THE EXTENDED-OCTREE SPHEROID SUBDIVISION AND CODING MODEL

Discrete Global Grid has been widely used as the basic data model of digital earth. But it is only confined to the earth surface, and it can not reach to the earth inside or outside. The extended-Octree (e-Octree) spheroid subdivision and coding model proposed here provides a new kind of global 3D grid. This e-Octree model is based on the extension of octree structure, and there are three kinds of extended mechanisms including regular octree, degraded octree and adaptive octree. The process of partition and coding is discussed in details. The prototype system of e-Octree model is implemented, in which e-Octree model has been used to visualize global terrain and space object orbits. These typical applications experiments show that the e-Octree model could not only be used in global change research and earth system science, but also be used for dynamic simulation and spatial index.