Network Boundaries and System-ness

Robert A. Hanneman
robert.hanneman@ucr.edu

Hiroko Inoue
hiroko.inoue@email.ucr.edu

Christopher Chase-Dunn
chriscd@ucr.edu

Department of Sociology
University of California, Riverside

Systems of human settlements are conceptualized as multi-level network of population concentrations linked by economic, cultural, and political relations. Regions are defined as areas in the network where ties are denser than expected in a random graph of the same density. The “modularity” index is proposed as a criterion for identifying the number of regions and their membership – and hence for drawing boundaries. Modularity, as well as other network metrics (density, path length, and centralization) provide indexes of the degree of “system-ness” of the settlement system. Two examples (African and Middle-eastern settlements during the Roman Empire; Central European large urban places c. 1500) illustrate the approach. The examples, treat each level (relation) of multi-level networks separately, and treat them jointly.