MOTIVATION: Clinicians, health officials and researchers are interested in the epidemic spread of pathogens in both space and time to support the optimization of intervention measures and public health policies. Large sequence databases of virus sequences provide an interesting opportunity to study this spread through phylogenetic analysis. To infer knowledge from large phylogenetic trees, potentially encompassing tens of thousands of virus strains, an efficient method for data exploration is required. The clades that are visited during this exploration should be annotated with strain characteristics (e.g. transmission risk group, tropism, drug resistance profile) and their geographic context. RESULTS: PhyloGeoTool implements a visual method to explore large phylogenetic trees and to depict characteristics of strains and clades, including their geographic context, in an interactive way. PhyloGeoTool also provides the possibility to position new virus strains relative to the existing phylogenetic tree, allowing users to gain insight in the placement of such new strains without the need to perform a de novo reconstruction of the phylogeny. AVAILABILITY AND IMPLEMENTATION: https://github.com/rega-cev/phylogeotool (Freely available: open source software project). CONTACT: [email protected]. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Aggregate data are obtained by applying statistical aggregations and statistical analysis functions over raw data. We believe that a major adherence of aggregate data to the process that generates them can make their modeling simpler and more effective. We propose a formal description of the aggregation process and derive from this description a data structure for the representation of aggregate data. Several new concepts are introduced, in particular the implicit attributes, and an extension of the aggregation operator, called the generalized summarization. We also show that the introduced data structure allows us to identify in a simple way the population of a statistical object.