Generate your own tree clouds!
One of my research interest is tag-cloud drawing. The domain is a natural extension to the classical Graph Drawing problems. However, it is much more open-ended. I keep seeing new types of tag clouds each year!
Tree clouds are a hybrid of trees and tag clouds. To my knowledge, they were first introduced by Jean Véronis. Here is an example:
Philippe Gambette has made available Python software to generate tree clouds. Together with Jean Véronis, he also gave a presentation on the topic recently:
Montreal, Canada 
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This is very cool. For whatever reason, the title made me expect an April Fool’s joke–perhaps because of this post:
http://www.redmonk.com/jgovernor/2009/04/01/cloud-standards-breakthrough-with-new-cloud-source-license/
I hope others were not so predisposed and took a serious look! I sometimes miss working on graph drawing.
Comment by Daniel Tunkelang — 1/4/2009 @ 16:06
Nah. Tag clouds are no joke to me.
However, you should have seen the face of my wife when I she asked me once “what are you working on”… “Well, honey, you see these tag clouds on the web… right? Ok, I’m trying to find ways to draw them better.” “Why can’t you solve world hunger instead?”
Comment by Daniel Lemire — 1/4/2009 @ 16:47
Well, I devoted several years to pretty pictures myself:
http://www.cs.cmu.edu/~quixote/#Graph%20Layout
There will be time to work on solving world hunger after we find a better approach to minimizing edge crossings in general graph layouts. Or at least making them look pretty on iPhones.
Comment by Daniel Tunkelang — 1/4/2009 @ 18:22
Daniel, I like the visualization! If you like mixing tags and trees you may want to take a look at my jquery machine tag trees: http://tagaholic.me/blog.html#gem I haven’t written anything on them yet but will soon.
Comment by gabriel — 2/4/2009 @ 17:15