Measuring the homogeneity of urban fabric using 2D geometry data

Abstract

To preserve the urban fabric or characteristics in specific quarters, there is often a need to either strengthen or lessen the homogeneity of the urban fabric when inserting new buildings. Evaluating the form of urban fabric is fundamentally important for urban design practice and relevant policy making. However, the quantitative methods and attempts are rare due to the lack of available methods. To address this deficiency, this article presents a GIS-based method to measure the homogeneity of urban fabric by extracting attributes directly from the geometry of 2D building footprints, including the angles between buildings, areas of building footprints, and distances between buildings. These attributes are calculated for separate overlaid grids in the open space between buildings, where each grid holds the measured values for one attribute. We test the method on a prototype, which we applied on four real sites using OpenStreetMap data. The results show how to categorize different kinds of urban fabric based on the new measure of homogeneity. The method can be used to interactively inform urban planners how new design proposals would affect the homogeneity of a neighborhood. Furthermore, the measure can be used to synthesize new design variants with a defined homogeneity.