Create Surface from GIS Data - Wrong Elevations

[JlimingDHJ3N]

Hello All,

I'm having a tough time getting Create Surface from GIS Data to display the correct elevations. My workflow is as follows

1. Create Drawing
2. Assign spatial coordinates (in this case, IN83-EF, as my data is in Nashville, Indiana)
3. Create Surface from GIS Data using a 7.5x7.5 minute shapefile (elev_contour) I downloaded from the USGS National Map (USGS Topo Map Vector Data (Vector) 3238 Belmont, Indiana), windowed to match an area of a couple .tiffs

The problem is, the surface that is created has the wrong elevations. The range should be between ~600~1000, but its coming in in the high 1000s~2000s. I tried lowering the surface but that did not seem to work much either.

I'll attach a screenshots showing the discrepancy, the created contour has an elevation of 1936 while the nearest shapefile contour has one of 590, and the shapefile.

I'm not sure what I'm doing wrong, I know the contours shouldn't match perfectly but they shouldn't be off by such a large amount.

[Pointdump · Accepted solution]

Hi @JlimingDHJ3N,
Welcome to the Autodesk Forums. And thanks for posting your data. It really helps.
You're not doing anything wrong. I get the same using Create Surface from GIS Data.
Try this instead. MAPIMPORT the contours and Create Object Data. Save and Close the drawing. Open a new drawing and use the ATTACH/QUERY method to bring in your contours at elevation. Then you'll get the results you want.
Classic Jason Porter video >>>Here<<<.
Dave

[JlimingDHJ3N]

Oh wow! Thanks for the help. I was banging my head against the wall, this was the solution I needed