Terrain Model Processing Methods Based On The Features Of Building And Road In3DGIS

3DGIS can describe the planar and the vertical relationship of the space entities.It can transfer and express more space information, and widely used in the city,mining, geological and the related field. With the deepening of application of GIS theory and technology, it put forward higher request. How to improve the3D visual effect and express3D entity scene of the world real and accurately are still the key problems in the further research.It has important meaning for geographic information system application services.Building model, road model and3D digital terrain model are important part of the3DGIS environment. Among them, the three-dimensional digital terrain model is the bearing of the3DGIS environment, establishing a high real3D terrain model is helpful for people to solve the evaluation analysis and make decision, etc. all the elements of ground rely on terrain model.the fusion of terrain model and ground feature model must be considered in the process of model integration. If ground feature model did not very good match with terrain model,it can cause the objective facts, such as terrain model bore into the underground or float in the sky. Terrain model must be do some processing after set up the terrain model in order that buildings and roads model can be very good match with the terrain model in the process of model integration.The geometric modeling technology of the entity is the most important content in3DGIS.The paper analyzes the modeling method of the building model, road model and3D terrain model and the3D data access method,it provides the model for the construction of a lifelike3D digital environment.At the process of the3D digital environment model integration,The paper makes the detailed research and experiment to the existing situation that the buildings and road model does not match.It puts forward the processing method of the terrain model,And it realizes accurate match between the regional building model and the terrain model through the modeling,it greatly improved the visual effect of the3DGIS environment. At the same time, The paper analyses the problems of the3D terrain modeling and restores the true form of the roads and the terrains with the method based on the features of road. Finally, the experimental results were summarized,and it points out the existing deficiency and the areas in need of improvement.