Huerta, Schade, Granell (Eds): Connecting a Digital Europe through Location and Place. Proceedings of the AGILE'2014 International Conference on Geographic Information Science, Castellón, June, 3-6, 2014. ISBN: 978-90-816960-4-3 1 Introduction Urban sprawl represents urban growth characterized by a sharp imbalance between urban spatial expansion and the underlying population growth [1], discontinuous spatial development patterns [5] and low densities [3]. Critics of sprawl have emphasized its negative impacts and especially the fact that it leads to increasing car-dependency for transportation, need for more infrastructure, loss of agricultural and natural land, higher energy consumption and degradation of periurban ecosystems [11]. This paper addresses the issue of urban sprawl through the application of an urban growth model based on Cellular Automata (CA). Spatially explicit urban expansion models can effectively trace development patterns of the past and assess possible expansion/future scenarios, they can be therefore regarded as important tools in urban sprawl analysis and could be of use to planners [13]. The model takes into account a wide range of demographic, accessibility, socioeconomic, environmental and urban planning data, as well as, a set of local characteristics at the cell level. The model’s logic, structure and calibration procedure are briefly outlined in this paper. A more detailed discussion is provided in [8]. The case study area is the urban agglomeration of Thessaloniki in Greece, an area in which the traditional monocentric and radial growth has been supplanted in the last 20 years by rapid periurbanization and extensive urban sprawl. The model is used to compare two growth scenarios for the period 2010-2030; one assuming a continuation of the existing trends and the second one assuming the adoption of various land use regulations with the objective to contain urban sprawl. 2 Methodology 2.1 CA models and urban sprawl Cellular automata (CA) is a class of spatially disaggregate models consisting of a two-dimensional lattice of cells, in which each cell is characterized by a particular state determined by a set of transition rules [14]. Each cell corresponds to a patch of land, and the state(s) of the cells represent the different land-uses. CA are discrete, iterative and dynamic mathematical constructs in which the state of each cell depends on its previous state and on the state of the cells in its neighbourhood [15]. Urban sprawl is a dynamic phenomenon that can be modelled through an analysis of land use and land cover changes [10], therefore extensive research has been carried out to demonstrate the CA’s model suitability for simulating urban expansion and sprawl. Among various widely applied models reference can be made to SLEUTH [2, 7], MOLAND [9], DUEM [18], the SimLand model [17], the model developed by He et al. [6], the model developed by Torrens [12] etc. 2.2 Model framework and structure In the present context a CA-based model is applied in the region of Thessaloniki, to explore future development scenarios. The model integrates a statistical model at the regional level with a CA model at the local level, in order to Applying a CA-based model to explore land-use policy scenarios to contain sprawl in Thessaloniki, Greece Apostolos Lagarias Aristotle University of Thessaloniki (AUTH) & Regional Analysis Division, Institute of Applied and Computation Mathematics, Foundation for Research and Technology - Hellas, 100 N. Plastira, Vassilika Vouton, 70013 Heraklion, Crete, Greece lagarias@iacm.forth.gr Poulicos Prastacos Regional Analysis Division, Institute of Applied and Computation Mathematics, Foundation for Research and Technology - Hellas, 100 N. Plastira, Vassilika Vouton, 70013 Heraklion, Crete, Greece poulicos@iacm.forth.gr Abstract This study addresses the issue of urban sprawl through the application of a Cellular Automata (CA) based model in the area of Thessaloniki, Greece. To link macro-scale to micro-dynamic processes the model integrates a statistical model at the regional level with a CA model at the local level. The model is used to compare two scenarios of growth of Thessaloniki to year 2030; the first one assuming a continuation of existing trends, whereas the second one assuming the enactment of various land use regulations in order to contain urban sprawl. The comparison of the results demonstrate that in the second scenario there is a smaller degree of leapfrog growth, with high percentage of new developed land being inside the existing city plans with development in areas outside the plans and in agricultural areas being minimized. Keywords: Cellular Automata, urban sprawl, urban modelling, land-use policy, Thessaloniki