Visualize SpatialHadoop indexes

I received several requests asking for help in building visualizations for SpatialHadoop indexes. In many of my papers, posters, and presentation, I display a visualization of spatial indexes like the one shown below.

[Click to enlarge] A Quad-tree-based index for a 400 GB dataset that represents the world road network extracted from OpenStreetMap.

There are actually several ways to visualize these indexes and the good news is that all of them are fairly simple. You can choose between them based on your needs.