Errors and uncertainties in urban cellular automata

Errors and uncertainties are important issues in most geographical analyses and modelling processes. Cellular automata (CA) have been increasingly used for modelling geographical phenomena, such as the evolution of urban systems. Urban simulation frequently involves the inputs of a large set of spatial variables from GIS. The errors of data source in GIS can propagate through CA modelling processes. Moreover, CA models themselves also have modeling uncertainties because they are just an approximation to reality. These uncertainties have impacts on the outcome of urban simulation. Identification and evaluation of these errors and uncertainties are crucial for understanding and implementing the simulation results of urban CA modelling. It is found that some of the characteristics of errors and uncertainties in urban CA are quite unique which are not present in traditional GIS models. The study can help urban modelers and planners to understand more clearly the characteristics and implications of CA modelling.