What global coordinate system does AutoCAD 3D 2012 use?
I want to register a section map from an inactive mine. The map is a simple .jpg file.
The "Help" is not very helpful. Does anyone have any tips?
AutoCAD by itself does not use a global coordinate system in the sense of mapping. The 0,0,0 point is the origin, but is completely arbitrary and unrelated to any other coordinate system. You can use the GeoLocation tools to map _any_ xy to a LatLong, but that's it.
Sounds like you need to look into Map3d - where you can assing a known coordinate system for georeferencing, or look for a third party app that can handle it.
If you have known coordinate values for a location in the jpg, you can manually move the image to that locations, and scale it to a known distance -- accuracy and reliability might be questionable.....