Guy Engelen

The use of constrained cellular automata for high-resolution modelling of urban land-use dynamics

A cellular automaton is specified to give a spatially detailed representation of the evolution of urban land-use patterns. Cell states represent land uses, and transition rules express the likelihood of a change from one state to another as a function both of existing land use in the 113-cell neighbourhood of the cell and of the inherent suitability of the cell for each possible use. The model is used to simulate the land-use pattern of Cincinnati, Ohio. The simulation results are realistic and sensitivity analysis shows that the predictions of the model are relatively accurate and reproducible, thus suggesting that cellular ast;automata-based models may be useful in a planning context.

High-resolution integrated modelling of the spatial dynamics of urban and regional systems

Abstract An emerging branch of geocomputing involves the modelling of spatial processes. A variety of techniques are being used, the most important being traditional regionalized system dynamics approaches, multi-agent systems, and cellular automata (CA). The techniques are frequently combined to model processes operating at different spatial scales. Urban and regional models based on CA give good representations of the spatial dynamics of land use. In a current application, a cellular model of The Netherlands at 500 m resolution is driven by a macro-scale dynamical spatial interaction model defined on 40 economic regions; this model is in turn driven by national planning projections and policy goals. Given the national totals, the macro-scale model generates regional demands for population and a number of economic activities. These demands are translated into demands for cell space, which the CA then attempts to locate. In turn, information on conditions at the cellular level, such as the quantity and quality of land available to various activities and actual densities at the cellular scale, are returned to the regional model to modify parameter values there. Linking the two models operating at the two scales improves the performance of both. The results of high-resolution modelling of spatial dynamics raise several methodological issues. One of the most pressing concerns evaluation of the results. Another issue concerns predictability. To the extent that these models capture the evolving nature of real cities and regions, they cannot be strictly predictive.

Cellular Automata as the Basis of Integrated Dynamic Regional Modelling

We present an integrated model of regional spatial dynamics consisting of a cellular automaton-based model of land use linked both to a geographic information system (GIS) and to standard nonspatial models of regional economics and demographics, as well as to a simple model of environmental change. The operation of the model is illustrated with an application to the island of St Lucia developed for the purpose of providing insights into the possible socioeconomic consequences for the island of global climate change. On the basis of results from this and other applications of the model, we conclude that cellular automata not only permit a detailed modelling and realistic prediction of land-use patterns, but they also provide a means of introducing the effects of spatially localized environmental factors, as represented in the GIS, into the operation of standard economic and demographic models, which are otherwise unconstrained.

Using cellular automata for integrated modelling of socio-environmental systems

Cellular automata provide the key to a dynamic modelling and simulation framework that integrates socio-economic with environmental models, and that operates at both micro and macro geographical scales. An application to the problem of forecasting the effect of climate change on a small island state suggests that such modelling techniques could help planners and policy makers design more effective policies — policies better tuned both to specific local needs and to overall socio-economic and environmental constraints.

Integration of multi-scale dynamic spatial models of socio-economic and physical processes for river basin management

Planners, policy-makers and their technicians have the difficult task to intervene in complex human-natural systems. It is not enough for them to focus on individual processes; rather it is necessary to address the system as a complex integral whole. In the given circumstances, integrated models as part of Policy Support Systems (PSS) can provide support. The MedAction PSS incorporates socio-economic and physical processes in a strongly coupled manner. It is implemented with the GEONAMICA application framework and is intended to support planning and policy making in the fields of land degradation, desertification, water management and sustainable farming. The objective of this paper is to provide some insight in the individual models, the model integration achieved, as well as the actual use of the MedAction PSS. For the latter an application example is developed. The paper also argues that technical and scientific aspects of Policy Support Systems are not the sole elements deciding on their use in practice and concludes with some lessons learned during the development and use of the MedAction PSS and similar systems. 2005 Elsevier Ltd. All rights reserved.

A review of Bayesian belief networks in ecosystem service modelling

A wide range of quantitative and qualitative modelling research on ecosystem services (ESS) has recently been conducted. The available models range between elementary, indicator-based models and complex process-based systems. A semi-quantitative modelling approach that has recently gained importance in ecological modelling is Bayesian belief networks (BBNs). Due to their high transparency, the possibility to combine empirical data with expert knowledge and their explicit treatment of uncertainties, BBNs can make a considerable contribution to the ESS modelling research. However, the number of applications of BBNs in ESS modelling is still limited. This review discusses a number of BBN-based ESS models developed in the last decade. A SWOT analysis highlights the advantages and disadvantages of BBNs in ESS modelling and pinpoints remaining challenges for future research. The existing BBN models are suited to describe, analyse, predict and value ESS. Nevertheless, some weaknesses have to be considered, including poor flexibility of frequently applied software packages, difficulties in eliciting expert knowledge and the inability to model feedback loops. BBNs are increasingly used to analyse, predict and value ecosystem services (ESS).Most BBN applications in ESS modelling target only a single service.Numerous advantages of BBNs in ESS modelling are demonstrated in current applications.Model drawbacks are absence of feedback loops and obligatory variable discretization.Spatially explicit modelling and modelling of ESS bundles are future opportunities.

