NASA and Japan released an improved version of a digital topographic map Oct. 17 that was produced with measurements from NASA’s Terra Earth-observing satellite.
The map, known as the global digital elevation model, was created from imagery collected by Japan’s Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard Terra, the nearly 5-ton spacecraft NASA launched in 1999 as the flagship of its Earth Observing System.
Stereo-pair images are created by merging two sets of slightly offset images to produce a three-dimensional effect. The first version of the map was released in June 2009 by NASA and Japan’s Ministry of Economy, Trade and Industry.
“The ASTER global digital elevation model was already the most complete, consistent global topographic map in the world,” Woody Turner, ASTER program scientist at NASA headquarters in Washington, said in a statement. “With these enhancements, its resolution is in many respects comparable to the U.S. data from NASA’s Shuttle Radar Topography Mission, while covering more of the globe.”
NASA said 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 1 kilometer in diameter.
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 30 meters apart.