四孔六边形全球离散格网一致瓦片层次结构编码运算

全球离散格网系统是支持多源地球空间信息融合处理的有效解决方案，格网系统单元层次关系及全球统一编码运算是研究难点。首先，根据四孔六边形剖分特点，提出封闭二十面体表面的一致瓦片层次结构；然后，利用复进制数建立一致瓦片层次结构的编码数学模型，并等价设计全球统一编码运算、编码邻近查询、编码与地理坐标转换等算法；最后，设计了格网层次结构验证和编码运算效率测试实验。实验结果表明，一致瓦片层次结构的编码与地理坐标转换平均效率分别约是同类成果的2.74、1.73倍，编码邻近查询平均效率约是其7.46倍，且随着格网层次升高, 效率优势更显著；与同类成果相比，所提方案瓦片具有一致性, 且数量更少，算法复杂度低；层次结构的原理简明易懂，计算机执行效率高，可为多源对地观测数据统一组织管理、处理分析提供理论和技术支撑。

Encoding and Operation for the Aperture-4 Hexagonal Discrete Global Grids on Uniform Tiles

  Objectives  Discrete global grid systems are the preferred data models supporting multisource geospatial information fusion. Hexagonal grids have become more popular in many applications due to their geometric characteristics within uniform adjacent.  Methods  We design a uniform tiles hierarchy on the surface of the icosahedron according to the characteristics of the aperture-4 hexagonal discrete global grids, using complex numbers to build a unified coding and operation model. We also design algorithms including interoperating between geographic coordinates and codes, querying neighborhood codes.  Results  The experimental results show that interoperation between geographic coordinates and codes efficiency of the proposed algorithm is approximately 2.74 and 1.73 times that of the traditional algorithm respectively, and that neighborhood codes query efficiency of the proposed algorithm is approximately 7.46 times that of the traditional algorithm. As the grid level rises, the advantages of the proposed algorithm become more obvious.  Conclusions  The results of this paper are expected to provide theoretical and technical supports for the unified organization, management, processing and analysis of multi-source earth observation data.