Assessing Global Digital Elevation Models Using the Runway Method: The Advanced Spaceborne Thermal Emission and Reflection Radiometer Versus the Shuttle Radar Topography Mission Case

The accuracy of global digital elevation models (GDEMs or DEMs), i.e., the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM), has been reassessed using the "runway" method. The runway method uses the vertical profiles of runways as reference data to which corresponding profiles extracted from investigated DEMs are compared. The major advantage of the runway method is that only the source of instrument-induced errors of DEMs is captured. This ultimate effect is achieved due to the flatness and the homogeneous materials from which runways are constructed. A cross-comparison of the two DEMs has helped to highlight a few important facts: both exhibit a negative elevation bias, and the ASTER DEM contains outliers that may be relatively easy to detect and correct, particularly in flat terrain.