A simplified model of urban morphology: application to an analysis of the environmental performance of cities

The evidence for the influence of urban configuration on outdoor climate conditions, on the energy balance of buildings, and on diffusion of pollutants is quite conclusive. But the exact characterization of this complex link remains critical, especially because of the extreme morphological heterogeneity at a fine granularity level: the building and its close environment. In this approach I try to cope with this difficulty, by working at the district or city scale, by assimilating the urban fabric into a porous medium with a rigid solid skeleton, and by proposing a simple spatial model based on a set of original morphological indicators of environmental performance: density, rugosity, porosity, sinuosity, occlusivity, compacity, contiguity, solar admittance, and mineralization. This system of indicators has been embedded in a shell of development of GIS and applied to various urban fabrics. The possible applications of this model are diverse: simplified analysis of outdoor microclimate tendencies, sustained environmental evaluation of a neighborhood, interdistrict or intercity comparisons, or modelling of the climate effect on future urban amenities.