Spatial dynamics of urban expansion: The case of Innsbruck, Austria

The spatial dynamics of the growth and development of urban regions is frequently represented in an unidimensional way. In contrast, this report demonstrates the use of five increasingly complex tools for the analysis of urban decentralization. All of them provided evidence for a population decline process in the central city. The tools differ, however, in the amount of information provided for the distribution of growth in the surrounding area. The dichotomous tool simply stated that population growth is higher outside of the central city without giving any clue to the location of this growth. The second tool provided averages of population growth for distance bands. The general trend revealed by this tool was substantiated in more detail by the following models. The third tool supplied a more detailed directional profile of population change. However, this solution relied on the assumption that the process of population spread is concentric and is not affected by the settlements' directional position with respect to the central city. The two final tools attempted to relax this assumption. The fourth tool provided profiles of generalized population change for three groups of settlements located in the same general direction, while the fifth tool estimated the population change value for each settlement at its actual position with respect to the central city. The cartographic results obtained via the fifth tool make it possible to draw population change profiles virtually to any direction. While the first two tools are based on simple arithmetic, the last three are based on ordinary least square (OLS) regression models thus they allow for a statistical evaluation of the fit of the results. The applied method has proved an useful instrument for the analysis of spatial dynamics even in orographically structured urban regions like those of Innsbruck, a typical alpine town. So the paper may also be regarded as a contribution to the ongoing discussion of two themes of European urban research: discussion of the central-place-model and discussion of the development of alpine towns.