Die Klassifikation der innerstädtischen Subzentren in Köln mit Hilfe clusteranalytischer Verfahren.

Ein methodischer Beitrag zur intraurbanen Zentralitätsforschung

Abstract

The investigation of central place systems within cities has developed to one of the most important subjects of urban geography over the past four decades. Geographers created a great variety of methods to analyze the structure and hierarchy of intra-urban centres. In particular, they have used commercial characteristics and principles, the number, size and distribution of retail and administrative facilities, physiognomical features or the number of employees to evaluate urban subcentres. Unfortunately, all attempts to work out intra-urban central place systems show one common failure: only one or two different variables were used to describe centrality. The analysis of the 20 largest subcentres of Cologne shows that the classification of subcentres depends in a very close way on the selected variable. As a consequence, it is necessary to use a set of balanced indicators describing both the internal structure and the use of subcentres. Here the number of shopping facilities and other institutions of the tertiary sector, the percentage of shops selling long term goods, the percentage of shops offering short term goods, the number of stores and finally the pedestrian frequencies have been chosen as suitable variables reflecting the centrality of the Cologne subcentres. Based on these Variables the intra-urban subcentres can be allocated to three different groups by using a cluster analysis. In connection with their potential catchment areas, one can distinguish between neighbourhood subcentres, community subcentres and district subcentres. In this study the cluster analysis is taken to be a suitable method for working out the internal structure of the central place system within a city based on a complete set of variables that project centrality in a very close way.