Large Scale Mapping Based On TLS Point Cloud Data And Its Quality Evaluation

The traditional large-scale topographic maps have a large amount of field work,a small number of sampling points,a slow update speed,and a long cycle.It requires a lot of manpower and material resources,and cannot adapt well to the rapid development of social economy.How to use new measurement methods to improve production efficiency while reducing labor intensity is a concern,which requires exploring new methods,new technologies and new processes to improve work efficiency.The terrestrial laser scanning technology is used for large-scale topographic map measurement,breaking through the traditional single-point measurement,realizing the “area” scan data acquisition,simple operation,and high-efficiency,fast and high-resolution field data acquisition capability.It has reduced the intensity of field work to a certain extent,effectively improved the efficiency of field data collection,and is another innovation and progress of digital mapping.Therefore,this paper analyzes and studies the large-scale mapping of terrestrial laser scanning point cloud data and its quality evaluation.This article has carried out the following work:(1)Explain the composition,working principle,technical characteristics of the terrestrial laser scanning system and the Lecia Scanstation 2 scanning system,as well as the point cloud data preprocessing method.(2)The ground point cloud data filtering method and terrain modeling method are reviewed.The moving surface fitting point cloud filtering algorithm,existing problems and improved algorithms are studied.The improved moving surface fitting point cloud filtering is verified by an example.The effectiveness of the algorithm is analyzed.The advantages and disadvantages of two methods based on regular grid terrain modeling and irregular grid terrain modeling are analyzed.(3)The ground point cloud data filtering method and terrain modeling method are reviewed.The moving surface fitting point cloud filtering algorithm and existing problems are studied.An improved algorithm is proposed.The improved moving surface fitting point cloud filtering algorithm is verified by an example.The effectiveness of the two methods based on regular grid terrain modeling and irregular grid terrain modeling is analyzed.(4)Selecting the terrain scanning point cloud data of a certain area in Xi’an,and analyzing the method and process of large-scale mapping,including data acquisition,point cloud data processing and topographic map drawing,and the quality of its mapping.An evaluation analysis was conducted.