Inspired in part by the release of the draft tree of life (doi:10.1073/pnas.1423041112 by the Open Tree of Life, I've been revisiting (yet again) ways to visualise very big phylogenies (see Very large phylogeny viewer for my last attempt). My latest experiment uses Google Maps to render a large tree. Google Maps uses "tiles" to create a zoomable interface, so we need to create tiles for different zoom levels for the phylogeny.