 02129 | Main | St
77 Massachusetts Avenue, Cambridge, MA 02139 | Massachusetts | Ave
25 Wizard of Oz, Walaford, KS 99912323 | Wizard of Oz |

See Also

Geocode, Pprint_Addy

13.1.14 Pagc_Normalize_Address

Pagc_Normalize_Address — Given a textual street address, returns a composite norm_addy type that has road suffix, prefix
and type standardized, street, streetname etc. broken into separate fields. This function will work with just the lookup data
packaged with the tiger_geocoder (no need for tiger census data). Requires address_standardizer extension.

Synopsis

norm_addy pagc_normalize_address(varchar in_address);

Description

Given a textual street address, returns a composite norm_addy type that has road suffix, prefix and type standardized, street,
streetname etc. broken into separate fields. This is the first step in the geocoding process to get all addresses into normalized
postal form. No other data is required aside from what is packaged with the geocoder.
This function just uses the various pagc_* lookup tables preloaded with the tiger_geocoder and located in the tiger schema,
so it doesn’t need you to download tiger census data or any other additional data to make use of it. You may find the need to add
more abbreviations or alternative namings to the various lookup tables in the tiger schema.
It uses various control lookup tables located in tiger schema to normalize the input address.
Fields in the norm_addy type object returned by this function in this order where () indicates a field required by the geocoder,
[] indicates an optional field:
There are slight variations in casing and formatting over the Normalize_Address.
Availability: 2.1.0

This method needs address_standardizer extension.

(address) [predirAbbrev] (streetName) [streetTypeAbbrev] [postdirAbbrev] [internal] [location] [stateAbbrev] [zip]
The native standardaddr of address_standardizer extension is at this time a bit richer than norm_addy since its designed to support
international addresses (including country). standardaddr equivalent fields are:
house_num,predir, name, suftype, sufdir, unit, city, state, postcode
Enhanced: 2.4.0 norm_addy object includes additional fields zip4 and address_alphanumeric.
PostGIS 2.4.3 Manual 690 / 803

1. address is an integer: The street number

2. predirAbbrev is varchar: Directional prefix of road such as N, S, E, W etc. These are controlled using the direction_looku
table.
3. streetName varchar
4. streetTypeAbbrev varchar abbreviated version of street type: e.g. St, Ave, Cir. These are controlled using the
street_type_lookup table.
5. postdirAbbrev varchar abbreviated directional suffice of road N, S, E, W etc. These are controlled using the direction_loo
table.
6. internal varchar internal address such as an apartment or suite number.
7. location varchar usually a city or governing province.
8. stateAbbrev varchar two character US State. e.g MA, NY, MI. These are controlled by the state_lookup table.
9. zip varchar 5-digit zipcode. e.g. 02109.
10. parsed boolean - denotes if addess was formed from normalize process. The normalize_address function sets this to true
before returning the address.
11. zip4 last 4 digits of a 9 digit zip code. Availability: PostGIS 2.4.0.
12. address_alphanumeric Full street number even if it has alpha characters like 17R. Parsing of this is better using
Pagc_Normalize_Address function. Availability: PostGIS 2.4.0.

Examples

Single call example

SELECT addy.*
FROM pagc_normalize_address('9000 E ROO ST STE 999, Springfield, CO') AS addy;

address | predirabbrev | streetname | streettypeabbrev | postdirabbrev | internal | ←-

location | stateabbrev | zip | parsed
---------+--------------+------------+------------------+---------------+-----------+-------------+--

9000 | E | ROO | ST | | SUITE 999 | ←-

SPRINGFIELD | CO | | t

Batch call. There are currently speed issues with the way postgis_tiger_geocoder wraps the address_standardizer. These will
hopefully be resolved in later editions. To work around them, if you need speed for batch geocoding to call generate a normaddy
in batch mode, you are encouraged to directly call the address_standardizer standardize_address function as shown below which
is similar exercise to what we did in Normalize_Address that uses data created in Geocode.
WITH g AS (SELECT address, ROW((sa).house_num, (sa).predir, (sa).name
, (sa).suftype, (sa).sufdir, (sa).unit , (sa).city, (sa).state, (sa).postcode, true):: ←-
norm_addy As na
FROM (SELECT address, standardize_address('tiger.pagc_lex'
, 'tiger.pagc_gaz'
, 'tiger.pagc_rules', address) As sa
FROM addresses_to_geocode) As g)
SELECT address As orig, (g.na).streetname, (g.na).streettypeabbrev
FROM g;

orig | streetname | streettypeabbrev

-----------------------------------------------------+---------------+------------------
529 Main Street, Boston MA, 02129 | MAIN | ST
77 Massachusetts Avenue, Cambridge, MA 02139 | MASSACHUSETTS | AVE
PostGIS 2.4.3 Manual 691 / 803

25 Wizard of Oz, Walaford, KS 99912323 | WIZARD OF |

26 Capen Street, Medford, MA | CAPEN | ST
124 Mount Auburn St, Cambridge, Massachusetts 02138 | MOUNT AUBURN | ST
950 Main Street, Worcester, MA 01610 | MAIN | ST

See Also

Normalize_Address, Geocode

13.1.15 Pprint_Addy

Pprint_Addy — Given a norm_addy composite type object, returns a pretty print representation of it. Usually used in conjunc-
tion with normalize_address.

Synopsis

varchar pprint_addy(norm_addy in_addy);

Description

Given a norm_addy composite type object, returns a pretty print representation of it. No other data is required aside from what
is packaged with the geocoder.
Usually used in conjunction with Normalize_Address.

Examples

Pretty print a single address

SELECT pprint_addy(normalize_address('202 East Fremont Street, Las Vegas, Nevada 89101')) ←-
As pretty_address;
pretty_address
---------------------------------------
202 E Fremont St, Las Vegas, NV 89101

Pretty print address a table of addresses

SELECT address As orig, pprint_addy(normalize_address(address)) As pretty_address
FROM addresses_to_geocode;

orig | pretty_address
-----------------------------------------------------+------------------------------------------- ←-

529 Main Street, Boston MA, 02129 | 529 Main St, Boston MA, 02129
77 Massachusetts Avenue, Cambridge, MA 02139 | 77 Massachusetts Ave, Cambridge, MA ←-
02139
28 Capen Street, Medford, MA | 28 Capen St, Medford, MA
124 Mount Auburn St, Cambridge, Massachusetts 02138 | 124 Mount Auburn St, Cambridge, MA ←-
02138
950 Main Street, Worcester, MA 01610 | 950 Main St, Worcester, MA 01610

See Also

Normalize_Address
PostGIS 2.4.3 Manual 692 / 803

13.1.16 Reverse_Geocode

Reverse_Geocode — Takes a geometry point in a known spatial ref sys and returns a record containing an array of theoretically
possible addresses and an array of cross streets. If include_strnum_range = true, includes the street range in the cross streets.

Synopsis

record Reverse_Geocode(geometry pt, boolean include_strnum_range=false, geometry[] OUT intpt, norm_addy[] OUT addy,
varchar[] OUT street);

Description

Takes a geometry point in a known spatial ref and returns a record containing an array of theoretically possible addresses and
an array of cross streets. If include_strnum_range = true, includes the street range in the cross streets. include_strnum_range
defaults to false if not passed in. Addresses are sorted according to which road a point is closest to so first address is most likely
the right one.
Why do we say theoretical instead of actual addresses. The Tiger data doesn’t have real addresses, but just street ranges. As such
the theoretical address is an interpolated address based on the street ranges. Like for example interpolating one of my addresses
returns a 26 Court St. and 26 Court Sq., though there is no such place as 26 Court Sq. This is because a point may be at a corner
of 2 streets and thus the logic interpolates along both streets. The logic also assumes addresses are equally spaced along a street,
which of course is wrong since you can have a municipal building taking up a good chunk of the street range and the rest of the
buildings are clustered at the end.
Note: Hmm this function relies on Tiger data. If you have not loaded data covering the region of this point, then hmm you will
get a record filled with NULLS.
Returned elements of the record are as follows:

1. intpt is an array of points: These are the center line points on the street closest to the input point. There are as many
points as there are addresses.
2. addy is an array of norm_addy (normalized addresses): These are an array of possible addresses that fit the input point.
The first one in the array is most likely. Generally there should be only one, except in the case when a point is at the corner
of 2 or 3 streets, or the point is somewhere on the road and not off to the side.
3. street an array of varchar: These are cross streets (or the street) (streets that intersect or are the street the point is
projected to be on).

Enhanced: 2.4.1 if optional zcta5 dataset is loaded, the reverse_geocode function can resolve to state and zip even if the specific
state data is not loaded. Refer to Loader_Generate_Nation_Script for details on loading zcta5 data.
Availability: 2.0.0

Examples

Example of a point at the corner of two streets, but closest to one. This is approximate location of MIT: 77 Massachusetts Ave,
Cambridge, MA 02139 Note that although we don’t have 3 streets, PostgreSQL will just return null for entries above our upper
bound so safe to use. This includes street ranges
SELECT pprint_addy(r.addy[1]) As st1, pprint_addy(r.addy[2]) As st2, pprint_addy(r.addy[3]) ←-
As st3,
array_to_string(r.street, ',') As cross_streets
FROM reverse_geocode(ST_GeomFromText('POINT(-71.093902 42.359446)',4269),true) As r ←-
;

result
------
st1 | st2 | st3 | cross_streets
PostGIS 2.4.3 Manual 693 / 803

-------------------------------------------+-----+-----+---------------------------------------------

67 Massachusetts Ave, Cambridge, MA 02139 | | | 67 - 127 Massachusetts Ave,32 - 88 ←-

Vassar St

Here we choose not to include the address ranges for the cross streets and picked a location really really close to a corner of 2
streets thus could be known by two different addresses.
SELECT pprint_addy(r.addy[1]) As st1, pprint_addy(r.addy[2]) As st2,
pprint_addy(r.addy[3]) As st3, array_to_string(r.street, ',') As cross_str
FROM reverse_geocode(ST_GeomFromText('POINT(-71.06941 42.34225)',4269)) As r;

result
--------
st1 | st2 | st3 | cross_str
---------------------------------+---------------------------------+-----+------------------------ ←

5 Bradford St, Boston, MA 02118 | 49 Waltham St, Boston, MA 02118 | | Waltham St

For this one we reuse our geocoded example from Geocode and we only want the primary address and at most 2 cross streets.
SELECT actual_addr, lon, lat, pprint_addy((rg).addy[1]) As int_addr1,
(rg).street[1] As cross1, (rg).street[2] As cross2
FROM (SELECT address As actual_addr, lon, lat,
reverse_geocode( ST_SetSRID(ST_Point(lon,lat),4326) ) As rg
FROM addresses_to_geocode WHERE rating > -1) As foo;

actual_addr | lon | lat | ←-

int_addr1 | ←-| cross1
cross2
-----------------------------------------------------+-----------+----------+------------------------

529 Main Street, Boston MA, 02129 | -71.07181 | 42.38359 | 527 Main St, ←-
Boston, MA 02129 | Medford St |
77 Massachusetts Avenue, Cambridge, MA 02139 | -71.09428 | 42.35988 | 77 ←-
Massachusetts Ave, Cambridge, MA 02139 | Vassar St |
26 Capen Street, Medford, MA | -71.12377 | 42.41101 | 9 Edison Ave, ←-
Medford, MA 02155 | Capen St | Tesla Ave
124 Mount Auburn St, Cambridge, Massachusetts 02138 | -71.12304 | 42.37328 | 3 University ←-
Rd, Cambridge, MA 02138 | Mount Auburn St |
950 Main Street, Worcester, MA 01610 | -71.82368 | 42.24956 | 3 Maywood St, ←-
Worcester, MA 01603 | Main St | Maywood Pl

See Also

Pprint_Addy, Geocode, Loader_Generate_Nation_Script

13.1.17 Topology_Load_Tiger

Topology_Load_Tiger — Loads a defined region of tiger data into a PostGIS Topology and transforming the tiger data to spatial
reference of the topology and snapping to the precision tolerance of the topology.

Synopsis

text Topology_Load_Tiger(varchar topo_name, varchar region_type, varchar region_id);

PostGIS 2.4.3 Manual 694 / 803

Description

Loads a defined region of tiger data into a PostGIS Topology. The faces, nodes and edges are transformed to the spatial reference
system of the target topology and points are snapped to the tolerance of the target topology. The created faces, nodes, edges
maintain the same ids as the original Tiger data faces, nodes, edges so that datasets can be in the future be more easily reconciled
with tiger data. Returns summary details about the process.
This would be useful for example for redistricting data where you require the newly formed polygons to follow the center lines
of streets and for the resulting polygons not to overlap.

Note
This function relies on Tiger data as well as the installation of the PostGIS topology module. For more information, refer
to Chapter 11 and Section 2.4.1. If you have not loaded data covering the region of interest, then no topology records
will be created. This function will also fail if you have not created a topology using the topology functions.

Note
Most topology validation errors are a result of tolerance issues where after transformation the edges points don’t quite
line up or overlap. To remedy the situation you may want to increase or lower the precision if you get topology validation
failures.

Required arguments:

1. topo_name The name of an existing PostGIS topology to load data into.

2. region_type The type of bounding region. Currently only place and county are supported. Plan is to have several
more. This is the table to look into to define the region bounds. e.g tiger.place, tiger.county
3. region_id This is what TIGER calls the geoid. It is the unique identifier of the region in the table. For place it is the
plcidfp column in tiger.place. For county it is the cntyidfp column in tiger.county

Availability: 2.0.0

Example: Boston, Massachusetts Topology

Create a topology for Boston, Massachusetts in Mass State Plane Feet (2249) with tolerance 0.25 feet and then load in Boston
city tiger faces, edges, nodes.
SELECT topology.CreateTopology('topo_boston', 2249, 0.25);
createtopology
--------------
15
-- 60,902 ms ~ 1 minute on windows 7 desktop running 9.1 (with 5 states tiger data loaded)
SELECT tiger.topology_load_tiger('topo_boston', 'place', '2507000');
-- topology_loader_tiger --
29722 edges holding in temporary. 11108 faces added. 1875 edges of faces added. 20576 ←-
nodes added.
19962 nodes contained in a face. 0 edge start end corrected. 31597 edges added.

-- 41 ms --
SELECT topology.TopologySummary('topo_boston');
-- topologysummary--
Topology topo_boston (15), SRID 2249, precision 0.25
20576 nodes, 31597 edges, 11109 faces, 0 topogeoms in 0 layers

-- 28,797 ms to validate yeh returned no errors --

SELECT * FROM
PostGIS 2.4.3 Manual 695 / 803

topology.ValidateTopology('topo_boston');

error | id1 | id2

-------------------+----------+-----------

Example: Suffolk, Massachusetts Topology

Create a topology for Suffolk, Massachusetts in Mass State Plane Meters (26986) with tolerance 0.25 meters and then load in
Suffolk county tiger faces, edges, nodes.
SELECT topology.CreateTopology('topo_suffolk', 26986, 0.25);
-- this took 56,275 ms ~ 1 minute on Windows 7 32-bit with 5 states of tiger loaded
-- must have been warmed up after loading boston
SELECT tiger.topology_load_tiger('topo_suffolk', 'county', '25025');
-- topology_loader_tiger --
36003 edges holding in temporary. 13518 faces added. 2172 edges of faces added.
24761 nodes added. 24075 nodes contained in a face. 0 edge start end corrected. 38175 ←-
edges added.
-- 31 ms --
SELECT topology.TopologySummary('topo_suffolk');
-- topologysummary--
Topology topo_suffolk (14), SRID 26986, precision 0.25
24761 nodes, 38175 edges, 13519 faces, 0 topogeoms in 0 layers

-- 33,606 ms to validate --
SELECT * FROM
topology.ValidateTopology('topo_suffolk');

error | id1 | id2

-------------------+----------+-----------
coincident nodes | 81045651 | 81064553
edge crosses node | 81045651 | 85737793
edge crosses node | 81045651 | 85742215
edge crosses node | 81045651 | 620628939
edge crosses node | 81064553 | 85697815
edge crosses node | 81064553 | 85728168
edge crosses node | 81064553 | 85733413

See Also

CreateTopology, CreateTopoGeom, TopologySummary, ValidateTopology

13.1.18 Set_Geocode_Setting

Set_Geocode_Setting — Sets a setting that affects behavior of geocoder functions.

Synopsis

text Set_Geocode_Setting(text setting_name, text setting_value);

Description

Sets value of specific setting stored in tiger.geocode_settings table. Settings allow you to toggle debugging of func-
tions. Later plans will be to control rating with settings. Current list of settings are listed in Get_Geocode_Setting.
Availability: 2.1.0
PostGIS 2.4.3 Manual 696 / 803

Example return debugging setting

If you run Geocode when this function is true, the NOTICE log will output timing and queries.
SELECT set_geocode_setting('debug_geocode_address', 'true') As result;
result
---------
true

See Also

Get_Geocode_Setting
PostGIS 2.4.3 Manual 697 / 803

Chapter 14

PostGIS Special Functions Index

14.1 PostGIS Aggregate Functions

The functions given below are spatial aggregate functions provided with PostGIS that can be used just like any other sql aggregate
function such as sum, average.

• ST_3DExtent - an aggregate function that returns the box3D bounding box that bounds rows of geometries.
• ST_Accum - Aggregate. Constructs an array of geometries.
• ST_AsGeobuf - Return a Geobuf representation of a set of rows.
• ST_AsMVT - Return a Mapbox Vector Tile representation of a set of rows.
• ST_ClusterIntersecting - Aggregate. Returns an array with the connected components of a set of geometries
• ST_ClusterWithin - Aggregate. Returns an array of GeometryCollections, where each GeometryCollection represents a set of
geometries separated by no more than the specified distance.
• ST_Collect - Return a specified ST_Geometry value from a collection of other geometries.
• ST_Extent - an aggregate function that returns the bounding box that bounds rows of geometries.
• ST_MakeLine - Creates a Linestring from point, multipoint, or line geometries.
• ST_MemUnion - Same as ST_Union, only memory-friendly (uses less memory and more processor time).
• ST_Polygonize - Aggregate. Creates a GeometryCollection containing possible polygons formed from the constituent linework
of a set of geometries.
• ST_SameAlignment - Returns true if rasters have same skew, scale, spatial ref, and offset (pixels can be put on same grid
without cutting into pixels) and false if they don’t with notice detailing issue.
• ST_Union - Returns a geometry that represents the point set union of the Geometries.
• TopoElementArray_Agg - Returns a topoelementarray for a set of element_id, type arrays (topoelements)

14.2 PostGIS Window Functions

The functions given below are spatial window functions provided with PostGIS that can be used just like any other sql window
function such as row_numer(), lead(), lag(). All these require an SQL OVER() clause.

• ST_ClusterDBSCAN - Windowing function that returns integer id for the cluster each input geometry is in based on 2D
implementation of Density-based spatial clustering of applications with noise (DBSCAN) algorithm.
• ST_ClusterKMeans - Windowing function that returns integer id for the cluster each input geometry is in.
PostGIS 2.4.3 Manual 698 / 803

14.3 PostGIS SQL-MM Compliant Functions

The functions given below are PostGIS functions that conform to the SQL/MM 3 standard

Note
SQL-MM defines the default SRID of all geometry constructors as 0. PostGIS uses a default SRID of -1.

• ST_3DDWithin - For 3d (z) geometry type Returns true if two geometries 3d distance is within number of units. This method
implements the SQL/MM specification. SQL-MM ?
• ST_3DDistance - For geometry type Returns the 3-dimensional cartesian minimum distance (based on spatial ref) between two
geometries in projected units. This method implements the SQL/MM specification. SQL-MM ?
• ST_3DIntersects - Returns TRUE if the Geometries "spatially intersect" in 3d - only for points, linestrings, polygons, polyhe-
dral surface (area). With SFCGAL backend enabled also supports TINS This method implements the SQL/MM specification.
SQL-MM 3: ?
• ST_AddEdgeModFace - Add a new edge and, if in doing so it splits a face, modify the original face and add a new face. This
method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.13
• ST_AddEdgeNewFaces - Add a new edge and, if in doing so it splits a face, delete the original face and replace it with two new
faces. This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.12
• ST_AddIsoEdge - Adds an isolated edge defined by geometry alinestring to a topology connecting two existing isolated nodes
anode and anothernode and returns the edge id of the new edge. This method implements the SQL/MM specification. SQL-
MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.4
• ST_AddIsoNode - Adds an isolated node to a face in a topology and returns the nodeid of the new node. If face is null, the
node is still created. This method implements the SQL/MM specification. SQL-MM: Topo-Net Routines: X+1.3.1
• ST_Area - Returns the area of the surface if it is a Polygon or MultiPolygon. For geometry, a 2D Cartesian area is determined
with units specified by the SRID. For geography, area is determined on a curved surface with units in square meters. This
method implements the SQL/MM specification. SQL-MM 3: 8.1.2, 9.5.3
• ST_AsBinary - Return the Well-Known Binary (WKB) representation of the geometry/geography without SRID meta data.
This method implements the SQL/MM specification. SQL-MM 3: 5.1.37

• ST_AsText - Return the Well-Known Text (WKT) representation of the geometry/geography without SRID metadata. This
method implements the SQL/MM specification. SQL-MM 3: 5.1.25
• ST_Boundary - Returns the closure of the combinatorial boundary of this Geometry. This method implements the SQL/MM
specification. SQL-MM 3: 5.1.14
• ST_Buffer - (T)Returns a geometry covering all points within a given distancefrom the input geometry. This method imple-
ments the SQL/MM specification. SQL-MM 3: 5.1.17
• ST_Centroid - Returns the geometric center of a geometry. This method implements the SQL/MM specification. SQL-MM 3:
8.1.4, 9.5.5
• ST_ChangeEdgeGeom - Changes the shape of an edge without affecting the topology structure. This method implements the
SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details X.3.6
• ST_Contains - Returns true if and only if no points of B lie in the exterior of A, and at least one point of the interior of B lies
in the interior of A. This method implements the SQL/MM specification. SQL-MM 3: 5.1.31
• ST_ConvexHull - The convex hull of a geometry represents the minimum convex geometry that encloses all geometries within
the set. This method implements the SQL/MM specification. SQL-MM 3: 5.1.16
PostGIS 2.4.3 Manual 699 / 803

• ST_CoordDim - Return the coordinate dimension of the ST_Geometry value. This method implements the SQL/MM specifi-
cation. SQL-MM 3: 5.1.3
• ST_CreateTopoGeo - Adds a collection of geometries to a given empty topology and returns a message detailing success. This
method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details -- X.3.18
• ST_Crosses - Returns TRUE if the supplied geometries have some, but not all, interior points in common. This method
implements the SQL/MM specification. SQL-MM 3: 5.1.29
• ST_CurveToLine - Converts a CIRCULARSTRING/CURVEPOLYGON to a LINESTRING/POLYGON This method imple-
ments the SQL/MM specification. SQL-MM 3: 7.1.7

• ST_Difference - Returns a geometry that represents that part of geometry A that does not intersect with geometry B. This
method implements the SQL/MM specification. SQL-MM 3: 5.1.20
• ST_Dimension - The inherent dimension of this Geometry object, which must be less than or equal to the coordinate dimension.
This method implements the SQL/MM specification. SQL-MM 3: 5.1.2

• ST_Disjoint - Returns TRUE if the Geometries do not "spatially intersect" - if they do not share any space together. This
method implements the SQL/MM specification. SQL-MM 3: 5.1.26
• ST_Distance - For geometry type Returns the 2D Cartesian distance between two geometries in projected units (based on
spatial ref). For geography type defaults to return minimum geodesic distance between two geographies in meters. This
method implements the SQL/MM specification. SQL-MM 3: 5.1.23

• ST_EndPoint - Returns the last point of a LINESTRING or CIRCULARLINESTRING geometry as a POINT. This method
implements the SQL/MM specification. SQL-MM 3: 7.1.4
• ST_Envelope - Returns a geometry representing the double precision (float8) bounding box of the supplied geometry. This
method implements the SQL/MM specification. SQL-MM 3: 5.1.15

• ST_Equals - Returns true if the given geometries represent the same geometry. Directionality is ignored. This method imple-
ments the SQL/MM specification. SQL-MM 3: 5.1.24
• ST_ExteriorRing - Returns a line string representing the exterior ring of the POLYGON geometry. Return NULL if the
geometry is not a polygon. Will not work with MULTIPOLYGON This method implements the SQL/MM specification. SQL-
MM 3: 8.2.3, 8.3.3

• ST_GMLToSQL - Return a specified ST_Geometry value from GML representation. This is an alias name for ST_GeomFromGML
This method implements the SQL/MM specification. SQL-MM 3: 5.1.50 (except for curves support).
• ST_GeomCollFromText - Makes a collection Geometry from collection WKT with the given SRID. If SRID is not given, it
defaults to 0. This method implements the SQL/MM specification.

• ST_GeomFromText - Return a specified ST_Geometry value from Well-Known Text representation (WKT). This method
implements the SQL/MM specification. SQL-MM 3: 5.1.40
• ST_GeomFromWKB - Creates a geometry instance from a Well-Known Binary geometry representation (WKB) and optional
SRID. This method implements the SQL/MM specification. SQL-MM 3: 5.1.41
• ST_GeometryFromText - Return a specified ST_Geometry value from Well-Known Text representation (WKT). This is an
alias name for ST_GeomFromText This method implements the SQL/MM specification. SQL-MM 3: 5.1.40
• ST_GeometryN - Return the 1-based Nth geometry if the geometry is a GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINE
MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE Otherwise, return NULL. This method implements the
SQL/MM specification. SQL-MM 3: 9.1.5

• ST_GeometryType - Return the geometry type of the ST_Geometry value. This method implements the SQL/MM specifica-
tion. SQL-MM 3: 5.1.4
• ST_GetFaceEdges - Returns a set of ordered edges that bound aface. This method implements the SQL/MM specification.
SQL-MM 3 Topo-Geo and Topo-Net 3: Routine Details: X.3.5
PostGIS 2.4.3 Manual 700 / 803

• ST_GetFaceGeometry - Returns the polygon in the given topology with the specified face id. This method implements the
SQL/MM specification. SQL-MM 3 Topo-Geo and Topo-Net 3: Routine Details: X.3.16
• ST_InitTopoGeo - Creates a new topology schema and registers this new schema in the topology.topology table and details
summary of process. This method implements the SQL/MM specification. SQL-MM 3 Topo-Geo and Topo-Net 3: Routine
Details: X.3.17
• ST_InteriorRingN - Return the Nth interior linestring ring of the polygon geometry. Return NULL if the geometry is not a
polygon or the given N is out of range. This method implements the SQL/MM specification. SQL-MM 3: 8.2.6, 8.3.5
• ST_Intersection - (T)Returns a geometry that represents the shared portion of geomA and geomB. This method implements
the SQL/MM specification. SQL-MM 3: 5.1.18
• ST_Intersects - Returns TRUE if the Geometries/Geography "spatially intersect in 2D" - (share any portion of space) and
FALSE if they don’t (they are Disjoint). For geography -- tolerance is 0.00001 meters (so any points that close are considered
to intersect) This method implements the SQL/MM specification. SQL-MM 3: 5.1.27

• ST_IsClosed - Returns TRUE if the LINESTRING’s start and end points are coincident. For Polyhedral surface is closed
(volumetric). This method implements the SQL/MM specification. SQL-MM 3: 7.1.5, 9.3.3
• ST_IsEmpty - Returns true if this Geometry is an empty geometrycollection, polygon, point etc. This method implements the
SQL/MM specification. SQL-MM 3: 5.1.7
• ST_IsRing - Returns TRUE if this LINESTRING is both closed and simple. This method implements the SQL/MM specifica-
tion. SQL-MM 3: 7.1.6
• ST_IsSimple - Returns (TRUE) if this Geometry has no anomalous geometric points, such as self intersection or self tangency.
This method implements the SQL/MM specification. SQL-MM 3: 5.1.8
• ST_IsValid - Returns true if the ST_Geometry is well formed. This method implements the SQL/MM specification. SQL-MM
3: 5.1.9
• ST_Length - Returns the 2D length of the geometry if it is a LineString or MultiLineString. geometry are in units of spatial
reference and geography are in meters (default spheroid) This method implements the SQL/MM specification. SQL-MM 3:
7.1.2, 9.3.4
• ST_LineFromText - Makes a Geometry from WKT representation with the given SRID. If SRID is not given, it defaults to 0.
This method implements the SQL/MM specification. SQL-MM 3: 7.2.8
• ST_LineFromWKB - Makes a LINESTRING from WKB with the given SRID This method implements the SQL/MM speci-
fication. SQL-MM 3: 7.2.9
• ST_LinestringFromWKB - Makes a geometry from WKB with the given SRID. This method implements the SQL/MM speci-
fication. SQL-MM 3: 7.2.9
• ST_M - Return the M coordinate of the point, or NULL if not available. Input must be a point. This method implements the
SQL/MM specification.
• ST_MLineFromText - Return a specified ST_MultiLineString value from WKT representation. This method implements the
SQL/MM specification.SQL-MM 3: 9.4.4

• ST_MPointFromText - Makes a Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0. This method
implements the SQL/MM specification. SQL-MM 3: 9.2.4
• ST_MPolyFromText - Makes a MultiPolygon Geometry from WKT with the given SRID. If SRID is not given, it defaults to
0. This method implements the SQL/MM specification. SQL-MM 3: 9.6.4

• ST_ModEdgeHeal - Heal two edges by deleting the node connecting them, modifying the first edgeand deleting the second
edge. Returns the id of the deleted node. This method implements the SQL/MM specification. SQL-MM: Topo-Geo and
Topo-Net 3: Routine Details: X.3.9
• ST_ModEdgeSplit - Split an edge by creating a new node along an existing edge, modifying the original edge and adding a
new edge. This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details: X.3.9
PostGIS 2.4.3 Manual 701 / 803

• ST_MoveIsoNode - Moves an isolated node in a topology from one point to another. If new apoint geometry exists as a node
an error is thrown. Returns description of move. This method implements the SQL/MM specification. SQL-MM: Topo-Net
Routines: X.3.2

• ST_NewEdgeHeal - Heal two edges by deleting the node connecting them, deleting both edges,and replacing them with an
edge whose direction is the same as the firstedge provided. This method implements the SQL/MM specification. SQL-MM:
Topo-Geo and Topo-Net 3: Routine Details: X.3.9
• ST_NewEdgesSplit - Split an edge by creating a new node along an existing edge, deleting the original edge and replacing it
with two new edges. Returns the id of the new node created that joins the new edges. This method implements the SQL/MM
specification. SQL-MM: Topo-Net Routines: X.3.8

• ST_NumGeometries - If geometry is a GEOMETRYCOLLECTION (or MULTI*) return the number of geometries, for single
geometries will return 1, otherwise return NULL. This method implements the SQL/MM specification. SQL-MM 3: 9.1.4
• ST_NumInteriorRings - Return the number of interior rings of a polygon geometry. This method implements the SQL/MM
specification. SQL-MM 3: 8.2.5

• ST_NumPatches - Return the number of faces on a Polyhedral Surface. Will return null for non-polyhedral geometries. This
method implements the SQL/MM specification. SQL-MM 3: ?
• ST_NumPoints - Return the number of points in an ST_LineString or ST_CircularString value. This method implements the
SQL/MM specification. SQL-MM 3: 7.2.4

• ST_OrderingEquals - Returns true if the given geometries represent the same geometry and points are in the same directional
order. This method implements the SQL/MM specification. SQL-MM 3: 5.1.43
• ST_Overlaps - Returns TRUE if the Geometries share space, are of the same dimension, but are not completely contained by
each other. This method implements the SQL/MM specification. SQL-MM 3: 5.1.32
• ST_PatchN - Return the 1-based Nth geometry (face) if the geometry is a POLYHEDRALSURFACE, POLYHEDRALSUR-
FACEM. Otherwise, return NULL. This method implements the SQL/MM specification. SQL-MM 3: ?
• ST_Perimeter - Return the length measurement of the boundary of an ST_Surface or ST_MultiSurface geometry or geography.
(Polygon, MultiPolygon). geometry measurement is in units of spatial reference and geography is in meters. This method
implements the SQL/MM specification. SQL-MM 3: 8.1.3, 9.5.4

• ST_Point - Returns an ST_Point with the given coordinate values. OGC alias for ST_MakePoint. This method implements the
SQL/MM specification. SQL-MM 3: 6.1.2
• ST_PointFromText - Makes a point Geometry from WKT with the given SRID. If SRID is not given, it defaults to unknown.
This method implements the SQL/MM specification. SQL-MM 3: 6.1.8
• ST_PointFromWKB - Makes a geometry from WKB with the given SRID This method implements the SQL/MM specification.
SQL-MM 3: 6.1.9
• ST_PointN - Return the Nth point in the first LineString or circular LineString in the geometry. Negative values are counted
backwards from the end of the LineString. Returns NULL if there is no linestring in the geometry. This method implements
the SQL/MM specification. SQL-MM 3: 7.2.5, 7.3.5

• ST_PointOnSurface - Returns a POINT guaranteed to lie on the surface. This method implements the SQL/MM specifica-
tion. SQL-MM 3: 8.1.5, 9.5.6. According to the specs, ST_PointOnSurface works for surface geometries (POLYGONs,
MULTIPOLYGONS, CURVED POLYGONS). So PostGIS seems to be extending what the spec allows here. Most databases
Oracle,DB II, ESRI SDE seem to only support this function for surfaces. SQL Server 2008 like PostGIS supports for all
common geometries.

