Accuracy Assessment of DCW DEM

Abstract

The Earth Resources Observation Systems (EROS) Data Center of the U.S. Geological Survey has been providing a 30arc second Digital Elevation Model (DEM) data set of the whole world (DCW DEM) through the Internet since 1995. Although the accuracy is one of the most important meta-information of the DEM data set, no such information has been provided by the data producer except for nominal accuracies of the original topographic maps. This paper summarizes a result of accuracy assessment of the part of the data covering Japan using existing higher accuracy DEM data sets developed by the Geographical Survey Institute (GSI). The assessment includes the investigation of the datum difference and the comparison between DCW DEM and GSI's DEM data. The calculated accuracy of DCW DEM is 89m RMSE. The datum investigation revealed that the datum of DCW DEM of Japan was Tokyo Datum instead of nominal WGS-84.