Visualize geo spatial map tile usage interactively using a heat map overlay.
Check out the binoculars demo at: http://binoculars.nodejitsu.com/map.html
binoculars provides a zoom-able and pan-able map view of the San Francisco bay area. It'll put a heat map inspired overlay on top of the map. The overlay is based on the view count of each tile. The map tile view count is based on the data from a major site on the web that gets thousands of users every day. Each tile ranges from dark red (no views) to bright green (most views).
Due to license restrictions I, unfortunately, can't open source the usage data of the base map tiles. If people are interested I can included the specification of the data format though. The mapping API and it's tiles are licensed under a proprietary (no ESRI or Google though). Restrictions apply. All other code included in the repo is free to anyone.
The app runs off node.js. The data gets fetched from in-memory storage redis on the fly before each map tile gets produced by the cairo backed server-side implementation of canvas (PNG). The usage data (not included) was extracted and aggregate from Apache logs using hadoop and pig.
Each base map tile triggers a separate request for an overlay tile to the node.js app that basically returns a PNG file. That way it integrates nicely with the underlying mapping API.
Hit me up if you have questions or ideas.