Exploring Treemaps: Design and
Implementation of Treemap 2000 with Dynamic Queries


Treemaps were created by Ben Shneiderman in 1990-91 to facilitate information visualization of hierarchical data sets, such as directory structures on disks, organizational budgets, and stock market data. The first implementation at the University of Maryland Human-Computer Interaction Lab was by Brian Johnson, whose TreeViz program was built for the Macintosh in 1991-94. Other implementations were done by David Turo and Marko Teittinen. The Treemap97 program was written in Delphi by Jerome Brown and Shaun Gittens.

Dynamic queries enable users to manipulate treemaps by using slider controls to selectively gray out and possibly hide nodes of the tree. This supports data exploration and facilitates location of extreme values and useful patterns. Treemap 2000 is a Java implementation of Treemap97 and includes dynamic queries.

In June 2001, Treemap 2000 was replaced by an improved implementation called Treemap 3.0

My three-month project can be divided into three parts:

1) The research and development of Treemap 97.
2) Implementation of the data structure and the GUI required for Treemap 2000.
3) Investigation and implementation of double sliders required for visualization of dynamic queries and filtering of data using these visual widgets, while maintaining the integrity of the project.

The final step was the most novel aspect of this project and an addendum
to Treemap 2000. This step distinguishes Treemap 97 from Treemap 2000.
The work was conducted at the Human Computer Interaction Laboratory at
the University of Maryland. The Treemap 2000 will be integrated with StarDOM,
which is another visualization software developed at University of Maryland.