Design And Realization Of Terrain Extraction And Analysis System Based On Airborne LiDAR

Terrian features are very important in drainage basin analysis, hydrological analysis and the progress of mineral exploration and evaluation. The spatial distribution characteristic of terrain attributes is an important indicator which used to describe space process changes. At present, many GIS softwares provide the function of terrain extraction and analysis such as the hydrological analysis expansion module of agcgis, the hydrological surface basin analyzing module of mapgis, rivertools, etc. LiDAR (short for Light Detection and Ranging) integrate laser scanner, GPS (short for Global Position System)and INS (short for Inertial Navigation System) together, can quickly and accurately obtain precision and high-density DEM (short for Digital Elevation Model) with few ground control points. The emergent of this technology provides a new kind of data source for large scale and high precision terrain analysis, and also put forward a new challenge to traditional terrain analysis algorithmsOn the basis of above discussions, this paper has a deep research in LiDAR data processing flow chart, design and implement a terrain extraction and analysis prototype system based on airborne LiDAR. The main work of this paper are as follows:(1) The algorithm of extracting basic terrain factors based on high resolution DEM are researched and realized. In hydrology information extraction, according to the problem that LiDAR-derived DEM has high-resolution and with large amount of complex depressions, a "multiple features search" algorithm is proposed, which used to improve traditional 3d surface water flow simulation method by uniting vector and grid operator to detect and classify depressions. Hence, the efficiency of searching composite depressions and the extraction accuracy for judging flow direction of plain can be improved effectively.(2) Terrain extraction and analysis prototype system based on airborne LiDAR is realized by the plugin pattern on the basis of domestic LiDAR data processing software "ALDPro". The system mainly include two main functions:using LiDAR point clouds to generate DEM and extracting terrian features based on LiDAR-derived DEM.