Researchers in the US and UK wanted to evaluate whether or not the regional boundaries established by governments reflected how people interacted on an individual level. They used 12 billion telephone calls placed over a one month period as their data set:
This paper proposes a novel, fine-grained approach to regional delineation, based on analyzing networks of billions of individual human transactions. Given a geographical area and some measure of the strength of links between its inhabitants, we show how to partition the area into smaller, non-overlapping regions while minimizing the disruption to each person's links. We tested our method on the largest non-Internet human network, inferred from a large telecommunications database in Great Britain. Our partitioning algorithm yields geographically cohesive regions that correspond remarkably well with administrative regions, while unveiling unexpected spatial structures that had previously only been hypothesized in the literature. We also quantify the effects of partitioning, showing for instance that the effects of a possible secession of Wales from Great Britain would be twice as disruptive for the human network than that of Scotland.
The paper goes into some detail about how their findings illuminate changes in Britain's regional cultures.
Link via io9 | Image: Ratti et al.