A Patch-based Cellular Automaton for Simulating Land-use Changes at Fine Spatial Resolution

While cellular automata have become popular tools for modeling land-use changes, there is a lack of studies reporting their application at very fine spatial resolutions (e.g. 5 m resolution). Traditional cellbased CA do not generate reliable results at such resolutions because single cells might only represent components of land-use entities (i.e. houses or parks in urban residential areas), while recently proposed entity-based CA models usually ignore the internal heterogeneity of the entities. This article describes a patch-based CA model designed to deal with this problem by integrating cell and object concepts. A patch is defined as a collection of adjacent cells that might have different attributes, but that represent a single land-use entity. In this model, a transition probability map was calculated at each cell location for each land-use transition using a weight of evidence method; then, land-use changes were simulated by employing a patch-based procedure based on the probability maps. This CA model, along with a traditional cellbased model were tested in the eastern part of the Elbow River watershed in southern Alberta, Canada, an area that is under considerable pressure for land development due to its proximity to the fast growing city of Calgary. The simulation results for the two models were compared to historical data using visual comparison, Ksimulation indices, and landscape metrics. The results reveal that the patch-based CA model generates more compact and realistic land-use patterns than the traditional cell-based CA. The Ksimulation values indicate that the land-use maps obtained with the patch-based CA are in higher agreement with the historical data than those created by the cell-based model, particularly regarding the location of change. The landscape metrics reveal that the patch-based model is able to adequately capture the land-use dynamics as observed in the historical data, while the cell-based CA is not able to provide a similar interpretation. The patch-based approach proposed in this study appears to be a simple and valuable solution to take into account the internal heterogeneity of land-use classes at fine spatial resolutions and simulate their transitions over time.