Design And Realization Of Overlap Analysis For 3D WebGIS Based On The Cesium Framework

3D visualized scene can bring immersive experience and the convenience of information analysis and management,which accelerates the integration of internet and geographical information system(GIS)technologies,and then the 3D Web GIS technologies emerge as the times require.Furthermore,newly developed open source3 D earth engine,named Cesium,provides good foundation for constructing 3D Web GIS framework.This paper designed and realized a 3D Web GIS based spatial overlapping analysis system for real applications involving some key technologies,such as data acquisition,key algorithms,creating database,and Cesium framework.The main content includes:(1)Acquisition of foundamental geographical spatial information data.Newly developed oblique photogrammetry technology was adopted to obtain the real scene 3D model data.The naked eye surveying technology was used to collect the geometrical vector data of object element of different types,i.e.point,line,and area entities,and then the corresponding attributes data is related to the geometrical vector.Test results indicate foundamental geographical spatial information data obtained by this method has higher precision and currency,which can provides good data source for 3D Web GIS system.(2)Analysis and application of polygon clipping algorithm based on Clipper Lib.This paper adopts the polygon clipping algorithm with good performance.For 3D Web GIS applications,this paper improved programmed this algorithm.Test results indicate that this algorithm can be used for GIS overlapping analysis.(3)Design and realization of overlapping analysis in 3D Web GIS based on Cesium and B/S framework.In this section,this paper firstlybuild a web back-end based on ASP.NET and MVC framework,which also includes constructing a Cesium framework based web front-end,and encapsulation of application program,data management based on My SQL database manage system.Test results demonstrated that the system has good performance in terms of stability,correctness and time efficiency.The paper has 56 pictures,7 tables,and 77 references.