Web-based Research On Vr-gis Terrain Data Organization And Visualization

All along, people wish that they can travel in the 3D world without leaving home. Now, development of virtual reality and Internet technologies makes this aspiration achieving gradually.This paper analyzes the 3D Virtual Reality Geographic Information System (VR-GIS), concept of Web-based VR-GIS as well as the development of the status quo at home and abroad, focuses on a number of key technologies about Web-based 3D VR-GIS from the data organization, data storage, data network transmission to the client-server interactions, etc. As follows:1. Terrain is the main body of a 3D scene, so this paper focuses on the virtualization of terrain. Allows for large amounts of data for the terrain and the special nature of network, I conduct a study on the organization and management of the terrain data, decide on using sub-block, multi-resolution form of organization, and using spatial database to store and manage the terrain data.2. In view of the natural advantages of XML in Internet applications, this paper applies the Extensible 3D Graphics Markup Language (X3D), which complies with the standard XML specification, as the format of 3D model data that transmitted on network including the terrain,. X3D has advantage on 3D modeling, data format conversion, programming and other aspects that this paper has explored in detail.3. Because of limit on the Internet bandwidth and the needs of the user experience, I try my best to optimize network progressive transmission and multi-resolution rendering of terrain, and introduce in Ajax technology to achieve asynchronous communication between client and server.Finally, based on the study above, I give an instance system about Web-based terrain rendering to verify the feasibility of the technology above; propose a set of feasible technical solutions.