Delineating Geographical Regions with Networks of Human Interactions in an Extensive Set of Countries

• DOI: 10.1371/journal.pone.0081707
• Publication Date: 2013-12-18T17:06:46Z
• Authors: Stanislav Sobolevsky; Michael Szell; Riccardo Campari; Thomas Couronné; Zbigniew Smoreda; Carlo Ratti
• Keywords: Social and Information Networks (cs.SI); FOS: Computer and information sciences; Physics - Physics and Society; Asia; Geography; Science; Q; R; Social Support; FOS: Physical sciences; Computer Science - Social and Information Networks; Physics and Society (physics.soc-ph); Europe; 03 medical and health sciences; 0302 clinical medicine; Residence Characteristics; Africa; 11. Sustainability; Medicine; Humans; Algorithms; Research Article

Large-scale networks of human interaction, in particular country-wide telephone call networks, can be used to redraw geographical maps by applying algorithms of topological community detection. The geographic projections of the emerging areas in a few recent studies on single regions have been suggested to share two distinct properties: first, they are cohesive, and second, they tend to closely follow socio-economic boundaries and are similar to existing political regions in size and number. Here we use an extended set of countries and clustering indices to quantify overlaps, providing ample additional evidence for these observations using phone data from countries of various scales across Europe, Asia, and Africa: France, the UK, Italy, Belgium, Portugal, Saudi Arabia, and Ivory Coast. In our analysis we use the known approach of partitioning country-wide networks, and an additional iterative partitioning of each of the first level communities into sub-communities, revealing that cohesiveness and matching of official regions can also be observed on a second level if spatial resolution of the data is high enough. The method has possible policy implications on the definition of the borderlines and sizes of administrative regions.<br/>10 pages, 4 figures<br/>