The only required variable role for the Treemap platform is Categories. If you specify only a Categories variable and no other variables, the rectangles in the treemap have these attributes:
If you specify two Categories variables, the treemap is grouped by the first variable, and sorts within groups by the second variable. For example, using the Cities.jmp sample data table, specify Region and city (in that order) as the Categories variables.

Help created on 10/11/2018