Treemapping

Treemapping is a method for displaying tree-structured data using nested rectangles.

History
In the early 1990s University of Maryland, College Park professor Ben Shneiderman, was plagued with chronic low disk space on the 80 MB server he was managing. He needed to find out how the space was being utilized; the largest files, and the users who were putting them there. Frustrated with the available tools that employed traditional tree structured node-link diagrams, Dr. Shneiderman conceived the Treemap.

Treemaps display rows of data as groups of rectangles that can be arranged, sized and colored to graphically reveal underlying data patterns. This visualization technique allows end users to easily recognize complicated data relationships that are otherwise non-obvious.

The Treemap algorithm
Two major factors drove the evolution and development of the Treemap algorithm: the aspect ratio and predictability of item placement, or order. It was noted early in the process that these properties have an inverse relationship. As the aspect ratio is optimized, the order of placement becomes less predictable. As the order becomes more stable, the aspect ratio is degraded.

To date, five primary treemap algorithms have been developed:

This can be explained more clearly soon.....
 * BinaryTree - Partially ordered, high aspect ratios, stable
 * Ordered - Partially ordered, medium aspect ratios, medium stability
 * SliceAndDice - Ordered, very high aspect ratios, stable
 * Squarified - Unordered, lowest aspect ratios, medium stability
 * Strip - Ordered, medium aspect ratios, medium stability

Examples

 * IBM's Many Eyes provides web-based treemap tools.
 * Newsmap, an example of treemaps applied to news.
 * Netscan treemap of Usenet
 * FSView, treemapping plugin for the KDE file manager Konqueror.
 * dirgraph directory usage application (Free)
 * RoomforMilk A keyword-based news aggregator using Treemaps as primary navigation.
 * ILOG Elixir's Treemap implementation using Flex.

Academic descriptions

 * History of Treemaps by Ben Shneiderman.
 * Treemap software
 * Indiana University description
 * Generalized treemaps

Open source

 * An open-source JavaScript treemap
 * Prefuse open source library for visualization that includes treemaps
 * Acts As Treemap Open source treemap implementation for Ruby on Rails.
 * A WPF treemap implementation
 * An open-source Java treemap
 * JTreeMap, another open-source Java treemap (Swing & SWT)
 * KDirStat, an open-source treemap
 * WinDirStat, an open-source treemap for Microsoft Windows
 * TreePie, an open-source sunburst diagram (similar to a treemap) for Microsoft Windows
 * Treemap, as a Perl module
 * GdMap, GTK+ based POSIX application
 * FSView (File System View), a KDE/Konqueror plugin

Commercial

 * Macrofocus Treemap An easy to use treemapping tool with some examples (Commercial).
 * Lab Escape's Heat Map Explorer available for the desktop, web or enterprise, or as a treemap SDK.
 * The Hive Group develops enterprise treemap software that is used by major corporations and government agencies.
 * ILOG JViews Charts, a commercial Java library with a thin client demo
 * ILOG Elixir, a commercial Flex library with a Flex/Flash demo
 * Cross-platform: AVS OpenViz offers commercial custom made Desktop, Enterprise, and Web enabled Treemap software
 * Incito offer enterprise and desktop Treemap products, that provide easy to use visual analysis tools.
 * MagnaView offers commercial desktop and enterprise visualization products, including a generalized version of treemaps.
 * TreeSize displays used hard disk space as Treemap.

Kacheldiagramm Treemapping