A review of quadtree-based strategies for interfacing coverage data with digital elevation models in grid form

Quadtrees represent two-dimensional (spatial) data in a way which takes advantage of spatial coherence in the phenomenon being represented. One major advantage of quadtrees is that they they are very effective for overlay (Boolean) operations; perhaps more important is the fact that quadtrees are compatible with digital elevation models in grid form. This paper reviews the use of quadtrees in geographical information systems. Attention is focused on linear quadtrees and, in particular, on two-dimensional run-encoding, an effective storage structure for quadtrees.