The world is constantly changing. Not only the names of cities and states but the very height of mountains and continental drift dislocations. NASA and Japan released a significantly improved version of the most complete digital topographic map of Earth on Monday, produced with detailed measurements from NASA's Terra spacecraft. The map, known as a global digital elevation model, was created from images collected by the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER, instrument aboard Terra. So-called stereo-pair images are produced by merging two slightly offset two-dimensional images to create the three-dimensional effect of depth. The first version of the map was released by NASA and Japan's Ministry of Economy, Trade and Industry (METI) in June 2009.
The world is constantly changing. Not only the names of cities and states but the very height of mountains and continental drift dislocations. NASA and Japan released a significantly improved version of the most complete digital topographic map of Earth on Monday, produced with detailed measurements from NASA's Terra spacecraft. The map, known as a global digital elevation model, was created from images collected by the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER, instrument aboard Terra. So-called stereo-pair images are produced by merging two slightly offset two-dimensional images to create the three-dimensional effect of depth. The first version of the map was released by NASA and Japan's Ministry of Economy, Trade and Industry (METI) in June 2009.
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ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is a Japanese sensor which is one of five remote sensory devices on board the Terra satellite launched into Earth orbit by NASA in 1999.
ASTER provides high-resolution images of the planet Earth in 15 different bands of the electromagnetic spectrum, ranging from visible to thermal infrared light. The resolution of images ranges between 15 to 90 meters. ASTER data are used to create detailed maps of surface temperature of land, emissivity, reflectance, and elevation.
The improved version of the map adds 260,000 additional stereo-pair images to improve coverage. It features improved spatial resolution, increased horizontal and vertical accuracy, more realistic coverage over water bodies and the ability to identify lakes as small as 0.6 miles (1 kilometer) in diameter. The map is available online to users everywhere at no cost.
"This updated version of the ASTER global digital elevation model provides civilian users with the highest-resolution global topography data available," said Mike Abrams, ASTER science team leader at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "These data can be used for a broad range of applications, from planning highways and protecting lands with cultural or environmental significance, to searching for natural resources."
The ASTER data cover 99 percent of Earth's landmass and span from 83 degrees north latitude to 83 degrees south. Each elevation measurement point in the data is 98 feet (30 meters) apart.
ASTER is one of five instruments launched on Terra in 1999. ASTER acquires images from visible to thermal infrared wavelengths, with spatial resolutions ranging from about 50 to 300 feet (15 to 90 meters).
Users of the new version of the ASTER data products are advised that while improved, the data still contain anomalies and artifacts that will affect its usefulness for certain applications.
Data users can download the ASTER global digital elevation model at: https://lpdaac.usgs.gov/ or http://www.ersdac.or.jp/GDEM/E/4.html
Photo: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA14895
For further information and photo: http://www.jpl.nasa.gov/news/news.cfm?release=2011-320&rn=news.xml&rst=3170
