NASA, Japan Enhance Earth Topographic Map

New map covers 99% of the planet, includes images collected by a Japanese radiometer onboard the U.S. space agency's Terra satellite.
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NASA has teamed with Japan to release the most complete digital topographic map of Earth to date, based on measurements taken aboard an agency spacecraft.

Images collected by Japan's Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra spacecraft have created a map--officially called Version 2 of the ASTER Global Digital Elevation Model--that covers 99% of the planet's landmass, from 83 degrees north latitude to 83 degrees south, according to the space agency.

The new map--which improves topographical coverage with the addition of 26,000 more stereo-pair images--is an update to one released by NASA and Japan's Ministry of Economy, Trade, and Industry (METI) in June 2009. Stereo-pair images are produced through the merging of two slightly offset two-dimensional images to create a 3-D depth affect, according to NASA.

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The partnership between NASA and METI is contributing data for the map to an international partnership called Group on Earth Observations' Global Earth Observational System of Systems (GEOSS). The system is aimed at collecting and sharing observational data to help monitor and forecast global environmental changes.

Engineers and researchers also can use the map for activities such as planning highways, land protection, or to search for natural resources, according to NASA.

Features of the new map are improved spatial resolution as well as increased accuracy for horizontal and vertical representation of the Earth. The map also provides more realistic coverage of bodies of water, including the ability to identify lakes as small as 0.6 miles in diameter, according to NASA.

Japan's ASTER is one of five instruments on Terra, the flagship satellite of its Earth Observing System that launched in 1999. The mission collects data about the Earth's atmosphere, lands, oceans, and radiant energy to track environmental and climate changes.

ASTER acquires images with spatial resolutions that range from about 50 feet to 300 feet, from visible to thermal infrared wavelengths. A team of scientists from both countries--with the U.S. team at NASA's Jet Propulsion Laboratory--validates and calibrates the instrument and the data it produces.