• ST_Polygon - Returns a polygon built from the specified linestring and SRID. This method implements the SQL/MM specifi-
cation. SQL-MM 3: 8.3.2
• ST_PolygonFromText - Makes a Geometry from WKT with the given SRID. If SRID is not given, it defaults to 0. This method
implements the SQL/MM specification. SQL-MM 3: 8.3.6
PostGIS 2.4.3 Manual 702 / 803

• ST_Relate - Returns true if this Geometry is spatially related to anotherGeometry, by testing for intersections between the
Interior, Boundary and Exterior of the two geometries as specified by the values in the intersectionMatrixPattern. If no in-
tersectionMatrixPattern is passed in, then returns the maximum intersectionMatrixPattern that relates the 2 geometries. This
method implements the SQL/MM specification. SQL-MM 3: 5.1.25

• ST_RemEdgeModFace - Removes an edge and, if the removed edge separated two faces,delete one of the them and modify
the other to take the space of both. This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net
3: Routine Details: X.3.15
• ST_RemEdgeNewFace - Removes an edge and, if the removed edge separated two faces,delete the original faces and replace
them with a new face. This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine
Details: X.3.14
• ST_RemoveIsoEdge - Removes an isolated edge and returns description of action. If the edge is not isolated, then an exception
is thrown. This method implements the SQL/MM specification. SQL-MM: Topo-Geo and Topo-Net 3: Routine Details:
X+1.3.3

• ST_RemoveIsoNode - Removes an isolated node and returns description of action. If the node is not isolated (is start or end
of an edge), then an exception is thrown. This method implements the SQL/MM specification. SQL-MM: Topo-Geo and
Topo-Net 3: Routine Details: X+1.3.3
• ST_SRID - Returns the spatial reference identifier for the ST_Geometry as defined in spatial_ref_sys table. This method
implements the SQL/MM specification. SQL-MM 3: 5.1.5

• ST_StartPoint - Returns the first point of a LINESTRING geometry as a POINT. This method implements the SQL/MM
specification. SQL-MM 3: 7.1.3
• ST_SymDifference - Returns a geometry that represents the portions of A and B that do not intersect. It is called a symmetric
difference because ST_SymDifference(A,B) = ST_SymDifference(B,A). This method implements the SQL/MM specification.
SQL-MM 3: 5.1.21

• ST_Touches - Returns TRUE if the geometries have at least one point in common, but their interiors do not intersect. This
method implements the SQL/MM specification. SQL-MM 3: 5.1.28
• ST_Transform - Return a new geometry with its coordinates transformed to a different spatial reference. This method imple-
ments the SQL/MM specification. SQL-MM 3: 5.1.6

• ST_Union - Returns a geometry that represents the point set union of the Geometries. This method implements the SQL/MM
specification. SQL-MM 3: 5.1.19 the z-index (elevation) when polygons are involved.
• ST_WKBToSQL - Return a specified ST_Geometry value from Well-Known Binary representation (WKB). This is an alias
name for ST_GeomFromWKB that takes no srid This method implements the SQL/MM specification. SQL-MM 3: 5.1.36

• ST_WKTToSQL - Return a specified ST_Geometry value from Well-Known Text representation (WKT). This is an alias name
for ST_GeomFromText This method implements the SQL/MM specification. SQL-MM 3: 5.1.34
• ST_Within - Returns true if the geometry A is completely inside geometry B This method implements the SQL/MM specifica-
tion. SQL-MM 3: 5.1.30
• ST_X - Return the X coordinate of the point, or NULL if not available. Input must be a point. This method implements the
SQL/MM specification. SQL-MM 3: 6.1.3
• ST_Y - Return the Y coordinate of the point, or NULL if not available. Input must be a point. This method implements the
SQL/MM specification. SQL-MM 3: 6.1.4
• ST_Z - Return the Z coordinate of the point, or NULL if not available. Input must be a point. This method implements the
SQL/MM specification.
PostGIS 2.4.3 Manual 703 / 803

14.4 PostGIS Geography Support Functions

The functions and operators given below are PostGIS functions/operators that take as input or return as output a geography data
type object.

Note
Functions with a (T) are not native geodetic functions, and use a ST_Transform call to and from geometry to do the
operation. As a result, they may not behave as expected when going over dateline, poles, and for large geometries or
geometry pairs that cover more than one UTM zone. Basic transform - (favoring UTM, Lambert Azimuthal (North/South),
and falling back on mercator in worst case scenario)

• ST_Area - Returns the area of the surface if it is a Polygon or MultiPolygon. For geometry, a 2D Cartesian area is determined
with units specified by the SRID. For geography, area is determined on a curved surface with units in square meters.
• ST_AsBinary - Return the Well-Known Binary (WKB) representation of the geometry/geography without SRID meta data.
• ST_AsEWKT - Return the Well-Known Text (WKT) representation of the geometry with SRID meta data.

• ST_AsGML - Return the geometry as a GML version 2 or 3 element.

• ST_AsGeoJSON - Return the geometry as a GeoJSON element.
• ST_AsKML - Return the geometry as a KML element. Several variants. Default version=2, default precision=15
• ST_AsSVG - Returns a Geometry in SVG path data given a geometry or geography object.

• ST_AsText - Return the Well-Known Text (WKT) representation of the geometry/geography without SRID metadata.
• ST_Azimuth - Returns the north-based azimuth as the angle in radians measured clockwise from the vertical on pointA to
pointB.
• ST_Buffer - (T)Returns a geometry covering all points within a given distancefrom the input geometry.

• ST_Centroid - Returns the geometric center of a geometry.

• ST_CoveredBy - Returns 1 (TRUE) if no point in Geometry/Geography A is outside Geometry/Geography B
• ST_Covers - Returns 1 (TRUE) if no point in Geometry B is outside Geometry A

• ST_DWithin - Returns true if the geometries are within the specified distance of one another. For geometry units are in those
of spatial reference and For geography units are in meters and measurement is defaulted to use_spheroid=true (measure around
spheroid), for faster check, use_spheroid=false to measure along sphere.
• ST_Distance - For geometry type Returns the 2D Cartesian distance between two geometries in projected units (based on
spatial ref). For geography type defaults to return minimum geodesic distance between two geographies in meters.

• ST_GeogFromText - Return a specified geography value from Well-Known Text representation or extended (WKT).
• ST_GeogFromWKB - Creates a geography instance from a Well-Known Binary geometry representation (WKB) or extended
Well Known Binary (EWKB).
• ST_GeographyFromText - Return a specified geography value from Well-Known Text representation or extended (WKT).

• = - Returns TRUE if the coordinates and coordinate order geometry/geography A are the same as the coordinates and coordinate
order of geometry/geography B.
• ST_Intersection - (T)Returns a geometry that represents the shared portion of geomA and geomB.
• ST_Intersects - Returns TRUE if the Geometries/Geography "spatially intersect in 2D" - (share any portion of space) and
FALSE if they don’t (they are Disjoint). For geography -- tolerance is 0.00001 meters (so any points that close are considered
to intersect)
PostGIS 2.4.3 Manual 704 / 803

• ST_Length - Returns the 2D length of the geometry if it is a LineString or MultiLineString. geometry are in units of spatial
reference and geography are in meters (default spheroid)
• ST_Perimeter - Return the length measurement of the boundary of an ST_Surface or ST_MultiSurface geometry or geography.
(Polygon, MultiPolygon). geometry measurement is in units of spatial reference and geography is in meters.
• ST_Project - Returns a POINT projected from a start point using a distance in meters and bearing (azimuth) in radians.
• ST_Segmentize - Return a modified geometry/geography having no segment longer than the given distance.
• ST_Summary - Returns a text summary of the contents of the geometry.
• <-> - Returns the 2D distance between A and B.
• && - Returns TRUE if A’s 2D bounding box intersects B’s 2D bounding box.

14.5 PostGIS Raster Support Functions

The functions and operators given below are PostGIS functions/operators that take as input or return as output a raster data type
object. Listed in alphabetical order.

• Box3D - Returns the box 3d representation of the enclosing box of the raster.
• @ - Returns TRUE if A’s bounding box is contained by B’s. Uses double precision bounding box.
• ~ - Returns TRUE if A’s bounding box is contains B’s. Uses double precision bounding box.
• = - Returns TRUE if A’s bounding box is the same as B’s. Uses double precision bounding box.
• && - Returns TRUE if A’s bounding box intersects B’s bounding box.
• &< - Returns TRUE if A’s bounding box is to the left of B’s.
• &> - Returns TRUE if A’s bounding box is to the right of B’s.
• ~= - Returns TRUE if A’s bounding box is the same as B’s.
• ST_Retile - Return a set of configured tiles from an arbitrarily tiled raster coverage.
• ST_AddBand - Returns a raster with the new band(s) of given type added with given initial value in the given index location.
If no index is specified, the band is added to the end.
• ST_AsBinary - Return the Well-Known Binary (WKB) representation of the raster.
• ST_AsGDALRaster - Return the raster tile in the designated GDAL Raster format. Raster formats are one of those supported
by your compiled library. Use ST_GDALDrivers() to get a list of formats supported by your library.
• ST_AsJPEG - Return the raster tile selected bands as a single Joint Photographic Exports Group (JPEG) image (byte array). If
no band is specified and 1 or more than 3 bands, then only the first band is used. If only 3 bands then all 3 bands are used and
mapped to RGB.
• ST_AsPNG - Return the raster tile selected bands as a single portable network graphics (PNG) image (byte array). If 1, 3, or
4 bands in raster and no bands are specified, then all bands are used. If more 2 or more than 4 bands and no bands specified,
then only band 1 is used. Bands are mapped to RGB or RGBA space.
• ST_AsRaster - Converts a PostGIS geometry to a PostGIS raster.
• ST_AsTIFF - Return the raster selected bands as a single TIFF image (byte array). If no band is specified, then will try to use
all bands.
• ST_Aspect - Returns the aspect (in degrees by default) of an elevation raster band. Useful for analyzing terrain.
• ST_Band - Returns one or more bands of an existing raster as a new raster. Useful for building new rasters from existing
rasters.
PostGIS 2.4.3 Manual 705 / 803

• ST_BandIsNoData - Returns true if the band is filled with only nodata values.
• ST_BandMetaData - Returns basic meta data for a specific raster band. band num 1 is assumed if none-specified.
• ST_BandNoDataValue - Returns the value in a given band that represents no data. If no band num 1 is assumed.
• ST_BandPath - Returns system file path to a band stored in file system. If no bandnum specified, 1 is assumed.
• ST_BandPixelType - Returns the type of pixel for given band. If no bandnum specified, 1 is assumed.
• ST_Clip - Returns the raster clipped by the input geometry. If band number not is specified, all bands are processed. If crop is
not specified or TRUE, the output raster is cropped.
• ST_ColorMap - Creates a new raster of up to four 8BUI bands (grayscale, RGB, RGBA) from the source raster and a specified
band. Band 1 is assumed if not specified.
• ST_Contains - Return true if no points of raster rastB lie in the exterior of raster rastA and at least one point of the interior of
rastB lies in the interior of rastA.
• ST_ContainsProperly - Return true if rastB intersects the interior of rastA but not the boundary or exterior of rastA.
• ST_ConvexHull - Return the convex hull geometry of the raster including pixel values equal to BandNoDataValue. For regular
shaped and non-skewed rasters, this gives the same result as ST_Envelope so only useful for irregularly shaped or skewed
rasters.
• ST_Count - Returns the number of pixels in a given band of a raster or raster coverage. If no band is specified defaults to band
1. If exclude_nodata_value is set to true, will only count pixels that are not equal to the nodata value.
• ST_CountAgg - Aggregate. Returns the number of pixels in a given band of a set of rasters. If no band is specified defaults to
band 1. If exclude_nodata_value is set to true, will only count pixels that are not equal to the NODATA value.
• ST_CoveredBy - Return true if no points of raster rastA lie outside raster rastB.
• ST_Covers - Return true if no points of raster rastB lie outside raster rastA.
• ST_DFullyWithin - Return true if rasters rastA and rastB are fully within the specified distance of each other.
• ST_DWithin - Return true if rasters rastA and rastB are within the specified distance of each other.
• ST_Disjoint - Return true if raster rastA does not spatially intersect rastB.
• ST_DumpAsPolygons - Returns a set of geomval (geom,val) rows, from a given raster band. If no band number is specified,
band num defaults to 1.
• ST_DumpValues - Get the values of the specified band as a 2-dimension array.
• ST_Envelope - Returns the polygon representation of the extent of the raster.
• ST_FromGDALRaster - Returns a raster from a supported GDAL raster file.
• ST_GeoReference - Returns the georeference meta data in GDAL or ESRI format as commonly seen in a world file. Default
is GDAL.
• ST_HasNoBand - Returns true if there is no band with given band number. If no band number is specified, then band number
1 is assumed.
• ST_Height - Returns the height of the raster in pixels.
• ST_HillShade - Returns the hypothetical illumination of an elevation raster band using provided azimuth, altitude, brightness
and scale inputs.
• ST_Histogram - Returns a set of record summarizing a raster or raster coverage data distribution separate bin ranges. Number
of bins are autocomputed if not specified.
• ST_Intersection - Returns a raster or a set of geometry-pixelvalue pairs representing the shared portion of two rasters or the
geometrical intersection of a vectorization of the raster and a geometry.
PostGIS 2.4.3 Manual 706 / 803

• ST_Intersects - Return true if raster rastA spatially intersects raster rastB.

• ST_IsEmpty - Returns true if the raster is empty (width = 0 and height = 0). Otherwise, returns false.
• ST_MakeEmptyCoverage - Cover georeferenced area with a grid of empty raster tiles.
• ST_MakeEmptyRaster - Returns an empty raster (having no bands) of given dimensions (width & height), upperleft X and Y,
pixel size and rotation (scalex, scaley, skewx & skewy) and reference system (srid). If a raster is passed in, returns a new raster
with the same size, alignment and SRID. If srid is left out, the spatial ref is set to unknown (0).
• ST_MapAlgebra - Callback function version - Returns a one-band raster given one or more input rasters, band indexes and one
user-specified callback function.
• ST_MapAlgebraExpr - 1 raster band version: Creates a new one band raster formed by applying a valid PostgreSQL algebraic
operation on the input raster band and of pixeltype provided. Band 1 is assumed if no band is specified.
• ST_MapAlgebraExpr - 2 raster band version: Creates a new one band raster formed by applying a valid PostgreSQL algebraic
operation on the two input raster bands and of pixeltype provided. band 1 of each raster is assumed if no band numbers are
specified. The resulting raster will be aligned (scale, skew and pixel corners) on the grid defined by the first raster and have its
extent defined by the "extenttype" parameter. Values for "extenttype" can be: INTERSECTION, UNION, FIRST, SECOND.
• ST_MapAlgebraFct - 1 band version - Creates a new one band raster formed by applying a valid PostgreSQL function on the
input raster band and of pixeltype prodived. Band 1 is assumed if no band is specified.
• ST_MapAlgebraFct - 2 band version - Creates a new one band raster formed by applying a valid PostgreSQL function on the
2 input raster bands and of pixeltype prodived. Band 1 is assumed if no band is specified. Extent type defaults to INTERSEC-
TION if not specified.
• ST_MapAlgebraFctNgb - 1-band version: Map Algebra Nearest Neighbor using user-defined PostgreSQL function. Return a
raster which values are the result of a PLPGSQL user function involving a neighborhood of values from the input raster band.
• ST_MapAlgebra - Expression version - Returns a one-band raster given one or two input rasters, band indexes and one or more
user-specified SQL expressions.
• ST_MemSize - Returns the amount of space (in bytes) the raster takes.
• ST_MetaData - Returns basic meta data about a raster object such as pixel size, rotation (skew), upper, lower left, etc.
• ST_MinConvexHull - Return the convex hull geometry of the raster excluding NODATA pixels.
• ST_NearestValue - Returns the nearest non-NODATA value of a given band’s pixel specified by a columnx and rowy or a
geometric point expressed in the same spatial reference coordinate system as the raster.
• ST_Neighborhood - Returns a 2-D double precision array of the non-NODATA values around a given band’s pixel specified
by either a columnX and rowY or a geometric point expressed in the same spatial reference coordinate system as the raster.
• ST_NotSameAlignmentReason - Returns text stating if rasters are aligned and if not aligned, a reason why.
• ST_NumBands - Returns the number of bands in the raster object.
• ST_Overlaps - Return true if raster rastA and rastB intersect but one does not completely contain the other.
• ST_PixelAsCentroid - Returns the centroid (point geometry) of the area represented by a pixel.
• ST_PixelAsCentroids - Returns the centroid (point geometry) for each pixel of a raster band along with the value, the X and
the Y raster coordinates of each pixel. The point geometry is the centroid of the area represented by a pixel.
• ST_PixelAsPoint - Returns a point geometry of the pixel’s upper-left corner.
• ST_PixelAsPoints - Returns a point geometry for each pixel of a raster band along with the value, the X and the Y raster
coordinates of each pixel. The coordinates of the point geometry are of the pixel’s upper-left corner.
• ST_PixelAsPolygon - Returns the polygon geometry that bounds the pixel for a particular row and column.
• ST_PixelAsPolygons - Returns the polygon geometry that bounds every pixel of a raster band along with the value, the X and
the Y raster coordinates of each pixel.
PostGIS 2.4.3 Manual 707 / 803

• ST_PixelHeight - Returns the pixel height in geometric units of the spatial reference system.
• ST_PixelOfValue - Get the columnx, rowy coordinates of the pixel whose value equals the search value.
• ST_PixelWidth - Returns the pixel width in geometric units of the spatial reference system.

• ST_Polygon - Returns a multipolygon geometry formed by the union of pixels that have a pixel value that is not no data value.
If no band number is specified, band num defaults to 1.
• ST_Quantile - Compute quantiles for a raster or raster table coverage in the context of the sample or population. Thus, a value
could be examined to be at the raster’s 25%, 50%, 75% percentile.

• ST_RasterToWorldCoord - Returns the raster’s upper left corner as geometric X and Y (longitude and latitude) given a column
and row. Column and row starts at 1.
• ST_RasterToWorldCoordX - Returns the geometric X coordinate upper left of a raster, column and row. Numbering of columns
and rows starts at 1.

• ST_RasterToWorldCoordY - Returns the geometric Y coordinate upper left corner of a raster, column and row. Numbering of
columns and rows starts at 1.
• ST_Reclass - Creates a new raster composed of band types reclassified from original. The nband is the band to be changed. If
nband is not specified assumed to be 1. All other bands are returned unchanged. Use case: convert a 16BUI band to a 8BUI
and so forth for simpler rendering as viewable formats.

• ST_Resample - Resample a raster using a specified resampling algorithm, new dimensions, an arbitrary grid corner and a set
of raster georeferencing attributes defined or borrowed from another raster.
• ST_Rescale - Resample a raster by adjusting only its scale (or pixel size). New pixel values are computed using the Nearest-
Neighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. Default is Nearest-
Neighbor.

• ST_Resize - Resize a raster to a new width/height

• ST_Reskew - Resample a raster by adjusting only its skew (or rotation parameters). New pixel values are computed using the
NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. Default is
NearestNeighbor.

• ST_Rotation - Returns the rotation of the raster in radian.

• ST_Roughness - Returns a raster with the calculated "roughness" of a DEM.
• ST_SRID - Returns the spatial reference identifier of the raster as defined in spatial_ref_sys table.
• ST_SameAlignment - Returns true if rasters have same skew, scale, spatial ref, and offset (pixels can be put on same grid
without cutting into pixels) and false if they don’t with notice detailing issue.
• ST_ScaleX - Returns the X component of the pixel width in units of coordinate reference system.
• ST_ScaleY - Returns the Y component of the pixel height in units of coordinate reference system.
• ST_SetBandIsNoData - Sets the isnodata flag of the band to TRUE.

• ST_SetBandNoDataValue - Sets the value for the given band that represents no data. Band 1 is assumed if no band is specified.
To mark a band as having no nodata value, set the nodata value = NULL.
• ST_SetGeoReference - Set Georeference 6 georeference parameters in a single call. Numbers should be separated by white
space. Accepts inputs in GDAL or ESRI format. Default is GDAL.

• ST_SetRotation - Set the rotation of the raster in radian.

• ST_SetSRID - Sets the SRID of a raster to a particular integer srid defined in the spatial_ref_sys table.
• ST_SetScale - Sets the X and Y size of pixels in units of coordinate reference system. Number units/pixel width/height.
PostGIS 2.4.3 Manual 708 / 803

• ST_SetSkew - Sets the georeference X and Y skew (or rotation parameter). If only one is passed in, sets X and Y to the same
value.
• ST_SetUpperLeft - Sets the value of the upper left corner of the pixel of the raster to projected X and Y coordinates.
• ST_SetValue - Returns modified raster resulting from setting the value of a given band in a given columnx, rowy pixel or the
pixels that intersect a particular geometry. Band numbers start at 1 and assumed to be 1 if not specified.
• ST_SetValues - Returns modified raster resulting from setting the values of a given band.
• ST_SkewX - Returns the georeference X skew (or rotation parameter).
• ST_SkewY - Returns the georeference Y skew (or rotation parameter).
• ST_Slope - Returns the slope (in degrees by default) of an elevation raster band. Useful for analyzing terrain.
• ST_SnapToGrid - Resample a raster by snapping it to a grid. New pixel values are computed using the NearestNeighbor
(english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. Default is NearestNeighbor.
• ST_Summary - Returns a text summary of the contents of the raster.
• ST_SummaryStats - Returns summarystats consisting of count, sum, mean, stddev, min, max for a given raster band of a raster
or raster coverage. Band 1 is assumed is no band is specified.
• ST_SummaryStatsAgg - Aggregate. Returns summarystats consisting of count, sum, mean, stddev, min, max for a given raster
band of a set of raster. Band 1 is assumed is no band is specified.
• ST_TPI - Returns a raster with the calculated Topographic Position Index.
• ST_TRI - Returns a raster with the calculated Terrain Ruggedness Index.
• ST_Tile - Returns a set of rasters resulting from the split of the input raster based upon the desired dimensions of the output
rasters.
• ST_Touches - Return true if raster rastA and rastB have at least one point in common but their interiors do not intersect.
• ST_Transform - Reprojects a raster in a known spatial reference system to another known spatial reference system using
specified resampling algorithm. Options are NearestNeighbor, Bilinear, Cubic, CubicSpline, Lanczos defaulting to Nearest-
Neighbor.
• ST_Union - Returns the union of a set of raster tiles into a single raster composed of 1 or more bands.
• ST_UpperLeftX - Returns the upper left X coordinate of raster in projected spatial ref.
• ST_UpperLeftY - Returns the upper left Y coordinate of raster in projected spatial ref.
• ST_Value - Returns the value of a given band in a given columnx, rowy pixel or at a particular geometric point. Band numbers
start at 1 and assumed to be 1 if not specified. If exclude_nodata_value is set to false, then all pixels include nodata pixels are
considered to intersect and return value. If exclude_nodata_value is not passed in then reads it from metadata of raster.
• ST_ValueCount - Returns a set of records containing a pixel band value and count of the number of pixels in a given band of a
raster (or a raster coverage) that have a given set of values. If no band is specified defaults to band 1. By default nodata value
pixels are not counted. and all other values in the pixel are output and pixel band values are rounded to the nearest integer.
• ST_Width - Returns the width of the raster in pixels.
• ST_Within - Return true if no points of raster rastA lie in the exterior of raster rastB and at least one point of the interior of
rastA lies in the interior of rastB.
• ST_WorldToRasterCoord - Returns the upper left corner as column and row given geometric X and Y (longitude and latitude)
or a point geometry expressed in the spatial reference coordinate system of the raster.
• ST_WorldToRasterCoordX - Returns the column in the raster of the point geometry (pt) or a X and Y world coordinate (xw,
yw) represented in world spatial reference system of raster.
• ST_WorldToRasterCoordY - Returns the row in the raster of the point geometry (pt) or a X and Y world coordinate (xw, yw)
represented in world spatial reference system of raster.
• UpdateRasterSRID - Change the SRID of all rasters in the user-specified column and table.
PostGIS 2.4.3 Manual 709 / 803

14.6 PostGIS Geometry / Geography / Raster Dump Functions

The functions given below are PostGIS functions that take as input or return as output a set of or single geometry_dump or
geomval data type object.

• ST_DumpAsPolygons - Returns a set of geomval (geom,val) rows, from a given raster band. If no band number is specified,
band num defaults to 1.
• ST_Intersection - Returns a raster or a set of geometry-pixelvalue pairs representing the shared portion of two rasters or the
geometrical intersection of a vectorization of the raster and a geometry.

• ST_Dump - Returns a set of geometry_dump (geom,path) rows, that make up a geometry g1.
• ST_DumpPoints - Returns a set of geometry_dump (geom,path) rows of all points that make up a geometry.
• ST_DumpRings - Returns a set of geometry_dump rows, representing the exterior and interior rings of a polygon.

14.7 PostGIS Box Functions

The functions given below are PostGIS functions that take as input or return as output the box* family of PostGIS spatial types.
The box family of types consists of box2d, and box3d

• Box2D - Returns a BOX2D representing the maximum extents of the geometry.

• Box3D - Returns a BOX3D representing the maximum extents of the geometry.
• Box3D - Returns the box 3d representation of the enclosing box of the raster.

• ST_3DExtent - an aggregate function that returns the box3D bounding box that bounds rows of geometries.
• ST_3DMakeBox - Creates a BOX3D defined by the given 3d point geometries.
• ST_AsMVTGeom - Transform a geometry into the coordinate space of a Mapbox Vector Tile.

• ST_AsTWKB - Returns the geometry as TWKB, aka "Tiny Well-Known Binary"

• ST_Box2dFromGeoHash - Return a BOX2D from a GeoHash string.
• ST_ClipByBox2D - Returns the portion of a geometry falling within a rectangle.
• ST_EstimatedExtent - Return the ’estimated’ extent of the given spatial table. The estimated is taken from the geometry
column’s statistics. The current schema will be used if not specified.
• ST_Expand - Returns bounding box expanded in all directions from the bounding box of the input geometry. Uses double-
precision
• ST_Extent - an aggregate function that returns the bounding box that bounds rows of geometries.

• ST_MakeBox2D - Creates a BOX2D defined by the given point geometries.

• ST_XMax - Returns X maxima of a bounding box 2d or 3d or a geometry.
• ST_XMin - Returns X minima of a bounding box 2d or 3d or a geometry.
• ST_YMax - Returns Y maxima of a bounding box 2d or 3d or a geometry.

• ST_YMin - Returns Y minima of a bounding box 2d or 3d or a geometry.

• ST_ZMax - Returns Z minima of a bounding box 2d or 3d or a geometry.
• ST_ZMin - Returns Z minima of a bounding box 2d or 3d or a geometry.
PostGIS 2.4.3 Manual 710 / 803

• ~(box2df,box2df) - Returns TRUE if a 2D float precision bounding box (BOX2DF) contains another 2D float precision bound-
ing box (BOX2DF).
• ~(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) contains a geometry’s 2D bonding box.

• ~(geometry,box2df) - Returns TRUE if a geometry’s 2D bonding box contains a 2D float precision bounding box (GIDX).
• @(box2df,box2df) - Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into another 2D float precision
bounding box.
• @(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into a geometry’s 2D
bounding box.
• @(geometry,box2df) - Returns TRUE if a geometry’s 2D bounding box is contained into a 2D float precision bounding box
(BOX2DF).
• &&(box2df,box2df) - Returns TRUE if two 2D float precision bounding boxes (BOX2DF) intersect each other.

• &&(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) intersects a geometry’s (cached) 2D
bounding box.
• &&(geometry,box2df) - Returns TRUE if a geometry’s (cached) 2D bounding box intersects a 2D float precision bounding box
(BOX2DF).

14.8 PostGIS Functions that support 3D

The functions given below are PostGIS functions that do not throw away the Z-Index.

• AddGeometryColumn - Adds a geometry column to an existing table of attributes. By default uses type modifier to define
rather than constraints. Pass in false for use_typmod to get old check constraint based behavior
• Box3D - Returns a BOX3D representing the maximum extents of the geometry.
• DropGeometryColumn - Removes a geometry column from a spatial table.

• GeometryType - Returns the type of the geometry as a string. Eg: ’LINESTRING’, ’POLYGON’, ’MULTIPOINT’, etc.
• ST_3DArea - Computes area of 3D surface geometries. Will return 0 for solids.
• ST_3DClosestPoint - Returns the 3-dimensional point on g1 that is closest to g2. This is the first point of the 3D shortest line.
• ST_3DDFullyWithin - Returns true if all of the 3D geometries are within the specified distance of one another.

• ST_3DDWithin - For 3d (z) geometry type Returns true if two geometries 3d distance is within number of units.
• ST_3DDifference - Perform 3D difference
• ST_3DDistance - For geometry type Returns the 3-dimensional cartesian minimum distance (based on spatial ref) between two
geometries in projected units.

• ST_3DExtent - an aggregate function that returns the box3D bounding box that bounds rows of geometries.
• ST_3DIntersection - Perform 3D intersection
• ST_3DIntersects - Returns TRUE if the Geometries "spatially intersect" in 3d - only for points, linestrings, polygons, polyhe-
dral surface (area). With SFCGAL backend enabled also supports TINS

• ST_3DLength - Returns the 3-dimensional or 2-dimensional length of the geometry if it is a linestring or multi-linestring.
• ST_3DLongestLine - Returns the 3-dimensional longest line between two geometries
• ST_3DMakeBox - Creates a BOX3D defined by the given 3d point geometries.
PostGIS 2.4.3 Manual 711 / 803

• ST_3DMaxDistance - For geometry type Returns the 3-dimensional cartesian maximum distance (based on spatial ref) between
two geometries in projected units.
• ST_3DPerimeter - Returns the 3-dimensional perimeter of the geometry, if it is a polygon or multi-polygon.

• ST_3DShortestLine - Returns the 3-dimensional shortest line between two geometries

• ST_3DUnion - Perform 3D union
• ST_Accum - Aggregate. Constructs an array of geometries.
• ST_AddMeasure - Return a derived geometry with measure elements linearly interpolated between the start and end points.

• ST_AddPoint - Add a point to a LineString.

• ST_Affine - Apply a 3d affine transformation to a geometry.
• ST_ApproximateMedialAxis - Compute the approximate medial axis of an areal geometry.

• ST_AsBinary - Return the Well-Known Binary (WKB) representation of the geometry/geography without SRID meta data.
• ST_AsEWKB - Return the Well-Known Binary (WKB) representation of the geometry with SRID meta data.
• ST_AsEWKT - Return the Well-Known Text (WKT) representation of the geometry with SRID meta data.
• ST_AsGML - Return the geometry as a GML version 2 or 3 element.

• ST_AsGeoJSON - Return the geometry as a GeoJSON element.

• ST_AsHEXEWKB - Returns a Geometry in HEXEWKB format (as text) using either little-endian (NDR) or big-endian (XDR)
encoding.
• ST_AsKML - Return the geometry as a KML element. Several variants. Default version=2, default precision=15

• ST_AsX3D - Returns a Geometry in X3D xml node element format: ISO-IEC-19776-1.2-X3DEncodings-XML

• ST_Boundary - Returns the closure of the combinatorial boundary of this Geometry.
• ST_BoundingDiagonal - Returns the diagonal of the supplied geometry’s bounding box.

• ST_CPAWithin - Returns true if the trajectories’ closest points of approachare within the specified distance.
• ST_ClosestPointOfApproach - Returns the measure at which points interpolated along two lines are closest.
• ST_Collect - Return a specified ST_Geometry value from a collection of other geometries.
• ST_ConvexHull - The convex hull of a geometry represents the minimum convex geometry that encloses all geometries within
the set.
• ST_CoordDim - Return the coordinate dimension of the ST_Geometry value.
• ST_CurveToLine - Converts a CIRCULARSTRING/CURVEPOLYGON to a LINESTRING/POLYGON
• ST_DelaunayTriangles - Return a Delaunay triangulation around the given input points.

• ST_Difference - Returns a geometry that represents that part of geometry A that does not intersect with geometry B.
• ST_DistanceCPA - Returns the distance between closest points of approach in two trajectories.
• ST_Dump - Returns a set of geometry_dump (geom,path) rows, that make up a geometry g1.

• ST_DumpPoints - Returns a set of geometry_dump (geom,path) rows of all points that make up a geometry.
• ST_DumpRings - Returns a set of geometry_dump rows, representing the exterior and interior rings of a polygon.
• ST_EndPoint - Returns the last point of a LINESTRING or CIRCULARLINESTRING geometry as a POINT.
PostGIS 2.4.3 Manual 712 / 803

• ST_ExteriorRing - Returns a line string representing the exterior ring of the POLYGON geometry. Return NULL if the
geometry is not a polygon. Will not work with MULTIPOLYGON
• ST_Extrude - Extrude a surface to a related volume

• ST_FlipCoordinates - Returns a version of the given geometry with X and Y axis flipped. Useful for people who have built
latitude/longitude features and need to fix them.
• ST_Force2D - Force the geometries into a "2-dimensional mode".
• ST_ForceCurve - Upcast a geometry into its curved type, if applicable.

• ST_ForceLHR - Force LHR orientation

• ST_ForcePolygonCCW - Orients all exterior rings counter-clockwise and all interior rings clockwise.
• ST_ForcePolygonCW - Orients all exterior rings clockwise and all interior rings counter-clockwise.
• ST_ForceRHR - Force the orientation of the vertices in a polygon to follow the Right-Hand-Rule.

• ST_ForceSFS - Force the geometries to use SFS 1.1 geometry types only.
• ST_Force_3D - Force the geometries into XYZ mode. This is an alias for ST_Force3DZ.
• ST_Force_3DZ - Force the geometries into XYZ mode.

• ST_Force_4D - Force the geometries into XYZM mode.

• ST_Force_Collection - Convert the geometry into a GEOMETRYCOLLECTION.
• ST_GeomFromEWKB - Return a specified ST_Geometry value from Extended Well-Known Binary representation (EWKB).
• ST_GeomFromEWKT - Return a specified ST_Geometry value from Extended Well-Known Text representation (EWKT).

• ST_GeomFromGML - Takes as input GML representation of geometry and outputs a PostGIS geometry object
• ST_GeomFromGeoJSON - Takes as input a geojson representation of a geometry and outputs a PostGIS geometry object
• ST_GeomFromKML - Takes as input KML representation of geometry and outputs a PostGIS geometry object

• ST_GeometricMedian - Returns the geometric median of a MultiPoint.

• ST_GeometryN - Return the 1-based Nth geometry if the geometry is a GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINE
MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE Otherwise, return NULL.
• ST_GeometryType - Return the geometry type of the ST_Geometry value.

• ST_HasArc - Returns true if a geometry or geometry collection contains a circular string

• ST_InteriorRingN - Return the Nth interior linestring ring of the polygon geometry. Return NULL if the geometry is not a
polygon or the given N is out of range.
• ST_InterpolatePoint - Return the value of the measure dimension of a geometry at the point closed to the provided point.

• ST_IsClosed - Returns TRUE if the LINESTRING’s start and end points are coincident. For Polyhedral surface is closed
(volumetric).
• ST_IsCollection - Returns TRUE if the argument is a collection (MULTI*, GEOMETRYCOLLECTION, ...)
• ST_IsPlanar - Check if a surface is or not planar

• ST_IsPolygonCCW - Returns true if all exterior rings are oriented counter-clockwise and all interior rings are oriented clock-
wise.
• ST_IsPolygonCW - Returns true if all exterior rings are oriented clockwise and all interior rings are oriented counter-clockwise.
• ST_IsSimple - Returns (TRUE) if this Geometry has no anomalous geometric points, such as self intersection or self tangency.
PostGIS 2.4.3 Manual 713 / 803

• ST_IsSolid - Test if the geometry is a solid. No validity check is performed.

