Comparison of new and existing global digital elevation models: ASTER G‐DEM and SRTM‐3

A new global elevation dataset known as G‐DEM, based on the ASTER satellite imagery, will be released in late 2008. G‐DEM will be the best freely available global digital elevation model (DEM) at a horizontal resolution of 1 arc second. We assess the quality of G‐DEM in comparison with 3‐arc‐second SRTM DEM, the best current global elevation dataset. Basic geomorphometric parameters (elevation, slope and curvature) were examined for a pre‐release version of G‐DEM and SRTM DEM for western Japan. G‐DEM has fewer missing cells than SRTM DEM, particularly in steep terrain. Also, G‐DEM gives smoother and more realistic representations of lowlands, valleys, steep slopes, and mountain ridges, whereas, SRTM DEM includes many local spikes and holes, and tends to overestimate valley‐floor elevation and underestimate ridge elevation. G‐DEM will be commonly used in geoscientific studies, because of its higher resolution, fewer missing data, and better topographic representation than SRTM DEM.