MUSE Raster File | USGS Digital Elevation Model | NIMA/NGA Mean Elevation Data | NIMA/NGA Terrain Cell Files | AGI World Terrain | MOLA

Technical Notes for Terrain Data Formats

MUSE Raster

The MUSE Raster file format is produced by the MUSE tools available from the National Geospatial-Intelligence Agency (NGA), formerly known as the National Imagery and Mapping Agency (NIMA). This was the first format supported by STK and has probably been obsoleted by the addition of standard formats. Additional information regarding this file format is outlined in the following table.

STK limitations none identified
Standard Documents Vertical datum - MSL_EGM96 (Mean Seal Level, Earth Geopotential Model of 1996)
Filename Format .dte

USGS Digital Elevation Model

The USGS Digital Elevation Model is the standard set forth by the US Geological Survey (USGS) for handling digital elevation data for the US and Puerto Rico. Additional information regarding this file format is outlined in the following table.

STK limitations Restricted to files whose ground planimetric reference system is Geographic. These are the 30-minute, 1-degree and Alaska DEM's.
Relevant standard document(s) Search for "Standards for Digital Elevation Models" on the U.S. Geological Survey Web site.
Vertical Datum NGVD29 (CONUS & Alaska), Local MSL (Hawaii & Puerto Rico)
Horizontal Datum NAD27, NAD83, WGS72, WGS84 (depends on file)
Filename Format .dem

NIMA/NGA Mean Elevation Data

The National Geospatial-Intelligence Agency (NGA) Mean Elevation Data Terrain Directory format supports DTED, Level 1 and DTED, Level 2 CDROMs by reading the directory file, "dmed" contained therein. The directory file specifies the minimum bounding rectangle covered by the data, though the data may actually be a subset of that area. Additional information regarding this file format is outlined in the following table.

STK limitations none identified
Relevant standard document(s) MIL-PRF-89020A
Vertical Datum MSL
Horizontal Datum WGS84
Filename Format .dmed

NIMA/NGA Terrain Cell

The National Geospatial-Intelligence Agency (NGA) Terrain Cell files are the individual cells available on DTED CDROMs.

Note: Starting with the STK 7 release, STK supports the use of individual terrain cell files. Previous releases of STK required that you set an environment variable in order to use these files.

Additional information regarding this file format is outlined in the following table.

STK limitations none identified
Relevant standard document(s) MIL-PRF-89020A
Vertical Datum MSL
Horizontal Datum WGS84
Filename Format .dt[0-5]

AGI World Terrain

AGI World Terrain uses the GTOPO30 dataset from the US Geological Survey (USGS), repackaged for improved access performance. Additional information regarding this file format is outlined in the following table.

STK limitations none
Relevant standard document(s) Search for GTOPO30 on www.usgs.gov.
Vertical Datum MSL_EGM96
Horizontal Datum WGS84
Filename Format .hdr

MOLA

The Mars Orbiter Laser Altimeter (MOLA) terrain, distributed in PDS format, is produced from binned data from the MOLA on the Mars Global Surveyor Spacecraft by the Planetary Data Systems Geosciences Node at Washington University, St. Louis, Missouri. STK can read the PDS gridded radius map data in image format. The Martian surface can be described via topography data specified relative to the Martian areoid, also available in image format, or by radius data. At this time, only the radius information should be used in STK since the areoid vertical datum is not supported. MOLA datasets can be downloaded from: MOLA Topographic Map page. Additional information regarding this file format is outlined in the following table.

STK limitations Only files containing radius data should be used since the aeroid vertical datum is not currently supported.
Relevant standard document(s) See the MOLA Topographic Map page.
Vertical Datum Sphere of radius 3396.0 km
Horizontal Datum Sphere of radius 3396.0 km
Filename Format *.lbl (label file), *.img (topography file)

For more information on the PDS format, see Support of PDS Topographic Information in AGI Products.

Warning: The use of topography data for bodies other than the Earth may require modifications to the reference shape of the body for accurate determination of the body surface. For more information, see Using Topography Data for Central Bodies Other than the Earth.

Note: If you use terrain data for the Moon from the Clementine mission (http://pds-geosciences.wustl.edu/missions/clementine/gravtopo.html), which models the Moon as an oblate spheroid, you must uncomment the following parameters in the Moon.cb file:
 
Shape      OblateSpheroid
MajorAxis  1738000.0
MiddleAxis 1738000.0
MinorAxis  1737400.0

 
You must also comment out using # the following parameters that model the Moon as a sphere from the Moon.cb file:
 
Shape        Sphere
MajorAxis    1737400.0
MiddleAxis   1737400.0
MinorAxis    1737400.0
RefDistance 1737400.0
MinRadius    1737400.0
 
The Moon.cb file is located in the <STK install folder>/STKData/CentralBodies/Moon folder.