三维地形数据的简化和空间分析的研究

Study on Simplification of 3D Terrain Data and Spatial Analysis

全球地形场景的建模是一个极富有挑战性的课题。地形动态简化是构建三维地形场景和虚拟现实的重要内容,基于视相关的地形裁剪技术是动态简化庞大地形数据的重要方法。本文根据地球椭球的特性,提出了在当前LOD层次下,实时裁剪视景体中的地形数据的算法。精确拾取地形点的三维大地坐标是进行正确的三维空间分析和查询操作的基础,也是3DGIS研究中的一个难点;而可视性分析是三维空间分析的重要研究内容。本文给出了这些的问题的算法。实验证明,这些算法具有较好的实用性。

Constructing global terrain models is a very challenging subject. Dynamic simplification of terrain is very important in construction of 3D terrain landscape and Virtual Reality. Terrain clipping based on the view-dependent technology is a very important method for dynamically simplifying massive terrain data. In this paper, an algorithm of judging the terrain bound of the current LOD within the view volume is discussed, according to the property of the ellipsoid. Picking up 3D Geo-coordinate of a spatial point accurately is the first step toward doing 3D spatial analysis and query, and is also a research difficulty. Visual field analysis is one of the important research contents. The authors give more efficient and accurate algorithms for them. The test in this paper is given to show the effectiveness and practicability of theses algorithms.