Fig. 2
From: Identification of key films and personalities in the history of cinema from a Western perspective
Densities of relationships between tags in Genres (a, b, c), Continents (d, e, f) and Countries (g, h, i): (a, d, g) shows how much a tag is used with other ones, divided by total number of movies belonging to the first tag, using the diagonal for counting when a tag is used alone; (b, e, h) show how much a tag references the other ones, divided by total number of movies belonging to the tag that makes at least one reference; (c, f, g) show how much a tag is referenced by the other ones, divided by total number of movies belonging to the tag that receives at least one reference. Since a movie can be labeled with multiple tags in the same item, rows sum to values bigger than one