MOUNT ZION COLLEGE OF ENGINEERING AND
TECHNOLOGY
DEPARTMENT OF CIVIL ENGINEERING
OGI352 GEOGRAPHICAL INFORMATION SYSTEM
IV YEAR / VII – SEMESTER
UNIT-2 SPATIAL DATA MODELS
K. ROJA, AP/CIVIL
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
COURSE OUTCOMES
• Able to explain the basic concepts, principles, and
components of GIS
• Provide an introduction to the fundamental concepts,
principles, and applications of GIS technology.
• Develop proficiency in performing basic spatial analysis
operations such as buffering, overlay analysis, and spatial
querying using GIS software.
• Gain the ability to acquire, format, and manage spatial data
from different sources (e.g., GPS, remote sensing) and in
various formats (e.g., vector, raster).
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
COURSE OBJECTIVE
• The main objectives collectively aim to equip
students with a solid foundation in GIS theory,
practical skills, and critical thinking abilities
necessary for applying GIS in various professional
and academic contexts.
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
COURSE OUTLINE
• 2.1 Data base Structure
• 2.2 Relational and Object oriented data structure model
• 2.3 Entities ER Diagram
• 2.4 Data Models
• 2.5 Raster Data Structure And Compression
• 2.6 Vector Data Structure
• 2.7 Raster Data Model Vs Vector Data Model
• 2.8 Triangulated Irregular Network (Tin)
• 2.9 Grid Data Model
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
TOPICS
• Previous class Topic
• 2.7 Raster Data Model Vs Vector Data Model
• Todays class
• 2.8 Triangulated Irregular Network (Tin)
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
TIN
• Triangular irregular networks (TIN) have been used by the
GIS community for many years and are a digital means to
represent surface morphology.
• TINs are a form of vector-based digital geographic data and
are constructed by triangulating a set of vertices (points).
• The vertices are connected with a series of edges to form a
network of triangles.
• There are different methods of interpolation to form these
triangles, such as Delaunay triangulation or distance
ordering. ArcGIS supports the Delaunay triangulation
method.
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
Advantages of TIN models
• Users can describe a surface at different levels of
resolution based on the points that were collected.
• TIN interpolation gives GIS users greater analytical
capabilities. TIN models are easy to create and use.
• They provide users a simplified model that represents
collected data points.
• Using a TIN surface in conjunction with Arc-Map
extensions such as Spatial Analysis and 3D Analyst,
TIN users can also derive slope, aspect, elevation,
contour lines, hill shades, etc.
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
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MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
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MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
Different Types of TIN Methods and
2.8
Processes
• Natural Neighbour,
• • Krigging,
• • Spline,
• • Nearest Neighbour and
• • Inversed Distance Weighting.
• These TIN interpolation methods use
mathematical algorithms in order to generate
• interpolated surfaces. Each of these methods will
produce different types of surfaces.
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
Structure of TIN Data Model
• The triangle number
• • The numbers of each adjacent triangle
• • The three nodes defining the triangle
• • The x, y coordinates of each node
• • The surface z value of each node
• • The edge type of each triangle edge (hard or
soft)
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
Components of TIN
• Nodes:
• Nodes are the fundamental building blocks of the
TIN. The nodes originate from the points and arc
vertices contained in the input data sources. Every
node is incorporated in the TIN triangulation. Every
node in the TIN surface model must have a z value.
• Edges:
• Every node is joined with its nearest neighbors by
edges to form triangles, which satisfy the Delaunay
criterion. Each edge has two nodes, but a node may
have two or more edges.
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
2.8
Four Tables for TIN Model
• Node Table it lists each triangle and the nodes
which define it.
• Edge Table it lists three triangles adjacent to
each facets. The triangles that border the
boundary of the TIN show only two adjacent
facets.
• XY Co-ordinate Table it lists the co-ordinate
values of each node.
• • Z Table it is the altitude value of each node.
MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
REFERENCES
• https://www.youtube.com/watch?v=vD3p1TrE
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• https://www.youtube.com/watch?v=7o01Y9b
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MZCET-CIVIL-VII SEM-OGI352-GIS-UNIT 2
