Creating a tin surface from USGS map

[csparber]

Hello All--

I am new to GIS and AutoCAD civil 3d.  I have a project that I need to map the terrain as a tin solid so that I can do some cut and fill analysis.  I have downloaded a orthographic and elevation data from the USGS website.  I cannot get AutoCAD civil 3d to create the contours properly.  Does anyone have any ideas? 

My current workflow is: use mapwspace to bring up the task pane.  Connect to the geotiff image in the 1-153383539 folder.  Then I try to create the contours and the option is greyed out.  

Thanks.

Sincerely,

Chris Sparber

[AllenJessup]

A quick look through your files and I didn't see any surface data. An OrthoTiff might contain surface data but I don't believe yours does. If you want to convert directly from GIS Data you need a file From ArcSDE, Oracle or a Shape file. See the AeccCreateSurfaceFromGISData command.

Your best bet is to see if you can download a DEM file. That would be a DEM, ESRI Arc Grid or a GeoTIFF with surface data. See: Creating a Grid Surface from a DEM

If you want to create a Civil 3D surface you need to use Civil 3D commands. Not Map 3D commands.

Allen Jessup