GIS and/or AutoCAD Users:
Is there any way to get a CAD drawing file to overlay a GIS basemap in the correct geographic location without having to georeference the CAD drawing? It seems that defining a spatial referenceffor the CAD drawing file does not do the trick. Does the person who created the CAD drawing have to assign a geographic coordinate system in AutoCAD? If so, what version of AutoCAD is needed to be able to do that?
Thanks for help!
Dan and Ted,
I have tried creating a prj file for the cad drawing, converting from cad
to geodatabase with the conversion tool, converting to shp file, etc, etc.
and none of this works. A spatial reference is assigned to the dwg file,
but it still does not appear in the correct location. I think this is
because the dwg is still not georeferenced via control points. In order to
create a world file, I have to create control points, but I want to avoid
having to manually pick control points because it introduces inaccuracy,
especially in areas where it not easy to see points/locations that
correspond to the dwg and the GIS base map. I am thinking the only solution
is to have the CAD technician assign the coordinate system when the drawing
is created.
GeoNet <https://community.esri.com/?et=watches.email.thread>
Re: CAD to GIS without georefencing?
reply from Ted Kowal
<https://community.esri.com/people/tkowal?et=watches.email.thread> in *ArcGIS
for AutoCAD* - View the full discussion
<https://community.esri.com/message/738063-re-cad-to-gis-without-georefencing?commentID=738063&et=watches.email.thread#comment-738063>
That would be the prudent decision.
In my experience either I geo-reference the CAD file (does not take long if you have enough control points), take a guess at the projections (trial and error -- this can be frustrating), or have the technician, if possible, use the correct projected seed file (I deal mainly with DGN's which uses a seed).