Towards an automatic calibration procedure for constrained cellular automata

This paper describes an automatic calibration method for the class of cellular automata (CA) characterized by additive transition rules. CA can serve as instruments to support decision-making in spatial systems, since they are in effect dynamic maps representing geographic processes. However, the quality of CA based decision support models depends on the adequacy of the transition rules, which must be complex in realistic models, and these rules typically contain a number of parameters that must be calibrated. At present there is no general method to calibrate the transition rule set other than a manual tuning of the rules. Existing automatic techniques are applicable only to very simple CA. The method presented here draws on several standard optimization and search techniques, adapting them to the CA calibration problem. The procedure is developed first for application to the general class of unconstrained additive transition rules, and is then modified in order to deal with the case of constrained additive rules, where the number of cells in each state at each iteration is determined exogenously to the CA; this latter class is important in urban modeling applications. The calibration procedure is shown to be capable of systematically modifying arbitrary, randomly generated rule sets in order to produce a set of rules that is able to correctly replicate a series of test maps.

Integrated modelling and decision-support tools: a Mediterranean example

A great deal of new knowledge and research material have been generated from research carried out under the auspices of the European Union (EU). However, only a small amount has been made available as practical policy-support tools. In this paper, we describe how EU funded research models and understanding have been integrated into an interactive decision-support system addressing physical, economic and social aspects of land degradation in the Mediterranean. We summarise the 10 constituent models that simulate hydrology, human influences, crops, natural vegetation and climatic conditions. The models operate on very different spatial and temporal scales and utilise different modelling techniques and implementation languages. Many scientific, modelling and technical issues were encountered during the transformation of ‘research’ models into ‘policy’ models. We highlight the differences between each type of model and discuss some of the ontological and technical problems in re-using research models for policy-support, including resolving differences in temporal scale and some of the software engineering aspects of model integration. The involvement of policy-makers, ‘stakeholders’ and other end-users is essential for the specification of relevant decision-making issues and the development of useful interactive support tools. We discuss the problems of identifying both the decision-makers and the issues they perceive as important, their receptivity to such tools, and their roles in the policy-making process. Finally, we note the lessons learned, the resources needed, and the types of end-users, scientists and mediators required to ensure effective communication, technical development and exploitation of spatial modelling tools for integrated environmental decision-making.

The SOLUTIONS project: Challenges and responses for present and future emerging pollutants in land and water resources management

SOLUTIONS (2013 to 2018) is a European Union Seventh Framework Programme Project (EU-FP7). The project aims to deliver a conceptual framework to support the evidence-based development of environmental policies with regard to water quality. SOLUTIONS will develop the tools for the identification, prioritisation and assessment of those water contaminants that may pose a risk to ecosystems and human health. To this end, a new generation of chemical and effect-based monitoring tools is developed and integrated with a full set of exposure, effect and risk assessment models. SOLUTIONS attempts to address legacy, present and future contamination by integrating monitoring and modelling based approaches with scenarios on future developments in society, economy and technology and thus in contamination. The project follows a solutions-oriented approach by addressing major problems of water and chemicals management and by assessing abatement options. SOLUTIONS takes advantage of the access to the infrastructure necessary to investigate the large basins of the Danube and Rhine as well as relevant Mediterranean basins as case studies, and puts major efforts on stakeholder dialogue and support. Particularly, the EU Water Framework Directive (WFD) Common Implementation Strategy (CIS) working groups, International River Commissions, and water works associations are directly supported with consistent guidance for the early detection, identification, prioritisation, and abatement of chemicals in the water cycle. SOLUTIONS will give a specific emphasis on concepts and tools for the impact and risk assessment of complex mixtures of emerging pollutants, their metabolites and transformation products. Analytical and effect-based screening tools will be applied together with ecological assessment tools for the identification of toxicants and their impacts. The SOLUTIONS approach is expected to provide transparent and evidence-based candidates or River Basin Specific Pollutants in the case study basins and to assist future review of priority pollutants under the WFD as well as potential abatement options.

Integrating constrained cellular automata models, GIS and decision support tools for urban planning and policy-making

In this paper we present a Decision Support System developed to assist urban planners and policy makers to simulate and analyse alternative urban layouts, land uses, and growth patterns. The core of the system is a modelli ng and simulation shell allowing the user to specify Constrained Cellular Automata models of urban and regional systems. Unlike conventional Cellular Automata, these are defined with a relatively large neighbourhood and a large number of states, representing both human and natural land-uses. They forecast changes in land-use for small parcels on the basis of both the activities present in the local neighbourhood and the specific characteristics of the parcels themselves. Since each parcel affects every other within its neighbourhood, complex dynamics emerge. More traditional dynamic models --ideally spatial interaction based models-control the overall dynamics of the cellular automata. In the DSS, a custom-built GIS is integrated in the modelli ng shell . It stores the detailed geographical characteristics and feeds them into the model at the cellular level as required. Thus the approach permits the straightforward integration of physical, environmental, technical and institutional factors into a single dynamic socio-economic model at a high level of spatial detail . By way of ill ustration, we report applications of the models to both intra-urban and inter-urban cases, and examine specifically the case where the cellular model is forced by means of a regionalised macro-model.