Research on Key Issues for Digital Earth Oriented Virtual Reality System
面向数字地球的虚拟现实系统关键技术研究

This paper addresses several key issues for digital earth oriented virtual reality system, with multi layer scene engine (MLSE), view dependent dynamic multiresolution terrain model(VDDMTM), ActiveX component based network model discussed. By means of scene layer, MLSE enables multi variates integration, scene rendering and user interaction. Quad tree structure is used for multi resolution terrain representation. View dependent terrain simplification and multi resolution texture mapping are applied to keep ROI(Region of interest) details and accelerate rendering. Client/Server based ActiveX network model not only meets specific needs for geo data modeling, but also well supports WWW browsers. Based on above research, a prototype system, virtual earth system(VES), was developed to visualize YongDing River and Mountain Himalayan.