Research On Integration Of Land And Water Terrain Data With Lidar And Multi Beam Point Cloud

In recent years,with the renewal of the national series of topographic maps and the implementation of major projects such as the survey of geographical conditions,the role of the existing geospatial data is fully played,and the integrated processing is achieved to the maximum extent,and the full coverage and integrated management of land terrain data are completed.However,there are relatively few studies at home and abroad on the mapping of underwater geographic information in inland waters,especially the lack of exploration and research on integrated water and land treatment.Through the research,we can integrate the land and water integration topography and carry out the research on the related waters topography.In order to provide technical support for inland water project planning,water environment management,terrain modification and other projects.In view of the problem of repairing and measuring the land and water terrain,this paper relies on the project of “underwater topography surveying and mapping”,chooses the Three Gorges of the Yangtze River as an experimental area.On the basis of existing data integration,processing and extraction,a method based on constrained edge Delaunay triangulation is proposed,and the integration of land and water terrain is studied.The main contents and conclusions are as follows:(1)Filtering of cloth simulation point cloud dataBased on the study of the obtained point cloud data filtering,the cloth simulation filtering method is applied to the ship carrier point cloud data.The method is used to synthetically analyze the angle,density and terrain information of the carrier point cloud data,and build virtual grid to simulate the ground surface according to the simple physical process,by setting the resolution control of the cloth.The distance between two adjacent nodes is calculated to improve the computation efficiency.By comparing with the moving window filtering method,the experimental results show that the filtering effect of the method is more ideal,the loss of ground information is less,the authenticity of the ground information is guaranteed and the filtering requirements of the ship's carrier point cloud data are satisfied.(2)Land and water terrain integration based on constrained edge Delaunay triangulationUsing DEM data generated from point cloud data as basic data,we study the integration of land and underwater terrain data.In order to solve the problem that the grid method and the non-constrained triangular mesh method have a large gap at the edge of the coastline,a method based on the constrained edge Delaunay triangulation is proposed,and the seamless stitching of land and water terrain can be realized in the integration.We use iterative exchange method to realize the embedment of coastline so as to build constrained Delaunay triangulation network.The results show that the triangular mesh constructed under the condition of shoreline constraints can better express the terrain on the edge of water and land,and the smooth effect is better.And the triangle has great flexibility in shape and size.It is easy to fuse the data of the coastline and reach the topographic features with the topographic fluctuation.It has a certain application price value.