A multifactorial GIS-based analytical method to determine the quality of urban green space and water bodies

Abstract

The type, size, and spatial distribution of public green spaces and water bodies are key factors for the microclimatic quality of urban areas, particularly within densely built-up districts, where they influence the quality of life. The analytical method presented in this paper looks at entire cities in a GIS-based approach that identifies potential critical areas of the city (with regard to heat stress or the accessability of green spaces) and quantifies their size and location in relation to green space and water bodies. The advantage of this method is that analysing the urban environment can be largely automated by the use of available geo base data. This requires the application of algorithms from the field of landscape ecology to the urban environment. The method is based on multifactorial evaluation. Comparisons between cities are made possible by extremum normalisation. Densely built-up areas as well as all green spaces and water bodies within settlements are quantified in the form of areal indicators. Thus the proximity of densely built-up areas to green space or water bodies is measured by the indicator "Euclidian distance." By correlating the resulting potential heat islands with population data from the 2011 National Census, it is possible to determine the likely number of residents affected. The method presented, which has been tested on seven cities in Germany, is part of a wide-ranging investigation into urban densities aimed at improving efficiency and environmental quality.