Construction Algorithm of Octahedron Based Hexagon Grid Systems
Ben Ji · Geo-information Science · 2015
A Discrete Global Grid System(DGGS) is a set of related global grids at various scales which tessellate the earth into areal cells and associated cell points. As a promising global reference model it supports fast,seamless assimilation of numerous and disparate geo-data sources and sensor networks, regardless of scale, origin, datum, or projection. Compared with square and triangle grids, hexagon grids are uniform adjacency and they have better symmetry and more quantizing efficiency. These properties have made hexagon grids the potential data structure for massive geospatial modeling, integration and analysis. This paper presents a new octahedron-based construction algorithm which yields all types of hexagon DGGSs. It combines two adjacent triangle facets of an octahedron into a logical quad structure on which a three-axis coordinate system is established to describe the location of multi-resolution grid cells produced by different types of hexagon partitions. According to the characteristics of the algorithm, an object oriented software model is designed. Experiments are carried out to examine the feasibility, validity and efficiency of the model. The results indicate that the proposed algorithm employs a uniform mathematical model to describe all types of hexagon DGGSs. The corresponding software model separates the unique features of an individual DGGS from the commonness of all DGGSs, which makes the model extendable and flexible. The results also reveal that the efficiency of the algorithm remains stable regardless the increase of partition level. Two dominant factors are found to be responsible to the phenomenon. One is the maximum processing ability of the computer in which the experiments were carried out. The other is the I/O bottleneck of the computer which makes the CPU idle during the procedure of data export.