基于菱形块的全球离散格网欧拉数计算

对全球离散格网的研究已成为目前国际GIS界的研究热点,其中欧拉数是讨论球面栅格区域局部拓扑不变量的重要参数,也是描述和推断球面栅格拓扑关系首先要解决的问题。本文以菱形块作为全球离散格网的数据组织单元,在利用线性四叉树Morton编码作为地址码对菱形块进行邻近搜索的基础上,在对菱形块进行剖分的同时,对其子菱形块进行行列号的剖分,然后利用菱形块行列号进行邻近搜索,最后利用邻近搜索的结果计算出全球离散格网的栅格区域进行欧拉数。最后,本文在C++和DirecX环境下验证了该算法的有效性和正确性。

Computing Euler number of global discrete grids based on diamond

Global Discrete Grids Based on Diamond has become a research topic recently which is one of important Global Discrete Grids. The Euler number is one of the important parameters to deal with the digital image. And the computation of Euler number of Spherical Grids is also the problem that should be solved firstly when describing and referring the spherical surface grids topological relation. In this paper, diamond-shaped block is taken as a basic unit of global discrete grids to compute the Spherical surface Grids Euler number. The rows and columns subdivision algorithm of spherical surface grids is given firstly when subdividing global discrete grids based on diamond, then the rows and columns are used to compute the binary code of diamond-shaped block and convert the binary code to the position code of linear quadtree, finally the position code of linear quadtree is used as keyword for diamond-shaped block adjacent search in global scale. Finally, the algorithm has been realized based on Direct3D and C++.