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 choropleth 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/
change to command line
As of version 1.13 (April 2017), the method of specifying input files has changed. The old way will continue to be supported for at least one year, but the new way is nicer. Read this tutorial for examples and help on switching to the new way.