To refer to or to cite this work, please use the citation to the published version:Van Nuffel, N., Saey, P., Derudder, B., Devriendt, L., Witlox, F. (2010 AbstractThis paper presents an examination of the empirical merits of a set of spatial interaction indices for measuring hierarchical differentiation (i.e. dominance and connectivity) in a spatial network. To allow for the comparison of the degree of hierarchical differentiation in networks with different number of nodes/links, we propose to normalize the ratio between the real measures and the corresponding values for a rank size distribution in order to obtain readily interpretable measures of hierarchical differentiation. When applied to data on 2 air passenger flows within Europe, the normalized indices, interpreted together, appear to give a good idea of the tendency towards hierarchical differentiation.The potential usefulness of this analytical framework is discussed in the context of studies on (transnational) inter-city relations and empirical assessments of changes in the spatial configuration of airline networks.

Abstract:This paper aims to refine existing approaches for classifying nodes in spatial networks. Apart from generally used variables measuring (i) the total connectivity of a node and (ii) the spatial make-up of this total connectivity, we argue that a third indicator should be taken into account when describing the structure of a spatial network, i.e. (iii) the degree of 'polarization' in a node's connectivity configuration. We measure 'polarization' by applying multiple linkage analysis, a technique that allows determining the number of meaningful connections for each node in the network. In this paper, we illustrate this approach by clustering 65 European cities based on their insertion in European air transport networks in 2005. The number of meaningful flows of a city is hereby considered alongside both traditional measures of connectivity. The results of the cluster analysis suggest that including a measure of polarization may indeed lead to a more satisfying typology.

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This paper presents an approach for extending the study of networking to areas other than daily urban systems. It examines whether key policy concepts of the Flanders Spatial Structure Plan fit in with the geographical structuring reflected in the spatial structure of commuting. The overall pattern of commuting flows is analysed by means of the degree of polarisation, determined on the basis of the number of significant flows and the convergence between two divisions in commuting zones. The development of multi-nodal patterns on the local and regional level is investigated by consideration of the degree of nodality and openness. In general, the spatial pattern of commuting corresponds to the structure of the overall urban system in Flanders as described in terms of fully developed and fragmental Christaller patterns. Networking has created the three types of urban system already described in the literature; a further fourth type can be recognised. Copyright (c) 2005 by the Royal Dutch Geographical Society KNAG.