Research On 3D Spatial Visualization Technology Based On CesiumJS

The activities of human beings near the surface structure are becoming more and more complicated,especially in the rapid urbanization and background of our country.A large number of dense artificial buildings appear on the ground and underground of the city.Especially for large cities,because of the scarcity of land resources in the city,construction activities continue to expand in the vertical direction.Intensive buildings,pipe networks,tunnels,roads and bridges bring new challenges to the city's space management.Nowadays,the concepts of digital cities and smart cities are becoming more and more mature,and the management and visualization of spatial data are getting more and more attention.Because of its excellent cross-platform features,easy to use,suitable for engineering,public-oriented and other groups,the browser-based Web platform 3D spatial visualization technology has become a potential 3D space visualization platform.However,the existing Web 3D visualization platform still has many defects when it is oriented to large-scale,complex type and threedimensional spatial data that spans the ground and underground.This study compares and analyzes common Web 3D visualization platforms such as Three.js,CesiumJS,BabylonJS,and Google Earth Web.Based on its characteristics,design goals,geographic environment visualization potential and other factors,this paper selects CesiumJS,an open source JavaScript.Library,as the base platform for unfolding text research.For the requirement of vertical space visualization,the problem that CesiumJS can not realize the visualization of spatial information below the surface is discussed,and the improvement of the surface transparency,the internal perspective of the Earth and the cutting of the surface image are proposed to obtain a complete underground visualization solution.For the problem of large-scale 3D model loading,based on the existing 3D Tiles model organization structure and hierarchical detail loading of CesiumJS,the optimization improvement scheme is proposed,including preloading through model tiles,enabling faster 3D scene browsing,and through platform-based Different dynamic screen space error methods to solve the system's adaptability problems on different performance platforms.Finally,in response to the above proposed space space visualization and 3D scene loading,based on the open source CesiumJS modified,and improved CesiumJS platform.Then,based on the improved platform obtained in this research,the secondary development of Web GIS was carried out,and the 3D visualization system of B/S structure was realized.The simulation of the underground tunnel and the loading of the campus model obtained by tilt photography modeling verify the feasibility of the visualization of the underground space and the feasibility of the large-scale 3D scene model loading optimization scheme.The research results are of great value to the development of digital cities and virtual earth technologies in the Web environment.