Friday 26 September 2008

Enhancing a GIS Cellular Automata Model of Land Use Change: Bayesian Networks, Influence Diagrams and Causality

Authors: Kocabas, Verda1; Dragicevic, Suzana2

Cellular Automata (CA) models at present do not adequately take into account the relationship and interactions between variables. However, land use change is influenced by multiple variables and their relationships.

The objective of this study is to develop a novel CA model within a geographic information system (GIS) that consists of Bayesian Network (BN) and Influence Diagram (ID) sub-models. Further, the proposed model is intended to simplify the definition of parameter values, transition rules and model structure. Multiple GIS layers provide inputs and the CA defines the transition rules by running the two sub-models. In the BN sub-model, land use drivers are encoded with conditional probabilities extracted from historical data to represent inter-dependencies between the drivers. Using the ID sub-model, the decision of changing from one land use state to another is made based on utility theory. The model was applied to simulate future land use changes in the Greater Vancouver Regional District (GVRD), Canada from 2001 to 2031. The results indicate that the model is able to detect spatio-temporal drivers and generate various scenarios of land use change making it a useful tool for exploring complex planning scenarios.

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