A Disaggregated Model of Urban Spatial Structure: Theoretical Framework

This paper describes a disaggregated model of urban spatial structure which combines the framework provided by the macroscale approach of social physics, to which most models developed to date belong, and the advantages derived from the use of the microscale approach provided by economic theory. The model attempts to integrate both approaches by means of the use of maximum entropy techniques together with concepts from microeconomic theory. The former provides an operational basis for the model, while the latter provides a theoretical explanation of the process. At a general level the model introduces the addition of a land market submodel and a transport submodel to the framework provided by Lowry (1964). At a more detailed level the model transforms the employment in the city into economic sectors, socioeconomic groups, and income groups. This allows for the conception of the urban spatial structure in terms of a market where transactions take place between buyers and sellers of goods. The disaggregated model presented here has been designed to provide a large number of variables which can be manipulated and controlled as part of policy decision making and planning analysis—this includes, for example, the normal planning controls such as density restriction and changes in the location of manufacturing, government, and agricultural employment. Also, the effect of changes in the costs of transport (car prices, fares, and routing) can be analysed. Taxes and subsidies on income, housing, and housing interest rates can be manipulated within the model.