The Global Digital Elevation Map, the most complete map of the Earth's surface, was published on June 29 and is free to download and use. The map was created using nearly 1.3 million images collected by a Japanese camera (Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER) on board NASA’s Terra satellite and covers 99 percent of the Earth's surface.

“Aster's accurate topographic data will be used for engineering, energy exploration, conserving natural resources, environmental management, public works design, firefighting, recreation, geology and city planning, to name just a few areas,” according to the Pasadena Jet Propulsion Laboratory's Aster science team leader Mike Abrams. Previously, the most complete topographical map of the planet was created by the Shuttle Radar Topography Mission, which only captured images of 80 percent of the planet's surface, between 60 degrees North latitude and 57 degrees South. The new image spans between 83 degrees North latitude and 83 degrees South, according to JPL.

“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. The GDEM is available for download from NASA’s EOS data archive (https://wist.echo.nasa.gov/~wist/api/imswelcome/) and Japan’s Ground Data System (http://www.gdem.aster.ersdac.or.jp/ ). This ASTER product is available at no charge for any user pursuant to an agreement between METI and NASA” (http://asterweb.jpl.nasa.gov/gdem.asp).