• ST_IsValidTrajectory - Returns true if the geometry is a valid trajectory.
• ST_Length_Spheroid - Calculates the 2D or 3D length/perimeter of a geometry on an ellipsoid. This is useful if the coordinates
of the geometry are in longitude/latitude and a length is desired without reprojection.
• ST_LineFromMultiPoint - Creates a LineString from a MultiPoint geometry.
• ST_LineInterpolatePoint - Returns a point interpolated along a line. Second argument is a float8 between 0 and 1 representing
fraction of total length of linestring the point has to be located.
• ST_LineSubstring - Return a linestring being a substring of the input one starting and ending at the given fractions of total 2d
length. Second and third arguments are float8 values between 0 and 1.
• ST_LineToCurve - Converts a LINESTRING/POLYGON to a CIRCULARSTRING, CURVEPOLYGON
• ST_LocateBetweenElevations - Return a derived geometry (collection) value with elements that intersect the specified range
of elevations inclusively. Only 3D, 4D LINESTRINGS and MULTILINESTRINGS are supported.
• ST_M - Return the M coordinate of the point, or NULL if not available. Input must be a point.
• ST_MakeLine - Creates a Linestring from point, multipoint, or line geometries.
• ST_MakePoint - Creates a 2D,3DZ or 4D point geometry.
• ST_MakePolygon - Creates a Polygon formed by the given shell. Input geometries must be closed LINESTRINGS.
• ST_MakeSolid - Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input geometry must be a
closed Polyhedral Surface or a closed TIN.
• ST_MakeValid - Attempts to make an invalid geometry valid without losing vertices.
• ST_MemSize - Returns the amount of space (in bytes) the geometry takes.
• ST_MemUnion - Same as ST_Union, only memory-friendly (uses less memory and more processor time).
• ST_NDims - Returns coordinate dimension of the geometry as a small int. Values are: 2,3 or 4.
• ST_NPoints - Return the number of points (vertexes) in a geometry.
• ST_NRings - If the geometry is a polygon or multi-polygon returns the number of rings.
• ST_Node - Node a set of linestrings.
• ST_NumGeometries - If geometry is a GEOMETRYCOLLECTION (or MULTI*) return the number of geometries, for single
geometries will return 1, otherwise return NULL.
• ST_NumPatches - Return the number of faces on a Polyhedral Surface. Will return null for non-polyhedral geometries.
• ST_Orientation - Determine surface orientation
• ST_PatchN - Return the 1-based Nth geometry (face) if the geometry is a POLYHEDRALSURFACE, POLYHEDRALSUR-
FACEM. Otherwise, return NULL.
• ST_PointFromWKB - Makes a geometry from WKB with the given SRID
• ST_PointN - Return the Nth point in the first LineString or circular LineString in the geometry. Negative values are counted
backwards from the end of the LineString. Returns NULL if there is no linestring in the geometry.
• ST_PointOnSurface - Returns a POINT guaranteed to lie on the surface.
• ST_Points - Returns a MultiPoint containing all of the coordinates of a geometry.
• ST_Polygon - Returns a polygon built from the specified linestring and SRID.
• ST_RemovePoint - Remove point from a linestring.
PostGIS 2.4.3 Manual 714 / 803

• ST_RemoveRepeatedPoints - Returns a version of the given geometry with duplicated points removed.
• ST_Reverse - Return the geometry with vertex order reversed.
• ST_Rotate - Rotate a geometry rotRadians counter-clockwise about an origin.
• ST_RotateX - Rotate a geometry rotRadians about the X axis.
• ST_RotateY - Rotate a geometry rotRadians about the Y axis.
• ST_RotateZ - Rotate a geometry rotRadians about the Z axis.
• ST_Scale - Scale a geometry by given factors.
• ST_SetPoint - Replace point of a linestring with a given point.
• ST_Shift_Longitude - Toggle geometry coordinates between -180..180 and 0..360 ranges.
• ST_SnapToGrid - Snap all points of the input geometry to a regular grid.
• ST_StartPoint - Returns the first point of a LINESTRING geometry as a POINT.
• ST_StraightSkeleton - Compute a straight skeleton from a geometry
• ST_SwapOrdinates - Returns a version of the given geometry with given ordinate values swapped.
• ST_SymDifference - Returns a geometry that represents the portions of A and B that do not intersect. It is called a symmetric
difference because ST_SymDifference(A,B) = ST_SymDifference(B,A).
• ST_Tesselate - Perform surface Tesselation of a polygon or polyhedralsurface and returns as a TIN or collection of TINS
• ST_TransScale - Translate a geometry by given factors and offsets.
• ST_Translate - Translate a geometry by given offsets.
• ST_UnaryUnion - Like ST_Union, but working at the geometry component level.
• ST_Volume - Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return 0.
• ST_WrapX - Wrap a geometry around an X value.
• ST_X - Return the X coordinate of the point, or NULL if not available. Input must be a point.
• ST_XMax - Returns X maxima of a bounding box 2d or 3d or a geometry.
• ST_XMin - Returns X minima of a bounding box 2d or 3d or a geometry.
• ST_Y - Return the Y coordinate of the point, or NULL if not available. Input must be a point.
• ST_YMax - Returns Y maxima of a bounding box 2d or 3d or a geometry.
• ST_YMin - Returns Y minima of a bounding box 2d or 3d or a geometry.
• ST_Z - Return the Z coordinate of the point, or NULL if not available. Input must be a point.
• ST_ZMax - Returns Z minima of a bounding box 2d or 3d or a geometry.
• ST_ZMin - Returns Z minima of a bounding box 2d or 3d or a geometry.
• ST_Zmflag - Returns ZM (dimension semantic) flag of the geometries as a small int. Values are: 0=2d, 1=3dm, 2=3dz, 3=4d.
• TG_Equals - Returns true if two topogeometries are composed of the same topology primitives.
• TG_Intersects - Returns true if any pair of primitives from thetwo topogeometries intersect.
• UpdateGeometrySRID - Updates the SRID of all features in a geometry column, geometry_columns metadata and srid. If
it was enforced with constraints, the constraints will be updated with new srid constraint. If the old was enforced by type
definition, the type definition will be changed.
PostGIS 2.4.3 Manual 715 / 803

• geometry_overlaps_nd - Returns TRUE if A’s n-D bounding box intersects B’s n-D bounding box.
• overlaps_nd_geometry_gidx - Returns TRUE if a geometry’s (cached) n-D bounding box intersects a n-D float precision
bounding box (GIDX).

• overlaps_nd_gidx_geometry - Returns TRUE if a n-D float precision bounding box (GIDX) intersects a geometry’s (cached)
n-D bounding box.
• overlaps_nd_gidx_gidx - Returns TRUE if two n-D float precision bounding boxes (GIDX) intersect each other.
• postgis_sfcgal_version - Returns the version of SFCGAL in use

14.9 PostGIS Curved Geometry Support Functions

The functions given below are PostGIS functions that can use CIRCULARSTRING, CURVEPOLYGON, and other curved
geometry types

• AddGeometryColumn - Adds a geometry column to an existing table of attributes. By default uses type modifier to define
rather than constraints. Pass in false for use_typmod to get old check constraint based behavior
• Box2D - Returns a BOX2D representing the maximum extents of the geometry.

• Box3D - Returns a BOX3D representing the maximum extents of the geometry.

• DropGeometryColumn - Removes a geometry column from a spatial table.
• GeometryType - Returns the type of the geometry as a string. Eg: ’LINESTRING’, ’POLYGON’, ’MULTIPOINT’, etc.
• PostGIS_AddBBox - Add bounding box to the geometry.

• PostGIS_DropBBox - Drop the bounding box cache from the geometry.

• PostGIS_HasBBox - Returns TRUE if the bbox of this geometry is cached, FALSE otherwise.
• ST_3DExtent - an aggregate function that returns the box3D bounding box that bounds rows of geometries.

• ST_Accum - Aggregate. Constructs an array of geometries.

• ST_Affine - Apply a 3d affine transformation to a geometry.
• ST_AsBinary - Return the Well-Known Binary (WKB) representation of the geometry/geography without SRID meta data.
• ST_AsEWKB - Return the Well-Known Binary (WKB) representation of the geometry with SRID meta data.

• ST_AsEWKT - Return the Well-Known Text (WKT) representation of the geometry with SRID meta data.
• ST_AsHEXEWKB - Returns a Geometry in HEXEWKB format (as text) using either little-endian (NDR) or big-endian (XDR)
encoding.
• ST_AsText - Return the Well-Known Text (WKT) representation of the geometry/geography without SRID metadata.

• ST_Collect - Return a specified ST_Geometry value from a collection of other geometries.

• ST_CoordDim - Return the coordinate dimension of the ST_Geometry value.
• ST_CurveToLine - Converts a CIRCULARSTRING/CURVEPOLYGON to a LINESTRING/POLYGON

• ST_Distance - For geometry type Returns the 2D Cartesian distance between two geometries in projected units (based on
spatial ref). For geography type defaults to return minimum geodesic distance between two geographies in meters.
• ST_Dump - Returns a set of geometry_dump (geom,path) rows, that make up a geometry g1.
• ST_DumpPoints - Returns a set of geometry_dump (geom,path) rows of all points that make up a geometry.
PostGIS 2.4.3 Manual 716 / 803

• ST_EndPoint - Returns the last point of a LINESTRING or CIRCULARLINESTRING geometry as a POINT.

• ST_EstimatedExtent - Return the ’estimated’ extent of the given spatial table. The estimated is taken from the geometry
column’s statistics. The current schema will be used if not specified.
• ST_FlipCoordinates - Returns a version of the given geometry with X and Y axis flipped. Useful for people who have built
latitude/longitude features and need to fix them.
• ST_Force2D - Force the geometries into a "2-dimensional mode".
• ST_ForceCurve - Upcast a geometry into its curved type, if applicable.
• ST_ForceSFS - Force the geometries to use SFS 1.1 geometry types only.
• ST_Force3D - Force the geometries into XYZ mode. This is an alias for ST_Force3DZ.
• ST_Force3DM - Force the geometries into XYM mode.
• ST_Force3DZ - Force the geometries into XYZ mode.
• ST_Force4D - Force the geometries into XYZM mode.
• ST_ForceCollection - Convert the geometry into a GEOMETRYCOLLECTION.
• ST_GeoHash - Return a GeoHash representation of the geometry.
• ST_GeogFromWKB - Creates a geography instance from a Well-Known Binary geometry representation (WKB) or extended
Well Known Binary (EWKB).
• ST_GeomFromEWKB - Return a specified ST_Geometry value from Extended Well-Known Binary representation (EWKB).
• ST_GeomFromEWKT - Return a specified ST_Geometry value from Extended Well-Known Text representation (EWKT).
• ST_GeomFromText - Return a specified ST_Geometry value from Well-Known Text representation (WKT).
• ST_GeomFromWKB - Creates a geometry instance from a Well-Known Binary geometry representation (WKB) and optional
SRID.
• ST_GeometryN - Return the 1-based Nth geometry if the geometry is a GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINE
MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE Otherwise, return NULL.
• = - Returns TRUE if the coordinates and coordinate order geometry/geography A are the same as the coordinates and coordinate
order of geometry/geography B.
• &<| - Returns TRUE if A’s bounding box overlaps or is below B’s.
• ST_HasArc - Returns true if a geometry or geometry collection contains a circular string
• ST_IsClosed - Returns TRUE if the LINESTRING’s start and end points are coincident. For Polyhedral surface is closed
(volumetric).
• ST_IsCollection - Returns TRUE if the argument is a collection (MULTI*, GEOMETRYCOLLECTION, ...)
• ST_IsEmpty - Returns true if this Geometry is an empty geometrycollection, polygon, point etc.
• ST_LineToCurve - Converts a LINESTRING/POLYGON to a CIRCULARSTRING, CURVEPOLYGON
• ST_MemSize - Returns the amount of space (in bytes) the geometry takes.
• ST_NPoints - Return the number of points (vertexes) in a geometry.
• ST_NRings - If the geometry is a polygon or multi-polygon returns the number of rings.
• ST_PointFromWKB - Makes a geometry from WKB with the given SRID
• ST_PointN - Return the Nth point in the first LineString or circular LineString in the geometry. Negative values are counted
backwards from the end of the LineString. Returns NULL if there is no linestring in the geometry.
PostGIS 2.4.3 Manual 717 / 803

• ST_Points - Returns a MultiPoint containing all of the coordinates of a geometry.

• ST_Rotate - Rotate a geometry rotRadians counter-clockwise about an origin.
• ST_RotateZ - Rotate a geometry rotRadians about the Z axis.

• ST_SRID - Returns the spatial reference identifier for the ST_Geometry as defined in spatial_ref_sys table.
• ST_Scale - Scale a geometry by given factors.
• ST_SetSRID - Set the SRID on a geometry to a particular integer value.

• ST_StartPoint - Returns the first point of a LINESTRING geometry as a POINT.

• ST_Summary - Returns a text summary of the contents of the geometry.
• ST_SwapOrdinates - Returns a version of the given geometry with given ordinate values swapped.
• ST_TransScale - Translate a geometry by given factors and offsets.

• ST_Transform - Return a new geometry with its coordinates transformed to a different spatial reference.
• ST_Translate - Translate a geometry by given offsets.
• ST_XMax - Returns X maxima of a bounding box 2d or 3d or a geometry.

• ST_XMin - Returns X minima of a bounding box 2d or 3d or a geometry.

• ST_YMax - Returns Y maxima of a bounding box 2d or 3d or a geometry.
• ST_YMin - Returns Y minima of a bounding box 2d or 3d or a geometry.
• ST_ZMax - Returns Z minima of a bounding box 2d or 3d or a geometry.

• ST_ZMin - Returns Z minima of a bounding box 2d or 3d or a geometry.

• ST_Zmflag - Returns ZM (dimension semantic) flag of the geometries as a small int. Values are: 0=2d, 1=3dm, 2=3dz, 3=4d.
• UpdateGeometrySRID - Updates the SRID of all features in a geometry column, geometry_columns metadata and srid. If
it was enforced with constraints, the constraints will be updated with new srid constraint. If the old was enforced by type
definition, the type definition will be changed.
• ~(box2df,box2df) - Returns TRUE if a 2D float precision bounding box (BOX2DF) contains another 2D float precision bound-
ing box (BOX2DF).
• ~(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) contains a geometry’s 2D bonding box.

• ~(geometry,box2df) - Returns TRUE if a geometry’s 2D bonding box contains a 2D float precision bounding box (GIDX).
• && - Returns TRUE if A’s 2D bounding box intersects B’s 2D bounding box.
• &&& - Returns TRUE if A’s n-D bounding box intersects B’s n-D bounding box.
• @(box2df,box2df) - Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into another 2D float precision
bounding box.
• @(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into a geometry’s 2D
bounding box.
• @(geometry,box2df) - Returns TRUE if a geometry’s 2D bounding box is contained into a 2D float precision bounding box
(BOX2DF).

• &&(box2df,box2df) - Returns TRUE if two 2D float precision bounding boxes (BOX2DF) intersect each other.
• &&(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) intersects a geometry’s (cached) 2D
bounding box.
PostGIS 2.4.3 Manual 718 / 803

• &&(geometry,box2df) - Returns TRUE if a geometry’s (cached) 2D bounding box intersects a 2D float precision bounding box
(BOX2DF).
• &&&(geometry,gidx) - Returns TRUE if a geometry’s (cached) n-D bounding box intersects a n-D float precision bounding
box (GIDX).
• &&&(gidx,geometry) - Returns TRUE if a n-D float precision bounding box (GIDX) intersects a geometry’s (cached) n-D
bounding box.
• &&&(gidx,gidx) - Returns TRUE if two n-D float precision bounding boxes (GIDX) intersect each other.

14.10 PostGIS Polyhedral Surface Support Functions

The functions given below are PostGIS functions that can use POLYHEDRALSURFACE, POLYHEDRALSURFACEM geome-
tries

• Box2D - Returns a BOX2D representing the maximum extents of the geometry.

• Box3D - Returns a BOX3D representing the maximum extents of the geometry.
• GeometryType - Returns the type of the geometry as a string. Eg: ’LINESTRING’, ’POLYGON’, ’MULTIPOINT’, etc.

• ST_3DArea - Computes area of 3D surface geometries. Will return 0 for solids.

• ST_3DClosestPoint - Returns the 3-dimensional point on g1 that is closest to g2. This is the first point of the 3D shortest line.
• ST_3DDFullyWithin - Returns true if all of the 3D geometries are within the specified distance of one another.
• ST_3DDWithin - For 3d (z) geometry type Returns true if two geometries 3d distance is within number of units.

• ST_3DDifference - Perform 3D difference

• ST_3DDistance - For geometry type Returns the 3-dimensional cartesian minimum distance (based on spatial ref) between two
geometries in projected units.
• ST_3DExtent - an aggregate function that returns the box3D bounding box that bounds rows of geometries.

• ST_3DIntersection - Perform 3D intersection

• ST_3DIntersects - Returns TRUE if the Geometries "spatially intersect" in 3d - only for points, linestrings, polygons, polyhe-
dral surface (area). With SFCGAL backend enabled also supports TINS
• ST_3DLongestLine - Returns the 3-dimensional longest line between two geometries

• ST_3DMaxDistance - For geometry type Returns the 3-dimensional cartesian maximum distance (based on spatial ref) between
two geometries in projected units.
• ST_3DShortestLine - Returns the 3-dimensional shortest line between two geometries
• ST_3DUnion - Perform 3D union

• ST_Accum - Aggregate. Constructs an array of geometries.

• ST_Affine - Apply a 3d affine transformation to a geometry.
• ST_ApproximateMedialAxis - Compute the approximate medial axis of an areal geometry.

• ST_Area - Returns the area of the surface if it is a Polygon or MultiPolygon. For geometry, a 2D Cartesian area is determined
with units specified by the SRID. For geography, area is determined on a curved surface with units in square meters.
• ST_AsBinary - Return the Well-Known Binary (WKB) representation of the geometry/geography without SRID meta data.
• ST_AsEWKB - Return the Well-Known Binary (WKB) representation of the geometry with SRID meta data.
PostGIS 2.4.3 Manual 719 / 803

• ST_AsEWKT - Return the Well-Known Text (WKT) representation of the geometry with SRID meta data.
• ST_AsGML - Return the geometry as a GML version 2 or 3 element.
• ST_AsX3D - Returns a Geometry in X3D xml node element format: ISO-IEC-19776-1.2-X3DEncodings-XML

• ST_CoordDim - Return the coordinate dimension of the ST_Geometry value.

• ST_Dimension - The inherent dimension of this Geometry object, which must be less than or equal to the coordinate dimension.
• ST_Dump - Returns a set of geometry_dump (geom,path) rows, that make up a geometry g1.

• ST_DumpPoints - Returns a set of geometry_dump (geom,path) rows of all points that make up a geometry.
• ST_Expand - Returns bounding box expanded in all directions from the bounding box of the input geometry. Uses double-
precision
• ST_Extent - an aggregate function that returns the bounding box that bounds rows of geometries.

• ST_Extrude - Extrude a surface to a related volume

• ST_FlipCoordinates - Returns a version of the given geometry with X and Y axis flipped. Useful for people who have built
latitude/longitude features and need to fix them.
• ST_Force2D - Force the geometries into a "2-dimensional mode".

• ST_ForceLHR - Force LHR orientation

• ST_ForceRHR - Force the orientation of the vertices in a polygon to follow the Right-Hand-Rule.
• ST_ForceSFS - Force the geometries to use SFS 1.1 geometry types only.
• ST_Force3D - Force the geometries into XYZ mode. This is an alias for ST_Force3DZ.

• ST_Force3DZ - Force the geometries into XYZ mode.

• ST_ForceCollection - Convert the geometry into a GEOMETRYCOLLECTION.
• ST_GeomFromEWKB - Return a specified ST_Geometry value from Extended Well-Known Binary representation (EWKB).

• ST_GeomFromEWKT - Return a specified ST_Geometry value from Extended Well-Known Text representation (EWKT).
• ST_GeomFromGML - Takes as input GML representation of geometry and outputs a PostGIS geometry object
• ST_GeometryN - Return the 1-based Nth geometry if the geometry is a GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINE
MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE Otherwise, return NULL.

• ST_GeometryType - Return the geometry type of the ST_Geometry value.

• = - Returns TRUE if the coordinates and coordinate order geometry/geography A are the same as the coordinates and coordinate
order of geometry/geography B.
• &<| - Returns TRUE if A’s bounding box overlaps or is below B’s.

• ~= - Returns TRUE if A’s bounding box is the same as B’s.

• ST_IsClosed - Returns TRUE if the LINESTRING’s start and end points are coincident. For Polyhedral surface is closed
(volumetric).
• ST_IsPlanar - Check if a surface is or not planar

• ST_IsSolid - Test if the geometry is a solid. No validity check is performed.

• ST_MakeSolid - Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input geometry must be a
closed Polyhedral Surface or a closed TIN.
• ST_MemSize - Returns the amount of space (in bytes) the geometry takes.
PostGIS 2.4.3 Manual 720 / 803

• ST_NPoints - Return the number of points (vertexes) in a geometry.

• ST_NumGeometries - If geometry is a GEOMETRYCOLLECTION (or MULTI*) return the number of geometries, for single
geometries will return 1, otherwise return NULL.

• ST_NumPatches - Return the number of faces on a Polyhedral Surface. Will return null for non-polyhedral geometries.
• ST_PatchN - Return the 1-based Nth geometry (face) if the geometry is a POLYHEDRALSURFACE, POLYHEDRALSUR-
FACEM. Otherwise, return NULL.
• ST_RemoveRepeatedPoints - Returns a version of the given geometry with duplicated points removed.

• ST_Reverse - Return the geometry with vertex order reversed.

• ST_Rotate - Rotate a geometry rotRadians counter-clockwise about an origin.
• ST_RotateX - Rotate a geometry rotRadians about the X axis.
• ST_RotateY - Rotate a geometry rotRadians about the Y axis.

• ST_RotateZ - Rotate a geometry rotRadians about the Z axis.

• ST_Scale - Scale a geometry by given factors.
• ST_ShiftLongitude - Toggle geometry coordinates between -180..180 and 0..360 ranges.

• ST_StraightSkeleton - Compute a straight skeleton from a geometry

• ST_Summary - Returns a text summary of the contents of the geometry.
• ST_SwapOrdinates - Returns a version of the given geometry with given ordinate values swapped.
• ST_Tesselate - Perform surface Tesselation of a polygon or polyhedralsurface and returns as a TIN or collection of TINS

• ST_Transform - Return a new geometry with its coordinates transformed to a different spatial reference.
• ST_Volume - Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return 0.
• ~(box2df,box2df) - Returns TRUE if a 2D float precision bounding box (BOX2DF) contains another 2D float precision bound-
ing box (BOX2DF).

• ~(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) contains a geometry’s 2D bonding box.
• ~(geometry,box2df) - Returns TRUE if a geometry’s 2D bonding box contains a 2D float precision bounding box (GIDX).
• && - Returns TRUE if A’s 2D bounding box intersects B’s 2D bounding box.

• &&& - Returns TRUE if A’s n-D bounding box intersects B’s n-D bounding box.
• @(box2df,box2df) - Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into another 2D float precision
bounding box.
• @(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into a geometry’s 2D
bounding box.

• @(geometry,box2df) - Returns TRUE if a geometry’s 2D bounding box is contained into a 2D float precision bounding box
(BOX2DF).
• &&(box2df,box2df) - Returns TRUE if two 2D float precision bounding boxes (BOX2DF) intersect each other.
• &&(box2df,geometry) - Returns TRUE if a 2D float precision bounding box (BOX2DF) intersects a geometry’s (cached) 2D
bounding box.
• &&(geometry,box2df) - Returns TRUE if a geometry’s (cached) 2D bounding box intersects a 2D float precision bounding box
(BOX2DF).
PostGIS 2.4.3 Manual 721 / 803

• &&&(geometry,gidx) - Returns TRUE if a geometry’s (cached) n-D bounding box intersects a n-D float precision bounding
box (GIDX).
• &&&(gidx,geometry) - Returns TRUE if a n-D float precision bounding box (GIDX) intersects a geometry’s (cached) n-D
bounding box.
• &&&(gidx,gidx) - Returns TRUE if two n-D float precision bounding boxes (GIDX) intersect each other.
• postgis_sfcgal_version - Returns the version of SFCGAL in use

14.11 PostGIS Function Support Matrix

Below is an alphabetical listing of spatial specific functions in PostGIS and the kinds of spatial types they work with or OGC/SQL
compliance they try to conform to.

• A means the function works with the type or subtype natively.

• A means it works but with a transform cast built-in using cast to geometry, transform to a "best srid" spatial ref and then
cast back. Results may not be as expected for large areas or areas at poles and may accumulate floating point junk.

• A means the function works with the type because of a auto-cast to another such as to box3d rather than direct type
support.

• A means the function only available if PostGIS compiled with SFCGAL support.

• A means the function support is provided by SFCGAL if PostGIS compiled with SFCGAL support, otherwise GEOS/built-
in support.
• geom - Basic 2D geometry support (x,y).
• geog - Basic 2D geography support (x,y).

• 2.5D - basic 2D geometries in 3 D/4D space (has Z or M coord).

• PS - Polyhedral surfaces
• T - Triangles and Triangulated Irregular Network surfaces (TIN)

Function geom geog 2.5D Curves SQL MM PS T

Box2D
Box3D
Find_SRID
GeometryType

ST_3DArea

ST_3DClosestPoint
ST_3DDFullyWithin
ST_3DDWithin

ST_3DDifference
PostGIS 2.4.3 Manual 722 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_3DDistance

ST_3DExtent

ST_3DIntersection

ST_3DIntersects

ST_3DLength
ST_3DLongestLine
ST_3DMakeBox
ST_3DMaxDistance
ST_3DPerimeter
ST_3DShortestLine

ST_3DUnion

ST_Accum
ST_AddMeasure
ST_AddPoint
ST_Affine

ST_ApproximateMedialAxis

ST_Area

ST_AsBinary
ST_AsEWKB
ST_AsEWKT
ST_AsEncodedPolyline
ST_AsGML
ST_AsGeoJSON
ST_AsGeobuf
ST_AsHEXEWKB
ST_AsKML
ST_AsLatLonText
ST_AsMVT
ST_AsMVTGeom
ST_AsSVG
ST_AsTWKB
ST_AsText
PostGIS 2.4.3 Manual 723 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_AsX3D
ST_Azimuth
ST_BdMPolyFromText
ST_BdPolyFromText
ST_Boundary
ST_BoundingDiagonal
ST_Box2dFromGeoHash

ST_Buffer

ST_BuildArea
ST_CPAWithin
ST_Centroid
ST_ClipByBox2D
ST_ClosestPoint
ST_ClosestPointOfApproach
ST_ClusterDBSCAN
ST_ClusterIntersecting
ST_ClusterKMeans
ST_ClusterWithin
ST_Collect
ST_CollectionExtract
ST_CollectionHomogenize
ST_ConcaveHull
ST_Contains
ST_ContainsProperly
ST_ConvexHull
ST_CoordDim
ST_CoveredBy
ST_Covers
ST_Crosses
ST_CurveToLine
ST_DFullyWithin
ST_DWithin
ST_DelaunayTriangles
ST_Difference
PostGIS 2.4.3 Manual 724 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_Dimension
ST_Disjoint

ST_Distance

ST_DistanceCPA
ST_DistanceSphere
ST_DistanceSpheroid
ST_Dump
ST_DumpPoints
ST_DumpRings
ST_EndPoint
ST_Envelope
ST_Equals
ST_EstimatedExtent
ST_Expand
ST_Extent
ST_ExteriorRing

ST_Extrude

ST_FlipCoordinates
ST_Force2D
ST_ForceCurve

ST_ForceLHR

ST_ForcePolygonCCW
ST_ForcePolygonCW
ST_ForceRHR
ST_ForceSFS
ST_Force3D
ST_Force3DM
ST_Force3DZ
ST_Force4D
ST_ForceCollection
ST_FrechetDistance
ST_GMLToSQL
ST_GeneratePoints
PostGIS 2.4.3 Manual 725 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_GeoHash
ST_GeogFromText
ST_GeogFromWKB
ST_GeographyFromText
ST_GeomCollFromText
ST_GeomFromEWKB
ST_GeomFromEWKT
ST_GeomFromGML
ST_GeomFromGeoHash
ST_GeomFromGeoJSON
ST_GeomFromKML
ST_GeomFromTWKB
ST_GeomFromText
ST_GeomFromWKB
ST_GeometricMedian
ST_GeometryFromText
ST_GeometryN
ST_GeometryType
|>>
<<|
~
@
=
<<
|&>
&<|
&<
&>
>>
~=
ST_HasArc
ST_HausdorffDistance
ST_InteriorRingN
ST_InterpolatePoint
PostGIS 2.4.3 Manual 726 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_Intersection

ST_Intersects

ST_IsClosed
ST_IsCollection
ST_IsEmpty

ST_IsPlanar

ST_IsPolygonCCW
ST_IsPolygonCW
ST_IsRing
ST_IsSimple

ST_IsSolid

ST_IsValid
ST_IsValidDetail
ST_IsValidReason
ST_IsValidTrajectory

ST_Length

ST_Length2D
ST_Length2D_Spheroid
ST_LengthSpheroid
ST_LineCrossingDirection
ST_LineFromEncodedPolyline
ST_LineFromMultiPoint
ST_LineFromText
ST_LineFromWKB
ST_LineInterpolatePoint
ST_LineLocatePoint
ST_LineMerge
ST_LineSubstring
ST_LineToCurve
ST_LinestringFromWKB
ST_LocateAlong
ST_LocateBetween
PostGIS 2.4.3 Manual 727 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_LocateBetweenElevations
ST_LongestLine
ST_M
ST_MLineFromText
ST_MPointFromText
ST_MPolyFromText
ST_MakeBox2D
ST_MakeEnvelope
ST_MakeLine
ST_MakePoint
ST_MakePointM
ST_MakePolygon

ST_MakeSolid

ST_MakeValid
ST_MaxDistance
ST_MemSize
ST_MemUnion
ST_MinimumBoundingCircle
ST_MinimumBoundingRadius
ST_MinimumClearance
ST_MinimumClearanceLine

ST_MinkowskiSum

ST_Multi
ST_NDims
ST_NPoints
ST_NRings
ST_Node
ST_Normalize
ST_NumGeometries
ST_NumInteriorRing
ST_NumInteriorRings
ST_NumPatches
ST_NumPoints
PostGIS 2.4.3 Manual 728 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_OffsetCurve
ST_OrderingEquals

ST_Orientation

ST_Overlaps
ST_PatchN
ST_Perimeter
ST_Perimeter2D
ST_Point
ST_PointFromGeoHash
ST_PointFromText
ST_PointFromWKB
ST_PointN
ST_PointOnSurface
ST_PointInsideCircle
ST_Points
ST_Polygon
ST_PolygonFromText
ST_Polygonize
ST_Project
ST_Relate
ST_RelateMatch
ST_RemovePoint
ST_RemoveRepeatedPoints
ST_Reverse
ST_Rotate
ST_RotateX
ST_RotateY
ST_RotateZ
ST_SRID
ST_Scale
ST_Segmentize
ST_SetEffectiveArea
ST_SetPoint
ST_SetSRID
PostGIS 2.4.3 Manual 729 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_SharedPaths
ST_ShiftLongitude
ST_ShortestLine
ST_Simplify
ST_SimplifyPreserveTopology
ST_SimplifyVW
ST_Snap
ST_SnapToGrid
ST_Split
ST_StartPoint

ST_StraightSkeleton

ST_Subdivide
ST_Summary
ST_SwapOrdinates
ST_SymDifference

ST_Tesselate

ST_Touches
ST_TransScale
ST_Transform
ST_Translate
ST_UnaryUnion
ST_Union

ST_Volume

ST_VoronoiLines
ST_VoronoiPolygons
ST_WKBToSQL
ST_WKTToSQL
ST_Within
ST_WrapX
ST_X
ST_XMax
ST_XMin
ST_Y
PostGIS 2.4.3 Manual 730 / 803

Function geom geog 2.5D Curves SQL MM PS T

ST_YMax
ST_YMin
ST_Z
ST_ZMax
ST_ZMin
ST_Zmflag
~(box2df,box2df)
~(box2df,geometry)
~(geometry,box2df)
<#>
<<#>>
<<->>
|=|
<->
&&
&&&
@(box2df,box2df)
@(box2df,geometry)
@(geometry,box2df)
&&(box2df,box2df)
&&(box2df,geometry)
&&(geometry,box2df)
&&&(geometry,gidx)
&&&(gidx,geometry)
&&&(gidx,gidx)
postgis.backend
postgis.enable_outdb_rasters
postgis.gdal_datapath
postgis.gdal_enabled_drivers
postgis_sfcgal_version

14.12 New, Enhanced or changed PostGIS Functions

14.12.1 PostGIS Functions new or enhanced in 2.4

The functions given below are PostGIS functions that were added or enhanced.
PostGIS 2.4.3 Manual 731 / 803

Functions new in PostGIS 2.4

• ST_AsGeobuf - Availability: 2.4.0 Return a Geobuf representation of a set of rows.

• ST_AsMVT - Availability: 2.4.0 Return a Mapbox Vector Tile representation of a set of rows.
• ST_AsMVTGeom - Availability: 2.4.0 Transform a geometry into the coordinate space of a Mapbox Vector Tile.
• ST_Centroid - Availability: 2.4.0 support for geography was introduced. Returns the geometric center of a geometry.
• ST_FrechetDistance - Availability: 2.4.0 - requires GEOS >= 3.7.0 Returns the Fréchet distance between two geometries. This
is a measure of similarity between curves that takes into account the location and ordering of the points along the curves. Units
are in the units of the spatial reference system of the geometries.
• ST_MakeEmptyCoverage - Availability: 2.4.0 Cover georeferenced area with a grid of empty raster tiles.

Functions enhanced in PostGIS 2.4

All aggregates now marked as parallel safe which should allow them to be used in plans that can employ parallelism.
PostGIS 2.4.1 postgis_tiger_geocoder set to load Tiger 2017 data. Can optionally load zip code 5-digit tabulation (zcta) as part
of the Loader_Generate_Nation_Script.

