Topic: Create USFoot elevation surface from Metric DEM file

[Jeff_M]

Actually, now that I look at the downloaded files more closely, it appears the data is there but C3D is not reading it (or not reading it correctly).

[Cathy]

And now that I have downloaded the files, I see that they are not USGS .dem files.  It appears to me that they are ArcGIS ASCII grid files.  You might try GDAL translate.  http://www.gdal.org/index.html 
I am still stuck in C3D 2008 -- not sure what version you are using, later versions may know how to read an ArcGIS ASCII grid file properly. 

[sdunn]

Actually, now that I look at the downloaded files more closely, it appears the data is there but C3D is not reading it (or not reading it correctly).

Jeff,
If you create a regular surface file, you can add DEM data.  The missing zone information for the DEM can then be entered correctly.  It will still not adjust the vertical though.

[mjfarrell]

I suggest new file from Metric template
new surface
insert the DEM data
Export to XML

New File from Imperial template
inport the XML file created above

[Novarese]

I suggest new file from Metric template
new surface
insert the DEM data
Export to XML
New File from Imperial template
inport the XML file created above

Brilliant, it works in my glorious Map2006.

I have no enough Ram to load http://data.tnris.org/data/Elevation/DEM_3296.zip so I tried with a small USGS dem (the Barringer crater in Arizona, UTM83 zone 12) surveyed in meters: check this out.

After your great tip, it appears like this in feet.

[sdunn]

I suggest new file from Metric template
new surface
insert the DEM data
Export to XML

New File from Imperial template
inport the XML file created above

This is what I am currently doing as a work-a-round. 

I was playing with the GDAL utilities as suggested by Cathy and using them you can convert the grid file to a SHP contour file.  This can then be used to create a surface as well.

[mjfarrell]

as far as I know the above is the only method that works correctly since C3D first appeared. (and in LDD)

[Cathy]

This is what I am currently doing as a work-a-round. 

I was playing with the GDAL utilities as suggested by Cathy and using them you can convert the grid file to a SHP contour file.  This can then be used to create a surface as well.

I would have used the GDAL utilities to create a USGS .dem file; I think it would be more accurate and C3D seems to know how to handle those properly

[drizzt]

drizzt, what tool did you use to scale the DEM elevations?  I am more interested in the method than getting the file converted.  This is not the only DEM file I am working with.  There are several work-a-rounds that I can do, but they are all convoluted and time consuming.  There are also a lot of crashes involved as most of the DEM files are pretty large.

I open with this http://www.bluemarblegeo.com/global-mapper/ then change the projection in global mapper and export dem, then inport into Civil

[Novarese]

then change the projection in global mapper and export dem

Are you really sure the resulting Dem is in feet..?

If I open the huge http://data.tnris.org/data/Elevation/DEM_3296.zip in Microdem, I get such an info:



You'd better check out your Dem from GM, sir...