Global Assessment of the New ASTER Global Digital Elevation Model

In 2009, the US National Aeronautics and Space Administration and Japan's Ministry of Economy, Trade and Industry released a new global digital elevation model (GDEM) derived from reprocessed Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data from the Terra satellite. An initial, empirical assessment of the accuracy and characteristics of the CDEM was carried out using a globally-distributed sample dataset. Statistical and visual analyses of the GDEM, using known reference DEMS and ground control points (GCPs) for comparison, revealed a systematic bias in the ASTER GDEM elevations, higher average noise levels, and a lower effective ground resolution compared to the reference data, as well as numerous topographic artifacts and anomalies. The GDEM appears to meet its accuracy specifications when compared to the reference DEMs, but compared to the GCPs, some of the areas are questionable. In areas that lack good quality terrain data, the GDEM may prove useful, but must be used with care.