Users can select nodes to explore further layers of the hierarchy.• Taxa reposition automatically on interaction.• Smooth animation maintains context.• Purple shows the browsing path.• Synapomorphies (characteristics that diagnose a node) are shown on links between nodes.

Tree Visualizations for Taxonomies and PhylogeniesCynthia Sims Parr, Bongshin Lee, Svetlana Yarosh, and Benjamin B. Bederson

University of Maryland, Human-Computer Interaction LaboratoryFree Download at http://www.cs.umd.edu/hcil/biodiversity

Users can search both the names in the classification and the full text of the Animal Diversity Web. • Search results are colored orange.• View is limited to nodes relevant to the search results.

TaxonTree links to online databases at University of Michigan’s Animal Diversity Web, University of Arizona’s Tree of Life, and University of California’s Museum of Paleontology. Our visualization provides easier access to existing information.

Tree of Life

UCMPAnimal Diversity Web

TaxonTree: Single tree visualization

Searching

External linkage

DoubleTree: Visualizing two treesOverviewWe are building information retrieval interfaces for the rapidly expanding domain of biodiversity databases. Biodiversity databases contain organism-related information such as taxonomy, natural history, and conservation data.  They are as complex as molecular and medical biology resources, and can be linked to them, yet serve a broader audience. Our goal is to help users more easily work with these complex structures.

TaxonTree To visualize the Linnaean classification for 200,000 taxonomic names in Kingdom Animalia we adapted a tool, SpaceTree, that we developed initially for visualizing corporate organizational hierarchies. TaxonTree combines dynamic query interfaces and zoomable graphics to visually accommodate highly interconnected data.

DoubleTree We built another tool to visualize multiple trees. DoubleTree allows users to compare and navigate two trees using coupled interaction.

Lessons Learned• Interaction with an animated, zoomable node-link diagram aided users' understanding of the data• Most users approached biodiversity data by browsing, using common names and general knowledge rather than the scientific keyword expertise necessary to search using traditional interfaces • Users with different levels of interest in the domain had different interaction preferences

PublicationsParr et al. “Tree visualizations for taxonomies and phylogenies” BioInformatics (in press)Lee et al. “How Users Interact with Biodiversity Information using TaxonTree” AVI 2004

Users can compare two trees in upper and lower frames of a window. • Selecting a node in one tree opens the corresponding node in the other tree.