NASA, Japan release the most detailed digital model yet of Earth
Topographical map, with images taken from Terra spacecraft, covers 99 perent of land mass
- By Kevin McCaney
- Jun 30, 2009
NASA and a Japanese agency have upped the ante of digital images of the Earth, releasing a topographical map that covers 99 percent of the planet's land mass, created from nearly 1.3 million images taken from NASA’s Terra spacecraft.
The global digital elevation model can be downloaded here and here, although the number of tiles that can be downloaded at one time could be restricted because of heavy server traffic. The map is divided into 22,600 tiles, each 1 degree by 1 degree, NASA spokesman Steve Cole said.
Bite-size samples are available here, where users can get detailed images of locations such as the Los Angeles Basin, Death Valley and Himalayan glaciers in Bhutan.
The images were collected by the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster) aboard Terra. Japan’s Ministry of Economy, Trade and Industry (METI) developed the data set, and released the map with NASA, the space agency said.. Aster, one of five Earth-observing instruments launched on Terra in December 1999, collects visible and thermal infrared images, with spatial resolutions ranging from about 50 to 300 feet. Each elevation measurement point on the new map, which NASA calls the Global Digital Elevation Model, is 98 feet apart, the space agency said.
"This is the most complete, consistent global digital elevation data yet made available to the world," said Woody Turner, Aster program scientist at NASA headquarters. The U.S. science team on the project is based at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
The map covers nearly all of the Earth’s land mass, from 83 degrees north latitude and 83 degrees south, NASA said, leaving only the poles uncovered. Before Aster, NASA's Shuttle Radar Topography Mission had developed the most complete topographic map publicly available, covering 80 percent of Earth's land mass, between 60 degrees north latitude and 57 degrees south.
Aside from covering more territory, the map also provides more detail. "The Aster data fill in many of the voids in the shuttle mission's data, such as in very steep terrains and in some deserts," said Michael Kobrick, Shuttle Radar Topography Mission project scientist at JPL. "NASA is working to combine the Aster data with that of the Shuttle Radar Topography Mission and other sources to produce an even better global topographic map."
Mike Abrams, Aster science team leader at JPL, said the topographic data would be of value in a variety of applications, including energy exploration, environmental management, public works and firefighting.
Data from the project is being contributed to the international Group on Earth Observations, based at World Meteorological Organization in Geneva. It will be distributed by NASA's Land Processes Distributed Active Archive Center and METI's Earth Remote Sensing Data Analysis Center. The data was validated by NASA, METI and the U.S. Geological Survey, with support from the U.S. National Geospatial-Intelligence Agency and other organizations, NASA said.
Kevin McCaney is a former editor of Defense Systems and GCN.