UPDATE TAIWAN DSM BY REPROCESSING ALS DATA USING HIGHEST RETURNS

摘要

Digital Surface Model (DSM) is the elevation representation that contains all vegetation and artificial objects (such as building and road). The common practice is to derive DSM by the interpolation of first returns in ALS (Airborne Laser Scanning) data. However, in some situations, some first returns have similar x-y coordinates but very different elevation values. The DSM derived for such situation would contain many discontinuous pixel values and would not be visually smooth. Generating the DSM using the highest returns of ALS can solve this problem effectively. An ALS-derived DSM, based on first return, for the whole Taiwan Island has been obtained after a seven year long ALS project. In this study, we update the DSM by using the highest return.