Other Elevation Data Formats

• ASTER DEM
  • ASTER ("Advanced Spaceborne Thermal Emission and Reflection Radiometer") is an imaging instrument that is flying on the TERRA satellite launched in December 1999 as part of NASA's Earth Observing System (EOS).
  • the quality is excellent, equivalent in resolution to USGS 30m DEM data
  • free download from the EOS Data Gateway (awkward interface)
  • the distribution file formats are HDF-EOS and 16-bit GeoTIFF (the latter can be read into VTBuilder)
  • see ASTER DEM article at Terrainmap.com, including a walkthrough of the ASTER DEM Download Procedure
  • ASTER DEM Coverage Map shows the spotty world coverage
• DTM
  • an older format, similar to DEM, but less often encountered
  • DTM files for Martian landscapes are available on NASA CDROM, and also available somewhere on line
• PGM
  • "portable greymap" format, capable of 16-bit resolution, making it useful for raw height grids
  • there are some free tools like hftools for creating PGM from other formats
• NTF
  • the UK Ordnance Survey historically used this 'National Transfer Format' to distribute a variety of data, including elevation raster
  • NTF features are always returned with the British National Grid coordinate system
• Surfer GRD
  • Surfer is a popular commercial program, which has a simple grid format
• Arc ASCII Grid
  • a simple ESRI text format for a grid of values, just a simple header followed by the values as plain text numbers
• Arc Binary Grid
  • above link is to a reverse-engineering of this proprietary ESRI format
• TerraGen TER
  • simple binary format, integer based, no support for geographical location
• BT (Binary Terrain)
  • the native elevation format of the VTP software