The Research Of Rendering Of Massive 3D Objects In Geographic Information System

With the rapid development of computer science, the research and evolution of geographic information system presents a flourish tendency. More and more enterprises once impossible will become possible to picture a city full of digital technology to move through the computer up, thousands of miles away from the computer end-users can easily access and view almost real City or other corners of the Earth through the Internet.Three-dimensional graphics rendering engine, not only the game engine but also GIS graphics-rendering engine cannot do without the support of the underlying rendering library for the specific needs of design and packaging-rendering engine as the primary task of developing such systems. The rendering engine which people developed faces not only a technical, as well as cross-language cross-platform and multi-faceted support to play a powerful CPU and GPU power.Three-dimensional rendering system, deals mainly with two types of objects: massive terrain and large-scale scenes. Massive Terrain involves in processing and rendering performance of the storage and LOD terrain rendering. There are a lot of research production to learn from, this article focuses on the large-scale processing and rendering performance of a scene, it is precisely because a single three-dimensional objects and a large amount of data Scene in the high number of three-dimensional objects, therefore, the overall rendering and performance of the scene is facing many problems, including memory and efficiency of the effect of realism and object storage, rapid modeling and rapid indexing, remote access, transmission efficiency and rendering effects.By comparison and analysis in popular language strengths and weaknesses of the mainstream rendering engine, therefore this system provides engine optimized room for improvement ideas and the possibility of large-scale scenarios in the study based on the theory of real-time rendering, design and implementation of large-scale real-time rendering sub-scene System, the index subsystem, network transmission subsystems, natural scenery module. Do some clever analysis of key issues, such as octree indexing and query system to create three-dimensional model of LOD simplification and rendering, networking and efficient design of concurrent asynchronous transfer processes.Finally, refering to summary of the deficiencies in this system, it is not only as the road map for future research, but also for other researchers to provide a comparable program.