SDTS Digital Elevation Model .DEM File Description

Surfer imports elevation data in the form of a uniform lattice from SDTS Digital Elevation Model .DEM data sets.

There are two separate types of SDTS DEM files. The Topological Vector Profile SDTS files contain boundary line information and can be used as a base map (Home | New Map | Base).

The Raster Profile SDTS files contain gridded elevation information and can be used to directly create a grid-based map such as a contour map.


It is not necessary to unzip the .TAR.GZ, .TAR, .ZIP, or .TGZ file. Surfer can read the information in the various files directly from the compressed file.

If you do unzip the .TAR.GZ, .TAR, .ZIP, or .TGZ file containing the DDF files, there is an option in WinZip (or other unzipping software) that needs to be disabled. Use the ClosedWinZip settings to disable this option. All .DDF files must be extracted into the same directory.

  1. In WinZip, use the Options | Configurationcommand to open the Configuration dialog.
  2. Click on theMiscellaneous tab.
  3. In the Other category, un-check TAR file smart CR/LF conversion.
  4. Click the OK button.
  5. The Tar.GZ file willnow properly unzip the files.

Format(s) Supported for Import

2D uniform lattice; 8-, 16-, 32-bit integer, float, double

Import Options Dialog

No import options dialog is displayed.

Import Automation Options

No import options are available.


SDTS data sets can contain elevation data or several other types of data that are not applicable to Surfer. If you attempt to import an SDTS data set that does not contain elevation data, an error message displays. If the error message displays after trying to create a grid based map, try clicking the Home | New Map | Base command instead.

See Also

USGS Digital Elevation Model File Description

File Format Chart