Expression Studies, Based On The Spatial Data Of The Spherical Hexagonal Grid System

The proposition of the concept of the Digital Earth, objectively requires a digital expression for the entire earth. Meanwhile, with the continuous development of the Earth Observation Technology, and the maturation of the Grid Technology, the study scope of the geospatial information has gradually expanded from the region to the world. How to express, organize and process the global multi-scale spatial data better, particularly the massive vector data, has become a problem that attracts common attention from the GIS scholars. At present, the Discrete Global Grid Systems (DGGS) is considered one of the most effective schemes to solve this problem. The DGGS is to use the discrete regular grid for the subdivision of the globe, organize and manage the spatial data by the sphere grids. Besides, the introductions of the Virtual Earth softwares, such as the Google Earth, also promote the study of the DGGS.The sphere grid system is mainly composed of two parts, which are the construction of sphere grids and the address coding of the grid units. By ponstructing a sphere hexagonal grid system based on the Truncated Icosahedrons Projection, this paper focuses on the study of the address coding mechanism of the sphere hexagonal grids, including the hierarchy coding schemes, the study of the positional relations among the grid units and the mutual conversion between the address codes of the grid units and the geographical coordinates. And surrounding the applications of the sphere hexagonal grid systems, drawing lessons from the related study work about the sphere QTM grid, discussed the expression and the indexing mechanism of the sphere spatial entity, proposed the basic principles and basic operations of the sphere gird indexing.Through the sphere grid systems, we can solve the limitation of the traditional plane grid model. This paper focuses on the study of the sphere hexagonal grid system, constructs a technical framework to satisfy with the expression and organization of the global multi-scale spatial data, enriches the theoretical system of the DGGS, and contributes to the early realization of the strategic objective of the Digital Earth.