Abstract
Abstract. In 2016, the US/Japan ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) project released Version 3 of the Global DEM (GDEM). This 30 m DEM covers the earth’s surface from 82N to 82S, and improves on two earlier versions by correcting some artefacts and filling in areas of missing DEMs by the acquisition of additional data. The GDEM was produced by stereocorrelation of 2 million ASTER scenes and operation on a pixel-by-pixel basis: cloud screening; stacking data from overlapping scenes; removing outlier values, and averaging elevation values. As previously, the GDEM is packaged in ~ 23,000 1 x 1 degree tiles. Each tile has a DEM file, and a NUM file reporting the number of scenes used for each pixel, and identifying the source for fill-in data (where persistent clouds prevented computation of an elevation value). An additional data set was concurrently produced and released: the ASTER Water Body Dataset (AWBD). This is a 30 m raster product, which encodes every pixel as either lake, river, or ocean; thus providing a global inland and shore-line water body mask. Water was identified through spectral analysis algorithms and manual editing. This product was evaluated against the Shuttle Water Body Dataset (SWBD), and the Landsat-based Global Inland Water (GIW) product. The SWBD only covers the earth between about 60 degrees north and south, so it is not a global product. The GIW only delineates inland water bodies, and does not deal with ocean coastlines. All products are at 30 m postings.
Highlights
1.1 ASTER instrumentThe Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a 15-channel imaging instrument operating on National Aeronautics and Space Administration (NASA)’s Earth Observing Terra morning orbital platform since 1999
On June 29, 2009 the Ministry of Economy, Trade, and Industry (METI) of Japan and the U.S National Aeronautics and Space Administration (NASA), jointly released Version 1 of the global digital elevation model (GDEM) of the Earth’s land surface, derived from 1.7 million images acquired by ASTER (Abrams et al, 2010)
The ASTER Global Digital Elevation Model (GDEM) is the most up-to-date, high spatial resolution, complete digital topographic data set of the Earth available at no cost to the public, covering the global land surface from 83 degrees north to 83 degrees south latitude
Summary
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a 15-channel imaging instrument operating on NASA’s Earth Observing Terra morning orbital platform since 1999. On June 29, 2009 the Ministry of Economy, Trade, and Industry (METI) of Japan and the U.S National Aeronautics and Space Administration (NASA), jointly released Version 1 of the global digital elevation model (GDEM) of the Earth’s land surface, derived from 1.7 million images acquired by ASTER (Abrams et al, 2010). The ASTER GDEM is the most up-to-date, high spatial resolution, complete digital topographic data set of the Earth available at no cost to the public, covering the global land surface from 83 degrees north to 83 degrees south latitude. Prior to the release of the ASTER GDEM, the most complete DEM available to the public was the Shuttle Radar Topography Mission (SRTM) data set (Farr and Kobrick, 2000; Farr et al, 2007). The resulting data were partitioned into 22,600 1 x 1 degree tiles
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