1 dimension (hierachical or not) + 1 metric
Represents a hierarchical dimension by encoding a metric on each node of the hierarchy. Example : The hierarchical dimension of geography. On the first level, we can see the distribution of the metric between continents. We can then explore a continent to see the distribution between countries, etc. (If the dimension isn’t hierarchical, it equates to a Camembert (pie chart)).
A simple example
Let’s say you want to check out where your visitors are located.
Try it with your own data on the Visualization Playground
Let's analyze a bit
At a mere glance, we can see that nearly have of your visitors are in Europe, a quarter in the Americas, the remainder in Asia, and but a few in Oceania and Africa.
The “Explore” button gives us a closer look at Europe, revealing that half of those visitors are in the West and the rest are split evenly between North, East, and South. Another “Explore” click and we see that more than half of your Western Europe visitors are in France.
A look at the Americas reveals that the United States accounts for 86% of viewers on the continent.
Is that where you should open your new office?