Do network charts tell us anything interesting about the Mabinogion?

Google fusion table showing relationships of characters in Pwyll:

https://www.google.com/fusiontables/DataSource?docid=15v6OMzslLUx80zrl54n2Y8kQQMs9w-E5vhOb47mj

Google fusion table showing relationships of characters in Owein:

https://www.google.com/fusiontables/DataSource?docid=1TwRls-WPKoz4LBa7lM5zSYyZKzA79jjad05_dQte