Tree Maps

Have you ever heard of Tree Maps? In fact, a Tree map is a Big Brother of both Bar Charts and Pie Charts.
Tree-maps are a complex but powerful information visualization technique.
They were introduced in Shneiderman, 1992. Tree Maps are used to visualize hierarchical data as a set of nested rectangles.
As mentioned, the concept of tree-maps is basically from Ben Shneiderman an American computer scientist from University of Maryland as a solution to his problem of understanding and visualizing who is using how much of disk space ( It was 80 MB  of disk space shared by 14 people in those days ! )
You can read a wonderful article by Ben Sheneiderman titled " Discovering Business Intelligence Using Tree-map Visualizations.
Tree maps can show relatives size of each component in the hierarchy and also use color coding to show another attribute. Here is an example of a simple tree-map .
This picture is taken from Wikipedia
The size of Rectangle denotes the waiting time for patients in NHS Primary care Trust in UK.

There is  another variant of Tree maps that uses circles instead of rectangles. Someone called it as pebbles. Here is an example of a pebbles Chart.
This shows GDP Per capita of countries in PPP Terms in $ International
This is the same data in a Tree chart
Creating Tree-maps is a Complex work and need considerable skills . Here I provide you two easiest ways to create Tree maps.

      1. Use Microsoft Excel

      2. Use ManyEyes, an IBM Initiative to create and share data visualizations on Web

Visit my earlier Post on Many Eyes : Text Visualization-Many Eyes

Microsoft  Research Provides a Free excel Add-in, that makes the job of creating Interactive Tree Maps in Excel easy.

Here is the link to download Excel Add-in

1.Tree Maps Free Excel add in - Link 1

2.Tree Maps Free Excel Add in - Alternative Link from Microsoft Store.

for more advanced users who can handle xmls , Here is a site to download a Java based Tree visualization Programme. Here is the Link

http://www.randelshofer.ch/treeviz/

According to the web site,

The project currently consists of a file browser demo, which visualizes the file system with the following tree diagrams:

• Hyperbolic Tree
• Circular Tree-map
• Rectangular Tree-map
• Sunburst Tree
• Icicle Tree
• Sunray Tree
• Iceray Tree

Try few Tree maps now....