The spatiotemporal form of urban growth: measurement, analysis and modeling

This study explores the combined application of remote sensing, spatial metrics and spatial modeling to the analysis and modeling of urban growth in Santa Barbara, California. The investigation is based on a 72-year time series data set compiled from interpreted historical aerial photography and from IKONOS satellite imagery. Spatial metrics were used both specifically to assess the impact of urban development in four administrative districts, and generally to analyze the spatial and temporal dynamics of urban growth. The metrics quantify the temporal and spatial properties of urban development, and show definitively the impacts of growth constraints imposed on expansion by topography and by local planning efforts. The SLEUTH urban growth and land use change model was calibrated using the multi-temporal data sets for the entire study region. The calibrated model allowed us to fill gaps in the discontinuous historical time series of urban spatial extent, since maps and images were available only for selected years between 1930 and 2001. The model also allowed a spatial forecast of urban growth to the year 2030. The spatial metrics provided a detailed description of the accuracy of the modelʹs historical simulations that applied also to forecasts of future development. The results illustrate the utility of modeling in explaining the amount and spatial pattern of urban growth. Even using modeling, however, the forecasting of urban development remains problematic and could benefit from further research on spatial metrics and their incorporation into the model calibration process. The combined approach using remote sensing, spatial metrics and urban modeling is powerful, and may prove a productive new direction for the improved understanding, representation and modeling of the spatiotemporal forms due to the process of urbanization.