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Using treemaps to understand hierarchical data
How to make sense of a complex visualization technique.
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I didn’t understand the point of treemaps until I worked with a large structured dataset.
As part of an extensive user research effort, we collected open-ended survey data from 130 participants. After standardizing the data and doing thematic analysis, the next topic was to try and figure out a way to visualize it.
After analyzing the data, it was a dataset with over 20 themes and several different categories of respondents. This was a much larger dataset than I was used to visualizing: what was I supposed to do?
That’s when I first started to learn about treemaps. To understand why let’s first examine why they were first created: what’s taking up all my hard drive space?
Understanding hierarchical data
In 1990, Ben Shneiderman, Human-Computer Interaction and Information Visualization pioneer, had an issue: his hard drive was full of files, but he didn’t know what was taking up so much space.
Rather than sort through several directories, he instead devised a method for visualizing the hierarchy of files by a technique called treemapping: this technique fills all available space with a hierarchy of…