NASA has announced the release of the most complete topographic data of the earth to date.
Over 99 percent of the earth’s surface was mapped using measurements obtained from NASA’s Terra spacecraft using the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer instrument, aka Aster. The global digital elevation model for Earth was developed using approximately 1.3 million distinct stereo-pair images.
Previously, the most comprehensive mapping of the earth’s topopgraphy was accomplished through the Shuttle Radar Topography Mission which produced data covering 80 percent of the earth’s surface.
On June 29, 2009, NASA and Japan’s METI released the ASTER GDEM, generated by processing 1.3 million optical images, covering Earth’s land surface between 83°N and 83°S latitudes. The GDEM offers 30-meter postings and is formatted as 23,000 one-degree tiles, available for download from NASA’s EOS data archive and Japan’s Ground Data System. In the colorized version, low elevations are purple, medium elevations are green and yellow, and high elevations are orange, red, and white.
The new Aster data covers the earth from 83 degrees north latitude and 83 degrees south and produces new data for mostly desert and steep terrain areas not covered previously.
For visualizations of the new Aster topographic data, visit: http://www.nasa.gov/topics/earth/features/20090629.html .
The Los Angeles Basin, bordered by the San Gabriel Mountains to the north, contains smaller basins separated by minor mountain ranges like the Verdugo Hills and Santa Monica Mountains. This northwest-facing perspective view uses ASTER simulated natural color image data, draped over digital topography from the ASTER GDEM dataset. Dodger Stadium is visible in the lower right, while NASA’s Jet Propulsion Laboratory appears as a light-colored area near the mountains in the upper right. The ASTER data, acquired on August 15, 2006, is located near 34.1°N latitude and 118.2°W longitude.
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.
