Defining Regions in Space via Partitioning Algorithms

December 23, 2010

Analyzing networks of billions of human transactions, researchers have demonstrated a fine-grained approach to the investigation of regional delineation. In this case, their use of partitioning algorithms has lead to a deeper appreciation of the growth of, and changes within, Great Britain.

The researchers' paper, titled "Redrawing the Map of Great Britain from a Network of Human Interactions" (PLoS ONE, December 8, 2010), belongs to the  relatively new field called "computational social sciences."

"Very little in network theory has been done, believe it or not, on networks in geographical Euclidean space," observed mathematician-researcher Steven Strogatz (Cornell University). "In reality, on top of the pure topology of who is connected to whom is the structure of actual distances,” he said. "The analysis of spatial networks could be a really important area in the next few years."

Unveiled in this study, meanwhile, were some unexpected spatial structures.

"We have discovered a new region just west of London which corroborates an earlier hypothesis of a 'western crescent' centered on high-tech activities," said Francesco Calabrese (MIT).

In another instance, it turned out that the "difference between Scotland and Wales is striking," added Carlo Ratti, director of the MIT SENSEable City Lab and one of the paper's authors. "Based on our landline data, Scotland is separated from the rest of Great Britain: just 23.3% of all call time placed or received there goes to or comes from another part of the country."

Wales, in spite of its unique cultural and linguistic heritage, appeared to be well integrated with its English neighbors to the East.

Source: Science Codex (December 9, 2010); Redrawing the Map of Great Britain from a Network of Human Interactions (pdf)

Image via PhysOrg. Caption: 

The core regions of Britain. By combining the output from several modularity optimization methods we obtain the results shown in this figure. The thick black boundary lines show the official Government Office Regions partitioning together with Scotland and Wales. The black background spots show Britain’s towns and cities, some of which are highlighted with a label doi:10.1371/journal.pone.0014248.g003