Urban Growth Modelling And GIS

Abstract

The purpose of this paper is to explore the application of mathematical models and numerical modelling concerning the growth of urban expansion areas. The models are tested on four case studies located in the 2nd Metropolitan Area of Portugal around the town of Oporto. An introduction to the approach taken is presented which can be summarised very briefly in three phases. The 1st phase deals with the selection of areas in terms of planning criteria and objectives of land-use plans evaluation as well as data availability. The 2nd phase concerns the delimitation of boundaries, preparation of aerial photographs, base maps, plans and finally, the actual computer mapping of the urban growth. The 3rd phase consists in overlay analysis and measurements of the aerial photography computer mapping performed in digital form associated to alpha-numerical databases. The results show that for the study areas of Metropolitan Area of Oporto, of around 20 Km each, the growth parameters for exponential and logistic curves are more similar according to the time period than depending on other factors, such as: i) existence of land-use plans for urban expansion; ii) classical mathematical models applied to growth phenomena, namely population. A second set of results allowed the conclusion that recent levels of external accessibility seem more determinant than levels of past urban growth. Nevertheless, the above mentioned results cannot be derived for other areas or for other periods as the available statistical data does not allow such extrapolations. But the importance of the adopted approach relies on the relatively low-cost, speed of results production as well as possibilities for generalisation and user-application. Transactions on Information and Communications Technologies vol 18, © 1998 WIT Press, www.witpress.com, ISSN 1743-3517