[OC] Full Tree of Life (ITIS edition)

ITIS Tree of Life

Just finished another visualization of entire taxonomy tree. Previous is buried here: GBIF ToL.

Main concept is very simple: each taxon is a point, and each taxon has a clockwise-bent arc from it's parent taxon.

Trick is to place those points in a meaningful way. At first, I was using force-directed algorithm to do it. In general, it succeeded in grouping points by clades, but introduced a lot of branch overlapping (check how purple Echinodermata is "intruded" into Arthopoda in GBIF version).

Force-directed algorithms can layout not only trees, but basically any graph, and I thought: maybe tree-specific algorithm will produce a better result? I've found out there is a cool Voronoi Treemap algorithm which for any given tree can build a set of nested polygons, a polygon for each node in a tree. Not only it eliminates branch overlapping problem, but also it ensures those branches fit into convex polygons and you can even add gaps between adjacent branches. So I've built a CLI wrapper around a Java implementation I've found on GitHub.

At first, I've used it for NCBI database, but I didn't use gaps and haven't published interactive version yet (but there are PNGs in Wikimedia Commons). Then, I've made a treemap for ITIS. Points are points and polygons have been used for mouse hover feature. When I was making force-directed GBIF, I had to separately compute those polygons for each clade of given ranks. Now both points and polygons are computed by an algorithm, which is nice.

What do you think?