Accuracy Evaluation and Gross Error Detection in Digital Elevation Models Based on LIDAR Data

With the LIDAR data more wide use in DEM products, especially in urban area DEM modeling, the research on Grid DEM with LIDAR data is more and more urgent. Also users are more desired to acquaint themselves with LIDAR data, especially to know more about the accuracy of Grid DEM based on LIDAR data. Therefore, it is rather necessary to explore the matter of accuracy of DEM based on LIDAR data. In this paper, firstly, the method of local detection with moving windows are introduced to detect and eliminate discrete errors, which will purify LIDAR data for later DEM modeling; secondly, with the rest regular ground points, via fitting second degree curved surface under the least square criteria and interpolating grid points, the finer Grid DEM based on LIDAR data would be generated; finally, RMSE will be hired to analyze the precision of previous Grid DEM. As a case study, 4000 LIDAR points preprocessed have been selected to test the method and has proved that the method is feasible. Through the experiment, the accuracy of DEM based on LIDAR data proves to be approximately 0.6m. The precision will be convenient for users to make best use of LIDAR data and be conducive to the actual applications of LIDAR data.