Research On DEM And Contour Lines Based On Airborne LiDAR Point Cloud Data

LiDAR is an effective technology for acquisition of altitude information,which is an active measurement instrument for processing high accuracy and high density three dimensional data.The terminology of airborne LiDAR refers to an airborne laser system consisting ofa laser scanner,a geodetic quality GPS receiver and an inertial measurement unit(IMU),which less depends on ground controls,little affected by weather conditions with high automation and short temporal data processing.The LiDAR system has made the data collecting effectively,which can effectively get accurate and higher-resolution digital surface model.LiDAR technology converts the data acquisition method from the traditional mode based on forward intersection into a consistent and automatic mode.LiDAR can also make the data processing more intelligent and automatic than before.This paper studies and analyzes some technical problems in the process of making DEM and contour from airborne LiDAR point cloud data from the perspective of engineering application.The main research contents are as follows:1.According to the characteristics of point cloud data and the specification requirements of DEM and contour line,the technical scheme of making DEM and contour line with appropriate airborne LiDAR point cloud data is designed.2.The pretreatment and classification technologies of airborne LiDAR point cloud data used in specific projects were analyzed,and the pre-production inspection of airborne LiDAR point cloud data,projection transformation and elevation correction of point cloud data,redundancy removal,automatic classification and manual accurate classification of point cloud data were discussed.3.Research on DEM production based on airborne LiDAR point cloud classification result data.The landform integrity is guaranteed by adding topographic fracture lines or adding points in areas without laser points.4.Research on the process of using DEM to generate contours and efficient and accurate research on contour editing.Under the lidar-DP software,according to the terrain categories of flat land,hilly land,mountain and high mountain,by adjusting the parameters of contour line generation and introducing different contour line editing methods,the efficiency and quality of contour line editing in the later period are guaranteed.