Application of the Shuttle Laser Altimeter in an Accuracy Assessment of Gtopo30, a Global 1-kilometer Digital Elevation Model

Continental-scale topographic profiles between 28.45° N and S latitudes acquired by the first flight of the Shuttle Laser Altimeter (SLA) experiment are used to evaluate the vertical accuracy of GTOPO30, a global digital elevation model with a grid spacing of approximately 1 km. GTOPO30 is a compilation of eight sources of elevation information, including raster and vector data sets. The mean and standard deviation of SLA to GTOPO30 elevation differences are computed for Africa, southern Asia, central South America, and Australia. Variations in mean differences between continental regions and GTOPO30 sources indicate that there are vertical datum discrepancies incorporated in GTOPO30 on the order of 10 m. Variation in the standard deviation of the differences confirms that raster sources in GTOPO30 are more accurate than vector sources.