Recent Developments of Complex Network Analysis in Spatial Planning

In the last years, we acknowledge a great scientific interest on complex network analysis, a method able to characterise systems with very large numbers of entities (the nodes or vertices) interlaced by a series of connections/relationships (the links or edges). The objects of analyses as such are biological (predator-pray); information (internet); social (actor-in the same movie); transportation (railway and road networks) systems. While in general a network is an abstract (topo) logical object, spatial networks belong to an important class of systems that includes nodes and edges with a clear reference to space. Recently the interest of scientists has focused on methods able to define and investigate on communities emerging from the structure of a network. In this respect the spatial factor can emerge both as the result of the topological community structure that maps back onto geography in the form of sensible spatial regions, or just as spatial clusterisation of nodes in principle embedded in space. In this essay, the authors aim at presenting a state of the art summary of the last advances in the field of network community detection methodologies with a detailed view to the case of spatial networks. Secondly, the paper will report on a case study concerning a major issue for policy makers and planners: the delimitation of sub-regional domains showing a sufficient level of homogeneity with respect to some specific territorial features. We compare some intermediate body partitions of the island of Sardinia (Italy) with the patterns of the communities of workers and students, by applying grouping methodologies based on the characterisation of the Sardinian commuters’ system as a complex weighted network.