Pinwheel Layout to Highlight Community Structure

Caption The intuitive appeal of force-directed layouts is due in part to their ability to represent underlying community structures. Such diagrams show dense pockets of nodes with bridges connecting across clusters. Yet, it is possible to start, rather than end, with community structure. This is a “pinwheel” diagram using the author’s Facebook personal network (captured July 15, 2009). Nodes represent the author’s friends and links represent friendships among them. The author is not shown. Each ‘wing’ radiating outwards is a partition using a greedy community detection algorithm (Wakita and Tsurumi, 2007). Wings are manually labeled. Node ordering within each wing is based on degree. Node color and size is also based on degree. Nodes position is based on a polar coordinate system: each node is on an equal angle of n/360o with a radius being a log-scaled measure of betweenness. Higher values are closer to the center indicating a sort of cross-partition ‘gravity’.