Abstract:

For realizing simulation and visualization of global multi-resolution terrain efficiently, a seamless modeling method of the global multi-resolution DEM is discussed based on spherical DQG (Degenerate Quadtree Grid) in this paper. The main contents are included as follows: First of all, a new modeling method of global block quadtree based on DQG is developed. Then, an self-adaptable seamless stitching algorithm is designed and achieved, in which the cracks exist within a quadtree block (without limiting the subdivision level of the adjacent nodes), between the different quadtree blocks, or between a quadtree block and a non-quadtree block. Finally, by using VC + + language and OpenGL tools, a relevant experimental visualization system is designed and developed. As a result, the proposed modeling method and the adaptive elimination algorithms of different types of cracks are verified. The experimental results show that the display efficiency of global DEM is improved obviously while ensuring the accuracy of the terrain expression. When the grid was subdivided into 12 levels, the simplification efficiency is 66.8%.

Key words: global block quadtree, crack elimination, multi-resolution, degenerate quadtree grid