Global Mapper Pro

Problem with custom projection

Reed94Reed94 Global Mapper UserPosts: 3
edited October 2013 in Projection Questions
I’m having problems with a custom projection. We have a bunch of .sid tiles and vector data supplied by the client that are in the custom projection but they are coming into Global Mapper about 150 feet off from the online imagery. Further testing this with a handheld gps point in UTM, I can see that the point lines up with the online imagery correctly. Checking with Arc, all data lines up perfectly. If I export the same gps point from Arc re-projected in the custom projection it imports into Global Mapper the same 150 feet off. This makes me think Global Mapper is having problems with the custom projection (please let me know if my logic is flawed here).

I have attached two shapefiles, the first is the original gps point in UTM and the other is the same point converted to the custom projection using Arc. If you overlay some online imagery, you’ll see where the point is supposed to be on top of the dirt pile and not on the road. If I open both of these shapefiles with Arc they both line up on top of each other.

If someone can take a look and offer some advice I would really appreciate it. Thanks!

Attachment not found.


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