Figure 1.

The BioPortal ontology repository. In the figure, the user is browsing the National Cancer Institute Thesaurus. A tree browser along the left-hand side of the screen allows the user to navigate the taxonomic hierarchy of the ontology. The visualization window on the right facilitates exploration of complex relationships—here, the pathway between the selected term (Lambert–Eaton myasthenic syndrome) and its superclasses in the hierarchy. The menu bar above the visualization window allows the user to change the view to examine the details of the selected term, end-user notes regarding the term or its descendants, mappings between the term and related terms in other ontologies, or links between the selected term and the data sources referenced in the National Center for Biomedical Ontology Resource Index.