Create (Flexible) Hierarchies

Some data is best presented with a fixed hierarchy. For example, census data falls nicely in a hierarchy of country, states, counties, and blocks which could not be rearranged. Some other data could be rearranged using various hierarchies based on the attributes available. For example, if you have health data provided for the 2 sexes, 3 races and 5 age groups, you could present the data in a variety of ways. One example would be by separating men and women at the 1st level, then splitting by race at the second level and then by age. Another hierarchy could be to split by age first, then sex, then race. Flexible hierarchies let you specify the order you want those attributes to be used when creating the hierarchy.

• If the (xml) data file you are using has a default hierarchy, you can first remove the default hierarchy. All nodes will appear together on the treemap without any hierarchy. Now you can create your own hierarchy.
• Choose from the list of available attributes (at the bottom), then click on the "Add" button and the attribute will be added in the Hierarchy List.
• Attributes that have only a few values (for example, sex or race) make good hierarchy attributes. Others like "age" need to have their values grouped in bins to split the tree nicely, e.g. you can split between young and old people by binning the age attribute into 2 bins. To BIN an ATTRIBUTE, click on the right most cell of the corresponding hierarchy attribute table.
• To remove an attribute, select the attribute and click the "Remove" button.
• You will find that it is better to use the last/bottom attribute as the label attribute and remove it from the hierarchy definition.
• You can create different permutations of the attributes in the Hierarchy List by using "Up" and "Down", or "auto", to permute automatically and review the many options. Treemap redraws the tree as you change the hierarchy.
• Once you are happy with a hierarchy you can give it a name (by typing a new name where it says "hierarchy: 1") and you can use the "New" button to create another hierarchy. Remember to save the settings as well!