A treemap is a hierarchical view of data: it breaks an area into rectangles representing branches of a tree. Each rectangle is broken in turn into subrectangles, representing subbranches. Each subrectangle can be associated with two different numbers, once of which may be set to a color; the other to a size.
A treemap can make it easy to discover how a whole is broken into parts: where the budget in your organization goes, or where the space on your disk has gone.
For example, here's an organization divided into four offices: North, South, West, and East. Each sells volumes of "food", "office", and "tech"; each of these, in turn, has subcategories. We're using the size of each box to represent sales volume, and the color to represent the profit.
Excel doesn't naturally have a way to represent hierarchical data: it likes rows and columns. In the Treemap module, you can enter data either as a name list, or as an id/parent set.
The Name List format might be most natural for things like disk space. In a name list, you enter as many columns as you need to represent the deepest part of the hierarchy--and then leave some parts of it blank. Here's an example from a disk:
|Level 2||Level 3||Level 4||Level 5|
You might also use the Name List to handle data that isn't completely hierarchical:
Note the "Volume" and "Profit" columns. We can use them for size and color, respectively.
If you have an organization chart stored in a database, then it might look different: you might have records with a person and their manager. Here's a small organization:
|David Freese||Wilfredo Baber|
|Wilfredo Baber||Yolanda Hill|
Since it's very annoying to switch between the "Name List" and the "Id/Parent" forms, the Treemap application accepts both.
Using the App
For basic instructions on starting up an App for Office, see the description on t.
The easiest way to get started with the app is to generate sample data. on the "Sample Data" tab, press either "Name List" or "ID/Parent".
After data is available, it will take three selections to build a complete chart: one to add the names; one to select the column for the size, and one more to select the column for color. Note that these last two columns are optional: it's a perfectly fine treemap even without size or color.