An enhanced global elevation model generalized from multiple higher resolution source datasets

Global digital elevation models are routinely used in a variety of earth science applications. GTOPO30, a widely used global elevation model produced by the U.S. Geological Survey, was produced in the mid-1990s from several regional sources of elevation information. Since the time GTOPO30 was developed, new and improved sources of elevation data have become available, and the U.S. Geological Survey and the National Geospatial-Intelligence Agency are collaborating on the development of a notably enhanced global elevation model that will replace GTOPO30 as the elevation dataset of choice for global and continental scale applications. The new model is being generated at three separate resolutions (horizontal post spacings) of 30 arc-seconds (about 1 kilometer), 15 arc-seconds (about 500 meters), and 7.5 arc-seconds (about 250 meters). An additional advantage of the new multiresolution global model over GTOPO30 is that seven new raster elevation products will be available at each resolution. The new elevation products are being produced using the following aggregation methods: minimum elevation, maximum elevation, mean elevation, median elevation, standard deviation of elevation, systematic subsample, and breakline emphasis. The primary source dataset for the new global model is the Shuttle Radar Topography Mission 1-arc-second data. When complete, the new global model will undergo a thorough accuracy assessment against reference geodetic control and a relative comparison against the existing GTOPO30 at the 30-arc-second resolution. Full documentation describing the input datasets, the processing, the characteristics of the new global model product layers, and the accuracy assessment results will be available to users. The development of the new global elevation model is in progress, with completion scheduled for mid-2009.