In the 1990s, Professor Shneiderman developed tree mapping, which uses interlocking rectangles to represent complicated data sets. The rectangles are sized and colored to convey different kinds of information, like revenue or geographic region, says Jim Bartoo, the chief executive of the Hive Group, a software company that uses tree mapping to help companies and government agencies monitor operational data. When executives or plant managers see the nested rectangles grouped together, he adds, they should be able to immediately spot anomalies or trends.
In one tree-map visualization of a sales department on the Hive Group site, red tiles represent underperforming sales representatives while green tiles represent people who exceeded their sales quotas. So it’s easy to identify the best sales rep in the company: the biggest green tile. But viewers can also reorganize the display — by region, say, or by sales manager — to see whether patterns exist that explain why some employees are falling behind.
“It’s the ability of the human brain to pick out size and color” that makes tree mapping so intuitive, Mr. Bartoo says. Information visualization, he adds, “suddenly starts answering questions that you didn’t know you had.”