The circle tree – a hierarchical structure for efficient storage, access and multi-scale representation of spatial data

A hierarchical tree structure, the circle tree, is proposed for the efficient storage, access and multi-scale representation of polygonal spatial data. The tree is built by optimally and recursively placing circles of decreasing size to fill a polygon, achieving a near-space filling effect. This paper establishes the precedent for the circle tree in the computer science (e.g. use of volume-filling spheres for quick 3D collision detection) and GIS literature (e.g. the sphere tree as an alternative to the Rtree indexing method) and explains how its development may build on some of these ideas. A project outline describing the comparison of a deterministically derived solution with one gained through evolutionary computation will then be given. Finally, a brief assessment of how the circle tree may facilitate efficient storage and access as well as the representation of a spatial object at multiple scales (and in doing so performing the cartographic processes of reduction and elimination) will be made.