Wednesday, October 17, 2012


6e1f1693ed5d70b2f495e9a2c8666114 reasonably smallJames Rosindell's OneZoom tree viewer is out and the paper describing the viewer has been published in PLoS One (disclosure, I was a reviewer):

Rosindell, J., & Harmon, L. J. (2012). OneZoom: A Fractal Explorer for the Tree of Life. PLoS Biology, 10(10), e1001406. doi:10.1371/journal.pbio.1001406.g004
Below is a video where James describes OneZoom.

OneZoom is fun, and is deservedly attracting a a lot of attention. But as visually striking as it is, I confess I have reservations about fractal-based viewers. For a start they make it hard to get a sense of the relative size of taxonomic groups. Looking at the mammal tree shown in the video above your eye is drawn to the monotremes, one of the smallest mammalian lineages. That the greatest number of extant mammals are either rodents or bats is not readily apparent. Fractal geometry also removes the timescale, so you can't discover whether radiations in different clades are the same age (unlike, say, if the tree was drawn in a "traditional" fashion with a linear timescale). In some ways I think fractal viewers are rather like the hyperbolic viewers that attracted attention about a decade ago - visually striking but ultimately difficult to interpret. What I'd like to see are studies which evaluate how easily people can navigate different trees and accomplish specific tasks (such as determining closest relationships, relative clade diversity, etc.).

HypviewerIn some ways OneZoom resembles Google Maps with its zoomable interface. But ironically this only serves to illustrate a key different between OneZoom and Google Maps. Part of the strength of the later is the consistent conventions for drawing maps (e.g., north is up, south is down) which, when coupled with agreed co-ordinates (latitude and longitude), enables people to mash up geographic data. What I'd like is the equivalent of CartoDB for trees.