How to convert X and Y axis to long lat by using formula
If your drawing is in UTM coordinates there are formulas to obtain lat/long values. However almost all of the time the coordinates must be projected to the lat/long system. Remember that lat/long is spherical and all drawing coordinates are planar, so even if you used coordinates of -180 to 180 your geometry will be distorted in the drawing.
Beware the AutoCAD Geolocation command that lets you pick a point and enter lat/long, etc. True mapping does not work that way and you could find yourself doing a lot of work that you later discover is worthless.
Your best solution is to enlist the help of a surveyor or geodesist to help get you started on the right track.
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