DBpedia Ontology Sunburst

The Sunburst shows the Ontology of DBpedia. The ontology used is not the one published on the DBpedia web site because not updated. In order to reconstruct the ontology, we ran a recursive procedure, starting from owl:Thing (the root class of the DBpedia Ontology), that performs SPARQL queries for retrieving the children class of a certain class and their amount of entities. The SPARQL query used is the following:

SELECT ?subclass (COUNT(?entity) AS ?count) {
  ?subclass rdfs:subClassOf owl:Thing .
  ?entity a ?subclass .
}

This is only the first query executed in the recursive procedure. Then, the same query is executed for each owl:Thing child class substituting owl:Thing with the name of the child class.

The sunburst shows ontology classes with colour-opacity while the entities/instances of the classes are highlighted for making them more visible. The most significative classes have been colored for making clear which are the most relevant DBpedia classes (Person, Organisation, Place, Work, Species and Event).

It turns out that:

• The most populated classes, at the first level of depth, are Agent and Place;
• The third most populated class, at the first level of depth, is CareerStation that is a class that keeps track the career step of a Person (in particular SoccerPlayer);
• The most populated class, between the colored classes, is Person;
• The maximum depth of the ontology is 6.

The gist is based on the Bostock and Kerry Rodden sunburst. (The data used have been collected in July 2014)