Where Do You Go is using gheat-ae to visualize !FourSquare checkins.

!NumberInvestigator is using gheat (with portions ported to PHP) to generate hourly maps of telemarketing victims.

Color of Change used gheat to visualize stories of what Obama's election meant to voters and how they participated in the campaign.

!VisTrac is using gheat to visualize clicks on web pages.

Russell Neches is using gheat to visualize auto and bike accidents in Davis, CA. The data is parsed from about 10,000 raw police reports.

Yvan Girard is using gheat to show Twitter activity in and around Tokyo.

The Australian Honeynet Project is using gheat to visualize the origin of spam that gets caught in their SensorNET honeypots.

The Conficker Working Group is using gheat to track the spread of the Conficker worm.

This is an animated heatmap of the conficker botnet as found in Australia (one frame a day, unique IPs per frame, with data from the end of January through June, 2009). This was produced using a heavily modified gheat. Here's a Flash example.

This is a standalone web app that responds to URLs of the form

/<color_scheme>/<zoom>/<x>,<y>.png

with 256px by 256px images like this:

You tell Google Maps (via their API) to place these images over your embedded map. The images are increasingly transparent as the zoom level increases, so they make a nice overlay.

• Python 2.5 (needs sqlite)
• Pygame 1.8.1 or PIL
• Aspen 0.8 (Python webserver)

• Pygame is three or four times faster than PIL.
• Pygame is three or four times harder to install than PIL.
• Get Gheat working with PIL first, then install Pygame.
• You need Pygame 1.8.1 (saving to PNG was broken in 1.8.0)
• You need to install numpy before you can use Pygame.

• Documentation
• Screencast
• Ruby starting-point (thanks David :^)
• other software from Zeta