Markers Of 3d City Modeling And Visualization

With the explosion of city,the problem about city construction and management becomes more and more acute day by day.Three dimensional city model is a real description of three dimensional city, people can gather natural and social information and interact within them. The constructions and applications of 3D City Model are presently the hot researches of the current GIS.Buildings are the most important manual features in a city,the best indicator of a city's information and the important content of city 3D models.The paper firstly introduced the definition of city three -dimensional geographic information system,the current research status both at home and abroad,the theoretical research sense of this paper and the paper's main content.Then introduced the theory base of three-dimensional city models construction,classification of the objects of city threedimensional models,classification of the application of three-dimensional city models,data acquisition methods,modeling methods,data model and the level of detail of buildings.Data model is the key.The paper introduced the theoretical foundation of the visualization of threedimensional models of buildings.It mainly introduced the light, material,projection,model conversion and viewport conversion of the building models in OpenGL and the acquisition of building height data and geometry data.At last,using 3dsmax to establish a small amount building models,and read these building models in the developed program and achieve the visualization and roaming of the building models.