Urban Morphometrics: a Decision Support Information System for Evidence-Based Urban Design Codes

Despite its mesmerising complexity, the physical form of cities can be reduced to a relatively limited number of structural elements: street networks, plots and buildings (Moudon, 1997; Kropf, 2017). These come in endless different combinations that constitute patterns of urban form, among the most complex of human artefacts. Urban Design codes, the regulatory statement attached to masterplans, are widely used to help shape such form and make our cities more viable, efficient, sustainable and satisfactory, but their potential is still limited for a number of reasons. Their quality varies, depending on who defines and sets them and there is no agreement on what elements of urban form in particular they should regulate, and on what ground of evidence. The problem of evidence in particular seems challenging: the extent
to which certain urban forms would correlate more or less than others to the way urban places ultimately work, i.e. to cities’ performance, are largely based on speculative or anecdotical evidence. This is due to a simple fact of science: the systematic and comprehensive description of urban form is a very labour/knowledge-intensive endeavour, to the point that it can only be undertaken on a very limited number of small cases or abruptly simplified in content. Without a systematic and comprehensive description of urban form, it is obviously difficult to link it up to other observable and measurable dynamics that take place in cities, such as for example gentrification, health, energy consumption or social inequality, on a solid scientific ground. Hence, the important contribution that urban form actually offers to achieving planning objectives of social, economic and environmental relevance may appear
somehow elusive.
Like all urban design codes, the NMDC (2021) is based on the assumption that cities are made of areas that are consistently identifiable by way of their distinctive visible form, which is linked to the way they are used. In the NMDC language, these are named “area-types”. The success of the NMDC lies then in being able to: a) set a description of the physical form of cities such that area-types can be in fact reliably identified on the ground; b) relate area-types to how places actually work locally, and c) set a system of prescriptions (codes) accordingly.
At the Urban Design Studies Unit of University of Strathclyde, we have for many years studied urban form in an urban design context. In particular, our research has long endeavoured to generate a system of evidence in the relation between description and prescription for masterplanning purposes. With this short pamphlet, we intend to shortly illustrate our latest research outcomes in this respect, which we gather under the umbrella of “Urban Morphometrics” (UMM).