分析了基于大圆弧QTM的球体八叉树与变长八叉树剖分的原理、方法及其网格体系的特点,推导了网格单元的体积公式,讨论了横向同层网格与径向同列网格的体积变形规律,并与退化八叉树剖分进行了比较,阐述了球体八叉树的编码与解码方法。研究表明,基于大圆弧QTM的球体剖分充分利用了大圆弧的特性,所得的网格体系具有简单、规整和变形适中的特点,可以用于天地一体化空间数据的组织与管理。
We describe the principle of QTM sphere solid partition based on great circle arc oetree and unequal octree and the features of their grid system, derive the volume formula of grid cells, discuss the size of the volume deformation among the grid ceils at the same layer and in the same column,and compare them with degenerated octree subdivision on the shape deformation, and explain the sphere octree encoding and decoding methods. The results show that, at the full use of great circle arc characteristics, global 3D-grids based on QTM sphere oetree of great circle arc have a simple shape, arranged in neat and moderate deformation. It can be used for the organization and management of spatial data of integrated earth.