Assessment of Accuracy of Digital Elevation Model Generation from ASTER Stereo Images by Using Rational Polynomial Coefficients and Toutin's Models

摘要

This study aims to generate Digital Elevation Model (DEM) by utilizing Rational Polynomial Coefficient (RPC) model (ENVI 4.8) and Toutin's Model (OrthoEngineSE of PCI Geomatics 10.3) to determine the suitable model. Thealong-track stereoimages of Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) sensor with 15 m resolution were used to generate DEM on an area with low and near Mean Sea Level (MSL) elevation in Johor Malaysia. In addition, the area under study was divided into three elevation ranges between 0-100 m (flat), 100-300 m (moderate) and 300-600 m (hilly) to evaluate the DEM accuracy in various terrains. Consequently, the uncorrected DEM of RPC model yielded RMSEz of ±32.96 m (0-100 m), ±23.38 m (100-300 m) and ±23.65 m (300-600 m) while after post-processing the RMSEz decreased to ±17.69 m (0-100 m), ±14.08 m (100-300 m) and ±17.77 m (300-600 m). Overall, the corrected DEM of RPC model reached the expectations with RMSEz of ±16.49 m. On the other hand, the DEM of Toutin's model contained many blunders and outliers which indicated the ineffectiveness of Toutin's model for area with low and near MSL elevation. The failure of Toutin's model may mostly be due to the inaccuracy and insufficiency of ASTER ephemeris data for low terrains as well as huge water body in the stereo images.