Urban Modelling

Abstract

Urban models are computer-based simulations used for testing theories about spatial location and interaction between land uses and related activities. They also provide digital environments for testing the consequences of physical planning policies on the future form of cities. As computers, software and data have become richer, and as our conception of the way complex systems such as cities grow from the bottom up have been reinforced, urban models have moved from theories and structures that articulate land use and movement in aggregate static terms, to more dynamic models of individual behaviour from which spatial structure emerges. We review this lineage, focusing on the shift from parsimonious models where the number of processes and variables is limited to much richer structures such as agent-based and cellular automata models which cannot be tested in the traditional way. We also identify more theoretical models based on simulating aggregate urban dynamics where the focus is on incorporating discontinuities in the growth of the urban system. We illustrate that urban modelling falls between the search for simplicity in articulating the structure of cities and the need to embrace the obvious complexity that confronts our understanding and intervention in such systems.