Multi-scalar urban densities: from the metropolitan to the street level

Abstract

Density is a key concept in urban research and theory, yet also much confused and abused. A main source of confusion in the analysis of urban densities, is that the spatial scale of measurement has a major impact on the outcome. From the scale of an urban block to that of a metropolitan area, densities can decrease a hundred-fold. Variations in the size of administrative and statistical districts can strongly bias comparative studies. For large metropolitan areas, the conventional average density measure obscures local concentrations, that are relevant for the urban experience, walking and public transport. Addressing these issues, a multi-scalar approach for mapping and measuring density is proposed, that captures concentration patterns in cities at scales relevant to everyday life: the micro-spatial scale of direct sensory experience, the meso-scale of walkable neighbourhoods, and the macro-scale of metropolitan areas. Demonstrating this approach, the Metropolitan Walkable Density (MWD) and the Urban Experiential Density (UED) are mapped and measured for cities in North America, Australia and Europe, based on census data. These multi-scalar approaches capture concentrations at scales that relate to how we access and experience the city. The findings show that lived densities vastly differ from conventional simple averages.