There are a few kinds of heat maps. This program is for when you have data points, each with a pair of orthogonal coordinates (X/Y, lat-lon) and you want to plot them on a map such that they blob together a bit to indicate density.
So, it's good for things like:
- eye tracking data
- lat/lon geocoded data points
- GPS tracks
It's not good for:
- showing results in realtime (because it's too slow)
- running in a browser (because it's in Python)
- automatically layering on proprietary map systems
So... why use a slow data visualizer that doesn't run in a browser? Because the output looks better.
There's another kind of heatmap, also called a cloropleth map, in which you divide your map into regions and color each region to indicate something. This tool is not for that.
A more thorough description and examples are posted at http://sethoscope.net/heatmap/