• Loader_Generate_Nation_Script - Enhanced: 2.4.1 zip code 5 tabulation area (zcta5) load step was fixed and when enabled,
zcta5 data is loaded as a single table called zcta5_all as part of the nation script load. Generates a shell script for the specified
platform that loads in the county and state lookup tables.
• Normalize_Address - Enhanced: 2.4.0 norm_addy object includes additional fields zip4 and address_alphanumeric. Given a
textual street address, returns a composite norm_addy type that has road suffix, prefix and type standardized, street, streetname
etc. broken into separate fields. This function will work with just the lookup data packaged with the tiger_geocoder (no need
for tiger census data).
• Pagc_Normalize_Address - Enhanced: 2.4.0 norm_addy object includes additional fields zip4 and address_alphanumeric.
Given a textual street address, returns a composite norm_addy type that has road suffix, prefix and type standardized, street,
streetname etc. broken into separate fields. This function will work with just the lookup data packaged with the tiger_geocoder
(no need for tiger census data). Requires address_standardizer extension.
• Reverse_Geocode - Enhanced: 2.4.1 if optional zcta5 dataset is loaded, the reverse_geocode function can resolve to state and
zip even if the specific state data is not loaded. Refer to for details on loading zcta5 data. Takes a geometry point in a known
spatial ref sys and returns a record containing an array of theoretically possible addresses and an array of cross streets. If
include_strnum_range = true, includes the street range in the cross streets.
• ST_AsTWKB - Enhanced: 2.4.0 memory and speed improvements. Returns the geometry as TWKB, aka "Tiny Well-Known
Binary"
• ST_Covers - Enhanced: 2.4.0 Support for polygon in polygon and line in polygon added for geography type Returns 1 (TRUE)
if no point in Geometry B is outside Geometry A
• ST_CurveToLine - Enhanced: 2.4.0 added support for max-deviation and max-angle tolerance, and for symmetric output.
Converts a CIRCULARSTRING/CURVEPOLYGON to a LINESTRING/POLYGON
• ST_Project - Enhanced: 2.4.0 Allow negative distance and non-normalized azimuth. Returns a POINT projected from a start
point using a distance in meters and bearing (azimuth) in radians.
• ST_Reverse - Enhanced: 2.4.0 support for curves was introduced. Return the geometry with vertex order reversed.

Functions changed in PostGIS 2.4

All PostGIS aggregates now marked as parallel safe. This will force a drop and recreate of aggregates during upgrade which may
fail if any user views or sql functions rely on PostGIS aggregates.

• = - Changed: 2.4.0, in prior versions this was bounding box equality not a geometric equality. If you need bounding box
equality, use instead. Returns TRUE if the coordinates and coordinate order geometry/geography A are the same as the
coordinates and coordinate order of geometry/geography B.
• ST_Node - Changed: 2.4.0 this function uses GEOSNode internally instead of GEOSUnaryUnion. This may cause the resulting
linestrings to have a different order and direction compared to Postgis < 2.4. Node a set of linestrings.
PostGIS 2.4.3 Manual 732 / 803

14.12.2 PostGIS Functions new or enhanced in 2.3

The functions given below are PostGIS functions that were added or enhanced.

Note
PostGIS 2.3.0: PostgreSQL 9.6+ support for parallel queries.

Note
PostGIS 2.3.0: PostGIS extension, all functions schema qualified to reduce issues in database restore.

Note
PostGIS 2.3.0: PostgreSQL 9.4+ support for BRIN indexes. Refer to Section 4.6.2.

Note
PostGIS 2.3.0: Tiger Geocoder upgraded to work with TIGER 2016 data.

Functions new in PostGIS 2.3

• ST_GeometricMedian - Availability: 2.3.0 Returns the geometric median of a MultiPoint.

• &&&(geometry,gidx) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a geometry’s (cached) n-D bounding box intersects a n-D float precision bounding box (GIDX).
• &&&(gidx,geometry) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a n-D float precision bounding box (GIDX) intersects a geometry’s (cached) n-D bounding box.
• &&&(gidx,gidx) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.
Returns TRUE if two n-D float precision bounding boxes (GIDX) intersect each other.
• &&(box2df,box2df) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if two 2D float precision bounding boxes (BOX2DF) intersect each other.
• &&(box2df,geometry) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a 2D float precision bounding box (BOX2DF) intersects a geometry’s (cached) 2D bounding box.
• &&(geometry,box2df) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a geometry’s (cached) 2D bounding box intersects a 2D float precision bounding box (BOX2DF).
• @(box2df,box2df) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.
Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into another 2D float precision bounding box.
• @(box2df,geometry) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a 2D float precision bounding box (BOX2DF) is contained into a geometry’s 2D bounding box.
• @(geometry,box2df) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a geometry’s 2D bounding box is contained into a 2D float precision bounding box (BOX2DF).
• Populate_Topology_Layer - Availability: 2.3.0 Adds missing entries to topology.layer table by reading metadata from topo
tables.
PostGIS 2.4.3 Manual 733 / 803

• ST_ClusterDBSCAN - Availability: 2.3.0 - requires GEOS Windowing function that returns integer id for the cluster each
input geometry is in based on 2D implementation of Density-based spatial clustering of applications with noise (DBSCAN)
algorithm.

• ST_ClusterKMeans - Availability: 2.3.0 - requires GEOS Windowing function that returns integer id for the cluster each input
geometry is in.
• ST_GeneratePoints - Availability: 2.3.0 Converts a polygon or multi-polygon into a multi-point composed of randomly location
points within the original areas.
• ST_MakeLine - Availability: 2.3.0 - Support for multipoint input elements was introduced Creates a Linestring from point,
multipoint, or line geometries.
• ST_MinimumClearance - Availability: 2.3.0 - requires GEOS >= 3.6.0 Returns the minimum clearance of a geometry, a
measure of a geometry’s robustness.
• ST_MinimumClearanceLine - Availability: 2.3.0 - requires GEOS >= 3.6.0 Returns the two-point LineString spanning a
geometry’s minimum clearance.
• ST_Points - Availability: 2.3.0 Returns a MultiPoint containing all of the coordinates of a geometry.
• ST_VoronoiLines - Availability: 2.3.0 - requires GEOS >= 3.5.0. Returns the boundaries between the cells of the Voronoi
diagram constructed from the vertices of a geometry.

• ST_VoronoiPolygons - Availability: 2.3.0 - requires GEOS >= 3.5.0. Returns the cells of the Voronoi diagram constructed
from the vertices of a geometry.
• ST_WrapX - Availability: 2.3.0 Wrap a geometry around an X value.
• TopoGeom_addElement - Availability: 2.3 Add an element to the definition of a TopoGeometry

• TopoGeom_remElement - Availability: 2.3 Remove an element from the definition of a TopoGeometry

• ~(box2df,box2df) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL 9.5+.
Returns TRUE if a 2D float precision bounding box (BOX2DF) contains another 2D float precision bounding box (BOX2DF).
• ~(box2df,geometry) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a 2D float precision bounding box (BOX2DF) contains a geometry’s 2D bonding box.

• ~(geometry,box2df) - Availability: 2.3.0 support for Block Range INdexes (BRIN) was introduced. Requires PostgreSQL
9.5+. Returns TRUE if a geometry’s 2D bonding box contains a 2D float precision bounding box (GIDX).

The functions given below are PostGIS functions that are enhanced in PostGIS 2.3.

• ST_Contains - Enhanced: 2.3.0 Enhancement to PIP short-circuit extended to support MultiPoints with few points. Prior
versions only supported point in polygon.
• ST_Covers - Enhanced: 2.3.0 Enhancement to PIP short-circuit for geometry extended to support MultiPoints with few points.
Prior versions only supported point in polygon.

• ST_Expand - Enhanced: 2.3.0 support was added to expand a box by different amounts in different dimensions.
• ST_Intersects - Enhanced: 2.3.0 Enhancement to PIP short-circuit extended to support MultiPoints with few points. Prior
versions only supported point in polygon.
• ST_Segmentize - Enhanced: 2.3.0 Segmentize geography now uses equal length segments

• ST_Transform - Enhanced: 2.3.0 support for direct PROJ.4 text was introduced.
• ST_Within - Enhanced: 2.3.0 Enhancement to PIP short-circuit for geometry extended to support MultiPoints with few points.
Prior versions only supported point in polygon.
PostGIS 2.4.3 Manual 734 / 803

14.12.3 PostGIS Functions new or enhanced in 2.2

The functions given below are PostGIS functions that were added or enhanced.

Note
postgis_sfcgal now can be installed as an extension using CREATE EXTENSION postgis_sfcgal;

Note
PostGIS 2.2.0: Tiger Geocoder upgraded to work with TIGER 2015 data.

Note
address_standardizer, address_standardizer_data_us extensions for standardizing address data refer to Chapter 12
for details.

Note
Many functions in topology rewritten as C functions for increased performance.

Functions new in PostGIS 2.2

• <<#>> - Availability: 2.2.0 -- KNN only available for PostgreSQL 9.1+ Returns the n-D distance between A and B bounding
boxes.
• <<->> - Availability: 2.2.0 -- KNN only available for PostgreSQL 9.1+ Returns the n-D distance between the centroids of A
and B boundingboxes.

• ST_3DDifference - Availability: 2.2.0 Perform 3D difference

• ST_3DUnion - Availability: 2.2.0 Perform 3D union
• ST_ApproximateMedialAxis - Availability: 2.2.0 Compute the approximate medial axis of an areal geometry.

• ST_AsEncodedPolyline - Availability: 2.2.0 Returns an Encoded Polyline from a LineString geometry.

• ST_AsTWKB - Availability: 2.2.0 Returns the geometry as TWKB, aka "Tiny Well-Known Binary"
• ST_BoundingDiagonal - Availability: 2.2.0 Returns the diagonal of the supplied geometry’s bounding box.
• ST_CPAWithin - Availability: 2.2.0 Returns true if the trajectories’ closest points of approachare within the specified distance.

• ST_ClipByBox2D - Availability: 2.2.0 - requires GEOS >= 3.5.0. Returns the portion of a geometry falling within a rectangle.
• ST_ClosestPointOfApproach - Availability: 2.2.0 Returns the measure at which points interpolated along two lines are closest.
• ST_ClusterIntersecting - Availability: 2.2.0 - requires GEOS Aggregate. Returns an array with the connected components of a
set of geometries

• ST_ClusterWithin - Availability: 2.2.0 - requires GEOS Aggregate. Returns an array of GeometryCollections, where each
GeometryCollection represents a set of geometries separated by no more than the specified distance.
PostGIS 2.4.3 Manual 735 / 803

• ST_CountAgg - Availability: 2.2.0 Aggregate. Returns the number of pixels in a given band of a set of rasters. If no band is
specified defaults to band 1. If exclude_nodata_value is set to true, will only count pixels that are not equal to the NODATA
value.

• ST_CreateOverview - Availability: 2.2.0 Create an reduced resolution version of a given raster coverage.
• ST_DistanceCPA - Availability: 2.2.0 Returns the distance between closest points of approach in two trajectories.
• ST_ForceCurve - Availability: 2.2.0 Upcast a geometry into its curved type, if applicable.
• ST_IsPlanar - Availability: 2.2.0: This was documented in 2.1.0 but got accidentally left out in 2.1 release. Check if a surface
is or not planar
• ST_IsSolid - Availability: 2.2.0 Test if the geometry is a solid. No validity check is performed.
• ST_IsValidTrajectory - Availability: 2.2.0 Returns true if the geometry is a valid trajectory.
• ST_LineFromEncodedPolyline - Availability: 2.2.0 Creates a LineString from an Encoded Polyline.

• ST_MakeSolid - Availability: 2.2.0 Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input
geometry must be a closed Polyhedral Surface or a closed TIN.
• ST_MapAlgebra - Availability: 2.2.0: Ability to add a mask Callback function version - Returns a one-band raster given one
or more input rasters, band indexes and one user-specified callback function.

• ST_MemSize - Availability: 2.2.0 Returns the amount of space (in bytes) the raster takes.
• ST_RemoveRepeatedPoints - Availability: 2.2.0 Returns a version of the given geometry with duplicated points removed.
• ST_Retile - Availability: 2.2.0 Return a set of configured tiles from an arbitrarily tiled raster coverage.
• ST_SetEffectiveArea - Availability: 2.2.0 Sets the effective area for each vertex, storing the value in the M ordinate. A
simplified geometry can then be generated by filtering on the M ordinate.
• ST_SimplifyVW - Availability: 2.2.0 Returns a "simplified" version of the given geometry using the Visvalingam-Whyatt
algorithm
• ST_Subdivide - Availability: 2.2.0 requires GEOS >= 3.5.0. Returns a set of geometry where no geometry in the set has more
than the specified number of vertices.

• ST_SummaryStatsAgg - Availability: 2.2.0 Aggregate. Returns summarystats consisting of count, sum, mean, stddev, min,
max for a given raster band of a set of raster. Band 1 is assumed is no band is specified.
• ST_SwapOrdinates - Availability: 2.2.0 Returns a version of the given geometry with given ordinate values swapped.
• ST_Volume - Availability: 2.2.0 Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return
0.
• parse_address - Availability: 2.2.0 Takes a 1 line address and breaks into parts
• postgis.enable_outdb_rasters - Availability: 2.2.0 A boolean configuration option to enable access to out-db raster bands.

• postgis.gdal_datapath - Availability: 2.2.0 A configuration option to assign the value of GDAL’s GDAL_DATA option. If not
set, the environmentally set GDAL_DATA variable is used.
• postgis.gdal_enabled_drivers - Availability: 2.2.0 A configuration option to set the enabled GDAL drivers in the PostGIS
environment. Affects the GDAL configuration variable GDAL_SKIP.
• standardize_address - Availability: 2.2.0 Returns an stdaddr form of an input address utilizing lex, gaz, and rule tables.

• |=| - Availability: 2.2.0. Index-supported only available for PostgreSQL 9.5+ Returns the distance between A and B trajectories
at their closest point of approach.

The functions given below are PostGIS functions that are enhanced in PostGIS 2.2.
PostGIS 2.4.3 Manual 736 / 803

• AsTopoJSON - Enhanced: 2.2.1 added support for puntal inputs

• ST_Area - Enhanced: 2.2.0 - measurement on spheroid performed with GeographicLib for improved accuracy and robustness.
Requires Proj >= 4.9.0 to take advantage of the new feature.

• ST_AsX3D - Enhanced: 2.2.0: Support for GeoCoordinates and axis (x/y, long/lat) flipping. Look at options for details.
• ST_Azimuth - Enhanced: 2.2.0 measurement on spheroid performed with GeographicLib for improved accuracy and robust-
ness. Requires Proj >= 4.9.0 to take advantage of the new feature.
• ST_Distance - Enhanced: 2.2.0 - measurement on spheroid performed with GeographicLib for improved accuracy and robust-
ness. Requires Proj >= 4.9.0 to take advantage of the new feature.
• ST_Scale - Enhanced: 2.2.0 support for scaling all dimension (geometry parameter) was introduced.
• ST_Summary - Enhanced: 2.2.0 Added support for TIN and Curves
• <-> - Enhanced: 2.2.0 -- True KNN ("K nearest neighbor") behavior for geometry and geography for PostgreSQL 9.5+. Note
for geography KNN is based on sphere rather than spheroid. For PostgreSQL 9.4 and below, geography support is new but
only supports centroid box.

14.12.4 PostGIS functions breaking changes in 2.2

The functions given below are PostGIS functions that have possibly breaking changes in PostGIS 2.2. If you use any of these,
you may need to check your existing code.

• Get_Geocode_Setting - Changed: 2.2.0 : default settings are now kept in a table called geocode_settings_default. Use cus-
tomized settingsa are in geocode_settings and only contain those that have been set by user.
• ST_3DClosestPoint - Changed: 2.2.0 - if 2 2D geometries are input, a 2D point is returned (instead of old behavior assuming
0 for missing Z). In case of 2D and 3D, Z is no longer assumed to be 0 for missing Z.

• ST_3DDistance - Changed: 2.2.0 - In case of 2D and 3D, Z is no longer assumed to be 0 for missing Z.
• ST_3DLongestLine - Changed: 2.2.0 - if 2 2D geometries are input, a 2D point is returned (instead of old behavior assuming
0 for missing Z). In case of 2D and 3D, Z is no longer assumed to be 0 for missing Z.
• ST_3DMaxDistance - Changed: 2.2.0 - In case of 2D and 3D, Z is no longer assumed to be 0 for missing Z.

• ST_3DShortestLine - Changed: 2.2.0 - if 2 2D geometries are input, a 2D point is returned (instead of old behavior assuming
0 for missing Z). In case of 2D and 3D, Z is no longer assumed to be 0 for missing Z.
• ST_DistanceSphere - Changed: 2.2.0 In prior versions this used to be called ST_Distance_Sphere
• ST_DistanceSpheroid - Changed: 2.2.0 In prior versions this used to be called ST_Distance_Spheroid

• ST_Equals - Changed: 2.2.0 Returns true even for invalid geometries if they are binary equal
• ST_LengthSpheroid - Changed: 2.2.0 In prior versions this used to be called ST_Length_Spheroid and used to have a
ST_3DLength_Spheroid alias
• ST_MemSize - Changed: 2.2.0 name changed to ST_MemSize to follow naming convention. In prior versions this function
was called ST_Mem_Size, old name deprecated though still available.
• ST_PointInsideCircle - Changed: 2.2.0 In prior versions this used to be called ST_Point_Inside_Circle
• ST_Split - Changed: 2.2.0 support for splitting a line by a multiline, a multipoint or (multi)polygon boundary was introduced.
• ValidateTopology - Changed: 2.2.0 values for id1 and id2 were swapped for ’edge crosses node’ to be consistent with error
description.
• <-> - Changed: 2.2.0 -- For PostgreSQL 9.5 users, old Hybrid syntax may be slower, so you’ll want to get rid of that hack if
you are running your code only on PostGIS 2.2+ 9.5+. See examples below.
PostGIS 2.4.3 Manual 737 / 803

14.12.5 PostGIS Functions new or enhanced in 2.1

The functions given below are PostGIS functions that were added or enhanced.

Note
More Topology performance Improvements. Please refer to Chapter 11 for more details.

Note
Bug fixes (particularly with handling of out-of-band rasters), many new functions (often shortening code you have to
write to accomplish a common task) and massive speed improvements to raster functionality. Refer to Chapter 9 for
more details.

Note
PostGIS 2.1.0: Tiger Geocoder upgraded to work with TIGER 2012 census data. geocode_settings added for
debugging and tweaking rating preferences, loader made less greedy, now only downloads tables to be loaded. PostGIS
2.1.1: Tiger Geocoder upgraded to work with TIGER 2013 data. Please refer to Section 13.1 for more details.

Functions new in PostGIS 2.1

• AsTopoJSON - Availability: 2.1.0 Returns the TopoJSON representation of a topogeometry.

• Drop_Nation_Tables_Generate_Script - Availability: 2.1.0 Generates a script that drops all tables in the specified schema that
start with county_all, state_all or state code followed by county or state.
• Get_Geocode_Setting - Availability: 2.1.0 Returns value of specific setting stored in tiger.geocode_settings table.
• Loader_Generate_Nation_Script - Availability: 2.1.0 Generates a shell script for the specified platform that loads in the county
and state lookup tables.
• Pagc_Normalize_Address - Availability: 2.1.0 Given a textual street address, returns a composite norm_addy type that has
road suffix, prefix and type standardized, street, streetname etc. broken into separate fields. This function will work with just
the lookup data packaged with the tiger_geocoder (no need for tiger census data). Requires address_standardizer extension.
• ST_3DArea - Availability: 2.1.0 Computes area of 3D surface geometries. Will return 0 for solids.
• ST_3DIntersection - Availability: 2.1.0 Perform 3D intersection
• ST_Box2dFromGeoHash - Availability: 2.1.0 Return a BOX2D from a GeoHash string.
• ST_ColorMap - Availability: 2.1.0 Creates a new raster of up to four 8BUI bands (grayscale, RGB, RGBA) from the source
raster and a specified band. Band 1 is assumed if not specified.
• ST_Contains - Availability: 2.1.0 Return true if no points of raster rastB lie in the exterior of raster rastA and at least one point
of the interior of rastB lies in the interior of rastA.
• ST_ContainsProperly - Availability: 2.1.0 Return true if rastB intersects the interior of rastA but not the boundary or exterior
of rastA.
• ST_CoveredBy - Availability: 2.1.0 Return true if no points of raster rastA lie outside raster rastB.
• ST_Covers - Availability: 2.1.0 Return true if no points of raster rastB lie outside raster rastA.
• ST_DFullyWithin - Availability: 2.1.0 Return true if rasters rastA and rastB are fully within the specified distance of each
other.
• ST_DWithin - Availability: 2.1.0 Return true if rasters rastA and rastB are within the specified distance of each other.
PostGIS 2.4.3 Manual 738 / 803

• ST_DelaunayTriangles - Availability: 2.1.0 - requires GEOS >= 3.4.0. Return a Delaunay triangulation around the given input
points.
• ST_Disjoint - Availability: 2.1.0 Return true if raster rastA does not spatially intersect rastB.

• ST_DumpValues - Availability: 2.1.0 Get the values of the specified band as a 2-dimension array.
• ST_Extrude - Availability: 2.1.0 Extrude a surface to a related volume
• ST_ForceLHR - Availability: 2.1.0 Force LHR orientation
• ST_FromGDALRaster - Availability: 2.1.0 Returns a raster from a supported GDAL raster file.

• ST_GeomFromGeoHash - Availability: 2.1.0 Return a geometry from a GeoHash string.

• ST_InvDistWeight4ma - Availability: 2.1.0 Raster processing function that interpolates a pixel’s value from the pixel’s neigh-
borhood.
• ST_MapAlgebra - Availability: 2.1.0 Callback function version - Returns a one-band raster given one or more input rasters,
band indexes and one user-specified callback function.
• ST_MapAlgebra - Availability: 2.1.0 Expression version - Returns a one-band raster given one or two input rasters, band
indexes and one or more user-specified SQL expressions.
• ST_MinConvexHull - Availability: 2.1.0 Return the convex hull geometry of the raster excluding NODATA pixels.

• ST_MinDist4ma - Availability: 2.1.0 Raster processing function that returns the minimum distance (in number of pixels)
between the pixel of interest and a neighboring pixel with value.
• ST_MinkowskiSum - Availability: 2.1.0 Performs Minkowski sum
• ST_NearestValue - Availability: 2.1.0 Returns the nearest non-NODATA value of a given band’s pixel specified by a columnx
and rowy or a geometric point expressed in the same spatial reference coordinate system as the raster.
• ST_Neighborhood - Availability: 2.1.0 Returns a 2-D double precision array of the non-NODATA values around a given band’s
pixel specified by either a columnX and rowY or a geometric point expressed in the same spatial reference coordinate system
as the raster.
• ST_NotSameAlignmentReason - Availability: 2.1.0 Returns text stating if rasters are aligned and if not aligned, a reason why.

• ST_Orientation - Availability: 2.1.0 Determine surface orientation

• ST_Overlaps - Availability: 2.1.0 Return true if raster rastA and rastB intersect but one does not completely contain the other.
• ST_PixelAsCentroid - Availability: 2.1.0 Returns the centroid (point geometry) of the area represented by a pixel.

• ST_PixelAsCentroids - Availability: 2.1.0 Returns the centroid (point geometry) for each pixel of a raster band along with the
value, the X and the Y raster coordinates of each pixel. The point geometry is the centroid of the area represented by a pixel.
• ST_PixelAsPoint - Availability: 2.1.0 Returns a point geometry of the pixel’s upper-left corner.
• ST_PixelAsPoints - Availability: 2.1.0 Returns a point geometry for each pixel of a raster band along with the value, the X and
the Y raster coordinates of each pixel. The coordinates of the point geometry are of the pixel’s upper-left corner.

• ST_PixelOfValue - Availability: 2.1.0 Get the columnx, rowy coordinates of the pixel whose value equals the search value.
• ST_PointFromGeoHash - Availability: 2.1.0 Return a point from a GeoHash string.
• ST_RasterToWorldCoord - Availability: 2.1.0 Returns the raster’s upper left corner as geometric X and Y (longitude and
latitude) given a column and row. Column and row starts at 1.

• ST_Resize - Availability: 2.1.0 Requires GDAL 1.6.1+ Resize a raster to a new width/height
• ST_Roughness - Availability: 2.1.0 Returns a raster with the calculated "roughness" of a DEM.
• ST_SetValues - Availability: 2.1.0 Returns modified raster resulting from setting the values of a given band.
PostGIS 2.4.3 Manual 739 / 803

• ST_Simplify - Availability: 2.1.0 Returns a "simplified" geometry version of the given TopoGeometry using the Douglas-
Peucker algorithm.
• ST_StraightSkeleton - Availability: 2.1.0 Compute a straight skeleton from a geometry

• ST_Summary - Availability: 2.1.0 Returns a text summary of the contents of the raster.
• ST_TPI - Availability: 2.1.0 Returns a raster with the calculated Topographic Position Index.
• ST_TRI - Availability: 2.1.0 Returns a raster with the calculated Terrain Ruggedness Index.
• ST_Tesselate - Availability: 2.1.0 Perform surface Tesselation of a polygon or polyhedralsurface and returns as a TIN or
collection of TINS
• ST_Tile - Availability: 2.1.0 Returns a set of rasters resulting from the split of the input raster based upon the desired dimen-
sions of the output rasters.
• ST_Touches - Availability: 2.1.0 Return true if raster rastA and rastB have at least one point in common but their interiors do
not intersect.
• ST_Union - Availability: 2.1.0 ST_Union(rast, unionarg) variant was introduced. Returns the union of a set of raster tiles into
a single raster composed of 1 or more bands.
• ST_Within - Availability: 2.1.0 Return true if no points of raster rastA lie in the exterior of raster rastB and at least one point
of the interior of rastA lies in the interior of rastB.

• ST_WorldToRasterCoord - Availability: 2.1.0 Returns the upper left corner as column and row given geometric X and Y
(longitude and latitude) or a point geometry expressed in the spatial reference coordinate system of the raster.
• Set_Geocode_Setting - Availability: 2.1.0 Sets a setting that affects behavior of geocoder functions.
• UpdateRasterSRID - Availability: 2.1.0 Change the SRID of all rasters in the user-specified column and table.

• clearTopoGeom - Availability: 2.1 Clears the content of a topo geometry

• postgis.backend - Availability: 2.1.0 The backend to service a function where GEOS and SFCGAL overlap. Options: geos or
sfcgal. Defaults to geos.
• postgis_sfcgal_version - Availability: 2.1.0 Returns the version of SFCGAL in use

The functions given below are PostGIS functions that are enhanced in PostGIS 2.1.

• ST_AddBand - Enhanced: 2.1.0 support for addbandarg added.

• ST_AddBand - Enhanced: 2.1.0 support for new out-db bands added.

• ST_AsBinary - Enhanced: 2.1.0 Addition of outasin

• ST_Aspect - Enhanced: 2.1.0 Uses ST_MapAlgebra() and added optional interpolate_nodata function parameter
• ST_Clip - Enhanced: 2.1.0 Rewritten in C

• ST_Distinct4ma - Enhanced: 2.1.0 Addition of Variant 2

• ST_HillShade - Enhanced: 2.1.0 Uses ST_MapAlgebra() and added optional interpolate_nodata function parameter
• ST_Max4ma - Enhanced: 2.1.0 Addition of Variant 2
• ST_Mean4ma - Enhanced: 2.1.0 Addition of Variant 2

• ST_Min4ma - Enhanced: 2.1.0 Addition of Variant 2

• ST_PixelAsPolygons - Enhanced: 2.1.0 exclude_nodata_value optional argument was added.
• ST_Polygon - Enhanced: 2.1.0 Improved Speed (fully C-Based) and the returning multipolygon is ensured to be valid.
PostGIS 2.4.3 Manual 740 / 803

• ST_Range4ma - Enhanced: 2.1.0 Addition of Variant 2

• ST_SameAlignment - Enhanced: 2.1.0 addition of Aggegrate variant
• ST_SetGeoReference - Enhanced: 2.1.0 Addition of ST_SetGeoReference(raster, double precision, ...) variant

• ST_SetValue - Enhanced: 2.1.0 Geometry variant of ST_SetValue() now supports any geometry type, not just point. The
geometry variant is a wrapper around the geomval[] variant of ST_SetValues()
• ST_Slope - Enhanced: 2.1.0 Uses ST_MapAlgebra() and added optional units, scale, interpolate_nodata function parameters
• ST_StdDev4ma - Enhanced: 2.1.0 Addition of Variant 2

• ST_Sum4ma - Enhanced: 2.1.0 Addition of Variant 2

• ST_Transform - Enhanced: 2.1.0 Addition of ST_Transform(rast, alignto) variant
• ST_Union - Enhanced: 2.1.0 Improved Speed (fully C-Based).

• ST_Union - Enhanced: 2.1.0 ST_Union(rast) (variant 1) unions all bands of all input rasters. Prior versions of PostGIS assumed
the first band.
• ST_Union - Enhanced: 2.1.0 ST_Union(rast, uniontype) (variant 4) unions all bands of all input rasters.
• ST_AsGML - Enhanced: 2.1.0 id support was introduced, for GML 3.

• ST_Boundary - Enhanced: 2.1.0 support for Triangle was introduced

• ST_DWithin - Enhanced: 2.1.0 improved speed for geography. See Making Geography faster for details.
• ST_DWithin - Enhanced: 2.1.0 support for curved geometries was introduced.
• ST_Distance - Enhanced: 2.1.0 improved speed for geography. See Making Geography faster for details.

• ST_Distance - Enhanced: 2.1.0 - support for curved geometries was introduced.

• ST_DumpPoints - Enhanced: 2.1.0 Faster speed. Reimplemented as native-C.
• ST_MakeValid - Enhanced: 2.1.0 added support for GEOMETRYCOLLECTION and MULTIPOINT.

• ST_Segmentize - Enhanced: 2.1.0 support for geography was introduced.

• ST_Summary - Enhanced: 2.1.0 S flag to denote if has a known spatial reference system
• toTopoGeom - Enhanced: 2.1.0 adds the version taking an existing TopoGeometry.

14.12.6 PostGIS functions breaking changes in 2.1

The functions given below are PostGIS functions that have possibly breaking changes in PostGIS 2.1. If you use any of these,
you may need to check your existing code.

• ST_Aspect - Changed: 2.1.0 In prior versions, return values were in radians. Now, return values default to degrees
• ST_HillShade - Changed: 2.1.0 In prior versions, azimuth and altitude were expressed in radians. Now, azimuth and altitude
are expressed in degrees
• ST_Intersects - Changed: 2.1.0 The behavior of the ST_Intersects(raster, geometry) variants changed to match that of ST_Intersects(geo
raster).
• ST_PixelAsCentroids - Changed: 2.1.1 Changed behavior of exclude_nodata_value.

• ST_PixelAsPoints - Changed: 2.1.1 Changed behavior of exclude_nodata_value.

• ST_PixelAsPolygons - Changed: 2.1.1 Changed behavior of exclude_nodata_value.
PostGIS 2.4.3 Manual 741 / 803

• ST_Polygon - Changed: 2.1.0 In prior versions would sometimes return a polygon, changed to always return multipolygon.
• ST_RasterToWorldCoordX - Changed: 2.1.0 In prior versions, this was called ST_Raster2WorldCoordX
• ST_RasterToWorldCoordY - Changed: 2.1.0 In prior versions, this was called ST_Raster2WorldCoordY
• ST_Resample - Changed: 2.1.0 Parameter srid removed. Variants with a reference raster no longer applies the reference raster’s
SRID. Use ST_Transform() to reproject raster. Works on rasters with no SRID.
• ST_Rescale - Changed: 2.1.0 Works on rasters with no SRID
• ST_Reskew - Changed: 2.1.0 Works on rasters with no SRID
• ST_Slope - Changed: 2.1.0 In prior versions, return values were in radians. Now, return values default to degrees
• ST_SnapToGrid - Changed: 2.1.0 Works on rasters with no SRID
• ST_WorldToRasterCoordX - Changed: 2.1.0 In prior versions, this was called ST_World2RasterCoordX
• ST_WorldToRasterCoordY - Changed: 2.1.0 In prior versions, this was called ST_World2RasterCoordY
• ST_EstimatedExtent - Changed: 2.1.0. Up to 2.0.x this was called ST_Estimated_Extent.
• ST_Force2D - Changed: 2.1.0. Up to 2.0.x this was called ST_Force_2D.
• ST_Force3D - Changed: 2.1.0. Up to 2.0.x this was called ST_Force_3D.
• ST_Force3DM - Changed: 2.1.0. Up to 2.0.x this was called ST_Force_3DM.
• ST_Force3DZ - Changed: 2.1.0. Up to 2.0.x this was called ST_Force_3DZ.
• ST_Force4D - Changed: 2.1.0. Up to 2.0.x this was called ST_Force_4D.
• ST_ForceCollection - Changed: 2.1.0. Up to 2.0.x this was called ST_Force_Collection.
• ST_LineInterpolatePoint - Changed: 2.1.0. Up to 2.0.x this was called ST_Line_Interpolate_Point.
• ST_LineLocatePoint - Changed: 2.1.0. Up to 2.0.x this was called ST_Line_Locate_Point.
• ST_LineSubstring - Changed: 2.1.0. Up to 2.0.x this was called ST_Line_Substring.
• ST_Segmentize - Changed: 2.1.0 As a result of the introduction of geography support: The construct SELECT ST_Segmentize(’LINES
2, 3 4)’,0.5); will result in ambiguous function error. You need to have properly typed object e.g. a geometry/geography col-
umn, use ST_GeomFromText, ST_GeogFromText or SELECT ST_Segmentize(’LINESTRING(1 2, 3 4)’::geometry,0.5);

14.12.7 PostGIS Functions new, behavior changed, or enhanced in 2.0

The functions given below are PostGIS functions that were added, enhanced, or have Section 14.12.8 breaking changes in 2.0
releases.
New geometry types: TIN and Polyhedral surfaces was introduced in 2.0

Note
Greatly improved support for Topology. Please refer to Chapter 11 for more details.

Note
In PostGIS 2.0, raster type and raster functionality has been integrated. There are way too many new raster functions
to list here and all are new so please refer to Chapter 9 for more details of the raster functions available. Earlier pre-2.0
versions had raster_columns/raster_overviews as real tables. These were changed to views before release. Functions
such as ST_AddRasterColumn were removed and replaced with AddRasterConstraints, DropRasterConstraints as
a result some apps that created raster tables may need changing.
PostGIS 2.4.3 Manual 742 / 803

Note
Tiger Geocoder upgraded to work with TIGER 2010 census data and now included in the core PostGIS documentation.
A reverse geocoder function was also added. Please refer to Section 13.1 for more details.

• && - Availability: 2.0.0 Returns TRUE if A’s bounding box intersects B’s bounding box.
• &&& - Availability: 2.0.0 Returns TRUE if A’s n-D bounding box intersects B’s n-D bounding box.
• <#> - Availability: 2.0.0 -- KNN only available for PostgreSQL 9.1+ Returns the 2D distance between A and B bounding
boxes.

• <-> - Availability: 2.0.0 -- Weak KNN provides nearest neighbors based on geometry centroid distances instead of true dis-
tances. Exact results for points, inexact for all other types. Available for PostgreSQL 9.1+ Returns the 2D distance between A
and B.
• AddEdge - Availability: 2.0.0 requires GEOS >= 3.3.0. Adds a linestring edge to the edge table and associated start and end
points to the point nodes table of the specified topology schema using the specified linestring geometry and returns the edgeid
of the new (or existing) edge.
• AddFace - Availability: 2.0.0 Registers a face primitive to a topology and gets its identifier.
• AddNode - Availability: 2.0.0 Adds a point node to the node table in the specified topology schema and returns the nodeid of
new node. If point already exists as node, the existing nodeid is returned.

