LODeX: A visualization tool for Linked Open Data navigation and querying.

We present LODeX, a tool for visualizing, browsing and querying a LOD source starting from the URL of its SPARQL endpoint. LODeX creates a visual summary for a LOD dataset and allows users to perfor queries on it. Users can select the classes of interest for discovering which instances are stored in the LOD source without any knowledge of the underlying vocabulary used for describing data. The tool couples the overall view of the LOD source with the preview of the instances so that the user can easily build and refine his/her query. The tool has been evaluated on hundreds of public SPARQL endpoints (listed in Data Hub). The schema summaries of 40 LOD sources are stored and available for online querying at http://dbgroup.unimo.it/lodex2.