[aprssig] Map Symbol Placement

[M J]

I notice that within some APRS programs, it is necessary to identify two lat/lon points on a map, and link them to the corresponding map's pixels.  Has anyone more publicly documented the equations used to plot a symbol on a map if you know the lat/lon that the symbol is supposed to appear on (once you know the previous info)?  I'm interested in learning more about that.  Thanks!  MJ




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