• AddOverviewConstraints - Availability: 2.0.0 Tag a raster column as being an overview of another.

• AddRasterConstraints - Availability: 2.0.0 Adds raster constraints to a loaded raster table for a specific column that constrains
spatial ref, scaling, blocksize, alignment, bands, band type and a flag to denote if raster column is regularly blocked. The table
must be loaded with data for the constraints to be inferred. Returns true of the constraint setting was accomplished and if issues
a notice.
• AsGML - Availability: 2.0.0 Returns the GML representation of a topogeometry.
• CopyTopology - Availability: 2.0.0 Makes a copy of a topology structure (nodes, edges, faces, layers and TopoGeometries).
• DropOverviewConstraints - Availability: 2.0.0 Untag a raster column from being an overview of another.

• DropRasterConstraints - Availability: 2.0.0 Drops PostGIS raster constraints that refer to a raster table column. Useful if you
need to reload data or update your raster column data.
• Drop_Indexes_Generate_Script - Availability: 2.0.0 Generates a script that drops all non-primary key and non-unique indexes
on tiger schema and user specified schema. Defaults schema to tiger_data if no schema is specified.

• Drop_State_Tables_Generate_Script - Availability: 2.0.0 Generates a script that drops all tables in the specified schema that
are prefixed with the state abbreviation. Defaults schema to tiger_data if no schema is specified.
• Geocode_Intersection - Availability: 2.0.0 Takes in 2 streets that intersect and a state, city, zip, and outputs a set of possible
locations on the first cross street that is at the intersection, also includes a geomout as the point location in NAD 83 long lat,
a normalized_address (addy) for each location, and the rating. The lower the rating the more likely the match. Results are
sorted by lowest rating first. Can optionally pass in maximum results, defaults to 10. Uses Tiger data (edges, faces, addr),
PostgreSQL fuzzy string matching (soundex, levenshtein).
• GetEdgeByPoint - Availability: 2.0.0 - requires GEOS >= 3.3.0. Find the edge-id of an edge that intersects a given point
• GetFaceByPoint - Availability: 2.0.0 - requires GEOS >= 3.3.0. Find the face-id of a face that intersects a given point

• GetNodeByPoint - Availability: 2.0.0 - requires GEOS >= 3.3.0. Find the id of a node at a point location
• GetNodeEdges - Availability: 2.0 Returns an ordered set of edges incident to the given node.
• GetRingEdges - Availability: 2.0.0 Returns the ordered set of signed edge identifiers met by walking on ana given edge side.
PostGIS 2.4.3 Manual 743 / 803

• GetTopoGeomElements - Availability: 2.0.0 Returns a set of topoelement objects containing the topological element_id,element_type
of the given TopoGeometry (primitive elements)
• GetTopologySRID - Availability: 2.0.0 Returns the SRID of a topology in the topology.topology table given the name of the
topology.
• Get_Tract - Availability: 2.0.0 Returns census tract or field from tract table of where the geometry is located. Default to
returning short name of tract.
• Install_Missing_Indexes - Availability: 2.0.0 Finds all tables with key columns used in geocoder joins and filter conditions that
are missing used indexes on those columns and will add them.
• Loader_Generate_Census_Script - Availability: 2.0.0 Generates a shell script for the specified platform for the specified states
that will download Tiger census state tract, bg, and tabblocks data tables, stage and load into tiger_data schema. Each state
script is returned as a separate record.
• Loader_Generate_Script - Availability: 2.0.0 to support Tiger 2010 structured data and load census tract (tract), block groups
(bg), and blocks (tabblocks) tables . Generates a shell script for the specified platform for the specified states that will download
Tiger data, stage and load into tiger_data schema. Each state script is returned as a separate record. Latest version supports
Tiger 2010 structural changes and also loads census tract, block groups, and blocks tables.
• Missing_Indexes_Generate_Script - Availability: 2.0.0 Finds all tables with key columns used in geocoder joins that are
missing indexes on those columns and will output the SQL DDL to define the index for those tables.
• Polygonize - Availability: 2.0.0 Find and register all faces defined by topology edges
• Reverse_Geocode - Availability: 2.0.0 Takes a geometry point in a known spatial ref sys and returns a record containing an
array of theoretically possible addresses and an array of cross streets. If include_strnum_range = true, includes the street range
in the cross streets.
• ST_3DClosestPoint - Availability: 2.0.0 Returns the 3-dimensional point on g1 that is closest to g2. This is the first point of
the 3D shortest line.
• ST_3DDFullyWithin - Availability: 2.0.0 Returns true if all of the 3D geometries are within the specified distance of one
another.
• ST_3DDWithin - Availability: 2.0.0 For 3d (z) geometry type Returns true if two geometries 3d distance is within number of
units.
• ST_3DDistance - Availability: 2.0.0 For geometry type Returns the 3-dimensional cartesian minimum distance (based on
spatial ref) between two geometries in projected units.
• ST_3DIntersects - Availability: 2.0.0 Returns TRUE if the Geometries "spatially intersect" in 3d - only for points, linestrings,
polygons, polyhedral surface (area). With SFCGAL backend enabled also supports TINS
• ST_3DLongestLine - Availability: 2.0.0 Returns the 3-dimensional longest line between two geometries
• ST_3DMaxDistance - Availability: 2.0.0 For geometry type Returns the 3-dimensional cartesian maximum distance (based on
spatial ref) between two geometries in projected units.
• ST_3DShortestLine - Availability: 2.0.0 Returns the 3-dimensional shortest line between two geometries
• ST_AddEdgeModFace - Availability: 2.0 Add a new edge and, if in doing so it splits a face, modify the original face and add
a new face.
• ST_AddEdgeNewFaces - Availability: 2.0 Add a new edge and, if in doing so it splits a face, delete the original face and
replace it with two new faces.
• ST_AsGDALRaster - Availability: 2.0.0 - requires GDAL >= 1.6.0. Return the raster tile in the designated GDAL Raster
format. Raster formats are one of those supported by your compiled library. Use ST_GDALDrivers() to get a list of formats
supported by your library.
• ST_AsJPEG - Availability: 2.0.0 - requires GDAL >= 1.6.0. Return the raster tile selected bands as a single Joint Photographic
Exports Group (JPEG) image (byte array). If no band is specified and 1 or more than 3 bands, then only the first band is used.
If only 3 bands then all 3 bands are used and mapped to RGB.
PostGIS 2.4.3 Manual 744 / 803

• ST_AsLatLonText - Availability: 2.0 Return the Degrees, Minutes, Seconds representation of the given point.
• ST_AsPNG - Availability: 2.0.0 - requires GDAL >= 1.6.0. Return the raster tile selected bands as a single portable network
graphics (PNG) image (byte array). If 1, 3, or 4 bands in raster and no bands are specified, then all bands are used. If more 2
or more than 4 bands and no bands specified, then only band 1 is used. Bands are mapped to RGB or RGBA space.
• ST_AsRaster - Availability: 2.0.0 - requires GDAL >= 1.6.0. Converts a PostGIS geometry to a PostGIS raster.
• ST_AsTIFF - Availability: 2.0.0 - requires GDAL >= 1.6.0. Return the raster selected bands as a single TIFF image (byte
array). If no band is specified, then will try to use all bands.

• ST_AsX3D - Availability: 2.0.0: ISO-IEC-19776-1.2-X3DEncodings-XML Returns a Geometry in X3D xml node element
format: ISO-IEC-19776-1.2-X3DEncodings-XML
• ST_Aspect - Availability: 2.0.0 Returns the aspect (in degrees by default) of an elevation raster band. Useful for analyzing
terrain.
• ST_Band - Availability: 2.0.0 Returns one or more bands of an existing raster as a new raster. Useful for building new rasters
from existing rasters.
• ST_BandIsNoData - Availability: 2.0.0 Returns true if the band is filled with only nodata values.
• ST_Clip - Availability: 2.0.0 Returns the raster clipped by the input geometry. If band number not is specified, all bands are
processed. If crop is not specified or TRUE, the output raster is cropped.

• ST_CollectionHomogenize - Availability: 2.0.0 Given a geometry collection, return the "simplest" representation of the con-
tents.
• ST_ConcaveHull - Availability: 2.0.0 The concave hull of a geometry represents a possibly concave geometry that encloses all
geometries within the set. You can think of it as shrink wrapping.

• ST_Count - Availability: 2.0.0 Returns the number of pixels in a given band of a raster or raster coverage. If no band is
specified defaults to band 1. If exclude_nodata_value is set to true, will only count pixels that are not equal to the nodata value.
• ST_CreateTopoGeo - Availability: 2.0 Adds a collection of geometries to a given empty topology and returns a message
detailing success.
• ST_Distinct4ma - Availability: 2.0.0 Raster processing function that calculates the number of unique pixel values in a neigh-
borhood.
• ST_FlipCoordinates - Availability: 2.0.0 Returns a version of the given geometry with X and Y axis flipped. Useful for people
who have built latitude/longitude features and need to fix them.
• ST_GDALDrivers - Availability: 2.0.0 - requires GDAL >= 1.6.0. Returns a list of raster formats supported by your lib gdal.
These are the formats you can output your raster using ST_AsGDALRaster.
• ST_GeomFromGeoJSON - Availability: 2.0.0 requires - JSON-C >= 0.9 Takes as input a geojson representation of a geometry
and outputs a PostGIS geometry object
• ST_GetFaceEdges - Availability: 2.0 Returns a set of ordered edges that bound aface.

• ST_HasNoBand - Availability: 2.0.0 Returns true if there is no band with given band number. If no band number is specified,
then band number 1 is assumed.
• ST_HillShade - Availability: 2.0.0 Returns the hypothetical illumination of an elevation raster band using provided azimuth,
altitude, brightness and scale inputs.
• ST_Histogram - Availability: 2.0.0 Returns a set of record summarizing a raster or raster coverage data distribution separate
bin ranges. Number of bins are autocomputed if not specified.
• ST_InterpolatePoint - Availability: 2.0.0 Return the value of the measure dimension of a geometry at the point closed to the
provided point.
• ST_IsEmpty - Availability: 2.0.0 Returns true if the raster is empty (width = 0 and height = 0). Otherwise, returns false.
PostGIS 2.4.3 Manual 745 / 803

• ST_IsValidDetail - Availability: 2.0.0 - requires GEOS >= 3.3.0. Returns a valid_detail (valid,reason,location) row stating if a
geometry is valid or not and if not valid, a reason why and a location where.
• ST_IsValidReason - Availability: 2.0 - requires GEOS >= 3.3.0 for the version taking flags. Returns text stating if a geometry
is valid or not and if not valid, a reason why.
• ST_MakeLine - Availability: 2.0.0 - Support for linestring input elements was introduced Creates a Linestring from point,
multipoint, or line geometries.
• ST_MakeValid - Availability: 2.0.0, requires GEOS-3.3.0 Attempts to make an invalid geometry valid without losing vertices.

• ST_MapAlgebraExpr - Availability: 2.0.0 1 raster band version: Creates a new one band raster formed by applying a valid
PostgreSQL algebraic operation on the input raster band and of pixeltype provided. Band 1 is assumed if no band is specified.
• ST_MapAlgebraExpr - Availability: 2.0.0 2 raster band version: Creates a new one band raster formed by applying a valid
PostgreSQL algebraic operation on the two input raster bands and of pixeltype provided. band 1 of each raster is assumed if no
band numbers are specified. The resulting raster will be aligned (scale, skew and pixel corners) on the grid defined by the first
raster and have its extent defined by the "extenttype" parameter. Values for "extenttype" can be: INTERSECTION, UNION,
FIRST, SECOND.
• ST_MapAlgebraFct - Availability: 2.0.0 1 band version - Creates a new one band raster formed by applying a valid PostgreSQL
function on the input raster band and of pixeltype prodived. Band 1 is assumed if no band is specified.
• ST_MapAlgebraFct - Availability: 2.0.0 2 band version - Creates a new one band raster formed by applying a valid PostgreSQL
function on the 2 input raster bands and of pixeltype prodived. Band 1 is assumed if no band is specified. Extent type defaults
to INTERSECTION if not specified.
• ST_MapAlgebraFctNgb - Availability: 2.0.0 1-band version: Map Algebra Nearest Neighbor using user-defined PostgreSQL
function. Return a raster which values are the result of a PLPGSQL user function involving a neighborhood of values from the
input raster band.

• ST_Max4ma - Availability: 2.0.0 Raster processing function that calculates the maximum pixel value in a neighborhood.
• ST_Mean4ma - Availability: 2.0.0 Raster processing function that calculates the mean pixel value in a neighborhood.
• ST_Min4ma - Availability: 2.0.0 Raster processing function that calculates the minimum pixel value in a neighborhood.

• ST_ModEdgeHeal - Availability: 2.0 Heal two edges by deleting the node connecting them, modifying the first edgeand
deleting the second edge. Returns the id of the deleted node.
• ST_NewEdgeHeal - Availability: 2.0 Heal two edges by deleting the node connecting them, deleting both edges,and replacing
them with an edge whose direction is the same as the firstedge provided.
• ST_Node - Availability: 2.0.0 - requires GEOS >= 3.3.0. Node a set of linestrings.

• ST_NumPatches - Availability: 2.0.0 Return the number of faces on a Polyhedral Surface. Will return null for non-polyhedral
geometries.
• ST_OffsetCurve - Availability: 2.0 - requires GEOS >= 3.2, improved with GEOS >= 3.3 Return an offset line at a given
distance and side from an input line. Useful for computing parallel lines about a center line

• ST_PatchN - Availability: 2.0.0 Return the 1-based Nth geometry (face) if the geometry is a POLYHEDRALSURFACE,
POLYHEDRALSURFACEM. Otherwise, return NULL.
• ST_PixelAsPolygon - Availability: 2.0.0 Returns the polygon geometry that bounds the pixel for a particular row and column.
• ST_PixelAsPolygons - Availability: 2.0.0 Returns the polygon geometry that bounds every pixel of a raster band along with
the value, the X and the Y raster coordinates of each pixel.
• ST_Project - Availability: 2.0.0 Returns a POINT projected from a start point using a distance in meters and bearing (azimuth)
in radians.
• ST_Quantile - Availability: 2.0.0 Compute quantiles for a raster or raster table coverage in the context of the sample or
population. Thus, a value could be examined to be at the raster’s 25%, 50%, 75% percentile.
PostGIS 2.4.3 Manual 746 / 803

• ST_Range4ma - Availability: 2.0.0 Raster processing function that calculates the range of pixel values in a neighborhood.
• ST_Reclass - Availability: 2.0.0 Creates a new raster composed of band types reclassified from original. The nband is the band
to be changed. If nband is not specified assumed to be 1. All other bands are returned unchanged. Use case: convert a 16BUI
band to a 8BUI and so forth for simpler rendering as viewable formats.
• ST_RelateMatch - Availability: 2.0.0 - requires GEOS >= 3.3.0. Returns true if intersectionMattrixPattern1 implies intersec-
tionMatrixPattern2
• ST_RemEdgeModFace - Availability: 2.0 Removes an edge and, if the removed edge separated two faces,delete one of the
them and modify the other to take the space of both.

• ST_RemEdgeNewFace - Availability: 2.0 Removes an edge and, if the removed edge separated two faces,delete the original
faces and replace them with a new face.
• ST_Resample - Availability: 2.0.0 Requires GDAL 1.6.1+ Resample a raster using a specified resampling algorithm, new
dimensions, an arbitrary grid corner and a set of raster georeferencing attributes defined or borrowed from another raster.

• ST_Rescale - Availability: 2.0.0 Requires GDAL 1.6.1+ Resample a raster by adjusting only its scale (or pixel size). New
pixel values are computed using the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos
resampling algorithm. Default is NearestNeighbor.
• ST_Reskew - Availability: 2.0.0 Requires GDAL 1.6.1+ Resample a raster by adjusting only its skew (or rotation parameters).
New pixel values are computed using the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or
Lanczos resampling algorithm. Default is NearestNeighbor.
• ST_SameAlignment - Availability: 2.0.0 Returns true if rasters have same skew, scale, spatial ref, and offset (pixels can be put
on same grid without cutting into pixels) and false if they don’t with notice detailing issue.
• ST_SetBandIsNoData - Availability: 2.0.0 Sets the isnodata flag of the band to TRUE.

• ST_SharedPaths - Availability: 2.0.0 requires GEOS >= 3.3.0. Returns a collection containing paths shared by the two input
linestrings/multilinestrings.
• ST_Slope - Availability: 2.0.0 Returns the slope (in degrees by default) of an elevation raster band. Useful for analyzing
terrain.

• ST_Snap - Availability: 2.0.0 requires GEOS >= 3.3.0. Snap segments and vertices of input geometry to vertices of a reference
geometry.
• ST_SnapToGrid - Availability: 2.0.0 Requires GDAL 1.6.1+ Resample a raster by snapping it to a grid. New pixel values
are computed using the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling
algorithm. Default is NearestNeighbor.

• ST_Split - Availability: 2.0.0 Returns a collection of geometries resulting by splitting a geometry.

• ST_StdDev4ma - Availability: 2.0.0 Raster processing function that calculates the standard deviation of pixel values in a
neighborhood.
• ST_Sum4ma - Availability: 2.0.0 Raster processing function that calculates the sum of all pixel values in a neighborhood.

• ST_SummaryStats - Availability: 2.0.0 Returns summarystats consisting of count, sum, mean, stddev, min, max for a given
raster band of a raster or raster coverage. Band 1 is assumed is no band is specified.
• ST_Transform - Availability: 2.0.0 Requires GDAL 1.6.1+ Reprojects a raster in a known spatial reference system to an-
other known spatial reference system using specified resampling algorithm. Options are NearestNeighbor, Bilinear, Cubic,
CubicSpline, Lanczos defaulting to NearestNeighbor.

• ST_UnaryUnion - Availability: 2.0.0 - requires GEOS >= 3.3.0. Like ST_Union, but working at the geometry component
level.
• ST_Union - Availability: 2.0.0 Returns the union of a set of raster tiles into a single raster composed of 1 or more bands.
PostGIS 2.4.3 Manual 747 / 803

• ST_ValueCount - Availability: 2.0.0 Returns a set of records containing a pixel band value and count of the number of pixels
in a given band of a raster (or a raster coverage) that have a given set of values. If no band is specified defaults to band 1. By
default nodata value pixels are not counted. and all other values in the pixel are output and pixel band values are rounded to
the nearest integer.
• TopoElementArray_Agg - Availability: 2.0.0 Returns a topoelementarray for a set of element_id, type arrays (topoelements)
• TopoGeo_AddLineString - Availability: 2.0.0 Adds a linestring to an existing topology using a tolerance and possibly splitting
existing edges/faces. Returns edge identifiers
• TopoGeo_AddPoint - Availability: 2.0.0 Adds a point to an existing topology using a tolerance and possibly splitting an
existing edge.
• TopoGeo_AddPolygon - Availability: 2.0.0 Adds a polygon to an existing topology using a tolerance and possibly splitting
existing edges/faces.
• TopologySummary - Availability: 2.0.0 Takes a topology name and provides summary totals of types of objects in topology
• Topology_Load_Tiger - Availability: 2.0.0 Loads a defined region of tiger data into a PostGIS Topology and transforming the
tiger data to spatial reference of the topology and snapping to the precision tolerance of the topology.
• toTopoGeom - Availability: 2.0 Converts a simple Geometry into a topo geometry
• ~= - Availability: 2.0.0 Returns TRUE if A’s bounding box is the same as B’s.

The functions given below are PostGIS functions that are enhanced in PostGIS 2.0.

• AddGeometryColumn - Enhanced: 2.0.0 use_typmod argument introduced. Defaults to creating typmod geometry column
instead of constraint-based.
• Box2D - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• Box3D - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• Geocode - Enhanced: 2.0.0 to support Tiger 2010 structured data and revised some logic to improve speed, accuracy of
geocoding, and to offset point from centerline to side of street address is located on. The new parameter max_results useful for
specifying number of best results or just returning the best result.
• GeometryType - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• Populate_Geometry_Columns - Enhanced: 2.0.0 use_typmod optional argument was introduced that allows controlling if
columns are created with typmodifiers or with check constraints.
• ST_Intersection - Enhanced: 2.0.0 - Intersection in the raster space was introduced. In earlier pre-2.0.0 versions, only intersec-
tion performed in vector space were supported.
• ST_Intersects - Enhanced: 2.0.0 support raster/raster intersects was introduced.
• ST_Value - Enhanced: 2.0.0 exclude_nodata_value optional argument was added.
• ST_3DExtent - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Accum - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Affine - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Area - Enhanced: 2.0.0 - support for 2D polyhedral surfaces was introduced.
• ST_AsBinary - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_AsBinary - Enhanced: 2.0.0 support for higher coordinate dimensions was introduced.
• ST_AsBinary - Enhanced: 2.0.0 support for specifying endian with geography was introduced.
• ST_AsEWKB - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
PostGIS 2.4.3 Manual 748 / 803

• ST_AsEWKT - Enhanced: 2.0.0 support for Geography, Polyhedral surfaces, Triangles and TIN was introduced.
• ST_AsGML - Enhanced: 2.0.0 prefix support was introduced. Option 4 for GML3 was introduced to allow using LineString
instead of Curve tag for lines. GML3 Support for Polyhedral surfaces and TINS was introduced. Option 32 was introduced to
output the box.
• ST_AsKML - Enhanced: 2.0.0 - Add prefix namespace. Default is no prefix
• ST_Azimuth - Enhanced: 2.0.0 support for geography was introduced.
• ST_ChangeEdgeGeom - Enhanced: 2.0.0 adds topological consistency enforcement
• ST_Dimension - Enhanced: 2.0.0 support for Polyhedral surfaces and TINs was introduced. No longer throws an exception if
given empty geometry.
• ST_Dump - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_DumpPoints - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Expand - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Extent - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Force2D - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_ForceRHR - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_Force3D - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_Force3DZ - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_ForceCollection - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_GMLToSQL - Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
• ST_GMLToSQL - Enhanced: 2.0.0 default srid optional parameter added.
• ST_GeomFromEWKB - Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
• ST_GeomFromEWKT - Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
• ST_GeomFromGML - Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
• ST_GeomFromGML - Enhanced: 2.0.0 default srid optional parameter added.
• ST_GeometryN - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_GeometryType - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_IsClosed - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_MakeEnvelope - Enhanced: 2.0: Ability to specify an envelope without specifying an SRID was introduced.
• ST_MakeValid - Enhanced: 2.0.1, speed improvements requires GEOS-3.3.4
• ST_NPoints - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ST_NumGeometries - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Relate - Enhanced: 2.0.0 - added support for specifying boundary node rule (requires GEOS >= 3.0).
• ST_Rotate - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Rotate - Enhanced: 2.0.0 additional parameters for specifying the origin of rotation were added.
• ST_RotateX - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_RotateY - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
PostGIS 2.4.3 Manual 749 / 803

• ST_RotateZ - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_Scale - Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
• ST_ShiftLongitude - Enhanced: 2.0.0 support for Polyhedral surfaces and TIN was introduced.
• ST_Summary - Enhanced: 2.0.0 added support for geography
• ST_Transform - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
• ValidateTopology - Enhanced: 2.0.0 more efficient edge crossing detection and fixes for false positives that were existent in
prior versions.
• && - Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.

14.12.8 PostGIS Functions changed behavior in 2.0

The functions given below are PostGIS functions that have changed behavior in PostGIS 2.0 and may require application changes.

Note
Most deprecated functions have been removed. These are functions that haven’t been documented since 1.2 or some
internal functions that were never documented. If you are using a function that you don’t see documented, it’s probably
deprecated, about to be deprecated, or internal and should be avoided. If you have applications or tools that rely on
deprecated functions, please refer to [?qandaentry] for more details.

Note
Bounding boxes of geometries have been changed from float4 to double precision (float8). This has an impact on
answers you get using bounding box operators and casting of bounding boxes to geometries. E.g ST_SetSRID(abbox)
will often return a different more accurate answer in PostGIS 2.0+ than it did in prior versions which may very well
slightly change answers to view port queries.

Note
The arguments hasnodata was replaced with exclude_nodata_value which has the same meaning as the older hasno-
data but clearer in purpose.

• AddGeometryColumn - Changed: 2.0.0 This function no longer updates geometry_columns since geometry_columns is a
view that reads from system catalogs. It by default also does not create constraints, but instead uses the built in type modifier
behavior of PostgreSQL. So for example building a wgs84 POINT column with this function is now equivalent to: ALTER
TABLE some_table ADD COLUMN geom geometry(Point,4326);
• AddGeometryColumn - Changed: 2.0.0 If you require the old behavior of constraints use the default use_typmod, but set it to
false.
• AddGeometryColumn - Changed: 2.0.0 Views can no longer be manually registered in geometry_columns, however views built
against geometry typmod tables geometries and used without wrapper functions will register themselves correctly because they
inherit the typmod behavior of their parent table column. Views that use geometry functions that output other geometries will
need to be cast to typmod geometries for these view geometry columns to be registered correctly in geometry_columns. Refer
to .
• DropGeometryColumn - Changed: 2.0.0 This function is provided for backward compatibility. Now that since geome-
try_columns is now a view against the system catalogs, you can drop a geometry column like any other table column using
ALTER TABLE
• DropGeometryTable - Changed: 2.0.0 This function is provided for backward compatibility. Now that since geometry_columns
is now a view against the system catalogs, you can drop a table with geometry columns like any other table using DROP TABLE
PostGIS 2.4.3 Manual 750 / 803

• Populate_Geometry_Columns - Changed: 2.0.0 By default, now uses type modifiers instead of check constraints to constrain
geometry types. You can still use check constraint behavior instead by using the new use_typmod and setting it to false.
• Box3D - Changed: 2.0.0 In pre-2.0 versions, there used to be a box2d instead of box3d. Since box2d is a deprecated type, this
was changed to box3d.
• ST_GDALDrivers - Changed: 2.0.6, 2.1.3 - by default no drivers are enabled, unless GUC or Environment variable gdal_enabled_driver
is set.
• ST_ScaleX - Changed: 2.0.0. In WKTRaster versions this was called ST_PixelSizeX.

• ST_ScaleY - Changed: 2.0.0. In WKTRaster versions this was called ST_PixelSizeY.

• ST_SetScale - Changed: 2.0.0 In WKTRaster versions this was called ST_SetPixelSize. This was changed in 2.0.0.
• ST_3DExtent - Changed: 2.0.0 In prior versions this used to be called ST_Extent3D
• ST_3DLength - Changed: 2.0.0 In prior versions this used to be called ST_Length3D

• ST_3DMakeBox - Changed: 2.0.0 In prior versions this used to be called ST_MakeBox3D

• ST_3DPerimeter - Changed: 2.0.0 In prior versions this used to be called ST_Perimeter3D
• ST_AsBinary - Changed: 2.0.0 Inputs to this function can not be unknown -- must be geometry. Constructs such as ST_AsBinary(’POIN
2)’) are no longer valid and you will get an n st_asbinary(unknown) is not unique error. Code like that needs to be changed to
ST_AsBinary(’POINT(1 2)’::geometry);. If that is not possible, then install legacy.sql.
• ST_AsGML - Changed: 2.0.0 use default named args
• ST_AsGeoJSON - Changed: 2.0.0 support default args and named args.
• ST_AsKML - Changed: 2.0.0 - uses default args and supports named args

• ST_AsSVG - Changed: 2.0.0 to use default args and support named args
• ST_EndPoint - Changed: 2.0.0 no longer works with single geometry multilinestrings. In older versions of PostGIS -- a single
line multilinestring would work happily with this function and return the start point. In 2.0.0 it just returns NULL like any
other multilinestring. The older behavior was an undocumented feature, but people who assumed they had their data stored as
LINESTRING may experience these returning NULL in 2.0 now.

• ST_GeomFromText - Changed: 2.0.0 In prior versions of PostGIS ST_GeomFromText(’GEOMETRYCOLLECTION(EMPTY)’)

was allowed. This is now illegal in PostGIS 2.0.0 to better conform with SQL/MM standards. This should now be written as
ST_GeomFromText(’GEOMETRYCOLLECTION EMPTY’)
• ST_GeometryN - Changed: 2.0.0 Prior versions would return NULL for singular geometries. This was changed to return the
geometry for ST_GeometryN(..,1) case.
• ST_IsEmpty - Changed: 2.0.0 In prior versions of PostGIS ST_GeomFromText(’GEOMETRYCOLLECTION(EMPTY)’) was
allowed. This is now illegal in PostGIS 2.0.0 to better conform with SQL/MM standards
• ST_Length - Changed: 2.0.0 Breaking change -- in prior versions applying this to a MULTI/POLYGON of type geography
would give you the perimeter of the POLYGON/MULTIPOLYGON. In 2.0.0 this was changed to return 0 to be in line with
geometry behavior. Please use ST_Perimeter if you want the perimeter of a polygon
• ST_LocateAlong - Changed: 2.0.0 in prior versions this used to be called ST_Locate_Along_Measure. The old name has been
deprecated and will be removed in the future but is still available.
• ST_LocateBetween - Changed: 2.0.0 - in prior versions this used to be called ST_Locate_Between_Measures. The old name
has been deprecated and will be removed in the future but is still available for backward compatibility.
• ST_ModEdgeSplit - Changed: 2.0 - In prior versions, this was misnamed ST_ModEdgesSplit
• ST_NumGeometries - Changed: 2.0.0 In prior versions this would return NULL if the geometry was not a collection/MULTI
type. 2.0.0+ now returns 1 for single geometries e.g POLYGON, LINESTRING, POINT.
PostGIS 2.4.3 Manual 751 / 803

• ST_NumInteriorRings - Changed: 2.0.0 - in prior versions it would allow passing a MULTIPOLYGON, returning the number
of interior rings of first POLYGON.
• ST_PointN - Changed: 2.0.0 no longer works with single geometry multilinestrings. In older versions of PostGIS -- a single
line multilinestring would work happily with this function and return the start point. In 2.0.0 it just returns NULL like any
other multilinestring.
• ST_StartPoint - Changed: 2.0.0 no longer works with single geometry multilinestrings. In older versions of PostGIS -- a single
line multilinestring would work happily with this function and return the start point. In 2.0.0 it just returns NULL like any
other multilinestring. The older behavior was an undocumented feature, but people who assumed they had their data stored as
LINESTRING may experience these returning NULL in 2.0 now.

14.12.9 PostGIS Functions new, behavior changed, or enhanced in 1.5

The functions given below are PostGIS functions that were introduced or enhanced in this minor release.

• PostGIS_LibXML_Version - Availability: 1.5 Returns the version number of the libxml2 library.

• ST_AddMeasure - Availability: 1.5.0 Return a derived geometry with measure elements linearly interpolated between the start
and end points.
• ST_AsBinary - Availability: 1.5.0 geography support was introduced. Return the Well-Known Binary (WKB) representation
of the geometry/geography without SRID meta data.

• ST_AsGML - Availability: 1.5.0 geography support was introduced. Return the geometry as a GML version 2 or 3 element.
• ST_AsGeoJSON - Availability: 1.5.0 geography support was introduced. Return the geometry as a GeoJSON element.
• ST_AsText - Availability: 1.5 - support for geography was introduced. Return the Well-Known Text (WKT) representation of
the geometry/geography without SRID metadata.

• ST_Buffer - Availability: 1.5 - ST_Buffer was enhanced to support different endcaps and join types. These are useful for
example to convert road linestrings into polygon roads with flat or square edges instead of rounded edges. Thin wrapper for
geography was added. - requires GEOS >= 3.2 to take advantage of advanced geometry functionality. (T)Returns a geometry
covering all points within a given distancefrom the input geometry.
• ST_ClosestPoint - Availability: 1.5.0 Returns the 2-dimensional point on g1 that is closest to g2. This is the first point of the
shortest line.
• ST_CollectionExtract - Availability: 1.5.0 Given a (multi)geometry, return a (multi)geometry consisting only of elements of
the specified type.
• ST_Covers - Availability: 1.5 - support for geography was introduced. Returns 1 (TRUE) if no point in Geometry B is outside
Geometry A

• ST_DFullyWithin - Availability: 1.5.0 Returns true if all of the geometries are within the specified distance of one another
• ST_DWithin - Availability: 1.5.0 support for geography was introduced Returns true if the geometries are within the specified
distance of one another. For geometry units are in those of spatial reference and For geography units are in meters and
measurement is defaulted to use_spheroid=true (measure around spheroid), for faster check, use_spheroid=false to measure
along sphere.
• ST_Distance - Availability: 1.5.0 geography support was introduced in 1.5. Speed improvements for planar to better handle
large or many vertex geometries For geometry type Returns the 2D Cartesian distance between two geometries in projected
units (based on spatial ref). For geography type defaults to return minimum geodesic distance between two geographies in
meters.

• ST_DistanceSphere - Availability: 1.5 - support for other geometry types besides points was introduced. Prior versions only
work with points. Returns minimum distance in meters between two lon/lat geometries. Uses a spherical earth and radius
derived from the spheroid defined by the SRID. Faster than ST_DistanceSpheroid , but less accurate. PostGIS versions prior
to 1.5 only implemented for points.
PostGIS 2.4.3 Manual 752 / 803

• ST_DistanceSpheroid - Availability: 1.5 - support for other geometry types besides points was introduced. Prior versions only
work with points. Returns the minimum distance between two lon/lat geometries given a particular spheroid. PostGIS versions
prior to 1.5 only support points.

• ST_DumpPoints - Availability: 1.5.0 Returns a set of geometry_dump (geom,path) rows of all points that make up a geometry.
• ST_Envelope - Availability: 1.5.0 behavior changed to output double precision instead of float4 Returns a geometry represent-
ing the double precision (float8) bounding box of the supplied geometry.
• ST_GMLToSQL - Availability: 1.5, requires libxml2 1.6+ Return a specified ST_Geometry value from GML representation.
This is an alias name for ST_GeomFromGML

• ST_GeomFromGML - Availability: 1.5, requires libxml2 1.6+ Takes as input GML representation of geometry and outputs a
PostGIS geometry object
• ST_GeomFromKML - Availability: 1.5,libxml2 2.6+ Takes as input KML representation of geometry and outputs a PostGIS
geometry object

• ~= - Availability: 1.5.0 changed behavior Returns TRUE if A’s bounding box is the same as B’s.
• ST_HausdorffDistance - Availability: 1.5.0 - requires GEOS >= 3.2.0 Returns the Hausdorff distance between two geometries.
Basically a measure of how similar or dissimilar 2 geometries are. Units are in the units of the spatial reference system of the
geometries.

