Challenges in phylogenetic tree visualization

I recently read an excellent review by Roderic Page, on the challenges in phylogenetic tree representation and visualization. It provides an overview  on existing software and tools (although he missed our ETE package, see image below for an example of ETE's visualization features). The number and diversity of existing tools is overwhelming, but probably matches the diversity of different interests and possible applications of phylogenetic trees. One may be interested in  overlaying sequence information (see below), while other would be interested in displaying information on the geographical distribution of the species. Some may need to represent uncertainty and overly different topologies, or networks to represent transfers of genetic material, the possibilities are unlimited.

 Most importantly he mentions some of the challenges of tree visualization software such as the ability to represent huge trees and to allow interactive behavior with the user. In our group we have encountered such needs and this is the reason behind implementing more visualization features in ETE. Fortunately new technologies are offering new opportunities as well, and I enjoyed imagining the possibilities that 3D visualization and touchscreen technologies will provide to researchers. Definitely is a field to follow.

 If you are interested in the topic. I recommend this video.