GDEM- Global Digital Elevation Model Based on Satellite Imagery

A second version of the ASTER GDEM (GDEM2) is released by NASA and the Ministry of Economy, Trade and Industry (METI) in mid-October, 2011. It is generated from data collected from the Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER), a space borne earth observing optical instrument. In this study, the general characteristics of GDEM2 are introduced. GDEM2 is employing an advanced algorithm to improve GDEM resolution and elevation accuracy and reprocessing a total of 1.5 million scene data including additional 250,000 scenes. A summary of the evaluations conducted by research teams on accuracies of GDEM are presented, in this study. Validation study of GDEM2 confirmed that elevation offset and horizontal resolution will be greatly improved in GDEM 2 and the enhanced horizontal resolution will serve to reduce the standard deviation of elevation and positional error.