• ST_Intersection - Availability: 1.5 support for geography data type was introduced. (T)Returns a geometry that represents the
shared portion of geomA and geomB.
• ST_Intersects - Availability: 1.5 support for geography was introduced. Returns TRUE if the Geometries/Geography "spatially
intersect in 2D" - (share any portion of space) and FALSE if they don’t (they are Disjoint). For geography -- tolerance is
0.00001 meters (so any points that close are considered to intersect)

• ST_Length - Availability: 1.5.0 geography support was introduced in 1.5. Returns the 2D length of the geometry if it is a
LineString or MultiLineString. geometry are in units of spatial reference and geography are in meters (default spheroid)
• ST_LongestLine - Availability: 1.5.0 Returns the 2-dimensional longest line points of two geometries. The function will only
return the first longest line if more than one, that the function finds. The line returned will always start in g1 and end in g2.
The length of the line this function returns will always be the same as st_maxdistance returns for g1 and g2.

• ST_MakeEnvelope - Availability: 1.5 Creates a rectangular Polygon formed from the given minimums and maximums. Input
values must be in SRS specified by the SRID.
• ST_MaxDistance - Availability: 1.5.0 Returns the 2-dimensional largest distance between two geometries in projected units.
• ST_ShortestLine - Availability: 1.5.0 Returns the 2-dimensional shortest line between two geometries

• && - Availability: 1.5.0 support for geography was introduced. Returns TRUE if A’s 2D bounding box intersects B’s 2D
bounding box.

14.12.10 PostGIS Functions new, behavior changed, or enhanced in 1.4

The functions given below are PostGIS functions that were introduced or enhanced in the 1.4 release.

• Populate_Geometry_Columns - Ensures geometry columns are defined with type modifiers or have appropriate spatial con-
straints This ensures they will be registered correctly in geometry_columns view. By default will convert all geometry columns
with no type modifier to ones with type modifiers. To get old behavior set use_typmod=false Availability: 1.4.0
• ST_AsSVG - Returns a Geometry in SVG path data given a geometry or geography object. Availability: 1.2.2. Availability:
1.4.0 Changed in PostGIS 1.4.0 to include L command in absolute path to conform to http://www.w3.org/TR/SVG/paths.html#PathData
• ST_Collect - Return a specified ST_Geometry value from a collection of other geometries. Availability: 1.4.0 - ST_Collect(geomarray)
was introduced. ST_Collect was enhanced to handle more geometries faster.
PostGIS 2.4.3 Manual 753 / 803

• ST_ContainsProperly - Returns true if B intersects the interior of A but not the boundary (or exterior). A does not contain
properly itself, but does contain itself. Availability: 1.4.0 - requires GEOS >= 3.1.0.
• ST_Extent - an aggregate function that returns the bounding box that bounds rows of geometries. Availability: 1.4.0

• ST_GeoHash - Return a GeoHash representation of the geometry. Availability: 1.4.0

• ST_IsValidReason - Returns text stating if a geometry is valid or not and if not valid, a reason why. Availability: 1.4 - requires
GEOS >= 3.1.0.
• ST_LineCrossingDirection - Given 2 linestrings, returns a number between -3 and 3 denoting what kind of crossing behavior.
0 is no crossing. Availability: 1.4
• ST_LocateBetweenElevations - Return a derived geometry (collection) value with elements that intersect the specified range
of elevations inclusively. Only 3D, 4D LINESTRINGS and MULTILINESTRINGS are supported. Availability: 1.4.0
• ST_MakeLine - Creates a Linestring from point, multipoint, or line geometries. Availability: 1.4.0 - ST_MakeLine(geomarray)
was introduced. ST_MakeLine aggregate functions was enhanced to handle more points faster.

• ST_MinimumBoundingCircle - Returns the smallest circle polygon that can fully contain a geometry. Default uses 48 segments
per quarter circle. Availability: 1.4.0 - requires GEOS
• ST_Union - Returns a geometry that represents the point set union of the Geometries. Availability: 1.4.0 - ST_Union was
enhanced. ST_Union(geomarray) was introduced and also faster aggregate collection in PostgreSQL. If you are using GEOS
3.1.0+ ST_Union will use the faster Cascaded Union algorithm described in http://blog.cleverelephant.ca/2009/01/must-faster-
unions-in-postgis-14.html

14.12.11 PostGIS Functions new in 1.3

The functions given below are PostGIS functions that were introduced in the 1.3 release.

• ST_AsGML - Return the geometry as a GML version 2 or 3 element. Availability: 1.3.2

• ST_AsGeoJSON - Return the geometry as a GeoJSON element. Availability: 1.3.4
• ST_SimplifyPreserveTopology - Returns a "simplified" version of the given geometry using the Douglas-Peucker algorithm.
Will avoid creating derived geometries (polygons in particular) that are invalid. Availability: 1.3.3
PostGIS 2.4.3 Manual 754 / 803

Chapter 15

Reporting Problems

15.1 Reporting Software Bugs

Reporting bugs effectively is a fundamental way to help PostGIS development. The most effective bug report is that enabling
PostGIS developers to reproduce it, so it would ideally contain a script triggering it and every information regarding the envi-
ronment in which it was detected. Good enough info can be extracted running SELECT postgis_full_version() [for
postgis] and SELECT version() [for postgresql].
If you aren’t using the latest release, it’s worth taking a look at its release changelog first, to find out if your bug has already been
fixed.
Using the PostGIS bug tracker will ensure your reports are not discarded, and will keep you informed on its handling process.
Before reporting a new bug please query the database to see if it is a known one, and if it is please add any new information you
have about it.
You might want to read Simon Tatham’s paper about How to Report Bugs Effectively before filing a new report.

15.2 Reporting Documentation Issues

The documentation should accurately reflect the features and behavior of the software. If it doesn’t, it could be because of a
software bug or because the documentation is in error or deficient.
Documentation issues can also be reported to the PostGIS bug tracker.
If your revision is trivial, just describe it in a new bug tracker issue, being specific about its location in the documentation.
If your changes are more extensive, a Subversion patch is definitely preferred. This is a four step process on Unix (assuming you
already have Subversion installed):

1. Check out a copy of PostGIS’ Subversion trunk. On Unix, type:

svn checkout http://svn.osgeo.org/postgis/trunk/
This will be stored in the directory ./trunk
2. Make your changes to the documentation with your favorite text editor. On Unix, type (for example):
vim trunk/doc/postgis.xml
Note that the documentation is written in DocBook XML rather than HTML, so if you are not familiar with it please follow
the example of the rest of the documentation.
3. Make a patch file containing the differences from the master copy of the documentation. On Unix, type:
svn diff trunk/doc/postgis.xml > doc.patch
4. Attach the patch to a new issue in bug tracker.
PostGIS 2.4.3 Manual 755 / 803

Appendix A

Appendix

A.1 Release 2.4.3

Release date: 2018/01/17

This is a bug fix and performance improvement release.

A.1.1 Bug Fixes and Enhancements

#3713, Support encodings that happen to output a ’\’ character

#3827, Set configure default to not do interrupt testing, was causing false negatives for many people. (Regina Obe) revised to be
standards compliant in #3988 (Greg Troxel)
#3930, Minimum bounding circle issues on 32-bit platforms
#3965, ST_ClusterKMeans used to lose some clusters on initialization (Darafei Praliaskouski)
#3956, Brin opclass object does not upgrade properly (Sandro Santilli)
#3982, ST_AsEncodedPolyline supports LINESTRING EMPTY and MULTIPOINT EMPTY (Darafei Praliaskouski)
#3975, ST_Transform runs query on spatial_ref_sys without schema qualification. Was causing restore issues. (Paul Ramsey)

A.2 Release 2.4.2

Release date: 2017/11/15

This is a bug fix and performance improvement release.

A.2.1 Bug Fixes and Enhancements

#3917, Fix zcta5 load

#3667, Fix for bug in geography ST_Segmentize
#3926, Add missing 2.2.6 and 2.3.4 upgrade paths (Muhammad Usama)

A.3 Release 2.4.1

Release date: 2017/10/18

This is a bug fix and performance improvement release.
PostGIS 2.4.3 Manual 756 / 803

A.3.1 Bug Fixes and Enhancements

#3864, Fix memory leaks in BTREE operators

#3869, Fix build with "gold" linker
#3845, Gracefully handle short-measure issue
#3871, Performance tweak for geometry cmp function
#3879, Division by zero in some arc cases
#3878, Single defn of signum in header
#3880, Undefined behaviour in TYPMOD_GET_SRID
#3875, Fix undefined behaviour in shift operation
#3864, Performance improvements for b-tree geometry sorts
#3874, lw_dist2d_pt_arc division by zero
#3882, undefined behaviour in zigzag with negative inputs
#3891, undefined behaviour in pointarray_to_encoded_polyline
#3895, throw error on malformed WKB input
#3886, fix rare missing boxes in geometry subdivision
#3907, Allocate enough space for all possible GBOX string outputs (Raúl Marín Rodríguez)

A.4 Release 2.4.0

Release date: 2017/09/30

A.4.1 New Features

#3822, Have postgis_full_version() also show and check version of PostgreSQL the scripts were built against (Sandro Santilli)
#2411, curves support in ST_Reverse (Sandro Santilli)
#2951, ST_Centroid for geography (Danny Götte)
#3788, Allow postgis_restore.pl to work on directory-style (-Fd) dumps (Roger Crew)
#3772, Direction agnostic ST_CurveToLine output (Sandro Santilli / KKGeo)
#2464, ST_CurveToLine with MaxError tolerance (Sandro Santilli / KKGeo)
#3599, Geobuf output support via ST_AsGeobuf (Björn Harrtell)
#3661, Mapbox vector tile output support via ST_AsMVT (Björn Harrtell / CartoDB)
#3689, Add orientation checking and forcing functions (Dan Baston)
#3753, Gist penalty speed improvements for 2D and ND points (Darafei Praliaskouski, Andrey Borodin)
#3677, ST_FrechetDistance (Shinichi Sugiyama)
Most aggregates (raster and geometry), and all stable / immutable (raster and geometry) marked as parallel safe
#2249, ST_MakeEmptyCoverage for raster (David Zwarg, ainomieli)
#3709, Allow signed distance for ST_Project (Darafei Praliaskouski)
#524, Covers support for polygon on polygon, line on line, point on line for geography (Danny Götte)
PostGIS 2.4.3 Manual 757 / 803

A.4.2 Enhancements and Fixes

Many corrections to docs and several translations almost complete. Andreas Schild who provided many corrections to core docs.
PostGIS Japanese translation team first to reach completion of translation.
Support for PostgreSQL 10
Preliminary support for PostgreSQL 11
#3645, Avoid loading logically deleted records from shapefiles
#3747, Add zip4 and address_alphanumeric as attributes to norm_addy tiger_geocoder type.
#3748, address_standardizer lookup tables update so pagc_normalize_address better standardizes abbreviations
#3647, better handling of noding in ST_Node using GEOSNode (Wouter Geraedts)
#3684, Update to EPSG register v9 (Even Rouault)
#3830, Fix initialization of incompatible type (>=9.6) address_standardizer
#3662, Make shp2pgsql work in debug mode by sending debug to stderr
#3405, Fixed memory leak in lwgeom_to_points
#3832, Support wide integer fields as int8 in shp2pgsql
#3841, Deterministic sorting support for empty geometries in btree geography
#3844, Make = operator a strict equality test, and < > to rough "spatial sorting"
#3855, ST_AsTWKB memory and speed improvements

A.4.3 Breaking Changes

Dropped support for PostgreSQL 9.2.

#3810, GEOS 3.4.0 or above minimum required to compile
Most aggregates now marked as parallel safe, which means most aggs have to be dropped / recreated. If you have views that
utilize PostGIS aggs, you’ll need to drop before upgrade and recreate after upgrade
#3578, ST_NumInteriorRings(POLYGON EMPTY) now returns 0 instead of NULL
_ST_DumpPoints removed, was no longer needed after PostGIS 2.1.0 when ST_DumpPoints got reimplemented in C
B-Tree index operators < = > changed to provide better spatial locality on sorting and have expected behavior on GROUP BY. If
you have btree index for geometry or geography, you need to REINDEX it, or review if it was created by accident and needs to
be replaced with GiST index. If your code relies on old left-to-right box compare ordering, update it to use << >> operators.

A.5 Release 2.3.5

Release date: 2017/11/15

This is a bug fix and performance improvement release.

A.5.1 Bug Fixes and Enhancements

#3667, Fix for bug in geography ST_Segmentize

#3926, Add missing 2.2.6 upgrade path
PostGIS 2.4.3 Manual 758 / 803

A.6 Release 2.3.4

Release date: 2017/10/18

This is a bug fix and performance improvement release.

A.6.1 Bug Fixes and Enhancements

PostgreSQL 10 support
#3782, Memory leak in lwline_from_wkb_state (Even Rouault)
#3101, Fix buffer overflow in pgsql2shp (Sandro Santilli)
#3786, ptarray null and heap issues on is_closed
#3795, Solaris build issues due to missing isfinite define (Julian Schauder)
#3792, mark all 3D related including SFCGAL as parallel safe
#3800, shp2pgql-gui allow export of foreign tables, materialized views, and partitioned tables
#3806, Reverse geocoder missing suffix direction when present
#3698, loading census tabblock is broken
#3839, loader tests sometimes crash because of variables not initialized also reenable cunit loader tess to always run.
#3774, Trigonometric length for CompoundCurves
#3731, Crash on very small table of homogenous data
#2836, Receiving ERROR: ExteriorRing: geom is not a polygon with ST_ConcaveHull
#3781, Not-quite curved CurvePolygon rejected by ST_Contains
#3818, Triangles unclosed in M should be parseable
#3866, Rare crash generating TWKB with large coordinate values
#3869, Fix build with "gold" linker
#3845, Gracefully handle short-measure issue
#3879, Division by zero in some arc cases
#3878, Single defn of signum in header
#3880, Undefined behaviour in TYPMOD_GET_SRID
#3875, Fix undefined behaviour in shift operation
#3874, lw_dist2d_pt_arc division by zero
#3882, undefined behaviour in zigzag with negative inputs
#3891, undefined behaviour in pointarray_to_encoded_polyline
#3895, throw error on malformed WKB input
#3907, Allocate enough space for all possible GBOX string outputs (Raúl Marín Rodríguez)

A.7 Release 2.3.3

Release date: 2017/07/01

This is a bug fix and performance improvement release.
PostGIS 2.4.3 Manual 759 / 803

A.7.1 Bug Fixes and Enhancements

#3777, GROUP BY anomaly with empty geometries

#3711, Azimuth error upon adding 2.5D edges to topology
#3726, PDF manual from dblatex renders fancy quotes for programlisting (Mike Toews)
#3738, raster: Using -s without -Y in raster2pgsql transforms raster data instead of setting srid
#3744, ST_Subdivide loses subparts of inverted geometries (Darafei Praliaskouski Komzpa)
#3750, @ and ~ operator not always schema qualified in geometry and raster functions. Causes restore issues. (Shane StClair of
Axiom Data Science)
#3682, Strange fieldlength for boolean in result of pgsql2shp
#3701, Escape double quotes issue in pgsql2shp
#3704, ST_AsX3D crashes on empty geometry
#3730, Change ST_Clip from Error to Notice when ST_Clip can’t compute a band

A.8 Release 2.3.2

Release date: 2017/01/31

This is a bug fix and performance improvement release.

A.8.1 Bug Fixes and Enhancements

#3418, KNN recheck in 9.5+ fails with index returned tuples in wrong order
#3675, Relationship functions not using an index in some cases
#3680, PostGIS upgrade scripts missing GRANT for views
#3683, Unable to update postgis after postgres pg_upgrade going from < 9.5 to pg > 9.4
#3688, ST_AsLatLonText: round minutes

A.9 Release 2.3.1

Release date: 2016/11/28

This is a bug fix and performance improvement release.

A.9.1 Bug Fixes and Enhancements

#1973, st_concavehull() returns sometimes empty geometry collection Fix from gde
#3501, add raster constraint max extent exceeds array size limit for large tables
#3643, PostGIS not building on latest OSX XCode
#3644, Deadlock on interrupt
#3650, Mark ST_Extent, ST_3DExtent and ST_Mem* agg functions as parallel safe so they can be parallelized
#3652, Crash on Collection(MultiCurve())
#3656, Fix upgrade of aggregates from 2.2 or lower version
#3659, Crash caused by raster GUC define after CREATE EXTENSION using wrong memory context. (manaeem)
#3665, Index corruption and memory leak in BRIN indexes patch from Julien Rouhaud (Dalibo)
#3667, geography ST_Segmentize bug patch from Hugo Mercier (Oslandia)
PostGIS 2.4.3 Manual 760 / 803

A.10 Release 2.3.0

Release date: 2016/09/26

This is a new feature release, with new functions, improved performance, all relevant bug fixes from PostGIS 2.2.3,and other
goodies.

A.10.1 Important / Breaking Changes

#3466, Casting from box3d to geometry now returns a 3D geometry (Julien Rouhaud of Dalibo)
#3396, ST_EstimatedExtent, throw WARNING instead of ERROR (Regina Obe)

A.10.2 New Features

Add support for custom TOC in postgis_restore.pl (Christoph Moench-Tegeder)

Add support for negative indexing in ST_PointN and ST_SetPoint (Rémi Cura)
Add parameters for geography ST_Buffer (Thomas Bonfort)
TopoGeom_addElement, TopoGeom_remElement (Sandro Santilli)
populate_topology_layer (Sandro Santilli)
#454, ST_WrapX and lwgeom_wrapx (Sandro Santilli)
#1758, ST_Normalize (Sandro Santilli)
#2236, shp2pgsql -d now emits "DROP TABLE IF EXISTS"
#2259, ST_VoronoiPolygons and ST_VoronoiLines (Dan Baston)
#2841 and #2996, ST_MinimumBoundingRadius and new ST_MinimumBoundingCircle implementation using Welzl’s algo-
rithm (Dan Baston)
#2991, Enable ST_Transform to use PROJ.4 text (Mike Toews)
#3059, Allow passing per-dimension parameters in ST_Expand (Dan Baston)
#3339, ST_GeneratePoints (Paul Ramsey)
#3362, ST_ClusterDBSCAN (Dan Baston)
#3364, ST_GeometricMedian (Dan Baston)
#3391, Add table inheritance support in ST_EstimatedExtent (Alessandro Pasotti)
#3424, ST_MinimumClearance (Dan Baston)
#3428, ST_Points (Dan Baston)
#3465, ST_ClusterKMeans (Paul Ramsey)
#3469, ST_MakeLine with MULTIPOINTs (Paul Norman)
#3549, Support PgSQL 9.6 parallel query mode, as far as possible (Paul Ramsey, Regina Obe)
#3557, Geometry function costs based on query stats (Paul Norman)
#3591, Add support for BRIN indexes. PostgreSQL 9.4+ required. (Giuseppe Broccolo of 2nd Quadrant, Julien Rouhaud and
Ronan Dunklau of Dalibo)
#3496, Make postgis non-relocateable for extension install, schema qualify calls in functions (Regina Obe) Should resolve once
and for all for extensions #3494, #3486, #3076
#3547, Update tiger geocoder to support TIGER 2016 and to support both http and ftp.
#3613, Segmentize geography using equal length segments (Hugo Mercier of Oslandia)
PostGIS 2.4.3 Manual 761 / 803

A.10.3 Bug Fixes

All relevant bug fixes from PostGIS 2.2.3

#2841, ST_MinimumBoundingCircle not covering original
#3604, pgcommon/Makefile.in orders CFLAGS incorrectly leading to wrong liblwgeom.h (Greg Troxel)

A.10.4 Performance Enhancements

#75, Enhancement to PIP short circuit (Dan Baston)

#3383, Avoid deserializing small geometries during index operations (Dan Baston)
#3400, Minor optimization of PIP routines (Dan Baston)
Make adding a line to topology interruptible (Sandro Santilli)
Documentation updates from Mike Toews

A.11 Release 2.2.2

Release date: 2016/03/22

This is a bug fix and performance improvement release.

A.11.1 New Features

#3463, Fix crash on face-collapsing edge change

#3422, Improve ST_Split robustness on standard precision double systems (arm64, ppc64el, s390c, powerpc, ...)
#3427, Update spatial_ref_sys to EPSG version 8.8
#3433, ST_ClusterIntersecting incorrect for MultiPoints
#3435, ST_AsX3D fix rendering of concave geometries
#3436, memory handling mistake in ptarray_clone_deep
#3437, ST_Intersects incorrect for MultiPoints
#3461, ST_GeomFromKML crashes Postgres when there are innerBoundaryIs and no outerBoundaryIs
#3429, upgrading to 2.3 or from 2.1 can cause loop/hang on some platforms
#3460, ST_ClusterWithin ’Tolerance not defined’ error after upgrade
#3490, Raster data restore issues, materialized views. Scripts postgis_proc_set_search_path.sql, rtpostgis_proc_set_search_path.sql
refer to http://postgis.net/docs/manual-2.2/RT_FAQ.html#faq_raster_data_not_restore
#3426, failing POINT EMPTY tests on fun architectures

A.12 Release 2.2.1

Release date: 2016/01/06

This is a bug fix and performance improvement release.
PostGIS 2.4.3 Manual 762 / 803

A.12.1 New Features

#2232, avoid accumulated error in SVG rounding

#3321, Fix performance regression in topology loading
#3329, Fix robustness regression in TopoGeo_addPoint
#3349, Fix installation path of postgis_topology scripts
#3351, set endnodes isolation on ST_RemoveIsoEdge (and lwt_RemIsoEdge)
#3355, geography ST_Segmentize has geometry bbox
#3359, Fix toTopoGeom loss of low-id primitives from TopoGeometry definition
#3360, _raster_constraint_info_scale invalid input syntax
#3375, crash in repeated point removal for collection(point)
#3378, Fix handling of hierarchical TopoGeometries in presence of multiple topologies
#3380, #3402, Decimate lines on topology load
#3388, #3410, Fix missing end-points in ST_Removepoints
#3389, Buffer overflow in lwgeom_to_geojson
#3390, Compilation under Alpine Linux 3.2 gives an error when compiling the postgis and postgis_topology extension
#3393, ST_Area NaN for some polygons
#3401, Improve ST_Split robustness on 32bit systems
#3404, ST_ClusterWithin crashes backend
#3407, Fix crash on splitting a face or an edge defining multiple TopoGeometry objects
#3411, Clustering functions not using spatial index
#3412, Improve robustness of snapping step in TopoGeo_addLinestring
#3415, Fix OSX 10.9 build under pkgsrc
Fix memory leak in lwt_ChangeEdgeGeom [liblwgeom]

A.13 Release 2.2.0

Release date: 2015/10/07

This is a new feature release, with new functions, improved performance, and other goodies.

A.13.1 New Features

Topology API in liblwgeom (Sandro Santilli / Regione Toscana - SITA)

New lwgeom_unaryunion method in liblwgeom
New lwgeom_linemerge method in liblwgeom
New lwgeom_is_simple method in liblwgeom
#3169, Add SFCGAL 1.1 support: add ST_3DDifference, ST_3DUnion, ST_Volume, ST_MakeSolid, ST_IsSolid (Vincent Mora
/ Oslandia)
#3169, ST_ApproximateMedialAxis (Sandro Santilli)
ST_CPAWithin (Sandro Santilli / Boundless)
PostGIS 2.4.3 Manual 763 / 803

Add |=| operator with CPA semantic and KNN support with PgSQL 9.5+ (Sandro Santilli / Boundless)
#3131, KNN support for the geography type (Paul Ramsey / CartoDB)
#3023, ST_ClusterIntersecting / ST_ClusterWithin (Dan Baston)
#2703, Exact KNN results for all geometry types, aka "KNN re-check" (Paul Ramsey / CartoDB)
#1137, Allow a tolerance value in ST_RemoveRepeatedPoints (Paul Ramsey / CartoDB)
#3062, Allow passing M factor to ST_Scale (Sandro Santilli / Boundless)
#3139, ST_BoundingDiagonal (Sandro Santilli / Boundless)
#3129, ST_IsValidTrajectory (Sandro Santilli / Boundless)
#3128, ST_ClosestPointOfApproach (Sandro Santilli / Boundless)
#3152, ST_DistanceCPA (Sandro Santilli / Boundless)
Canonical output for index key types
ST_SwapOrdinates (Sandro Santilli / Boundless)
#2918, Use GeographicLib functions for geodetics (Mike Toews)
#3074, ST_Subdivide to break up large geometry (Paul Ramsey / CartoDB)
#3040, KNN GiST index based centroid (<<->>) n-D distance operators (Sandro Santilli / Boundless)
Interruptibility API for liblwgeom (Sandro Santilli / CartoDB)
#2939, ST_ClipByBox2D (Sandro Santilli / CartoDB)
#2247, ST_Retile and ST_CreateOverview: in-db raster overviews creation (Sandro Santilli / Vizzuality)
#899, -m shp2pgsql attribute names mapping -m switch (Regina Obe / Sandro Santilli)
#1678, Added GUC postgis.gdal_datapath to specify GDAL config variable GDAL_DATA
#2843, Support reprojection on raster import (Sandro Santilli / Vizzuality)
#2349, Support for encoded_polyline input/output (Kashif Rasul)
#2159, report libjson version from postgis_full_version()
#2770, ST_MemSize(raster)
Add postgis_noop(raster)
Added missing variants of ST_TPI(), ST_TRI() and ST_Roughness()
Added GUC postgis.gdal_enabled_drivers to specify GDAL config variable GDAL_SKIP
Added GUC postgis.enable_outdb_rasters to enable access to rasters with out-db bands
#2387, address_standardizer extension as part of PostGIS (Stephen Woodbridge / imaptools.com, Walter Sinclair, Regina Obe)
#2816, address_standardizer_data_us extension provides reference lex,gaz,rules for address_standardizer (Stephen Woodbridge
/ imaptools.com, Walter Sinclair, Regina Obe)
#2341, New mask parameter for ST_MapAlgebra
#2397, read encoding info automatically in shapefile loader
#2430, ST_ForceCurve
#2565, ST_SummaryStatsAgg()
#2567, ST_CountAgg()
#2632, ST_AsGML() support for curved features
#2652, Add --upgrade-path switch to run_test.pl
#2754, sfcgal wrapped as an extension
#2227, Simplification with Visvalingam-Whyatt algorithm ST_SimplifyVW, ST_SetEffectiveArea (Nicklas Avén)
Functions to encode and decode TWKB ST_AsTWKB, ST_GeomFromTWKB (Paul Ramsey / Nicklas Avén / CartoDB)
PostGIS 2.4.3 Manual 764 / 803

A.13.2 Enhancements

#3223, Add memcmp short-circuit to ST_Equals (Daniel Baston)

#3227, Tiger geocoder upgraded to support Tiger 2015 census
#2278, Make liblwgeom compatible between minor releases
#897, ST_AsX3D support for GeoCoordinates and systems "GD" "WE" ability to flip x/y axis (use option = 2, 3)
ST_Split: allow splitting lines by multilines, multipoints and (multi)polygon boundaries
#3070, Simplify geometry type constraint
#2839, Implement selectivity estimator for functional indexes, speeding up spatial queries on raster tables. (Sandro Santilli /
Vizzuality)
#2361, Added spatial_index column to raster_columns view
#2390, Testsuite for pgsql2shp
#2527, Added -k flag to raster2pgsql to skip checking that band is NODATA
#2616, Reduce text casts during topology building and export
#2717, support startpoint, endpoint, pointn, numpoints for compoundcurve
#2747, Add support for GDAL 2.0
#2754, SFCGAL can now be installed with CREATE EXTENSION (Vincent Mora @ Oslandia)
#2828, Convert ST_Envelope(raster) from SQL to C
#2829, Shortcut ST_Clip(raster) if geometry fully contains the raster and no NODATA specified
#2906, Update tiger geocoder to handle tiger 2014 data
#3048, Speed up geometry simplification (J.Santana @ CartoDB)
#3092, Slow performance of geometry_columns with many tables

A.14 Release 2.1.8

Release date: 2015-07-07

This is a critical bug fix release.

A.14.1 Bug Fixes

#3159, do not force a bbox cache on ST_Affine

#3018, GROUP BY geography sometimes returns duplicate rows
#3084, shp2pgsql - illegal number format when specific system locale set
#3094, Malformed GeoJSON inputs crash backend
#3104, st_asgml introduces random characters in ID field
#3155, Remove liblwgeom.h on make uninstall
#3177, gserialized_is_empty cannot handle nested empty cases
Fix crash in ST_LineLocatePoint
PostGIS 2.4.3 Manual 765 / 803

A.15 Release 2.1.7

Release date: 2015-03-30

This is a critical bug fix release.

A.15.1 Bug Fixes

#3086, ST_DumpValues() crashes backend on cleanup with invalid band indexes

#3088, Do not (re)define strcasestr in a liblwgeom.h
#3094, Malformed GeoJSON inputs crash backend

A.16 Release 2.1.6

Release date: 2015-03-20

This is a bug fix and performance improvement release.

A.16.1 Enhancements

#3000, Ensure edge splitting and healing algorithms use indexes

#3048, Speed up geometry simplification (J.Santana @ CartoDB)
#3050, Speed up geometry type reading (J.Santana @ CartoDB)

A.16.2 Bug Fixes

#2941, allow geography columns with SRID other than 4326

#3069, small objects getting inappropriately fluffed up w/ boxes
#3068, Have postgis_typmod_dims return NULL for unconstrained dims
#3061, Allow duplicate points in JSON, GML, GML ST_GeomFrom* functions
#3058, Fix ND-GiST picksplit method to split on the best plane
#3052, Make operators <-> and <#> available for PostgreSQL < 9.1
#3045, Fix dimensionality confusion in &&& operator
#3016, Allow unregistering layers of corrupted topologies
#3015, Avoid exceptions from TopologySummary
#3020, ST_AddBand out-db bug where height using width value
#3031, Allow restore of Geometry(Point) tables dumped with empties in them

A.17 Release 2.1.5

Release date: 2014-12-18

This is a bug fix and performance improvement release.
PostGIS 2.4.3 Manual 766 / 803

A.17.1 Enhancements

#2933, Speedup construction of large multi-geometry objects

A.17.2 Bug Fixes

#2947, Fix memory leak in lwgeom_make_valid for single-component collection input

#2949, Fix memory leak in lwgeom_mindistance2d for curve input
#2931, BOX representation is case sensitive
#2942, PostgreSQL 9.5 support
#2953, 2D stats not generated when Z/M values are extreme
#3009, Geography cast may effect underlying tuple

A.18 Release 2.1.4

Release date: 2014-09-10

This is a bug fix and performance improvement release.

A.18.1 Enhancements

#2745, Speedup ST_Simplify calls against points

#2747, Support for GDAL 2.0
#2749, Make rtpostgis_upgrade_20_21.sql ACID
#2811, Do not specify index names when loading shapefiles/rasters
#2829, Shortcut ST_Clip(raster) if geometry fully contains the raster and no NODATA specified
#2895, Raise cost of ST_ConvexHull(raster) to 300 for better query plans

A.18.2 Bug Fixes

#2605, armel: _ST_Covers() returns true for point in hole

#2911, Fix output scale on ST_Rescale/ST_Resample/ST_Resize of rasters with scale 1/-1 and offset 0/0.
Fix crash in ST_Union(raster)
#2704, ST_GeomFromGML() does not work properly with array of gml:pos (Even Roualt)
#2708, updategeometrysrid doesn’t update srid check when schema not specified. Patch from Marc Jansen
#2720, lwpoly_add_ring should update maxrings after realloc
#2759, Fix postgis_restore.pl handling of multiline object comments embedding sql comments
#2774, fix undefined behavior in ptarray_calculate_gbox_geodetic
Fix potential memory fault in ST_MakeValid
#2784, Fix handling of bogus argument to --with-sfcgal
#2772, Premature memory free in RASTER_getBandPath (ST_BandPath)
#2755, Fix regressions tests against all versions of SFCGAL
#2775, lwline_from_lwmpoint leaks memory
PostGIS 2.4.3 Manual 767 / 803

#2802, ST_MapAlgebra checks for valid callback function return value

#2803, ST_MapAlgebra handles no userarg and STRICT callback function
#2834, ST_Estimated_Extent and mixedCase table names (regression bug)
#2845, Bad geometry created from ST_AddPoint
#2870, Binary insert into geography column results geometry being inserted
#2872, make install builds documentation (Greg Troxell)
#2819, find isfinite or replacement on Centos5 / Solaris
#2899, geocode limit 1 not returning best answer (tiger geocoder)
#2903, Unable to compile on FreeBSD
#2927 reverse_geocode not filling in direction prefix (tiger geocoder) get rid of deprecated ST_Line_Locate_Point called

A.19 Release 2.1.3

Release date: 2014/05/13

This is a bug fix and security release.

A.19.1 Important changes

Starting with this version offline raster access and use of GDAL drivers are disabled by default.
An environment variable is introduced to allow for enabling specific GDAL drivers: POSTGIS_GDAL_ENABLED_DRIVERS.
By default, all GDAL drivers are disabled
An environment variable is introduced to allow for enabling out-db raster bands: POSTGIS_ENABLE_OUTDB_RASTERS. By
default, out-db raster bands are disabled
The environment variables must be set for the PostgreSQL process, and determines the behavior of the whole cluster.

A.19.2 Bug Fixes

#2697, invalid GeoJSON Polygon input crashes server process

#2700, Fix dumping of higher-dimension datasets with null rows
#2706, ST_DumpPoints of EMPTY geometries crashes server

A.20 Release 2.1.2

Release date: 2014/03/31

This is a bug fix release, addressing issues that have been filed since the 2.1.1 release.

A.20.1 Bug Fixes

#2666, Error out at configure time if no SQL preprocessor can be found

#2534, st_distance returning incorrect results for large geographies
#2539, Check for json-c/json.h presence/usability before json/json.h
#2543, invalid join selectivity error from simple query
PostGIS 2.4.3 Manual 768 / 803

#2546, GeoJSON with string coordinates parses incorrectly

#2547, Fix ST_Simplify(TopoGeometry) for hierarchical topogeoms
#2552, Fix NULL raster handling in ST_AsPNG, ST_AsTIFF and ST_AsJPEG
#2555, Fix parsing issue of range arguments of ST_Reclass
#2556, geography ST_Intersects results depending on insert order
#2580, Do not allow installing postgis twice in the same database
#2589, Remove use of unnecessary void pointers
#2607, Cannot open more than 1024 out-db files in one process
#2610, Ensure face splitting algorithm uses the edge index
#2615, EstimatedExtent (and hence, underlying stats) gathering wrong bbox
#2619, Empty rings array in GeoJSON polygon causes crash
#2634, regression in sphere distance code
#2638, Geography distance on M geometries sometimes wrong
#2648, #2653, Fix topology functions when "topology" is not in search_path
#2654, Drop deprecated calls from topology
#2655, Let users without topology privileges call postgis_full_version()
#2674, Fix missing operator = and hash_raster_ops opclass on raster
#2675, #2534, #2636, #2634, #2638, Geography distance issues with tree optimization

A.20.2 Enhancements

#2494, avoid memcopy in GiST index (hayamiz)

#2560, soft upgrade: avoid drop/recreate of aggregates that hadn’t changed

A.21 Release 2.1.1

Release date: 2013/11/06

This is a bug fix release, addressing issues that have been filed since the 2.1.0 release.

