Follow

What's the difference between Map | Change Projection and Map | Coordinate Conversion in Didger?

In Didger, the Map | Change Projection command is used to change the projection of the existing projected project. 

The Map | Coordinate Conversion command is used to “calibrate” the project (either to calibrate/georeference an imported vector file, or to calibrate/recalibrate a project that has both raster and vector data in it).

For example:

1. If you import an AutoCAD DXF file and you know the coordinates in the DXF file are in UTM, then you can import the file as UTM, and then use Map | Change Projection to change it to some other projection (like State Plane).

2. If you import an image georeferenced with a projection (or download a WMS image), and want to change the projection from UTM to State Plane, use the Map | Change Projection command.

3. If you import an AutoCAD DXF file and the coordinates in the DXF file are some random special coordinate units unique only to that particular site (say they are meters based of a 0 baseline). You would use the Map | Coordinate Conversion command to georeference the DXF file to UTM, then use Map | Change Projection to change the projection to State Plane.

4. If you import a georeferenced image, digitize some points/polylines/polygons on it, then realize the georeferencing is 50m off, you would use Map | Coordinate Conversion to recalibrate the project.

Updated October 6, 2016

Was this article helpful?
0 out of 0 found this helpful
Have more questions? Submit a request

0 Comments

Please sign in to leave a comment.