Research on the Multi-scale Electronic Map Overlaying and Rendering in Global 3D Terrain Environment

In order to overlay multiscale 2D electronic map in the 3D virtual geographic environment, this study presents and implements symbolic method in 3D API for the different types of feature, studies visualization of vector data based on the sphere, and discuss a number of issues need to be resolved. It proposes the way of multiscale expression based on multiscale topographic map and achieves fast expression and organization of multiscale data in 3D space through multi-thread technology and memory pool. It uses frame buffer object technology to generate symbolic vector data texture in real-time, and implements visualization of vector data in 3D terrain by multi-texture technology. Finally, this paper verified the feasibility of these methods by experiments.