Quadtree [25] and octree [26] use four and eight nodes to achieve uniform partition in two and three dimensions, respectively. Point range quadtree [27], a variant of quadtree, controls the volume of leaf nodes
GeoSOT-3D subdivides a space downward as an octree and encodes the elements in order, as shown in Figure 5a. The direction of z-order encoding is closely associated with the positions of the volume elements. In the northeast quadrant, for example, the longitude is encoded in an ascending ...