A constrained CA model for the simulation and planning of sustainable urban forms by using GIS

A constrained cellular automata (CA) model based on 'grey cells' for the simulation of different types of urban forms and developments is developed within a raster GIS. Remote sensing and GIS are used to supply information on environmental constraints and locations of growth centers for the simulation. The model is able to consider different criteria, such as urban forms, environmental suitability, and land consumption for the planning of sustainable cities. Seven different types of urban forms and developments that range from compact-monocentric, compact-polycentric, compact-monocentric-environmental, compact-polycentric-environmental, dispersed, highly dispersed, to very highly dispersed developments were simulated by using the model. The model can generate urban forms and developments with fractal structures that are close to real cities. The simulated patterns were evaluated by using different cost indicators related to sustainable development principles.