Research And Implementation Of Map Symbols Visualization In 3D GIS Based On Texture Mapping

GIS (Geographic Information System) development has gone through more than 30 years, the traditional two-dimensional geographic information system has been considerable development, two-dimensional display is simple and straightforward, and many well-known at home and abroad are based on two-dimensional mapping software to do is displayed, so far the vast majority of GIS information and data are based on two-dimensional space. Three-dimensional GIS, based on two-dimensional GIS developed from a three-dimensional graphics technology and GIS-related product of the integration of technology integration in GIS is a very important one. Compared with the traditional 2DGIS, three-dimensional GIS for the display of spatial information more intuitive way to display richer, with a strong multi-dimensional spatial analysis functions.Map symbol is the language of the map, geographic information is that people commonly known as an abstract expression of the agreement. The development of two-dimensional GIS, map drawing and symbols to develop over a long period of development have formed a complete set of standards, GIS also has been widely used. Has become the standard for the expression in 3D GIS map symbols also should continue to use, how to map three-dimensional GIS in the accurate expression of the symbol is the subject of the main contents of the study.Paper on the characteristics of map symbols were analyzed for the image stored in the map symbol used in the way of texture mapping symbols of expression, in the process of texture mapping technology roadmap developed a texture mapping process to resolve or deal with issues arising from, combined with DEM data characteristics model with regular grid terrain model; geographic information system for location information and high accuracy requirements, will address the various layers and the alignment between the terrain model as the primary address the issue problem; three-dimensional terrain generation, the terrain model of the surface uplift, the terrain textures in the triangulation may produce distortion of the issues handled by a interpolation method to enlarge the texture, the use of pre-filtering approach Mipmap reduce texture distortion; layer position information on registration, the use of texture synthesis approach to map symbol layer and landscape integration layers.Finally, the paper describes the technical route than under the system implementation process, the use of modular development approach the structure of the system design and development, will 3DGIS map as an experimental platform of visual symbols and important modules to the system.