A RESEARCH ON DIGITAL CITY THREE-DIMENSIONAL VISUALIZATION SYSTEM BASED ON SKYLINE

摘要

As an important living place for human beings, city is regarded as a main place for the birth, spread and development of human civilization. With the continuous improvement of "Digital City", to build Digital City three-dimensional (3D) visualization system has become a research focus in Geographic Information System (GIS). The 3D visualization platform, as one of the key technologies of Digital Earth, organically combines the virtual display with 3D GIS by using 3D model and visualization technology. The establishment of city virtual 3D visualization can provide a platform for the application of 3D GIS in every walk of life and build various city scenes in omni-directional and intuitive ways, which greatly improves the sharing and using level of city spatial information. This paper, based on the principle of system development and combining with the need of building "Digital City", makes an overall design of the "Digital City" 3D visualization system. Firstly, a 3D ground objects model, i.e. x files, is made through inputting the ground objects of the experimental area into 3DSMAX, then, the x files are converted to xpo files in order to achieve a better displaying effect in producing a 3D landscape. Secondly, the author makes corresponding pre-processing to the aerial photos, satellite images, topographic data, digital elevation models and a variety of vector geographic data, and then superimposes and loads these data into Terra Builder module of Skyline software, which generates 3D topography landscape, that is, .MPT files and forms the terrain database required in Terra Explorer Pro software. Next, a 3D landscape is preliminarily established by inputting the 3D terrain model and the 3D ground objects model, i.e. .MPT files and .xpl files, in Terra Explorer Pro, and by editing a real and accurate 3D geographic model and a real Digital City 3D landscape model, that is, FLY files, are respectively formed. Finally, on the basis of the 3D landscape model, the system is developed by using Visual Basic + TerraDeveloper and the basic operation of 3D, spatial analysis, visible analysis and other basic functions are preliminarily achieved.