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Georeferencing Guide for GIS Users

This document provides step-by-step instructions for georeferencing a raster image in ArcGIS. It details 27 steps to add data layers, create control points by linking known locations on the raster to coordinates, define coordinate systems, export the georeferenced data, and rectify the image. Key steps include creating a text file with coordinate pairs, assigning projections, adding control points by clicking locations on the raster and target data, examining residual errors, and saving the rectified image. The process georeferences a raster image to real-world coordinates so it can be analyzed alongside other geospatial data layers.

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Praveen Kalura
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126 views7 pages

Georeferencing Guide for GIS Users

This document provides step-by-step instructions for georeferencing a raster image in ArcGIS. It details 27 steps to add data layers, create control points by linking known locations on the raster to coordinates, define coordinate systems, export the georeferenced data, and rectify the image. Key steps include creating a text file with coordinate pairs, assigning projections, adding control points by clicking locations on the raster and target data, examining residual errors, and saving the rectified image. The process georeferences a raster image to real-world coordinates so it can be analyzed alongside other geospatial data layers.

Uploaded by

Praveen Kalura
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Exercise no. 1 : Georefrencing


Submitted by : Praveen Kalura R. No. 141868
Step 1 : Add the layer residing in map coordinates (target data) and the raster you want
to georeference.
Go to file menu> Add Data>> ENTER


Step 2: Open Notepad.

Step 3 : Create two columns X, Y (where X = Longitude, Y = Latitude).

Step 4 : Key in the X, Y Value of four corner points in Decimal degree in a way that your
file should appear as illustrated in the picture below. Do not press ENTER Key
after adding last co-ordinate.


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Step 5 : Click File on the Menu and click Save as and then scroll to the D:\2014
batch\141868\new folder
and save your text file by the name 56N7.txt. Close the file by clicking CLOSE
button of Notepad Window.

Step 6: To convert text file into point locations, In ArcMap click on Tools\Add X, Y data.


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Step 7 : Add XY data dialog box will appear, click on folder icon to browse the text file
you created in the earlier step. The XY data dialog box should show X & Y in X
field and Y Field respectively

Step 8 :Click on the edit button to provide a geographic coordinate system to your data.

Step 9 :A Spatial reference property dialog box will open where you can define your
Geographic coordinate system.

Step 10 : Click on Select button and browse to Geographic Coordinate system\Asia\
Everest India and Nepal for your projection system.

Step 11 :Click Apply and OK to Spatial reference property dialog box.
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Step 12 :Four Point features will appear on your ArcMap as shown below.

Step 13 :Click on Coordinate System tab, for defining a New Projected coordinate
system click on New Projected Coordinate System.



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Step 14 : A New Projected Coordinate System window will open type in the following
details in the Projected Coordinate System window
Step 15 : Projection name: Select Polyconic from the drop-down menu.
Central Meridian: 79.375 (Longitude)
Origin of latitude: 18.375 (Latitude)




Step 16 : For geographic coordinate system click onSelect tab and browse to Geographic
Coordinate system\Asia\ Everest India and Nepal.Click ADD.

Step 17 : Click OK to New Project Co-Ordinate System Window. Click Apply and OK to
Data Frame Property Box.

Step 18 :Note: Next Step is necessary if you have the data in different datums. In case
datum of the data is same then skip the step no. 15.

Step 19 : On the data frame property window click Transformation. A Geographic
coordinate system transformation window will open, Click New on this window
to open New Geographic transformation window. Click OK without making
changes.

Step 20 : Click Apply & OK to Geographic coordinate system transformation window for
transforming your data.

Step 21 : Right click on the new1.txt Events in the Table of Content, in context menu
click Data\Export data.

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Step 22 : In Export data window click use the second option i.e. The Data Frame
and specify the Output Path & Name for you frame data
(D:\2014batch\141868\Export_Output4.shp). Click OK

Step 23 : From the Georeferencing toolbar, click the Layer dropdown arrow and select
the raster layer you want to georeference.

Step 24 : Click the Control Points button to add control points.

Step 25 : To add a link, click the mouse pointer over a known location on the raster
(Source),then over a known location on the target data using Zoom to layer
option. You may find it useful to use a Magnification Window to add your links in.










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Step 26 : Click View Link Table to evaluate the transformation. You can examine the
Residual Error for each link and the RMS Error.


Step 27 : Click Georeferencing tool and click Rectify, using default save the rectified
image at a desired location on your hard disc D:\ the D:\2014
batch\141868\new\ 56N7.img.




End..

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