Settings for no projection
MichelNoel
Global Mapper User
Hi,
I suspect that this problem has been addressed in the Forum but I could not locate it...
Is there a way to cancel all projection corrections inside Global Mapper so we get a completely flat and square grid? Global Mapper's Equirectangular does not work as it introduces some corrections as per this example:
I have a DXF with a closed 2D polyline (elevation set at 0) drawn in an unknown projection/grid system (not lat/long). The irregular geometry gives an area of 7731498 and a perimeter of 12347 m in Autocad (no projection specified, thus square and flat grid) while Global Mapper gives an area of 7731499 m2 and a perimeter of 10339 m. I am puzzled that the areas matches but the perimeter does not. Any explanation? Can Global Mapper be set to operate in a regular square grid?
Thanks,
Michel
I suspect that this problem has been addressed in the Forum but I could not locate it...
Is there a way to cancel all projection corrections inside Global Mapper so we get a completely flat and square grid? Global Mapper's Equirectangular does not work as it introduces some corrections as per this example:
I have a DXF with a closed 2D polyline (elevation set at 0) drawn in an unknown projection/grid system (not lat/long). The irregular geometry gives an area of 7731498 and a perimeter of 12347 m in Autocad (no projection specified, thus square and flat grid) while Global Mapper gives an area of 7731499 m2 and a perimeter of 10339 m. I am puzzled that the areas matches but the perimeter does not. Any explanation? Can Global Mapper be set to operate in a regular square grid?
Thanks,
Michel
Comments

Hello Michel,
All coordinate systems in Global Mapper are geodetically based, so presently there is no way to work in a flat earth system. However, for measurement of distances in your native ground system, if you have assigned a coordinate system (in your case, Equirectangular) you can rightclick with the Measure Tool enabled to select "Use Grid Distance for Distance/Path Display". This will calculate distances using straight grid coordinates, so the projection won't matter.
Regards,
Sam Knight
Blue Marble Geographics 
I'd like to welcome Sam and congratulate him on the first official Global Mapper support response on the forum that wasn't from me!
Thanks,
Mike Childs
Global Mapper Guru
mikec@bluemarblegeo.com
http://www.globalmapper.com 
That is a pretty big milestone! Nice job Sam!

Thank you for the information and the quick reply.
Michel
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