正二十面体六边形全球离散格网编码运算

全球离散格网系统是指把地球表面按照一定规则离散分割成多分辨率层次结构的格网单元,广泛应用于海量多源空间数据的组织、管理和分析中。六边形全球离散格网具有优良的几何特性,非常适合于空间数据的处理,如何进一步提高六边形全球离散格网编码运算的效率仍是当前研究的重点。本文采用正二十面体施耐德投影四孔径六边形全球离散格网模型,基于六边形三轴坐标与编码的二进制数的对应关系构建四孔六边形的基础编码结构,将二十面体划分为32个基础六边形,并将之分为3种基础六边形剖分瓦片,在每个六边形剖分瓦片采用基础编码结构进行编码,建立了四孔六边形全球离散格网编码,同时设计了并实现了四孔六边形编码与六边形三轴坐标之间的快速转换,基于此构建了一种高效的四孔六边形全球离散格网编码运算方案,包括编码的算数运算、空间拓扑运算和邻域检索运算及跨面运算。与现有的六边形全球离散格网编码运算方案相比,本文的方案进一步提高了编码算数运算、空间拓扑运算和邻域检索运算的效率,编码加法运算是HLQT的2～3倍,邻域检索运算分别是HLQT的3～5倍和H3的2～3倍,且受格网编码层次的影响较小,编码的跨面邻域检索运算时间略高于面内的运算,可以为全...

Code Operation Scheme for the Icosahedral Hexagonal Discrete Global Grid System

The discrete global grid system refers to the discrete partitioning of the earth's surface into grid cells with multi-resolution hierarchical structure according to certain rules, which is widely used in organization, management, and analysis of massive multi-source spatial data. The hexagonal global discrete grid has excellent geometric properties and is well suited for spatial data processing. However, how to further improve the efficiency of the hexagonal global discrete grid coding operation is still the focus of current research. In this paper, we adopt the model of icosahedral snyder equal-area projection aperture 4 hexagonal discrete global grid system and construct the base coding structure of aperture 4 hexagon based on the correspondence between the hexagonal triaxial coordinates and the coded binary numbers, consisting of 7 base digits in the first layer and 4 base digits int the other layer. We divide the icosahedron into 3 base hexagonal subdivision tiles according to the different subdivision structures and adopt the base coding structure for coding scheme in each hexagonal subdivision tile to establish the aperture 4 hexagonal discrete global grid coding scheme. Besides, this paper designs and implements a fast conversion between aperture 4 hexagonal code and hexagonal triaxial coordinates, based on which an efficient aperture 4 hexagonal discrete global grid encoding operation scheme is constructed, including arithmetic operation of encoding, spatial topology operation, and neighbourhood retrieval operation and cross-plane operation of encoding. Compared with the existing hexagonal discrete global grid coding scheme, the coding scheme proposed in this paper has fewer base code digits, is more concise, and facilitates faster conversion to the hexagonal triaxial coordinates of the grid. Compared with the existing coding operation scheme, the proposed scheme further improves the efficiency of coding arithmetic operation, spatial topology operation, and neighbourhood retrieval operation. The coding addition operation is 2~3 times more efficient than HLQT. The neighbourhood retrieval operation is 3~5 times and 2~3 times more efficient than HLQT and H3, respectively, and is less affected by the coding level of the grid coding. The proposed coding scheme in this paper has the same efficiency of additive operation and subtractive operation, and the efficiency of spatial topology operation is 2 times that of arithmetic operation. The coding cross-plane neighbourhood retrieval operation time is slightly longer than that of the in-plane operation, and the impact on the overall operation time is not significant. This study provides support for the research application of discrete global grid system.