Grontcrawler transforms OWL-EL ontologies (a restricted subset, see paper for details) into undirected graphs by following rule-based, fix-point edge-production procedure. Graph representation of ontologies allows us to study the axiomatic structure of the underlying OWL-EL ontology (both TBox and ABox, i.e., definitions and instances) by exploring its graph representaion using the graph drawing techniques. - View it on GitHub