A global hierarchical and Equal-Area Sphere Grid and Its Geometry Distortion Analysis
A spatial data management and analysis frame is required for global problem application. Global Discrete Grid (GDG) has seamless, excellent hierarchy characteristics. GDG has been used for spatial data management, indexing and cartographic generalization. However, most GDGs are unequal-area. To extend GDG application ranges in spatial modelling and statistical analysis, the method for constructing hierarchical and equal-area GDG is discussed in this paper. The detail steps to build GDG based on inscribe polyhedron is presented. The method of transferring polyhedron surface grids onto sphere surface is described. The ratio of max, min length of grid edges and grid angle is acquired. Length ratio converges to1.7 and angle ratio converges to 3.0. The result indicates that there exists difference in length and grid angle and the ratios of them are convergent.