Trees work well for visualizing the nested structure of a taxonomy (or any other kind of tree), but what we can't easily visualize are the values attached to each of the node. Say, for instance, that each of our end nodes in our taxonomy had an additional value attached. This attached value would represent some information about that specific species (for example, the current total population). In a tree-based visualization, this would be difficult to represent. We could perhaps change their size, but then we'd quickly run out of space. When you have such a value that you want to represent besides the structure, a treemap or partition visualization might be better suited. The following figure shows the biggest cities in a large number of countries:
In this section, we're going to use these two visualizations to show some nested data. The data we used in the previous section...