三维含拓扑地质剖面三角剖分可视化研究

三维剖面是地质对象表达和地质问题分析中最基本和最常用的数据。该文分析三维复杂地质折剖面可视化存在的问题,并提出展开剖分算法。该方法保证了各点之间的水平距离与剖面拓扑关系不变,能够对由"多边形-弧段-结点"矢量结构构成的三维折剖面进行有效剖分。在此基础上实现了三维剖面的可视化,尤其合理解决了纹理映射中的纹理变形与重复接缝等问题。

Triangulation Visualization of Three-Dimensional Topological Geology Section

Geological section is the most basic and common data in three-dimensional(3D) geological modeling and visualization.Three topological relationships under"polygon-arc-node"structure,including connectivity,adjacency and inclusion,as well as the"olding-back"traits in 3D sections were introduced in this paper.Visualization of the geological section lied on the generation of Triangulated Irregular Network(TIN),and moreover filling it with geologic symbols.However,conventional method of projecting 3D points onto 2D plane is not suitable for the triangulation of 3D geological section because of its folding characteristics.This paper presented a"section-expanding"method.First,geological section was unfolded to a Flat Section(FS) on a 2D plane.The FS was triangulated by projecting-algorithm,and issues of multi-values and hanging-triangles could be eliminated by taking polygon edges and folding lines as constraint lines.Second,the triangulation of the complex geological sections including fault and lenticular body was discussed in detail.Third,geologic symbols were casted upon TINs using texture mapping.The erofos texture-synthesis algorithm was imported to solve the problems of texture distortion and patch-gaps in texture mapping.Finally,some cases based on this method in"management and service of 3D urban geological data"were conducted using the real data in Beijing,China.