Land Use Evolution and Impact Assessment Model
| Industry | Software Geographic Information Systems (GIS) |
|---|---|
| Founded | University of Illinois at Urbana-Champaign |
| Owner | Brian Deal, Varkki Pallathucheril |
| Website | www.leamgroup.com/ |
The Land Use Evolution and Impact Assessment Model (or LEAM) is a computer model that forecasts land use change and assesses the impacts of that change. It is used most commonly to simulate future alternative land use scenarios. Originally developed in the Department of Urban and Regional Planning at the University of Illinois at Urbana-Champaign, LEAM determines the probability of change across an entire region at a 30x30-meter cell resolution. Population, geography, economics, transportation, utilities, neighboring land uses, random chance, and more all contribute to a final growth decision within a given cell.
The mission of the LEAMgroup is to help others understand the relationships between human economic and cultural activities and biophysical cycles from a change and impact perspective. A better understanding of the extent of how different systems affect each other leads to improved land use management and more informed decision-making.
History
LEAM was first developed in the LEAMlab at the University of Illinois at Urbana-Champaign in the late 1990s. Its gain in popularity with counties and regional agencies in and around Illinois led to technological licensing from the University of Illinois and commercialization. LEAMgroup, Inc. is a spin-off company of the LEAMlab that was founded in 2003 by professors Dr. Brian Deal and Dr. Varkki Pallathucheril. Since then, LEAM and its associated tools have been applied by planning agencies all over the U.S. and abroad.
Users
LEAM generates models mainly for regional metropolitan planning organizations (MPOs), Councils of Governments, and various military installations.
LEAM Approach
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 submodel that runs simultaneously, yet independently, in each grid cell of raster-based GIS maps. Submodels are completed and run independently within the LEAM framework so that variables can be scaled and plotted in formats that help visualize and calibrate submodel behavior before they become integrated into the larger model. The submodel driver outcomes are weighted and combined to determine the probability of change.
Current driver submodels 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. Final land use change is determined by culminated cell probability, nearest neighbor activity, and a randomness factor.
Model drivers represent the dynamic interactions between the urban system and the surrounding landscape. Altering input parameters changes the spatial outcome of the scenario being studied, enabling what-if planning scenarios that can be visually examined and interpreted in each simulation exercise.
Change in land use is then used as input to many impact assessment models to determine the implications of policy decisions. Some of the impact models include: transportation demand, water quality and quantity, air quality, habitat fragmentation, threatened/endangered species, energy use and demand, and economic impacts (societal and fiscal).
Model applications are presented in a web-based graphic user interface. Scenario results and impact assessments are displayed as simulation movies, through a built-in mapping tool, in graph or chart displays, or simply as raw data.
Literature
- Zhanli Sun, Brian Deal and Varkki George Pallathucheril, 2005. "The Land-use Evolution and Impact Assessment Model: A Comprehensive Urban Planning Support System" The Urban and Regional Information System Association (URISA). [1]