A.21.1 Important Changes

#2514, Change raster license from GPL v3+ to v2+, allowing distribution of PostGIS Extension as GPLv2.

A.21.2 Bug Fixes

#2396, Make regression tests more endian-agnostic

#2434, Fix ST_Intersection(geog,geog) regression in rare cases
#2454, Fix behavior of ST_PixelAsXXX functions regarding exclude_nodata_value parameter
#2489, Fix upgrades from 2.0 leaving stale function signatures
#2525, Fix handling of SRID in nested collections
#2449, Fix potential infinite loop in index building
#2493, Fix behavior of ST_DumpValues when passed an empty raster
#2502, Fix postgis_topology_scripts_installed() install schema
#2504, Fix segfault on bogus pgsql2shp call
#2512, Support for foreign tables and materialized views in raster_columns and raster_overviews
PostGIS 2.4.3 Manual 769 / 803

A.21.3 Enhancements

#2478, support for tiger 2013

#2463, support for exact length calculations on arc geometries

A.22 Release 2.1.0

Release date: 2013/08/17

This is a minor release addressing both bug fixes and performance and functionality enhancements addressing issues since 2.0.3
release. If you are upgrading from 2.0+, only a soft upgrade is required. If you are upgrading from 1.5 or earlier, a hard upgrade
is required.

A.22.1 Important / Breaking Changes

#1653, Removed srid parameter from ST_Resample(raster) and variants with reference raster no longer apply reference raster’s
SRID.
#1962 ST_Segmentize - As a result of the introduction of geography support, The construct: SELECT ST_Segmentize(’LINESTRI
2, 3 4)’,0.5); will result in ambiguous function error
#2026, ST_Union(raster) now unions all bands of all rasters
#2089, liblwgeom: lwgeom_set_handlers replaces lwgeom_init_allocators.
#2150, regular_blocking is no longer a constraint. column of same name in raster_columns now checks for existance of spa-
tially_unique and coverage_tile constraints
ST_Intersects(raster, geometry) behaves in the same manner as ST_Intersects(geometry, raster).
point variant of ST_SetValue(raster) previously did not check SRID of input geometry and raster.
ST_Hillshade parameters azimuth and altitude are now in degrees instead of radians.
ST_Slope and ST_Aspect return pixel values in degrees instead of radians.
#2104, ST_World2RasterCoord, ST_World2RasterCoordX and ST_World2RasterCoordY renamed to ST_WorldToRasterCoord,
ST_WorldToRasterCoordX and ST_WorldToRasterCoordY. ST_Raster2WorldCoord, ST_Raster2WorldCoordX and ST_Raster2WorldC
renamed to ST_RasterToWorldCoord, ST_RasterToWorldCoordX and ST_RasterToWorldCoordY
ST_Estimated_Extent renamed to ST_EstimatedExtent
ST_Line_Interpolate_Point renamed to ST_LineInterpolatePoint
ST_Line_Substring renamed to ST_LineSubstring
ST_Line_Locate_Point renamed to ST_LineLocatePoint
ST_Force_XXX renamed to ST_ForceXXX
ST_MapAlgebraFctNgb and 1 and 2 raster variants of ST_MapAlgebraFct. Use ST_MapAlgebra instead
1 and 2 raster variants of ST_MapAlgebraExpr. Use expression variants of ST_MapAlgebra instead

A.22.2 New Features

- Refer to http://postgis.net/docs/manual-2.1/PostGIS_Special_Functions_Index.html#NewFunctions_2_1 for complete list of

new functions
#310, ST_DumpPoints converted to a C function (Nathan Wagner) and much faster
#739, UpdateRasterSRID()
PostGIS 2.4.3 Manual 770 / 803

#945, improved join selectivity, N-D selectivity calculations, user accessible selectivity and stats reader functions for testing
(Paul Ramsey / OpenGeo)
toTopoGeom with TopoGeometry sink (Sandro Santilli / Vizzuality)
clearTopoGeom (Sandro Santilli / Vizzuality)
ST_Segmentize(geography) (Paul Ramsey / OpenGeo)
ST_DelaunayTriangles (Sandro Santilli / Vizzuality)
ST_NearestValue, ST_Neighborhood (Bborie Park / UC Davis)
ST_PixelAsPoint, ST_PixelAsPoints (Bborie Park / UC Davis)
ST_PixelAsCentroid, ST_PixelAsCentroids (Bborie Park / UC Davis)
ST_Raster2WorldCoord, ST_World2RasterCoord (Bborie Park / UC Davis)
Additional raster/raster spatial relationship functions (ST_Contains, ST_ContainsProperly, ST_Covers, ST_CoveredBy, ST_Disjoint,
ST_Overlaps, ST_Touches, ST_Within, ST_DWithin, ST_DFullyWithin) (Bborie Park / UC Davis)
Added array variants of ST_SetValues() to set many pixel values of a band in one call (Bborie Park / UC Davis)
#1293, ST_Resize(raster) to resize rasters based upon width/height
#1627, package tiger_geocoder as a PostgreSQL extension
#1643, #2076, Upgrade tiger geocoder to support loading tiger 2011 and 2012 (Regina Obe / Paragon Corporation) Funded by
Hunter Systems Group
GEOMETRYCOLLECTION support for ST_MakeValid (Sandro Santilli / Vizzuality)
#1709, ST_NotSameAlignmentReason(raster, raster)
#1818, ST_GeomFromGeoHash and friends (Jason Smith (darkpanda))
#1856, reverse geocoder rating setting for prefer numbered highway name
ST_PixelOfValue (Bborie Park / UC Davis)
Casts to/from PostgreSQL geotypes (point/path/polygon).
Added geomval array variant of ST_SetValues() to set many pixel values of a band using a set of geometries and corresponding
values in one call (Bborie Park / UC Davis)
ST_Tile(raster) to break up a raster into tiles (Bborie Park / UC Davis)
#1895, new r-tree node splitting algorithm (Alex Korotkov)
#2011, ST_DumpValues to output raster as array (Bborie Park / UC Davis)
#2018, ST_Distance support for CircularString, CurvePolygon, MultiCurve, MultiSurface, CompoundCurve
#2030, n-raster (and n-band) ST_MapAlgebra (Bborie Park / UC Davis)
#2193, Utilize PAGC parser as drop in replacement for tiger normalizer (Steve Woodbridge, Regina Obe)
#2210, ST_MinConvexHull(raster)
lwgeom_from_geojson in liblwgeom (Sandro Santilli / Vizzuality)
#1687, ST_Simplify for TopoGeometry (Sandro Santilli / Vizzuality)
#2228, TopoJSON output for TopoGeometry (Sandro Santilli / Vizzuality)
#2123, ST_FromGDALRaster
#613, ST_SetGeoReference with numerical parameters instead of text
#2276, ST_AddBand(raster) variant for out-db bands
#2280, ST_Summary(raster)
#2163, ST_TPI for raster (Nathaniel Clay)
PostGIS 2.4.3 Manual 771 / 803

#2164, ST_TRI for raster (Nathaniel Clay)

#2302, ST_Roughness for raster (Nathaniel Clay)
#2290, ST_ColorMap(raster) to generate RGBA bands
#2254, Add SFCGAL backend support. (Backend selection throught postgis.backend var) Functions available both throught
GEOS or SFCGAL: ST_Intersects, ST_3DIntersects, ST_Intersection, ST_Area, ST_Distance, ST_3DDistance New functions
available only with SFCGAL backend: ST_3DIntersection, ST_Tesselate, ST_3DArea, ST_Extrude, ST_ForceLHR ST_Orientation,
ST_Minkowski, ST_StraightSkeleton postgis_sfcgal_version New function available in PostGIS: ST_ForceSFS (Olivier Courtin
and Hugo Mercier / Oslandia)

A.22.3 Enhancements

For detail of new functions and function improvements, please refer to Section 14.12.5.
Much faster raster ST_Union, ST_Clip and many more function additions operations
For geometry/geography better planner selectivity and a lot more functions.
#823, tiger geocoder: Make loader_generate_script download portion less greedy
#826, raster2pgsql no longer defaults to padding tiles. Flag -P can be used to pad tiles
#1363, ST_AddBand(raster, ...) array version rewritten in C
#1364, ST_Union(raster, ...) aggregate function rewritten in C
#1655, Additional default values for parameters of ST_Slope
#1661, Add aggregate variant of ST_SameAlignment
#1719, Add support for Point and GeometryCollection ST_MakeValid inputs
#1780, support ST_GeoHash for geography
#1796, Big performance boost for distance calculations in geography
#1802, improved function interruptibility.
#1823, add parameter in ST_AsGML to use id column for GML 3 output (become mandatory since GML 3.2.1)
#1856, tiger geocoder: reverse geocoder rating setting for prefer numbered highway name
#1938, Refactor basic ST_AddBand to add multiple new bands in one call
#1978, wrong answer when calculating length of a closed circular arc (circle)
#1989, Preprocess input geometry to just intersection with raster to be clipped
#2021, Added multi-band support to ST_Union(raster, ...) aggregate function
#2006, better support of ST_Area(geography) over poles and dateline
#2065, ST_Clip(raster, ...) now a C function
#2069, Added parameters to ST_Tile(raster) to control padding of tiles
#2078, New variants of ST_Slope, ST_Aspect and ST_HillShade to provide solution to handling tiles in a coverage
#2097, Added RANGE uniontype option for ST_Union(raster)
#2105, Added ST_Transform(raster) variant for aligning output to reference raster
#2119, Rasters passed to ST_Resample(), ST_Rescale(), ST_Reskew(), and ST_SnapToGrid() no longer require an SRID
#2141, More verbose output when constraints fail to be added to a raster column
#2143, Changed blocksize constraint of raster to allow multiple values
#2148, Addition of coverage_tile constraint for raster
#2149, Addition of spatially_unique constraint for raster
PostGIS 2.4.3 Manual 772 / 803

TopologySummary output now includes unregistered layers and a count of missing TopoGeometry objects from their natural
layer.
ST_HillShade(), ST_Aspect() and ST_Slope() have one new optional parameter to interpolate NODATA pixels before running
the operation.
Point variant of ST_SetValue(raster) is now a wrapper around geomval variant of ST_SetValues(rast).
Proper support for raster band’s isnodata flag in core API and loader.
Additional default values for parameters of ST_Aspect and ST_HillShade
#2178, ST_Summary now advertises presence of known srid with an [S] flag
#2202, Make libjson-c optional (--without-json configure switch)
#2213, Add support libjson-c 0.10+
#2231, raster2pgsql supports user naming of filename column with -n
#2200, ST_Union(raster, uniontype) unions all bands of all rasters
#2264, postgis_restore.pl support for restoring into databases with postgis in a custom schema
#2244, emit warning when changing raster’s georeference if raster has out-db bands
#2222, add parameter OutAsIn to flag whether ST_AsBinary should return out-db bands as in-db bands

A.22.4 Fixes

#1839, handling of subdatasets in GeoTIFF in raster2pgsql.

#1840, fix logic of when to compute # of tiles in raster2pgsql.
#1870, align the docs and actual behavior of raster’s ST_Intersects
#1872, fix ST_ApproxSummarystats to prevent division by zero
#1875, ST_SummaryStats returns NULL for all parameters except count when count is zero
#1932, fix raster2pgsql of syntax for index tablespaces
#1936, ST_GeomFromGML on CurvePolygon causes server crash
#1939, remove custom data types: summarystats, histogram, quantile, valuecount
#1951, remove crash on zero-length linestrings
#1957, ST_Distance to a one-point LineString returns NULL
#1976, Geography point-in-ring code overhauled for more reliability
#1981, cleanup of unused variables causing warnings with gcc 4.6+
#1996, support POINT EMPTY in GeoJSON output
#2062, improve performance of distance calculations
#2057, Fixed linking issue for raster2psql to libpq
#2077, Fixed incorrect values returning from ST_Hillshade()
#2019, ST_FlipCoordinates does not update bbox
#2100, ST_AsRaster may not return raster with specified pixel type
#2126, Better handling of empty rasters from ST_ConvexHull()
#2165, ST_NumPoints regression failure with CircularString
#2168, ST_Distance is not always commutative
#2182, Fix issue with outdb rasters with no SRID and ST_Resize
PostGIS 2.4.3 Manual 773 / 803

#2188, Fix function parameter value overflow that caused problems when copying data from a GDAL dataset
#2198, Fix incorrect dimensions used when generating bands of out-db rasters in ST_Tile()
#2201, ST_GeoHash wrong on boundaries
#2203, Changed how rasters with unknown SRID and default geotransform are handled when passing to GDAL Warp API
#2215, Fixed raster exclusion constraint for conflicting name of implicit index
#2251, Fix bad dimensions when rescaling rasters with default geotransform matrix
#2133, Fix performance regression in expression variant of ST_MapAlgebra
#2257, GBOX variables not initialized when testing with empty geometries
#2271, Prevent parallel make of raster
#2282, Fix call to undefined function nd_stats_to_grid() in debug mode
#2307, ST_MakeValid outputs invalid geometries
#2309, Remove confusing INFO message when trying to get SRS info
#2336, FIPS 20 (KS) causes wildcard expansion to wget all files
#2348, Provide raster upgrade path for 2.0 to 2.1
#2351, st_distance between geographies wrong
#2359, Fix handling of schema name when adding overview constraints
#2371, Support GEOS versions with more than 1 digit in micro
#2383, Remove unsafe use of \’ from raster warning message
#2384, Incorrect variable datatypes for ST_Neighborhood

A.22.5 Known Issues

#2111, Raster bands can only reference the first 256 bands of out-db rasters

A.23 Release 2.0.5

Release date: 2014/03/31

This is a bug fix release, addressing issues that have been filed since the 2.0.4 release. If you are using PostGIS 2.0+ a soft
upgrade is required. For users of PostGIS 1.5 or below, a hard upgrade is required.

A.23.1 Bug Fixes

#2494, avoid memcpy in GIST index

#2502, Fix postgis_topology_scripts_installed() install schema
#2504, Fix segfault on bogus pgsql2shp call
#2528, Fix memory leak in ST_Split / lwline_split_by_line
#2532, Add missing raster/geometry commutator operators
#2533, Remove duplicated signatures
#2552, Fix NULL raster handling in ST_AsPNG, ST_AsTIFF and ST_AsJPEG
#2555, Fix parsing issue of range arguments of ST_Reclass
#2589, Remove use of unnecessary void pointers
PostGIS 2.4.3 Manual 774 / 803

#2607, Cannot open more than 1024 out-db files in process

#2610, Ensure face splitting algorithm uses the edge index
#2619, Empty ring array in GeoJSON polygon causes crash
#2638, Geography distance on M geometries sometimes wrong

A.23.2 Important Changes

##2514, Change raster license from GPL v3+ to v2+, allowing distribution of PostGIS Extension as GPLv2.

A.24 Release 2.0.4

Release date: 2013/09/06

This is a bug fix release, addressing issues that have been filed since the 2.0.3 release. If you are using PostGIS 2.0+ a soft
upgrade is required. For users of PostGIS 1.5 or below, a hard upgrade is required.

A.24.1 Bug Fixes

#2110, Equality operator between EMPTY and point on origin

Allow adding points at precision distance with TopoGeo_addPoint
#1968, Fix missing edge from toTopoGeom return
#2165, ST_NumPoints regression failure with CircularString
#2168, ST_Distance is not always commutative
#2186, gui progress bar updates too frequent
#2201, ST_GeoHash wrong on boundaries
#2257, GBOX variables not initialized when testing with empty geometries
#2271, Prevent parallel make of raster
#2267, Server crash from analyze table
#2277, potential segfault removed
#2307, ST_MakeValid outputs invalid geometries
#2351, st_distance between geographies wrong
#2359, Incorrect handling of schema for overview constraints
#2371, Support GEOS versions with more than 1 digit in micro
#2372, Cannot parse space-padded KML coordinates
Fix build with systemwide liblwgeom installed
#2383, Fix unsafe use of \’ in warning message
#2410, Fix segmentize of collinear curve
#2412, ST_LineToCurve support for lines with less than 4 vertices
#2415, ST_Multi support for COMPOUNDCURVE and CURVEPOLYGON
#2420, ST_LineToCurve: require at least 8 edges to define a full circle
#2423, ST_LineToCurve: require all arc edges to form the same angle
#2424, ST_CurveToLine: add support for COMPOUNDCURVE in MULTICURVE
#2427, Make sure to retain first point of curves on ST_CurveToLine
PostGIS 2.4.3 Manual 775 / 803

A.24.2 Enhancements

#2269, Avoid uselessly detoasting full geometries on ANALYZE

A.24.3 Known Issues

#2111, Raster bands can only reference the first 256 bands of out-db rasters

A.25 Release 2.0.3

Release date: 2013/03/01

This is a bug fix release, addressing issues that have been filed since the 2.0.2 release. If you are using PostGIS 2.0+ a soft
upgrade is required. For users of PostGIS 1.5 or below, a hard upgrade is required.

A.25.1 Bug Fixes

#2126, Better handling of empty rasters from ST_ConvexHull()

#2134, Make sure to process SRS before passing it off to GDAL functions
Fix various memory leaks in liblwgeom
#2173, Fix robustness issue in splitting a line with own vertex also affecting topology building (#2172)
#2174, Fix usage of wrong function lwpoly_free()
#2176, Fix robustness issue with ST_ChangeEdgeGeom
#2184, Properly copy topologies with Z value
postgis_restore.pl support for mixed case geometry column name in dumps
#2188, Fix function parameter value overflow that caused problems when copying data from a GDAL dataset
#2216, More memory errors in MultiPolygon GeoJSON parsing (with holes)
Fix Memory leak in GeoJSON parser

A.25.2 Enhancements

#2141, More verbose output when constraints fail to be added to a raster column
Speedup ST_ChangeEdgeGeom

A.26 Release 2.0.2

Release date: 2012/12/03

This is a bug fix release, addressing issues that have been filed since the 2.0.1 release.
PostGIS 2.4.3 Manual 776 / 803

A.26.1 Bug Fixes

#1287, Drop of "gist_geometry_ops" broke a few clients package of legacy_gist.sql for these cases
#1391, Errors during upgrade from 1.5
#1828, Poor selectivity estimate on ST_DWithin
#1838, error importing tiger/line data
#1869, ST_AsBinary is not unique added to legacy_minor/legacy.sql scripts
#1885, Missing field from tabblock table in tiger2010 census_loader.sql
#1891, Use LDFLAGS environment when building liblwgeom
#1900, Fix pgsql2shp for big-endian systems
#1932, Fix raster2pgsql for invalid syntax for setting index tablespace
#1936, ST_GeomFromGML on CurvePolygon causes server crash
#1955, ST_ModEdgeHeal and ST_NewEdgeHeal for doubly connected edges
#1957, ST_Distance to a one-point LineString returns NULL
#1976, Geography point-in-ring code overhauled for more reliability
#1978, wrong answer calculating length of closed circular arc (circle)
#1981, Remove unused but set variables as found with gcc 4.6+
#1987, Restore 1.5.x behaviour of ST_Simplify
#1989, Preprocess input geometry to just intersection with raster to be clipped
#1991, geocode really slow on PostgreSQL 9.2
#1996, support POINT EMPTY in GeoJSON output
#1998, Fix ST_{Mod,New}EdgeHeal joining edges sharing both endpoints
#2001, ST_CurveToLine has no effect if the geometry doesn’t actually contain an arc
#2015, ST_IsEmpty(’POLYGON(EMPTY)’) returns False
#2019, ST_FlipCoordinates does not update bbox
#2025, Fix side location conflict at TopoGeo_AddLineString
#2026, improve performance of distance calculations
#2033, Fix adding a splitting point into a 2.5d topology
#2051, Fix excess of precision in ST_AsGeoJSON output
#2052, Fix buffer overflow in lwgeom_to_geojson
#2056, Fixed lack of SRID check of raster and geometry in ST_SetValue()
#2057, Fixed linking issue for raster2psql to libpq
#2060, Fix "dimension" check violation by GetTopoGeomElementArray
#2072, Removed outdated checks preventing ST_Intersects(raster) from working on out-db bands
#2077, Fixed incorrect answers from ST_Hillshade(raster)
#2092, Namespace issue with ST_GeomFromKML,ST_GeomFromGML for libxml 2.8+
#2099, Fix double free on exception in ST_OffsetCurve
#2100, ST_AsRaster() may not return raster with specified pixel type
#2108, Ensure ST_Line_Interpolate_Point always returns POINT
PostGIS 2.4.3 Manual 777 / 803

#2109, Ensure ST_Centroid always returns POINT

#2117, Ensure ST_PointOnSurface always returns POINT
#2129, Fix SRID in ST_Homogenize output with collection input
#2130, Fix memory error in MultiPolygon GeoJson parsing
Update URL of Maven jar

A.26.2 Enhancements

#1581, ST_Clip(raster, ...) no longer imposes NODATA on a band if the corresponding band from the source raster did not have
NODATA
#1928, Accept array properties in GML input multi-geom input (Kashif Rasul and Shoaib Burq / SpacialDB)
#2082, Add indices on start_node and end_node of topology edge tables
#2087, Speedup topology.GetRingEdges using a recursive CTE

A.27 Release 2.0.1

Release date: 2012/06/22

This is a bug fix release, addressing issues that have been filed since the 2.0.0 release.

A.27.1 Bug Fixes

#1264, fix st_dwithin(geog, geog, 0).

#1468 shp2pgsql-gui table column schema get shifted
#1694, fix building with clang. (vince)
#1708, improve restore of pre-PostGIS 2.0 backups.
#1714, more robust handling of high topology tolerance.
#1755, ST_GeographyFromText support for higher dimensions.
#1759, loading transformed shapefiles in raster enabled db.
#1761, handling of subdatasets in NetCDF, HDF4 and HDF5 in raster2pgsql.
#1763, topology.toTopoGeom use with custom search_path.
#1766, don’t let ST_RemEdge* destroy peripheral TopoGeometry objects.
#1774, Clearer error on setting an edge geometry to an invalid one.
#1775, ST_ChangeEdgeGeom collision detection with 2-vertex target.
#1776, fix ST_SymDifference(empty, geom) to return geom.
#1779, install SQL comment files.
#1782, fix spatial reference string handling in raster.
#1789, fix false edge-node crossing report in ValidateTopology.
#1790, fix toTopoGeom handling of duplicated primitives.
#1791, fix ST_Azimuth with very close but distinct points.
#1797, fix (ValidateTopology(xxx)).* syntax calls.
#1805, put back the 900913 SRID entry.
PostGIS 2.4.3 Manual 778 / 803

#1813, Only show readable relations in metadata tables.

#1819, fix floating point issues with ST_World2RasterCoord and ST_Raster2WorldCoord variants.
#1820 compilation on 9.2beta1.
#1822, topology load on PostgreSQL 9.2beta1.
#1825, fix prepared geometry cache lookup
#1829, fix uninitialized read in GeoJSON parser
#1834, revise postgis extension to only backup user specified spatial_ref_sys
#1839, handling of subdatasets in GeoTIFF in raster2pgsql.
#1840, fix logic of when to compute # of tiles in raster2pgsql.
#1851, fix spatial_ref_system parameters for EPSG:3844
#1857, fix failure to detect endpoint mismatch in ST_AddEdge*Face*
#1865, data loss in postgis_restore.pl when data rows have leading dashes.
#1867, catch invalid topology name passed to topogeo_add*
#1872, fix ST_ApproxSummarystats to prevent division by zero
#1873, fix ptarray_locate_point to return interpolated Z/M values for on-the-line case
#1875, ST_SummaryStats returns NULL for all parameters except count when count is zero
#1881, shp2pgsql-gui -- editing a field sometimes triggers removing row
#1883, Geocoder install fails trying to run create_census_base_tables() (Brian Panulla)

A.27.2 Enhancements

More detailed exception message from topology editing functions.

#1786, improved build dependencies
#1806, speedup of ST_BuildArea, ST_MakeValid and ST_GetFaceGeometry.
#1812, Add lwgeom_normalize in LIBLWGEOM for more stable testing.

A.28 Release 2.0.0

Release date: 2012/04/03

This is a major release. A hard upgrade is required. Yes this means a full dump reload and some special preparations if you
are using obsolete functions. Refer to Section 2.10.2 for details on upgrading. Refer to Section 14.12.7 for more details and
changed/new functions.

A.28.1 Testers - Our unsung heroes

We are most indebted to the numerous members in the PostGIS community who were brave enough to test out the new features
in this release. No major release can be successful without these folk.
Below are those who have been most valiant, provided very detailed and thorough bug reports, and detailed analysis.
Andrea Peri - Lots of testing on topology, checking for correctness
Andreas Forø Tollefsen - raster testing
Chris English - topology stress testing loader functions
Salvatore Larosa - topology robustness testing
Brian Hamlin - Benchmarking (also experimental experimental branches before they are folded into core) , general testing of various p
Mike Pease - Tiger geocoder testing - very detailed reports of issues
Tom van Tilburg - raster testing
PostGIS 2.4.3 Manual 779 / 803

A.28.2 Important / Breaking Changes

#722, #302, Most deprecated functions removed (over 250 functions) (Regina Obe, Paul Ramsey)
Unknown SRID changed from -1 to 0. (Paul Ramsey)
-- (most deprecated in 1.2) removed non-ST variants buffer, length, intersects (and internal functions renamed) etc.
-- If you have been using deprecated functions CHANGE your apps or suffer the consequences. If you don’t see a function
documented -- it ain’t supported or it is an internal function. Some constraints in older tables were built with deprecated functions.
If you restore you may need to rebuild table constraints with populate_geometry_columns(). If you have applications or tools
that rely on deprecated functions, please refer to [?qandaentry] for more details.
#944 geometry_columns is now a view instead of a table (Paul Ramsey, Regina Obe) for tables created the old way reads (srid,
type, dims) constraints for geometry columns created with type modifiers reads rom column definition
#1081, #1082, #1084, #1088 - Mangement functions support typmod geometry column creation functions now default to typmod
creation (Regina Obe)
#1083 probe_geometry_columns(), rename_geometry_table_constraints(), fix_geometry_columns(); removed - now obsolete
with geometry_column view (Regina Obe)
#817 Renaming old 3D functions to the convention ST_3D (Nicklas Avén)
#548 (sorta), ST_NumGeometries,ST_GeometryN now returns 1 (or the geometry) instead of null for single geometries (Sandro
Santilli, Maxime van Noppen)

A.28.3 New Features

KNN Gist index based centroid (<->) and box (<#>) distance operators (Paul Ramsey / funded by Vizzuality)
Support for TIN and PolyHedralSurface and enhancement of many functions to support 3D (Olivier Courtin / Oslandia)
Raster support integrated and documented (Pierre Racine, Jorge Arévalo, Mateusz Loskot, Sandro Santilli, David Zwarg, Regina
Obe, Bborie Park) (Company developer and funding: University Laval, Deimos Space, CadCorp, Michigan Tech Research
Institute, Azavea, Paragon Corporation, UC Davis Center for Vectorborne Diseases)
Making spatial indexes 3D aware - in progress (Paul Ramsey, Mark Cave-Ayland)
Topology support improved (more functions), documented, testing (Sandro Santilli / Faunalia for RT-SIGTA), Andrea Peri,
Regina Obe, Jose Carlos Martinez Llari
3D relationship and measurement support functions (Nicklas Avén)
ST_3DDistance, ST_3DClosestPoint, ST_3DIntersects, ST_3DShortestLine and more...
N-Dimensional spatial indexes (Paul Ramsey / OpenGeo)
ST_Split (Sandro Santilli / Faunalia for RT-SIGTA)
ST_IsValidDetail (Sandro Santilli / Faunalia for RT-SIGTA)
ST_MakeValid (Sandro Santilli / Faunalia for RT-SIGTA)
ST_RemoveRepeatedPoints (Sandro Santilli / Faunalia for RT-SIGTA)
ST_GeometryN and ST_NumGeometries support for non-collections (Sandro Santilli)
ST_IsCollection (Sandro Santilli, Maxime van Noppen)
ST_SharedPaths (Sandro Santilli / Faunalia for RT-SIGTA)
ST_Snap (Sandro Santilli)
ST_RelateMatch (Sandro Santilli / Faunalia for RT-SIGTA)
ST_ConcaveHull (Regina Obe and Leo Hsu / Paragon Corporation)
ST_UnaryUnion (Sandro Santilli / Faunalia for RT-SIGTA)
ST_AsX3D (Regina Obe / Arrival 3D funding)
ST_OffsetCurve (Sandro Santilli, Rafal Magda)
ST_GeomFromGeoJSON (Kashif Rasul, Paul Ramsey / Vizzuality funding)
PostGIS 2.4.3 Manual 780 / 803

A.28.4 Enhancements

Made shape file loader tolerant of truncated multibyte values found in some free worldwide shapefiles (Sandro Santilli)
Lots of bug fixes and enhancements to shp2pgsql Beefing up regression tests for loaders Reproject support for both geometry
and geography during import (Jeff Adams / Azavea, Mark Cave-Ayland)
pgsql2shp conversion from predefined list (Loic Dachary / Mark Cave-Ayland)
Shp-pgsql GUI loader - support loading multiple files at a time. (Mark Leslie)
Extras - upgraded tiger_geocoder from using old TIGER format to use new TIGER shp and file structure format (Stephen Frost)
Extras - revised tiger_geocoder to work with TIGER census 2010 data, addition of reverse geocoder function, various bug
fixes, accuracy enhancements, limit max result return, speed improvements, loading routines. (Regina Obe, Leo Hsu / Paragon
Corporation / funding provided by Hunter Systems Group)
Overall Documentation proofreading and corrections. (Kasif Rasul)
Cleanup PostGIS JDBC classes, revise to use Maven build. (Maria Arias de Reyna, Sandro Santilli)

A.28.5 Bug Fixes

#1335 ST_AddPoint returns incorrect result on Linux (Even Rouault)

A.28.6 Release specific credits

We thank U.S Department of State Human Information Unit (HIU) and Vizzuality for general monetary support to get PostGIS
2.0 out the door.

A.29 Release 1.5.4

Release date: 2012/05/07

This is a bug fix release, addressing issues that have been filed since the 1.5.3 release.

A.29.1 Bug Fixes

#547, ST_Contains memory problems (Sandro Santilli)

#621, Problem finding intersections with geography (Paul Ramsey)
#627, PostGIS/PostgreSQL process die on invalid geometry (Paul Ramsey)
#810, Increase accuracy of area calculation (Paul Ramsey)
#852, improve spatial predicates robustness (Sandro Santilli, Nicklas Avén)
#877, ST_Estimated_Extent returns NULL on empty tables (Sandro Santilli)
#1028, ST_AsSVG kills whole postgres server when fails (Paul Ramsey)
#1056, Fix boxes of arcs and circle stroking code (Paul Ramsey)
#1121, populate_geometry_columns using deprecated functions (Regin Obe, Paul Ramsey)
#1135, improve testsuite predictability (Andreas ’ads’ Scherbaum)
#1146, images generator crashes (bronaugh)
#1170, North Pole intersection fails (Paul Ramsey)
#1179, ST_AsText crash with bad value (kjurka)
PostGIS 2.4.3 Manual 781 / 803

#1184, honour DESTDIR in documentation Makefile (Bryce L Nordgren)

#1227, server crash on invalid GML
#1252, SRID appearing in WKT (Paul Ramsey)
#1264, st_dwithin(g, g, 0) doesn’t work (Paul Ramsey)
#1344, allow exporting tables with invalid geometries (Sandro Santilli)
#1389, wrong proj4text for SRID 31300 and 31370 (Paul Ramsey)
#1406, shp2pgsql crashes when loading into geography (Sandro Santilli)
#1595, fixed SRID redundancy in ST_Line_SubString (Sandro Santilli)
#1596, check SRID in UpdateGeometrySRID (Mike Toews, Sandro Santilli)
#1602, fix ST_Polygonize to retain Z (Sandro Santilli)
#1697, fix crash with EMPTY entries in GiST index (Paul Ramsey)
#1772, fix ST_Line_Locate_Point with collapsed input (Sandro Santilli)
#1799, Protect ST_Segmentize from max_length=0 (Sandro Santilli)
Alter parameter order in 900913 (Paul Ramsey)
Support builds with "gmake" (Greg Troxel)

A.30 Release 1.5.3

Release date: 2011/06/25

This is a bug fix release, addressing issues that have been filed since the 1.5.2 release. If you are running PostGIS 1.3+, a soft
upgrade is sufficient otherwise a hard upgrade is recommended.

A.30.1 Bug Fixes

#1056, produce correct bboxes for arc geometries, fixes index errors (Paul Ramsey)
#1007, ST_IsValid crash fix requires GEOS 3.3.0+ or 3.2.3+ (Sandro Santilli, reported by Birgit Laggner)
#940, support for PostgreSQL 9.1 beta 1 (Regina Obe, Paul Ramsey, patch submitted by stl)
#845, ST_Intersects precision error (Sandro Santilli, Nicklas Avén) Reported by cdestigter
#884, Unstable results with ST_Within, ST_Intersects (Chris Hodgson)
#779, shp2pgsql -S option seems to fail on points (Jeff Adams)
#666, ST_DumpPoints is not null safe (Regina Obe)
#631, Update NZ projections for grid transformation support (jpalmer)
#630, Peculiar Null treatment in arrays in ST_Collect (Chris Hodgson) Reported by David Bitner
#624, Memory leak in ST_GeogFromText (ryang, Paul Ramsey)
#609, Bad source code in manual section 5.2 Java Clients (simoc, Regina Obe)
#604, shp2pgsql usage touchups (Mike Toews, Paul Ramsey)
#573 ST_Union fails on a group of linestrings Not a PostGIS bug, fixed in GEOS 3.3.0
#457 ST_CollectionExtract returns non-requested type (Nicklas Avén, Paul Ramsey)
#441 ST_AsGeoJson Bbox on GeometryCollection error (Olivier Courtin)
#411 Ability to backup invalid geometries (Sando Santilli) Reported by Regione Toscana
#409 ST_AsSVG - degraded (Olivier Courtin) Reported by Sdikiy
#373 Documentation syntax error in hard upgrade (Paul Ramsey) Reported by psvensso
PostGIS 2.4.3 Manual 782 / 803

A.31 Release 1.5.2

Release date: 2010/09/27

This is a bug fix release, addressing issues that have been filed since the 1.5.1 release. If you are running PostGIS 1.3+, a soft
upgrade is sufficient otherwise a hard upgrade is recommended.

