Every drawing as a pin on a map

I built a tool that scans a drive full of Civil 3D drawings and drops a pin on a map for each one, using its GEODATA. Read the coordinate system, look at the drawing, plot the pin. That was the whole plan, and it worked, until it produced a result that could not be true.

Two drawings, from two different locations, a road corridor and a light rail station, not near each other, landed on the exact same point. Not close. The same coordinates, to fifteen digits.

Why would that happen? Neither drawing was wrong. Typically, a coordinate system gets assigned to a drawing. This routine was reading that correctly. What I thought was happening next was that the drawing's data location would be read and plotted on the map. What was actually happening was the center of a drawing's coordinate system was being plotted. Thus, the duplicates.

So, the pin cannot come from that process anymore. The tool now looks first at the drawing's own geometry and computes a center from that instead, the real content, not the inherited coordinate system. It does, of course, check all drawings to see if a coordinate system is assigned at all. One that fails that check gets dropped, not shown anyway.

No pin is better than the wrong pin. A map that shows you something false is worse than a map with a gap in it, because the gap tells you to go look, and the false pin tells you that you already know.

Be better - know where things are.