The tree shows the classes of the DBpedia Ontology.
Due to the size of the ontology tree, it is not possible to look at a complete overview. Even if zoom mechanism was introduced the overview would results confusing. Furthermore, the overlapping edges make difficult to read relationships between classes.
The Mike Bostock Cluster Dendogram has been used for constructing the visualization.
@fabiovalse I'm curious, how did you generate the data? Particulary, where did the counts come from? I'm guessing there was an external script or SPARQL query? Thanks!