This is the most basic treemap you can do. The input dataset is simple: we just have 3 groups, and each has a value which we map to an area.

It allows to learn the syntax of the treemap library: you need to provide at least a dataset (data), the column that provides groups (index), and the column that gives the size of each group (vSize).

See graph #235 to learn how to add subgroups, and graph #236 to customize the chart appearance.