利用球体剖分瓦块构建真三维数字地球平台

摘要

Discrete global grids,a model ing framework for big geo-spatial data,is always used to bui ld the Digital Earth platform.Based on the sphere spl it bricks (Earth system spatial grids),it can not only bui ld the true three-dimensional digital Earth model,but also can achieve integration,fusion,expression and appl ication of the spatial data which locates on,under or above the Earth subsurface.The theoretical system of spheroid geodesic QTM octree grid is discussed,including the partition principle,analysis of grid geometry features and coding/decoding method etc,and a prototype system of true-3D digital Earth plat-form with the sphere spl it bricks is developed.The functions of the system mainly include the arbitrary sphere segmentation and the visual ization of physical models of underground,surface and aerial entities. Results show that the sphere geodesic QTM octree grid has many appl ication advantages,such as simple subdivision rules,the grid system neat,clear geometric features,strong appl icabi l ity etc.In particular,it can be extended to the el l ipsoid,so it can be used for organization,management,integration and appl i-cation of the global spatial big data.%全球离散网格是面向空间大数据的模型框架，常用于构建数字地球平台。基于球体的剖分瓦块不仅可以构建真三维的数字地球模型，而且可以实现天地一体化的空间数据集成、融合、表达和应用。本文详细论述了球体大圆弧 QTM 八叉树网格的剖分原理、网格几何特征分析和编解码方法等理论体系，并利用剖分瓦块实现了球体的任意分割以及地下、地表和空中实体的可视化建模。研究表明，球体QTM 网格具有剖分规则简单、体系规整、几何特征明晰，适用性强等特点，尤其是可以推广到椭球。因而，该方案可用于天地一体化的空间数据的组织、管理与应用。