''(The present contents of this page are not to be confused with the JavaLanguage Tree''''''Map class.)''

A TreeMap is a structured data visualization invented over a decade ago by BenShneiderman as a way to look at his own disk space usage.

I thought a tree map would be a handy representation if I could render one using html tables. Here is my best attempt to date. This script generates random data and renders it with nested html tables. The result is fixed height but conveniently squishy in width. Unfortunately the whole scheme breaks down when I add text to the cells because my browser's table rendering engine enlarges cells beyond the space they have been allocated and this leads to misfitting regions and unwanted whitespace. Bummer. -- WardCunningham

''(refresh these pages for more maps,)''
* http://c2.com/wiki/TreeMap.cgi?n=2 -- simple map of 12 cells
* http://c2.com/wiki/TreeMap.cgi?n=4 -- nice map of 144 cells
* http://c2.com/wiki/TreeMap.cgi?n=6 -- big map of 1728 cells

''Interesting. Pretty.''

''Can your share the source with us, Ward, or is it proprietary? ''
''Also a suggestion: use a tool-tip tag to add the identifying text so it wont impact the layout? ''
''     PaulObrien''


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Here are some interesting tree maps that are tied to live data.

* http://www.smartmoney.com/marketmap/ -- stock market ''(Requires Java-applets)''
* http://www.marumushi.com/apps/newsmap/newsmap.cfm -- news headlines

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SpaceMonger (http://www.werkema.com/software/spacemonger.html) is a nice Windows freeware that shows your disk usage as a TreeMap.

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Panopticon Software used to provide a treemap tool very neatly integrated with Excel: Spreadsheet Mapper. It gave you an extra toolbar in Excel and allowed you to create vastly configurable heat maps (treemaps) from any data in a spreadsheet. If you used live data feeds through queries, you were able to make use of the real-time updates capacity. Spreadsheet Mapper was taken off the market in 2005. If you representent a company or other organization, you can request an evaluation copy of their latest product Panopticon EX via this URL:
* http://www.panopticon.com/products/trial.htm  
Panopticon EX not only offers treemap visualization, but a collection of about 10 different graphs.
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For the fundementals of Tree Mapping, I have found no better source than "Squarified Tree-Maps" by Mark Bruls, Kees Huizing & J.J van Wijk (http://www.win.tue.nl/~vanwijk/stm.pdf). It explains the underlying algorithms very well.

PaulObrien