CAD Projection

ChrisSlinko — Thu, 21 Feb 2013 17:33:55 GMT

I have a project to get NAIP imagery for a project to be used in AutoCAD. The problem is the NAIP imagery won't line up with a CAD drawing in AutoCAD Civil 3D 2013. The NAIP imagery is in it's native projection for the study area which is UTM Zone 19 NAD 83 Meters. I sent the imgery to the drafters and they said that they can't change the project when they import it into CAD and it is not lining up with their drawing. The CAD drawings project is in USA, Maine Harn/ME States Plane, East Zone, Meters. I tried looking for it in Toolbox/Raster/Project and I found one that is close but it did not work. Next, with the advice of ESRI tech support I added the CAD drawing to ArcMap 10.1 and it had an undifined coordinate system but in AutoCAD it has a defined coordinate system. Can anyone offer any suggestions for this. I'm not a CAD person I'm a GIS person.

Re: CAD Projection

KarenHodge — Tue, 26 Feb 2013 16:31:11 GMT

There's a couple of ways you can work with this, but I'll give you a couple of ideas.

First, I agree that it will help you to start by adding your CAD drawing to ArcMap 10.1 to see what the CAD folks are seeing. However, they are storing the coordinate system in the drawing using Civil 3D's proprietary system--which ArcMap can't read. You can assign a coordinate system to the CAD drawing within ArcMap. When you say the coordinate system didn't work, what happened? Was it close, but not quite? Or did you see no difference whatsoever?

If you are unable to find a coordinate system that matches, you can ask your CAD drafters to generate the WKT from the Civil 3D coordinate system. From that, you can create a PRJ file and associate that PRJ with both your CAD drawing and your map data frame.

Does that help?

--Karen

I have a project to get NAIP imagery for a project to be used in AutoCAD. The problem is the NAIP imagery won't line up with a CAD drawing in AutoCAD Civil 3D 2013. The NAIP imagery is in it's native projection for the study area which is UTM Zone 19 NAD 83 Meters. I sent the imgery to the drafters and they said that they can't change the project when they import it into CAD and it is not lining up with their drawing. The CAD drawings project is in USA, Maine Harn/ME States Plane, East Zone, Meters. I tried looking for it in Toolbox/Raster/Project and I found one that is close but it did not work. Next, with the advice of ESRI tech support I added the CAD drawing to ArcMap 10.1 and it had an undifined coordinate system but in AutoCAD it has a defined coordinate system. Can anyone offer any suggestions for this. I'm not a CAD person I'm a GIS person.

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CAD Projection

Re: CAD Projection