Sphere quadtrees: a new data structure to support the visualization of spherically distributed data

Most databases for spherically distributed data are not structured in a manner consistent with their geometry. As a result, such databases possess undesirable artifacts, including the introduction of "tears" in the data when they are mapped onto a flat file system. Furthermore, it is difficult to make queries about the topological relationship among the data components without performing real arithmetic. Therefore, a new representation for spherical data is introduced called the sphere quadree, which is based on the recursive subdivision of spherical triangles obtained by projecting the faces of an icosahedron onto a sphere. Sphere quadtrees allow the representation of data at multiple levels and arbitrary resolution. For actual data, such a hierarchical data structure provides the ability to correlate geographic data by providing a consistent reference among data sets of different resolutions or data that are not geographically registered. Furthermore, efficient search strategies can be easily implemented for the selection of data to be rendered or analyzed by a specific technique. In addition, sphere quadtrees offer significant potential for improving the accuracy and efficiency of spherical surface rendering algorithms as well as for spatial data management and geographic information systems.