Treemap Visualizations

Data visualization is an area I find very interesting and have been working with Treemaps as an effective way of visualizing large data sets. Treemaps were first designed by Ben Shneiderman at the University of Maryland. For more information and the history of treemaps see: Treemap History.

I've been experimenting with the idea of generating HTML treemaps for display in a web browser. I created an open source treemap library in ruby which allows you to output treemaps in HTML and customize the display with css. An example is a treemap built from spidering sourceforge data. The treemap below shows a random sample of projects organized by category. The size of the square represents the number of downloads received for the month of January 2006. The color represents the rate of change in downloads over the prior month. Click here to see the actual HTML treemap.

While at O'Reilly, much of my work involved building analysis tools to help visualize data. The Research group at O'Reilly receives weekly point-of-sale data feeds from Neilsen Bookscan which are loaded into a MySQL data warehouse. For a more detailed overview see: Book Sales as a Technology Trend Indicator. One of the tools that I worked on to visualize the data warehouse is a Treemap application which displays the category hierarchy and sales data of more than 8,000 titles.