Leaderboard

There is a formula to convert latitude-longitude to a grid (northing-easting) - something I looked at a while ago when it was quiet in work. If I remember right the formula is dependent on your position in the world - the closer you are to the poles the more correction needed to make straight perpendicular lines. If you have the formula that you are happy with then it should be possible to convert that to a LISP and see if it is quicker to do it within CAD, noting that while the conversion might be slower taking away the human speed element to send the coordinated to your API and then back again might make the process overall quicker. Big-Al I suspect will be along shortly to tell you to use the function in civil 3d (mapimport) rather than creating something new. After that it will just need a rule of which points to connect as lines