Submitted by humtechnet on


Nothing's better than free data, except maybe free data that came from a satellite.

A recent announement by NASA and Japan's Ministry of Economy, Trade and Industry should make more than a few geographic information systems (GIS) students happy, as data gathered by the Advanced Spaceborne Thermal Emission and Reflection Radiometer sensor onboard the Terra satellite is now available as a free download.

This particular Global Digital Elevation Map (GDEM) represents the most complete dataset available to the public today.  While the average Google Earth user won't find this data particulary useful, it is of significant value to geo-scientists who use elevation maps for modeling, simulation, and analysis of the real world.

Read the technical announcement below:

"Japan’s Ministry of Economy, Trade and industry (METI) and NASA announced the release of the ASTER Global Digital Elevation Model (GDEM) on June 29, 2009. The GDEM was created by stereo-correlating the 1.3 million scene ASTER VNIR archive, covering the Earth’s land surface between 83N and 83S latitudes. The GDEM is produced with 30 meter postings, and is formatted in 1 x 1 degree tiles as GeoTIFF files. Each GDEM file is accompanied by a Quality Assessment file, either giving the number of ASTER scenes used to calculate a pixel’s value, or indicating the source of external DEM data used to fill the ASTER voids."

Download instructions can be found at the ASTER website: