I have recently published a free calendar heatmap extension to compare values on a day-per-day basis over a long period of time (several years). The extension is developed using D3 and an existing visualization called “Calendar View” by Mike Bostok.
The data passed to the extension is displayed in a diverging color scale. The values are visualized as colored cells per day. Days are arranged into columns by week, then grouped by month and years.
There are several scenarios where using this extension seems to be a helpful kind of visualization:
- Comparing changes of stock exchange prices
- Making out of stock trends visible
Download, Configuration & Source Code
GitHub-Repository to post issues, fork the source-code, etc.: