基于菱形块的全球离散格网层次建模

在球面四元三角格网（QTM）基础上，以“菱形”块（Diamonds）作为基本单元，构建了全球离散格网的分块层次模型．用线性四叉树成熟的Morton编码作为关键字来标识菱形块，发展了具有固定方向（fixed orientation）的“块”层次编码技术及邻近搜索算法．利用地址码的邻近特征，建立了块层次之间、块与格网之间和格网层次之间的关联关系，并设计了全球多层次“菱形块”的层次操作和动态调用方法．研究结果表明：该模型在保持原有精度基础上，几何结构更简单；既避免了传统算法各层次间数据存储冗余问题，又使邻近搜索、数据更新和显示操作变得方便易行．

Hierarchical Model of Global Discrete Grids Based on Diamonds

In this paper,a hierarchical model of the global discrete grids is approached based on quaternary triangular mesh(QTM),in which Diamonds are regarded as basic units.The quadtree Morton code is used as the index for addressing the Diamonds and a hierarchical coding scheme of Diamonds is developed based on its fixed orientation.A neighbor finding algorithm is presented in details,and the relationships between diamonds and hierarchy,diamond and grid,and grids and hierarchy are constructed using their adjacent properties of address codes.Moreover, the methods of hierarchical operation and dynamic data paging are designed.The results show that the geometry structure of this model is more simple in the basis of keeping the original precision.Not only the problem of redundant data in traditional algorithm is avoided,but it is easier in the operation of adjacent searching,data updating and visualization as well.