Three-dimensional Terrain Visualization Research Based On HTML5 And WebGL

The demand for geographic information has increased rapidly in recent years,more and more GIS applications become networking and mobility.WebGIS applications are also developed from 2D to 3D,and terrain visualization based on Web has become a research hotspot.But at present,the realization of 3D terrain visualization based on web is mostly based on Flash or third party plugins.However,the market share of these plugins is relatively low,and they cannot meet the demand of cross-platform.So it is difficult to adapt to the trend of mobility WebGIS which are becoming more and more popular now,and this greatly hinders the development of 3D WebGIS.In this paper,we use SRTM DEM terrain data and take Taishan scenic area as the study area to realize no plugins,cross-platform and mobility 3D visualization based on web by using HTML5 and WebGL the emerging web graphics standard.The main research work and contents are as follows:(1)According to the general Web technology and WebGL specification,carry out research plan to convert conventional digital terrain model SRTM DEM data,and on the basis of a comparative analysis of various formats,choose efficient and reasonable streamline data compression scheme to reduce network transmission of terrain data.(2)According to the relevant technology of WebGL 3D rendering,design the mapping scheme of the original DEM data coordinates,and the construction and optimization of terrain model will be based on the scheme.(3)DEM terrain renderings which are created by using traditional rendering methods are mapped to three-dimensional terrain models.Comparative analysis of different texture maps is carried out to evaluate the advantages and disadvantages of each texture in terrain 3D visualization.(4)Design and implement 3D terrain visualization application system based on HTML5 and WebGL.The interactive function of the system is tested and analyzed to verify that terrain visualization method based on HTML5 and WebGL technology is feasible and practical.(5)Cross platform testing is carried out on the terrain visualization application system using different mainstream mobile devices,and the performance of the application system is tested in different devices and operating systems.