Application Research On 3D GIS Modeling And Visualization Technology

With the fast development of computer multimedia technology, space technology, visualization technology, digital mapping technology, computer graphics technology, the concept of "digital earth" is deeply rooted among the people, and the GIS technology is getting a mature with every passing day. Using three-dimensional GIS technology to realize virtual visualization scene has already become reality. Three-dimensional GIS has already applied to a lot of fields broadly, such as territory resource management, urban planning, public security system, electric power telecommunication branch, forestry resource management.The paper has paid great attention to the popular three-dimensional GIS technology which has been in progress studying nowadays. It discusses and studies the three-dimensional GIS modeling method and the key visualization technology based on OpenGL. It designs and realizes a three-dimensional GIS simulation system.Combining with the related project, the paper has done the main studies as follows:1. It makes a summary of the research content and developed condition of current three-dimensional GIS and expatiates on the extensive application foreground of three-dimensional GIS.2. It discusses and studies 3D GIS modeling theory and method, and has explored several kinds of different spatial data models. There are three kinds of three-dimensional GIS model, such as surface-based model, volume-based model and mixed model. The surface-based model mainly emphasizes on surface presentation of 3D spatial model and is convenient for visualization and data renewal. But it is short of 3D geometrical description and the inner attribute notes, so it is difficult to do space analysis. The volume-based model mainly emphasizes on volume presentation of 3D spatial model, and is suitable for space operation and analysis. But the memory space occupancy is bigger, and the compute speed is also slower.3. It has expatiated the basal principle and method of OpenGL and has discussed the key visualization technologies based on OpenGL such as coordinate transform, lighting model, texture mapping and hiding technology. It also introduces 3D modeling software 3DS MAX to establish complicated model, and import 3ds model documents to scene in OpenGL.4. Making use of Visual C ++ 6.0 and combining with 3D graphics interface OpenGL 1.2 to develop the software platform, and apply 3D modeling software 3DS MAX 6.0 to establish complicated 3D model, it develops a 3D GIS reality visualization scene, which realizes 3DS model reading, interactive operation and cartoon roam.3D GIS is a very complicated project. It remains to be further to perfect and studied in a deeper way in data acquirement, structure modeling and 3D space data administration and analysis method. The 3D GIS scene has satisfied certain vision demand, and has reached certain reality and solid feeling. The research of this paper has certain value and important realistic significance to realize 3D GIS visualization system.