App for basic tree statistics

Here we build an app that calculates basic tree statistics for a given input tree.

Note that because we calculate the Gamma Statistic (Pybus and Harvey 2000), we need an ultrametric tree as input, meaning a tree where all the leaves are the same distance above the root.

In PhyloJS, you can check this using the isUltrametric() method on the Tree class, but for the sake of simplicity we leave it to the user to ensure the tree is ultrametric. As an aside, PhyloJS allows for a difference of 1e-6 between tip heights above the root when deciding if a tree is ultrametric. Users can set this tolerance though (see API).

If you don't have an ultremetric tree in any of the above formats handy to test out, then you can download a small Newick tree here.

See the Pen tree-stats by Leo Featherstone (@LeoFeatherstone) on CodePen.