It's worth noting that Treemaps have shifted over time from maps that were often used to show complete filesystems with high-levels of depth, to visualizations

It's worth noting that Treemaps have shifted over time from maps that were often used to show complete filesystems with high-levels of depth, to visualizations that showed data one-or-two level deeps. This later kind in what you tend to see in newspapers and in financial data analysis. If anyone's interested in generating Treemaps (especially of the later kind) I wrote a JS library to generate them after being frustrated how ugly all the existing off-the-shelf implementations were: https://github.com/imranghory/treemap-squared https://github.com/imranghory/treemap-squared