This is called a quadtree. Here's a comparison: http://blog.notdot.net/2009/11/Damn-Cool-Algorithms-Spatial-indexing-with-Quadtrees-and-Hilbert-Curves http://bl

This is called a quadtree. Here's a comparison: http://blog.notdot.net/2009/11/Damn-Cool-Algorithms-Spatial-indexing-with-Quadtrees-and-Hilbert-Curves http://blog.notdot.net/2009/11/Damn-Cool-Algorithms-Spatial-...