Global Mapper Pro

Settings for no projection

MichelNoel
MichelNoel Global Mapper User
edited November 2011 in Projection Questions
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

Comments

  • samknight
    samknight BMG Staff
    edited November 2011
    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 right-click 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
  • global_mapper
    global_mapper Administrator
    edited November 2011
    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
  • PaulTocknell
    PaulTocknell Forum Administrator Unconfirmed
    edited November 2011
    That is a pretty big milestone! Nice job Sam!
  • MichelNoel
    MichelNoel Global Mapper User
    edited November 2011
    Thank you for the information and the quick reply.
    Michel
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