Proof of concept for a technique for visualizing Census Tract level data on a map. The goal of this technique is to provide a performant map where you can pan and zooom, approximating a choropleth map. The problem with rendering all census tracts as a choropleth map is that there are just too many, and even WebGL struggles to render so many geometries.

Elements of this technique:

• Index census tracts in an R-tree
• Sample census tract data values over a uniform grid using the R-Tree
• Index the uniform grid in a Quadtree
• Aggregate data values up the quadtree using averaging
• Query the quadtree based on the map viewport and a size threshold
• Adjust the color scale based on the extend of those values
• Render the values as colored rectangles using Canvas

The idea is that this is a precursor to computing a dynamic contour map.