Research On Playback System For Three-Dimensional Landscape Of Digital City

The present thesis makes tentative research on how to achieve three-dimensional reproducing of city landscape on the basis of remote sense information. This research makes a comprehensive application of many techniques such as model recognition technique, OpenGL and visual Lisp programming technique, three-dimension model setting-up technique, virtual reality technique and technology of visual frequency composition. With the help of these techniques, the research has realized the following purposes: the vector processing of aerial photography and remote sense information; the rapid stereoscopic automatic producing of plan pictures; the reproducing of three-dimensional city landscape.This thesis presents model setting-up techniques and methods of various city three-dimensional surface models on the basis of deep research on model recognition technique to recognize and process remote sense pictures. Moreover this thesis touches on the study and development of rapid automatic reproducing of three-dimensional landscape, providing methods to form and store vector data to read these data then draw three-dimensional landscape and demonstrate these landscapes dynamically. By using such programming implements as VC++ and OpenGL the author has succeeded in the stereoscopic dynamic demonstration of city three-dimensional landscape.Considering the weakness of traditional method of three-dimension reproducing, the author advances the method to achieve virtual reproducing of three-dimensional landscape through virtual reality technique. This method comprises the advantages of such techniques as desktop virtual reality technique, three-dimensional model reproducing of digital city technique and tow building model-setting technique. In addition, it synthesizes such implements as AutoCAD, 3DSMAX and Photoshop and promotes the flexibility and convenience in dynamic demonstration and mutual observation of city three-dimensional landscape.Another method introduced by the thesis is the use of visual frequency composition in achieving dynamic demonstration of city three-dimensional landscape based on vector information. This method applies computer three-dimension animation technique to clearly show the interior and exterior structure of buildings and scour through buildings. At the same time this method can evaluate city environment, that is, virtually modeling the overall influence of designed buildings on surrounding environment, which is quite important in city planning and environment protection.The results of this research are able to provide stereoscopic picture information, data information and historical information of city landscape from any angle, thus enabling the digital visualization of city landscape information processing and calling in the form of pictures through network. In this way the capacity of processing and calling of city landscape can be highly developed, which can provide scientific basis for government policy and city planning. This is where the practical significance of this research lies.