High Level Overview

The fundamental LEAM approach to modeling urban land-use transformation dynamics begins with drivers, those forces (typically human) that contribute to land-use change. Each driver is developed as a contextual sub-model run simultaneously in each grid cell of raster-based GIS map(s); linked to form the main framework of the model and produce landscape simulation scenarios. Sub-models are completed and run independent of the larger LEAM framework so that variables can be scaled and plotted in formats that help visualize and calibrate sub-model behavior before it becomes integrated into the larger model.

Model drivers represent the dynamic interactions between the urban system and the surrounding landscape. Scenario maps visually represent the resulting land-use changes. Altering input parameters (different policies, trends, and unexpected events), change the spatial outcome of the scenario being studied. This enables what-if planning scenarios that can be visually examined and interpreted for each simulation exercise. Once model simulations are established, it is important to recognize the impacts that the resulting changing land use patterns will have on the environmental, economic and social systems of the community. The assessment of probable impacts is important for understanding the 'so-what' of simulations. If things change in this way, what does it mean for society, the economy, and the environment? Am I happy with that outcome? If not, what policies are needed to achieve results that I find more satisfactory? These 'so-what' impact assessments are also important for comparing simulation outcomes and results, needed to improve communal decision-making. The impacts assessed by the LEAM model are also used in the creation of sustainable indices and indicators that can feed back into the model drivers for new policy formation.

The LEAM spatial modeling environment: Simulation, drivers, and Impacts.

Current model driver sub-models (more are in production) include: Land Price, Economic factors, Population factors, Social factors, Geographic limits and factors, Transportation mechanisms and factors, Utility and Infrastructure requirements, Neighborhood development factors, Resource limitations and factors, Open space requirements, and Stochastic scenario drivers.

Impact assessment sub-models currently include: Water quality and quantity, Air quality, Habitat fragmentation, Threatened/Endangered species, Energy impacts, Economic impacts (societal and fiscal), and Ecological impacts.

LEAM model applications are processed in a distributed, high-performance computing environment and results are presented using an easy-to-navigate, Web-based graphic user interface. Scenario results and impact assessments can be displayed in a number of ways: as simulation movies, through a built-in mapping tool, in graph or chart displays, or simply as raw data.