Assessing the accuracy of SRTM DEM and ASTER GDEM datasets for the coastal zone of shandong province, Eastern China

This study assessed the performance of recently released 3 arc second SRTM DEM version 4.1 by CSI-CGIAR and 1 arc second ASTER GDEM version 1 and version 2 by METI-NASA in comparison with ground control points from 1:50000 digital line graphs for the coastal zone of Shandong Province, Easter China. The vertical accuracy of SRTM DEM is 13.74 m root mean square error (RMSE), and GDEM version 1 reaches 24.11 m RMSE. Version 2 of ASTER GDEM shows better performance than version 1 and SRTM DEM with a RMSE of 12.12 m. A strong correlation of the magnitude of elevation error with slope and elevation is identified, with lager error magnitudes in the steeper slopes and higher elevations. Taking into account slope and elevation has the potential to considerably improve the accuracy of the SRTM DEM and GDEM version 1 products. However, this improvement for GDEM version 2 can be negligible due to their limited explanatory power for the DEM elevation errors.