EvoLaps is a user-friendly web application for visualizing spatio-temporal spread of pathogens, from annotated maximum clade credibility tree obtained through a BEAST continuous phylogeographic inference. Changes of localities (transitions), in a "Top-Down" reading of the tree (from the root to its leaves in a recursive way), are represented by paths with a cartographic background. The set of paths is a phylogeographic scenario.

A raw reading of these transitions produces complex scenarios, and EvoLaps helps to analyze them with: • improved display of paths using multiple graphical variables with optional time-dependent gradients (line thickness, curvature, color, opacity), • phylogeographic scenario and tree cross-highlight and selection process, • specific spatio-temporal scales and production of synthetic views based on a dynamic and iterative clustering of localities into spatial clusters, • phylogeographic scenario animation, based on tree brushing (manual or automatic), gradually over time or at time interval, over the full tree or a specific clade, • additional views of the phylogeographic scenario through inter-connected modules (migration distance curves, intensity maps, inter-clusters exchange maps or ancestral character states computed from third-party discrete variables).

Contact: francois.chevenet@ird.fr