>Deep Green - Hyperbolic Trees
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Hyperbolic Trees

Graphical trees provide an intuitive way to display hierarchically organized information like biological classifications and phylogenies. Unfortunately, however, as static trees incorporate increased information, they become cumbersome and confusing. Hyperbolic trees, which are a dynamic representation of hierarchical structure, are an effective way to display complex trees clearly.

Deep Green will develop two different trees initially. One is aimed at students and teachers, and will include only a limited number of major branches but a lot of pictures, text, and links to other sources of data. The other is aimed at professional researchers, and will be as detailed a tree as can be achieved with current, up-to-date knowledge, and thus will contain thousands of branches. The latter will have no pictures (as that would make the huge tree hard to download), but there will be an intermediate webpage clickable from each node, giving its justification including synapomorphies, links to the actual data sets and literature in TreeBase, and biological information to facilitate macroevolutionary studies (such as estimated age of clade, amount of included diversity, etc.).

The maps at present are intended to be demonstrations of the technique, not finished products. They were constructed by Ray Cranfill and Dick Moe using data from Mishler et al. (Ann. Missouri Bot. Gard. 81. 1994), Soltis et al. (Nature 402. 1999) and R. Cranfill (unpublished).

The trees were made using Site Lens Studio, which was donated by Ramana Rao and Inxight Software Inc., in a collaboration fostered by a TED (Technology, Entertainment, and Design) conference in 2000.

Only browsers capable of using Java applets will be able to view the trees. This means Netscape 4.05 or higher, and Internet Explorer 4.5 or higher, with Java enabled. The files may be slow to load and start up, especially the first time they are invoked.

The display can be moved around the screen by clicking or clicking and dragging on the nodes. The display can be modified by using the panel at the lower left of the screen. Searches can be run by typing target words in a box in the panel. The portion of the tree pertinent to the search will be highlighted in red.


Research tree

Teaching tree

The Jepson Herbarium has an example of hyperbolic trees used to display indexes for plant distributions in California.