Hierarchical layouts

All hierarchical layouts are based on an abstract hierarchy layout designed for representing hierarchical data: a recursive parent-child structure. As mentioned earlier, imagine a tree or an organization chart.

All the code for the partition, tree, cluster, pack, and treemap layouts are defined in the d3-hierarchy module, and they all follow similar design patterns. The layouts are very similar and share lots of common aspects; so, to avoid repeating ourselves a whole bunch, we'll look at the common stuff first, and then focus on the differences.

First of all, we need some hierarchical data. In the book repository, I've provided a file called GoT-lineages-screentimes.json that contains all the character lineages (by father), the amount of time spent on screen, and the number of episodes a character is in. We'll use genealogies of each character as a way of creating a hierarchy, then time on screen to size various page elements in layouts that necessarily need them (I don...