NASA and Japan's Ministry of Economy, Trade
and Industry (METI) released a new digital topographic map of Earth
this summer that accurately portrays more of our planet than ever
before. Available free online, the Global Digital Elevation Model (GDEM)
comprises 1.3 million seamlessly integrated images acquired by
NASA's Terra satellite. A Japanese imaging instrument onboard Terra
called the Advanced Spaceborne Thermal Emission and Reflection
Radiometer (ASTER) captured the images.
Previously, the most complete topographic data set publicly
available was acquired by NASA's Shuttle Radar Topography Mission,
comprising 80 percent of Earth’s landmass between 60 degrees north
latitude and 57 degrees south. The new ASTER data expand coverage to
99 percent, between 83 degrees north latitude and 83 degrees south.
Elevation measurement points within the new data are 30 meters
apart.
NASA, METI and the U.S. Geological Survey (USGS) validated the data,
with support from the U.S. National Geospatial-Intelligence Agency
and other collaborators. The data will be distributed by NASA's Land
Processes Distributed Active Archive Center at the USGS Earth
Resources Observation and Science Data Center in Sioux Falls, S.D.,
and METI’s Earth Remote Sensing Data Analysis Center in Tokyo.
In this colorized version of the GDEM (above), low elevations appear
as purple; medium elevations as greens and yellows; and high
elevations as orange, red and white.