A.31.1 Bug Fixes

Loader: fix handling of empty (0-verticed) geometries in shapefiles. (Sandro Santilli)

#536, Geography ST_Intersects, ST_Covers, ST_CoveredBy and Geometry ST_Equals not using spatial index (Regina Obe,
Nicklas Aven)
#573, Improvement to ST_Contains geography (Paul Ramsey)
Loader: Add support for command-q shutdown in Mac GTK build (Paul Ramsey)
#393, Loader: Add temporary patch for large DBF files (Maxime Guillaud, Paul Ramsey)
#507, Fix wrong OGC URN in GeoJSON and GML output (Olivier Courtin)
spatial_ref_sys.sql Add datum conversion for projection SRID 3021 (Paul Ramsey)
Geography - remove crash for case when all geographies are out of the estimate (Paul Ramsey)
#469, Fix for array_aggregation error (Greg Stark, Paul Ramsey)
#532, Temporary geography tables showing up in other user sessions (Paul Ramsey)
#562, ST_Dwithin errors for large geographies (Paul Ramsey)
#513, shape loading GUI tries to make spatial index when loading DBF only mode (Paul Ramsey)
#527, shape loading GUI should always append log messages (Mark Cave-Ayland)
#504, shp2pgsql should rename xmin/xmax fields (Sandro Santilli)
#458, postgis_comments being installed in contrib instead of version folder (Mark Cave-Ayland)
#474, Analyzing a table with geography column crashes server (Paul Ramsey)
#581, LWGEOM-expand produces inconsistent results (Mark Cave-Ayland)
#513, Add dbf filter to shp2pgsql-gui and allow uploading dbf only (Paul Ramsey)
Fix further build issues against PostgreSQL 9.0 (Mark Cave-Ayland)
#572, Password whitespace for Shape File (Mark Cave-Ayland)
#603, shp2pgsql: "-w" produces invalid WKT for MULTI* objects. (Mark Cave-Ayland)

A.32 Release 1.5.1

Release date: 2010/03/11

This is a bug fix release, addressing issues that have been filed since the 1.4.1 release. If you are running PostGIS 1.3+, a soft
upgrade is sufficient otherwise a hard upgrade is recommended.
PostGIS 2.4.3 Manual 783 / 803

A.32.1 Bug Fixes

#410, update embedded bbox when applying ST_SetPoint, ST_AddPoint ST_RemovePoint to a linestring (Paul Ramsey)
#411, allow dumping tables with invalid geometries (Sandro Santilli, for Regione Toscana-SIGTA)
#414, include geography_columns view when running upgrade scripts (Paul Ramsey)
#419, allow support for multilinestring in ST_Line_Substring (Paul Ramsey, for Lidwala Consulting Engineers)
#421, fix computed string length in ST_AsGML() (Olivier Courtin)
#441, fix GML generation with heterogeneous collections (Olivier Courtin)
#443, incorrect coordinate reversal in GML 3 generation (Olivier Courtin)
#450, #451, wrong area calculation for geography features that cross the date line (Paul Ramsey)
Ensure support for upcoming 9.0 PgSQL release (Paul Ramsey)

A.33 Release 1.5.0

Release date: 2010/02/04

This release provides support for geographic coordinates (lat/lon) via a new GEOGRAPHY type. Also performance enhance-
ments, new input format support (GML,KML) and general upkeep.

A.33.1 API Stability

The public API of PostGIS will not change during minor (0.0.X) releases.
The definition of the =~ operator has changed from an exact geometric equality check to a bounding box equality check.

A.33.2 Compatibility

GEOS, Proj4, and LibXML2 are now mandatory dependencies

The library versions below are the minimum requirements for PostGIS 1.5
PostgreSQL 8.3 and higher on all platforms
GEOS 3.1 and higher only (GEOS 3.2+ to take advantage of all features)
LibXML2 2.5+ related to new ST_GeomFromGML/KML functionality
Proj4 4.5 and higher only

A.33.3 New Features

Section 14.12.9
Added Hausdorff distance calculations (#209) (Vincent Picavet)
Added parameters argument to ST_Buffer operation to support one-sided buffering and other buffering styles (Sandro Santilli)
Addition of other Distance related visualization and analysis functions (Nicklas Aven)

• ST_ClosestPoint

• ST_DFullyWithin
• ST_LongestLine
PostGIS 2.4.3 Manual 784 / 803

• ST_MaxDistance
• ST_ShortestLine

ST_DumpPoints (Maxime van Noppen)

KML, GML input via ST_GeomFromGML and ST_GeomFromKML (Olivier Courtin)
Extract homogeneous collection with ST_CollectionExtract (Paul Ramsey)
Add measure values to an existing linestring with ST_AddMeasure (Paul Ramsey)
History table implementation in utils (George Silva)
Geography type and supporting functions

• Spherical algorithms (Dave Skea)

• Object/index implementation (Paul Ramsey)
• Selectivity implementation (Mark Cave-Ayland)

• Serializations to KML, GML and JSON (Olivier Courtin)

• ST_Area, ST_Distance, ST_DWithin, ST_GeogFromText, ST_GeogFromWKB, ST_Intersects, ST_Covers, ST_Buffer (Paul
Ramsey)

A.33.4 Enhancements

Performance improvements to ST_Distance (Nicklas Aven)

Documentation updates and improvements (Regina Obe, Kevin Neufeld)
Testing and quality control (Regina Obe)
PostGIS 1.5 support PostgreSQL 8.5 trunk (Guillaume Lelarge)
Win32 support and improvement of core shp2pgsql-gui (Mark Cave-Ayland)
In place ’make check’ support (Paul Ramsey)

A.33.5 Bug fixes

http://trac.osgeo.org/postgis/query?status=closed&milestone=PostGIS+1.5.0&order=priority

A.34 Release 1.4.0

Release date: 2009/07/24

This release provides performance enhancements, improved internal structures and testing, new features, and upgraded docu-
mentation. If you are running PostGIS 1.1+, a soft upgrade is sufficient otherwise a hard upgrade is recommended.

A.34.1 API Stability

As of the 1.4 release series, the public API of PostGIS will not change during minor releases.
PostGIS 2.4.3 Manual 785 / 803

A.34.2 Compatibility

The versions below are the *minimum* requirements for PostGIS 1.4
PostgreSQL 8.2 and higher on all platforms
GEOS 3.0 and higher only
PROJ4 4.5 and higher only

A.34.3 New Features

ST_Union() uses high-speed cascaded union when compiled against GEOS 3.1+ (Paul Ramsey)
ST_ContainsProperly() requires GEOS 3.1+
ST_Intersects(), ST_Contains(), ST_Within() use high-speed cached prepared geometry against GEOS 3.1+ (Paul Ramsey /
funded by Zonar Systems)
Vastly improved documentation and reference manual (Regina Obe & Kevin Neufeld)
Figures and diagram examples in the reference manual (Kevin Neufeld)
ST_IsValidReason() returns readable explanations for validity failures (Paul Ramsey)
ST_GeoHash() returns a geohash.org signature for geometries (Paul Ramsey)
GTK+ multi-platform GUI for shape file loading (Paul Ramsey)
ST_LineCrossingDirection() returns crossing directions (Paul Ramsey)
ST_LocateBetweenElevations() returns sub-string based on Z-ordinate. (Paul Ramsey)
Geometry parser returns explicit error message about location of syntax errors (Mark Cave-Ayland)
ST_AsGeoJSON() return JSON formatted geometry (Olivier Courtin)
Populate_Geometry_Columns() -- automatically add records to geometry_columns for TABLES and VIEWS (Kevin Neufeld)
ST_MinimumBoundingCircle() -- returns the smallest circle polygon that can encompass a geometry (Bruce Rindahl)

A.34.4 Enhancements

Core geometry system moved into independent library, liblwgeom. (Mark Cave-Ayland)
New build system uses PostgreSQL "pgxs" build bootstrapper. (Mark Cave-Ayland)
Debugging framework formalized and simplified. (Mark Cave-Ayland)
All build-time #defines generated at configure time and placed in headers for easier cross-platform support (Mark Cave-Ayland)
Logging framework formalized and simplified (Mark Cave-Ayland)
Expanded and more stable support for CIRCULARSTRING, COMPOUNDCURVE and CURVEPOLYGON, better parsing,
wider support in functions (Mark Leslie & Mark Cave-Ayland)
Improved support for OpenSolaris builds (Paul Ramsey)
Improved support for MSVC builds (Mateusz Loskot)
Updated KML support (Olivier Courtin)
Unit testing framework for liblwgeom (Paul Ramsey)
New testing framework to comprehensively exercise every PostGIS function (Regine Obe)
Performance improvements to all geometry aggregate functions (Paul Ramsey)
Support for the upcoming PostgreSQL 8.4 (Mark Cave-Ayland, Talha Bin Rizwan)
PostGIS 2.4.3 Manual 786 / 803

Shp2pgsql and pgsql2shp re-worked to depend on the common parsing/unparsing code in liblwgeom (Mark Cave-Ayland)
Use of PDF DbLatex to build PDF docs and preliminary instructions for build (Jean David Techer)
Automated User documentation build (PDF and HTML) and Developer Doxygen Documentation (Kevin Neufeld)
Automated build of document images using ImageMagick from WKT geometry text files (Kevin Neufeld)
More attractive CSS for HTML documentation (Dane Springmeyer)

A.34.5 Bug fixes

http://trac.osgeo.org/postgis/query?status=closed&milestone=PostGIS+1.4.0&order=priority

A.35 Release 1.3.6

Release date: 2009/05/04

If you are running PostGIS 1.1+, a soft upgrade is sufficient otherwise a hard upgrade is recommended. This release adds support
for PostgreSQL 8.4, exporting prj files from the database with shape data, some crash fixes for shp2pgsql, and several small bug
fixes in the handling of "curve" types, logical error importing dbf only files, improved error handling of AddGeometryColumns.

A.36 Release 1.3.5

Release date: 2008/12/15

If you are running PostGIS 1.1+, a soft upgrade is sufficient otherwise a hard upgrade is recommended. This release is a bug
fix release to address a failure in ST_Force_Collection and related functions that critically affects using MapServer with LINE
layers.

A.37 Release 1.3.4

Release date: 2008/11/24

This release adds support for GeoJSON output, building with PostgreSQL 8.4, improves documentation quality and output
aesthetics, adds function-level SQL documentation, and improves performance for some spatial predicates (point-in-polygon
tests).
Bug fixes include removal of crashers in handling circular strings for many functions, some memory leaks removed, a linear
referencing failure for measures on vertices, and more. See the NEWS file for details.

A.38 Release 1.3.3

Release date: 2008/04/12

This release fixes bugs shp2pgsql, adds enhancements to SVG and KML support, adds a ST_SimplifyPreserveTopology function,
makes the build more sensitive to GEOS versions, and fixes a handful of severe but rare failure cases.

A.39 Release 1.3.2

Release date: 2007/12/01

This release fixes bugs in ST_EndPoint() and ST_Envelope, improves support for JDBC building and OS/X, and adds better
support for GML output with ST_AsGML(), including GML3 output.
PostGIS 2.4.3 Manual 787 / 803

A.40 Release 1.3.1

Release date: 2007/08/13

This release fixes some oversights in the previous release around version numbering, documentation, and tagging.

A.41 Release 1.3.0

Release date: 2007/08/09

This release provides performance enhancements to the relational functions, adds new relational functions and begins the migra-
tion of our function names to the SQL-MM convention, using the spatial type (SP) prefix.

A.41.1 Added Functionality

JDBC: Added Hibernate Dialect (thanks to Norman Barker)

Added ST_Covers and ST_CoveredBy relational functions. Description and justification of these functions can be found at
http://lin-ear-th-inking.blogspot.com/2007/06/subtleties-of-ogc-covers-spatial.html
Added ST_DWithin relational function.

A.41.2 Performance Enhancements

Added cached and indexed point-in-polygon short-circuits for the functions ST_Contains, ST_Intersects, ST_Within and ST_Disjoint
Added inline index support for relational functions (except ST_Disjoint)

A.41.3 Other Changes

Extended curved geometry support into the geometry accessor and some processing functions
Began migration of functions to the SQL-MM naming convention; using a spatial type (ST) prefix.
Added initial support for PostgreSQL 8.3

A.42 Release 1.2.1

Release date: 2007/01/11

This release provides bug fixes in PostgreSQL 8.2 support and some small performance enhancements.

A.42.1 Changes

Fixed point-in-polygon shortcut bug in Within().

Fixed PostgreSQL 8.2 NULL handling for indexes.
Updated RPM spec files.
Added short-circuit for Transform() in no-op case.
JDBC: Fixed JTS handling for multi-dimensional geometries (thanks to Thomas Marti for hint and partial patch). Additionally,
now JavaDoc is compiled and packaged. Fixed classpath problems with GCJ. Fixed pgjdbc 8.2 compatibility, losing support for
jdk 1.3 and older.
PostGIS 2.4.3 Manual 788 / 803

A.43 Release 1.2.0

Release date: 2006/12/08

This release provides type definitions along with serialization/deserialization capabilities for SQL-MM defined curved geome-
tries, as well as performance enhancements.

A.43.1 Changes

Added curved geometry type support for serialization/deserialization

Added point-in-polygon shortcircuit to the Contains and Within functions to improve performance for these cases.

A.44 Release 1.1.6

Release date: 2006/11/02

This is a bugfix release, in particular fixing a critical error with GEOS interface in 64bit systems. Includes an updated of the SRS
parameters and an improvement in reprojections (take Z in consideration). Upgrade is encouraged.

A.44.1 Upgrading

If you are upgrading from release 1.0.3 or later follow the soft upgrade procedure.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.44.2 Bug fixes

fixed CAPI change that broke 64-bit platforms

loader/dumper: fixed regression tests and usage output
Fixed setSRID() bug in JDBC, thanks to Thomas Marti

A.44.3 Other changes

use Z ordinate in reprojections

spatial_ref_sys.sql updated to EPSG 6.11.1
Simplified Version.config infrastructure to use a single pack of version variables for everything.
Include the Version.config in loader/dumper USAGE messages
Replace hand-made, fragile JDBC version parser with Properties

A.45 Release 1.1.5

Release date: 2006/10/13

This is an bugfix release, including a critical segfault on win32. Upgrade is encouraged.
PostGIS 2.4.3 Manual 789 / 803

A.45.1 Upgrading

If you are upgrading from release 1.0.3 or later follow the soft upgrade procedure.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.45.2 Bug fixes

Fixed MingW link error that was causing pgsql2shp to segfault on Win32 when compiled for PostgreSQL 8.2
fixed nullpointer Exception in Geometry.equals() method in Java
Added EJB3Spatial.odt to fulfill the GPL requirement of distributing the "preferred form of modification"
Removed obsolete synchronization from JDBC Jts code.
Updated heavily outdated README files for shp2pgsql/pgsql2shp by merging them with the manpages.
Fixed version tag in jdbc code that still said "1.1.3" in the "1.1.4" release.

A.45.3 New Features

Added -S option for non-multi geometries to shp2pgsql

A.46 Release 1.1.4

Release date: 2006/09/27

This is an bugfix release including some improvements in the Java interface. Upgrade is encouraged.

A.46.1 Upgrading

If you are upgrading from release 1.0.3 or later follow the soft upgrade procedure.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.46.2 Bug fixes

Fixed support for PostgreSQL 8.2

Fixed bug in collect() function discarding SRID of input
Added SRID match check in MakeBox2d and MakeBox3d
Fixed regress tests to pass with GEOS-3.0.0
Improved pgsql2shp run concurrency.

A.46.3 Java changes

reworked JTS support to reflect new upstream JTS developers’ attitude to SRID handling. Simplifies code and drops build depend
on GNU trove.
Added EJB2 support generously donated by the "Geodetix s.r.l. Company"
Added EJB3 tutorial / examples donated by Norman Barker <nbarker@ittvis.com>
Reorganized java directory layout a little.
PostGIS 2.4.3 Manual 790 / 803

A.47 Release 1.1.3

Release date: 2006/06/30

This is an bugfix release including also some new functionalities (most notably long transaction support) and portability enhance-
ments. Upgrade is encouraged.

A.47.1 Upgrading

If you are upgrading from release 1.0.3 or later follow the soft upgrade procedure.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.47.2 Bug fixes / correctness

BUGFIX in distance(poly,poly) giving wrong results.

BUGFIX in pgsql2shp successful return code.
BUGFIX in shp2pgsql handling of MultiLine WKT.
BUGFIX in affine() failing to update bounding box.
WKT parser: forbidden construction of multigeometries with EMPTY elements (still supported for GEOMETRYCOLLEC-
TION).

A.47.3 New functionalities

NEW Long Transactions support.

NEW DumpRings() function.
NEW AsHEXEWKB(geom, XDR|NDR) function.

A.47.4 JDBC changes

Improved regression tests: MultiPoint and scientific ordinates

Fixed some minor bugs in jdbc code
Added proper accessor functions for all fields in preparation of making those fields private later

A.47.5 Other changes

NEW regress test support for loader/dumper.

Added --with-proj-libdir and --with-geos-libdir configure switches.
Support for build Tru64 build.
Use Jade for generating documentation.
Don’t link pgsql2shp to more libs then required.
Initial support for PostgreSQL 8.2.
PostGIS 2.4.3 Manual 791 / 803

A.48 Release 1.1.2

Release date: 2006/03/30

This is an bugfix release including some new functions and portability enhancements. Upgrade is encouraged.

A.48.1 Upgrading

If you are upgrading from release 1.0.3 or later follow the soft upgrade procedure.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.48.2 Bug fixes

BUGFIX in SnapToGrid() computation of output bounding box

BUGFIX in EnforceRHR()
jdbc2 SRID handling fixes in JTS code
Fixed support for 64bit archs

A.48.3 New functionalities

Regress tests can now be run *before* postgis installation

New affine() matrix transformation functions
New rotate{,X,Y,Z}() function
Old translating and scaling functions now use affine() internally
Embedded access control in estimated_extent() for builds against pgsql >= 8.0.0

A.48.4 Other changes

More portable ./configure script

Changed ./run_test script to have more sane default behaviour

A.49 Release 1.1.1

Release date: 2006/01/23

This is an important Bugfix release, upgrade is highly recommended. Previous version contained a bug in postgis_restore.pl
preventing hard upgrade procedure to complete and a bug in GEOS-2.2+ connector preventing GeometryCollection objects to be
used in topological operations.

A.49.1 Upgrading

If you are upgrading from release 1.0.3 or later follow the soft upgrade procedure.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.
PostGIS 2.4.3 Manual 792 / 803

A.49.2 Bug fixes

Fixed a premature exit in postgis_restore.pl

BUGFIX in geometrycollection handling of GEOS-CAPI connector
Solaris 2.7 and MingW support improvements
BUGFIX in line_locate_point()
Fixed handling of postgresql paths
BUGFIX in line_substring()
Added support for localized cluster in regress tester

A.49.3 New functionalities

New Z and M interpolation in line_substring()

New Z and M interpolation in line_interpolate_point()
added NumInteriorRing() alias due to OpenGIS ambiguity

A.50 Release 1.1.0

Release date: 2005/12/21

This is a Minor release, containing many improvements and new things. Most notably: build procedure greatly simplified;
transform() performance drastically improved; more stable GEOS connectivity (CAPI support); lots of new functions; draft
topology support.
It is highly recommended that you upgrade to GEOS-2.2.x before installing PostGIS, this will ensure future GEOS upgrades
won’t require a rebuild of the PostGIS library.

A.50.1 Credits

This release includes code from Mark Cave Ayland for caching of proj4 objects. Markus Schaber added many improvements in
his JDBC2 code. Alex Bodnaru helped with PostgreSQL source dependency relief and provided Debian specfiles. Michael Fuhr
tested new things on Solaris arch. David Techer and Gerald Fenoy helped testing GEOS C-API connector. Hartmut Tschauner
provided code for the azimuth() function. Devrim GUNDUZ provided RPM specfiles. Carl Anderson helped with the new area
building functions. See the credits section for more names.

A.50.2 Upgrading

If you are upgrading from release 1.0.3 or later you DO NOT need a dump/reload. Simply sourcing the new lwpostgis_upgrade.sql
script in all your existing databases will work. See the soft upgrade chapter for more information.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.
PostGIS 2.4.3 Manual 793 / 803

A.50.3 New functions

scale() and transscale() companion methods to translate()

line_substring()
line_locate_point()
M(point)
LineMerge(geometry)
shift_longitude(geometry)
azimuth(geometry)
locate_along_measure(geometry, float8)
locate_between_measures(geometry, float8, float8)
SnapToGrid by point offset (up to 4d support)
BuildArea(any_geometry)
OGC BdPolyFromText(linestring_wkt, srid)
OGC BdMPolyFromText(linestring_wkt, srid)
RemovePoint(linestring, offset)
ReplacePoint(linestring, offset, point)

A.50.4 Bug fixes

Fixed memory leak in polygonize()

Fixed bug in lwgeom_as_anytype cast functions
Fixed USE_GEOS, USE_PROJ and USE_STATS elements of postgis_version() output to always reflect library state.

A.50.5 Function semantic changes

SnapToGrid doesn’t discard higher dimensions

Changed Z() function to return NULL if requested dimension is not available

A.50.6 Performance improvements

Much faster transform() function, caching proj4 objects

Removed automatic call to fix_geometry_columns() in AddGeometryColumns() and update_geometry_stats()

A.50.7 JDBC2 works

Makefile improvements
JTS support improvements
Improved regression test system
Basic consistency check method for geometry collections
Support for (Hex)(E)wkb
Autoprobing DriverWrapper for HexWKB / EWKT switching
fix compile problems in ValueSetter for ancient jdk releases.
fix EWKT constructors to accept SRID=4711; representation
added preliminary read-only support for java2d geometries
PostGIS 2.4.3 Manual 794 / 803

A.50.8 Other new things

Full autoconf-based configuration, with PostgreSQL source dependency relief

GEOS C-API support (2.2.0 and higher)
Initial support for topology modelling
Debian and RPM specfiles
New lwpostgis_upgrade.sql script

A.50.9 Other changes

JTS support improvements

Stricter mapping between DBF and SQL integer and string attributes
Wider and cleaner regression test suite
old jdbc code removed from release
obsoleted direct use of postgis_proc_upgrade.pl
scripts version unified with release version

A.51 Release 1.0.6

Release date: 2005/12/06

Contains a few bug fixes and improvements.

A.51.1 Upgrading

If you are upgrading from release 1.0.3 or later you DO NOT need a dump/reload.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.51.2 Bug fixes

Fixed palloc(0) call in collection deserializer (only gives problem with --enable-cassert)
Fixed bbox cache handling bugs
Fixed geom_accum(NULL, NULL) segfault
Fixed segfault in addPoint()
Fixed short-allocation in lwcollection_clone()
Fixed bug in segmentize()
Fixed bbox computation of SnapToGrid output

A.51.3 Improvements

Initial support for postgresql 8.2

Added missing SRID mismatch checks in GEOS ops
PostGIS 2.4.3 Manual 795 / 803

A.52 Release 1.0.5

Release date: 2005/11/25

Contains memory-alignment fixes in the library, a segfault fix in loader’s handling of UTF8 attributes and a few improvements
and cleanups.

Note
Return code of shp2pgsql changed from previous releases to conform to unix standards (return 0 on success).

A.52.1 Upgrading

If you are upgrading from release 1.0.3 or later you DO NOT need a dump/reload.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.52.2 Library changes

Fixed memory alignment problems

Fixed computation of null values fraction in analyzer
Fixed a small bug in the getPoint4d_p() low-level function
Speedup of serializer functions
Fixed a bug in force_3dm(), force_3dz() and force_4d()

A.52.3 Loader changes

Fixed return code of shp2pgsql

Fixed back-compatibility issue in loader (load of null shapefiles)
Fixed handling of trailing dots in dbf numerical attributes
Segfault fix in shp2pgsql (utf8 encoding)

A.52.4 Other changes

Schema aware postgis_proc_upgrade.pl, support for pgsql 7.2+

New "Reporting Bugs" chapter in manual

A.53 Release 1.0.4

Release date: 2005/09/09

Contains important bug fixes and a few improvements. In particular, it fixes a memory leak preventing successful build of GiST
indexes for large spatial tables.
PostGIS 2.4.3 Manual 796 / 803

A.53.1 Upgrading

If you are upgrading from release 1.0.3 you DO NOT need a dump/reload.
If you are upgrading from a release between 1.0.0RC6 and 1.0.2 (inclusive) and really want a live upgrade read the upgrade
section of the 1.0.3 release notes chapter.
Upgrade from any release prior to 1.0.0RC6 requires an hard upgrade.

A.53.2 Bug fixes

Memory leak plugged in GiST indexing

Segfault fix in transform() handling of proj4 errors
Fixed some proj4 texts in spatial_ref_sys (missing +proj)
Loader: fixed string functions usage, reworked NULL objects check, fixed segfault on MULTILINESTRING input.
Fixed bug in MakeLine dimension handling
Fixed bug in translate() corrupting output bounding box

A.53.3 Improvements

Documentation improvements
More robust selectivity estimator
Minor speedup in distance()
Minor cleanups
GiST indexing cleanup
Looser syntax acceptance in box3d parser

A.54 Release 1.0.3

Release date: 2005/08/08

Contains some bug fixes - including a severe one affecting correctness of stored geometries - and a few improvements.

A.54.1 Upgrading

Due to a bug in a bounding box computation routine, the upgrade procedure requires special attention, as bounding boxes cached
in the database could be incorrect.
An hard upgrade procedure (dump/reload) will force recomputation of all bounding boxes (not included in dumps). This is
required if upgrading from releases prior to 1.0.0RC6.
If you are upgrading from versions 1.0.0RC6 or up, this release includes a perl script (utils/rebuild_bbox_caches.pl) to force
recomputation of geometries’ bounding boxes and invoke all operations required to propagate eventual changes in them (ge-
ometry statistics update, reindexing). Invoke the script after a make install (run with no args for syntax help). Optionally run
utils/postgis_proc_upgrade.pl to refresh postgis procedures and functions signatures (see Soft upgrade).
PostGIS 2.4.3 Manual 797 / 803

A.54.2 Bug fixes

Severe bugfix in lwgeom’s 2d bounding box computation

Bugfix in WKT (-w) POINT handling in loader
Bugfix in dumper on 64bit machines
Bugfix in dumper handling of user-defined queries
Bugfix in create_undef.pl script

A.54.3 Improvements

Small performance improvement in canonical input function

Minor cleanups in loader
Support for multibyte field names in loader
Improvement in the postgis_restore.pl script
New rebuild_bbox_caches.pl util script

A.55 Release 1.0.2

Release date: 2005/07/04

Contains a few bug fixes and improvements.

A.55.1 Upgrading

If you are upgrading from release 1.0.0RC6 or up you DO NOT need a dump/reload.
Upgrading from older releases requires a dump/reload. See the upgrading chapter for more informations.

A.55.2 Bug fixes

Fault tolerant btree ops

Memory leak plugged in pg_error
Rtree index fix
Cleaner build scripts (avoided mix of CFLAGS and CXXFLAGS)

A.55.3 Improvements

New index creation capabilities in loader (-I switch)

Initial support for postgresql 8.1dev

A.56 Release 1.0.1

Release date: 2005/05/24

Contains a few bug fixes and some improvements.
PostGIS 2.4.3 Manual 798 / 803

A.56.1 Upgrading

If you are upgrading from release 1.0.0RC6 or up you DO NOT need a dump/reload.
Upgrading from older releases requires a dump/reload. See the upgrading chapter for more informations.

A.56.2 Library changes

BUGFIX in 3d computation of length_spheroid()

BUGFIX in join selectivity estimator

A.56.3 Other changes/additions

BUGFIX in shp2pgsql escape functions

better support for concurrent postgis in multiple schemas
documentation fixes
jdbc2: compile with "-target 1.2 -source 1.2" by default
NEW -k switch for pgsql2shp
NEW support for custom createdb options in postgis_restore.pl
BUGFIX in pgsql2shp attribute names unicity enforcement
BUGFIX in Paris projections definitions
postgis_restore.pl cleanups

A.57 Release 1.0.0

Release date: 2005/04/19

Final 1.0.0 release. Contains a few bug fixes, some improvements in the loader (most notably support for older postgis versions),
and more docs.

A.57.1 Upgrading

If you are upgrading from release 1.0.0RC6 you DO NOT need a dump/reload.
Upgrading from any other precedent release requires a dump/reload. See the upgrading chapter for more informations.

A.57.2 Library changes

BUGFIX in transform() releasing random memory address

BUGFIX in force_3dm() allocating less memory then required
BUGFIX in join selectivity estimator (defaults, leaks, tuplecount, sd)
PostGIS 2.4.3 Manual 799 / 803

A.57.3 Other changes/additions

BUGFIX in shp2pgsql escape of values starting with tab or single-quote

NEW manual pages for loader/dumper
NEW shp2pgsql support for old (HWGEOM) postgis versions
NEW -p (prepare) flag for shp2pgsql
NEW manual chapter about OGC compliancy enforcement
NEW autoconf support for JTS lib
BUGFIX in estimator testers (support for LWGEOM and schema parsing)

A.58 Release 1.0.0RC6

Release date: 2005/03/30

Sixth release candidate for 1.0.0. Contains a few bug fixes and cleanups.

A.58.1 Upgrading

You need a dump/reload to upgrade from precedent releases. See the upgrading chapter for more informations.

A.58.2 Library changes

BUGFIX in multi()
early return [when noop] from multi()

A.58.3 Scripts changes

dropped {x,y}{min,max}(box2d) functions

A.58.4 Other changes

BUGFIX in postgis_restore.pl scrip

BUGFIX in dumper’s 64bit support

A.59 Release 1.0.0RC5

Release date: 2005/03/25

Fifth release candidate for 1.0.0. Contains a few bug fixes and a improvements.

A.59.1 Upgrading

If you are upgrading from release 1.0.0RC4 you DO NOT need a dump/reload.
Upgrading from any other precedent release requires a dump/reload. See the upgrading chapter for more informations.
PostGIS 2.4.3 Manual 800 / 803

A.59.2 Library changes

BUGFIX (segfaulting) in box3d computation (yes, another!).

BUGFIX (segfaulting) in estimated_extent().

A.59.3 Other changes

Small build scripts and utilities refinements.

Additional performance tips documented.

A.60 Release 1.0.0RC4

Release date: 2005/03/18

Fourth release candidate for 1.0.0. Contains bug fixes and a few improvements.

A.60.1 Upgrading

You need a dump/reload to upgrade from precedent releases. See the upgrading chapter for more informations.

A.60.2 Library changes

BUGFIX (segfaulting) in geom_accum().

BUGFIX in 64bit architectures support.
BUGFIX in box3d computation function with collections.
NEW subselects support in selectivity estimator.
Early return from force_collection.
Consistency check fix in SnapToGrid().
Box2d output changed back to 15 significant digits.

A.60.3 Scripts changes

NEW distance_sphere() function.

Changed get_proj4_from_srid implementation to use PL/PGSQL instead of SQL.

A.60.4 Other changes

BUGFIX in loader and dumper handling of MultiLine shapes

BUGFIX in loader, skipping all but first hole of polygons.
jdbc2: code cleanups, Makefile improvements
FLEX and YACC variables set *after* pgsql Makefile.global is included and only if the pgsql *stripped* version evaluates to the
empty string
Added already generated parser in release
Build scripts refinements
improved version handling, central Version.config
improvements in postgis_restore.pl
PostGIS 2.4.3 Manual 801 / 803

A.61 Release 1.0.0RC3

Release date: 2005/02/24

Third release candidate for 1.0.0. Contains many bug fixes and improvements.

A.61.1 Upgrading

You need a dump/reload to upgrade from precedent releases. See the upgrading chapter for more informations.

A.61.2 Library changes

BUGFIX in transform(): missing SRID, better error handling.

BUGFIX in memory alignment handling
BUGFIX in force_collection() causing mapserver connector failures on simple (single) geometry types.
BUGFIX in GeometryFromText() missing to add a bbox cache.
reduced precision of box2d output.
prefixed DEBUG macros with PGIS_ to avoid clash with pgsql one
plugged a leak in GEOS2POSTGIS converter
Reduced memory usage by early releasing query-context palloced one.

A.61.3 Scripts changes

BUGFIX in 72 index bindings.

BUGFIX in probe_geometry_columns() to work with PG72 and support multiple geometry columns in a single table
NEW bool::text cast
Some functions made IMMUTABLE from STABLE, for performance improvement.

A.61.4 JDBC changes

jdbc2: small patches, box2d/3d tests, revised docs and license.

jdbc2: bug fix and testcase in for pgjdbc 8.0 type autoregistration
jdbc2: Removed use of jdk1.4 only features to enable build with older jdk releases.
jdbc2: Added support for building against pg72jdbc2.jar
jdbc2: updated and cleaned makefile
jdbc2: added BETA support for jts geometry classes
jdbc2: Skip known-to-fail tests against older PostGIS servers.
jdbc2: Fixed handling of measured geometries in EWKT.

A.61.5 Other changes

new performance tips chapter in manual

documentation updates: pgsql72 requirement, lwpostgis.sql
few changes in autoconf
BUILDDATE extraction made more portable
fixed spatial_ref_sys.sql to avoid vacuuming the whole database.
spatial_ref_sys: changed Paris entries to match the ones distributed with 0.x.
PostGIS 2.4.3 Manual 802 / 803

A.62 Release 1.0.0RC2

Release date: 2005/01/26

Second release candidate for 1.0.0 containing bug fixes and a few improvements.

A.62.1 Upgrading

You need a dump/reload to upgrade from precedent releases. See the upgrading chapter for more informations.

A.62.2 Library changes

BUGFIX in pointarray box3d computation

BUGFIX in distance_spheroid definition
BUGFIX in transform() missing to update bbox cache
NEW jdbc driver (jdbc2)
GEOMETRYCOLLECTION(EMPTY) syntax support for backward compatibility
Faster binary outputs
Stricter OGC WKB/WKT constructors

A.62.3 Scripts changes

More correct STABLE, IMMUTABLE, STRICT uses in lwpostgis.sql

stricter OGC WKB/WKT constructors

A.62.4 Other changes

Faster and more robust loader (both i18n and not)

Initial autoconf script

A.63 Release 1.0.0RC1

Release date: 2005/01/13

This is the first candidate of a major postgis release, with internal storage of postgis types redesigned to be smaller and faster on
indexed queries.

A.63.1 Upgrading

You need a dump/reload to upgrade from precedent releases. See the upgrading chapter for more informations.
PostGIS 2.4.3 Manual 803 / 803

A.63.2 Changes

Faster canonical input parsing.

Lossless canonical output.
EWKB Canonical binary IO with PG>73.
Support for up to 4d coordinates, providing lossless shapefile->postgis->shapefile conversion.
New function: UpdateGeometrySRID(), AsGML(), SnapToGrid(), ForceRHR(), estimated_extent(), accum().
Vertical positioning indexed operators.
JOIN selectivity function.
More geometry constructors / editors.
PostGIS extension API.
UTF8 support in loader.