Mercator settings from .PRJ

tjhbtjhb Global Mapper UserPosts: 454Trusted User
edited February 2011 in Bug Report

I shouldn't really call this a bug, since .PRJ files are inevitably approximate.

The issue is that for Mercator projections, GM 12.01 (and previous versions) overlooks the True Scale Latitude parameter written in a PRJ file (for some reason) as standard_parallel_1. It always defaults to 0.

This is the case even for .PRJ files GM has written itself.


  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited February 2011
    I would expect GM to write the true scale latitude to a parameter named 'latitude_of_origin' (seems to be the standard one used although really seems like the wrong one). In any case, I have updated the PRJ importer to recognize 'standard_parallel_1' for the True Scale Latitude parameter. I have placed a new build at with the change for you to try. Simply download that file and extract the contents into your existing v12.xx installation folder to give it a try. If you are using the 64-bit v12 version there is a new build at .

    Let me know if I can be of further assistance.


    Global Mapper Support
  • tjhbtjhb Global Mapper User Posts: 454Trusted User
    edited February 2011

    For the files we were having difficulty with, the true scale latitude is now recognised effortlessly and correctly.

    Thank you very much.

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