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You can calibrate any vector file by using Didger's Map | Coordinate Conversion command and choosing the Georeference option. You will need to know at least three points on the vector file
- Click File | Import.
- Choose the vector file (e.g. DXF, SHP, MIF, etc.) and click Open.
- If the selected vector file is a .DXF file, click OK in the DXF Import Options dialog.
- If your file has a georeferencing file with it (i.e. GSR2, PRJ, WLD, etc.), it will come in calibrated. If your file doesn't have a georeferencing file with it,
- If you know the file is projected, toggle Projected Coordinates in the
- the Assign Coordinate System dialog, specify the coordinate system, and click OK.
- If it is not projected, or you do not know, click OK to accept the defaults. The file imports into Didger, however, it does not have the correct coordinates associated with it.
- Click Map | Coordinate Conversion.
- In the Coordinate Conversion dialog,
- Toggle Georeference.
- Click the Add button in the lower left corner of the dialog twice, so there are three rows in the Georeference table.
- Enter the real world coordinates of three known points into the World X and World Y columns. If the file you imported is in lat/long, the coordinates you enter must be in decimal degrees of longitude (X) and latitude (Y). Didger will use these values to establish the new coordinate system.
- Select one of the rows and click on the corresponding location in the plot window. Repeat for the other rows.
Establish at least three calibration points and enter the coordinates for those points in the World X and World Y columns. When you digitize a point in the plot window, Didger will automatically enter coordinates in the Source X and Source Y columns.
- Select the desired Georeference Method and click OK.
- You may need to click Map | Project Limits and reset the project limits and scaling.
Now the map is in the coordinate system you specified. You can digitize objects, resample lines, convert the projection (if applicable), or export to any of the supported formats.
Updated July 16, 2018
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