Tourism Resources Management Oriented 3-D Visualization Platform Design And Realization

Tourism resources 3-D visualization platform provids powerful means for the scientific programming and the management of tourism sight and full-sided information about tourism sight and has a broad appliance foreground. Presently, only two schemes, 3-D GIS and VR, are used to realize three dimensional visualization of tourism resources. But 3-D GIS system has a complicated structure and not very good visualization effect;while VR needs costly man-machine interface which restricts its popularization. To look for a feasible scheme to solve this problem, this article probed into SA, 3-D modeling methods of sight object and 3-D scene visualization, designed and realized a 3-D visualization platform of tourism resources management. The main research productions are as follows:(1)A component pattern 3-D visualization platform for tourism resources was constructed. In the process of the entire platform design and realization, based on the idea of software reuse, this article adopted the idea of SA, programmed various function module into DLL, and "assembled" a platform system finally;At the same time mature open source class libraries was adopted which established a foundation for efficient development and quality guarantee of this platform.(2)A terrain modeling method based on quadtrees structure of Delaunay triangular net was put forward. The terrain model is the most essential model in the tourism resources 3-D scene. The modeling method is complex and it is the main bottleneck which affects the system speed. Therefore, this article made an improvement to the Delaunay triangular net algorithm, used quadtrees structure to manage the characteristic point, the characteristic curve and the characteristic surface datum of terrain. In order to enhance the terrain modeling speed, each leaf node needs to contain the appropriate triangle apex number. Through experiments, the points contained each leaf node are limited in 16, and the terrain which contains 500,000 triangles may be produced in 17 seconds. The system test indicated that this method, compare with Delaunay triangular net algorithm, improved the speed of terrain production to 20.4% and provided the safeguard for the fast demonstration of 3-D scene.(3) This article established the mechanism of scene chart management and Viewing Volume cut and designed the LOD model, then realized real-time display and alternating operation of the 3-D scene. Among them, the scene chart management mechanism used the tree structure to manage the objects in the scene and used DFS to guarantee the order of the scene filter;The Viewing Volume cut mechanism cut out the 3-D scene cursorily in advance by deleting most of the invisible scenes, then input surplus scene datum to the 3-D engine, thus reduced the filter datum;The LOD model, on the basis of the distance between scene and view point, through different resolution establishment to the scene, solved the contradiction between model precision and demonstration speed elementarily. The test showed that the average production time overlapped by the complex terrain of buildings, roads and vegetation is 15.96 seconds, thus realized the roam in the complex 3-D scene fluently.