DEM ACCURACY GENARATED BY LiDAR TECHNOLOGY FOR CUU LONG RIVER DELTA IN VIETNAM

摘要

In last years, Light Detecting and Ranging (LiDAR) technology widely has gone through to topography investigation and in competition with airborne photogrammetric method. One of the efficient applications of LiDAR in topography is establishing DEM with high accuracy. DEM accuracy is dependent on some factors such as (1) accuracy of LiDAR data inputs, (2) scanning point density - the number of scanning points per unit surface, (3) models used to generate DEM, (4) filtering and terrain characteristics. In order to supervise the processing DEM generation, the estimation of those factors affecting on DEM quality is all-important problem, at first the accuracy of ground point coordinates determined by LiDAR data. The quality of derived LiDAR data affects strongly on DEM accuracy, especially for terrain with large coverage by objects and vegetations. In the processing of LiDAR data an adjustment strategy on the given geoid has been used for correcting exterior elements as recorded by dGPS (differential Global Positioning System) and IMU (Inertial Measure Unit) as well as interior orientation elements concerning the integrated Scanner-dGPS-IMU system. The paper outlines first algorithm to estimate the accuracy of ground point coordinates determined by LiDAR data. In experimental section the application of LiDAR technology for DEM generation of 1800 km~2 area in Cuu Long river delta with height accuracy of ±0.2m has been presented.