Individual LESA factor GRIDs were classified using a scale of 1–10, with 10 being the most suitable in every case. These GRIDs were combined using the Weighted Overlay tool in Spatial Analyst.
Using the Weighted Overlay tool, knowledge supplied by members of the public or by experts can be intertwined with GIS data quickly during public meetings. When using the Weighted Overlay tool, each GRID is assigned a percentage value denoting its relative importance such that when all importance percentages assigned are added together, they equal 100. For example, a public meeting process may reveal that the soil importance GRID is critical and is given a percentage value of 50, while aspect data is deemed less important and receives a percentage value of 5, with the other factor GRIDs receiving the remaining 45 percent. This weighting is crucial to tailoring LESA to local needs and interests and is a hallmark of the LESA framework.
The resulting GRID for the study area provides insights that typical individual parcel LESA scoring systems do not consider. Raster-based ELESA allows the landscape to be thought of as a continuous surface of LESA process rating. This rating visualization can help identify suitable acreage for people interested in agricultural land for a variety of reasons. The factor rating and weighting can be tailored to meet the desires of an individual or an entire community.
The model has the ability to include land protected by land trusts or other entities under agreements such as conservation easements and purchase of development rights programs. The model can also visualize how ELESA ratings change relative to agricultural uses when urbanization proposals are anticipated. The Lexington-Fayette County Purchase of Development Rights Program (www.lfucg.com/pdr/) is an award-winning program that protects almost 21,000 acres. (However, data from that program was not used in this article due to data licensing and privacy issues.)
Enhancing LESA: Ideas for Improving the Use and Capabilities of the Land Evaluation and Site Assessment System, a workshop held in 2003 in Nebraska City, Nebraska, generated recommendations that LESA should be enhanced with GIS capabilities and strengthened with applications for land-use planning and growth management.
Several of the workshop's recommendations were realized through the use of ModelBuilder as described in this article. GIS has enhanced the power of LESA for landscape analysis and participatory planning/decision making. The regional/landscape scale analysis performed in this ELESA model allows for broad scale and flexible analysis. The Weighted Overlay tool, used in conjunction with a relatively short reassessment time, is acceptable for participatory planning/decision-making applications used during a meeting or in the field. ELESA has the potential for areawide planning applications, and this model could be adapted for watershed-based applications and modified for use with ArcGIS Server.
For additional information, contact Brian D. Lee, Ph.D., assistant professor (email@example.com), or Collin D. Linebach, undergraduate student (Collin.Linebach@uky.edu), Department of Landscape Architecture, College of Agriculture, University of Kentucky.
The authors thank Karen Goodlet, Billy Van Pelt, Lori Garkovich, and C. Dana Tomlin for helpful advice with this project. General guidance for this particular model came from the LESA guidebook and the Lexington-Fayette County Purchase of Development Rights Program.
About the Authors
Brian D. Lee is an assistant professor of landscape architecture at the University of Kentucky. He received his doctorate and bachelor's degree in landscape architecture from Pennsylvania State University and both master's degrees at the University of Pennsylvania. He teaches land-use planning and GIS courses. He coauthored "Why Not Walk to School Today?" which appeared in the 2006 October–December issue of ArcUser.
Collin D. Linebach is a fifth-year landscape architecture undergraduate student at the University of Kentucky. He is involved in research on watershed characterization, urban sprawl assessment, and conservation planning.
DeMers, M. N. (1994). "Requirements Analysis for GIS LESA Modeling." In Steiner, F. R., J. R. Pease, and R. E. Coughlin (Eds.), A Decade with LESA: The Evolution of Land Evaluation and Site Assessment (pp. 242–259). Ankeny, Iowa: Soil and Water Conservation Society.
Land Information Bulletin (2000). Farmland Protection and GIS: GIS Interface Helps Pennsylvania Counties Prioritize Farmland for Preservation. National Consortium for Rural Geospatial Innovations, Chesapeake, Pennsylvania State University, University Park, Pennsylvania. Retrieved June 1, 2008, from www.lic.wisc.edu/pubs/Penn1.pdf.
Pease, J. R., and R. E. Coughlin (1996). Land Evaluation and Site Assessment: A Guidebook for Rating Agricultural Lands (2nd ed.). U.S. Department of Agriculture, Natural Resources Conservation Service. Retrieved June 1, 2008, from www.nrcs.usda.gov/programs/lesa/LESA%20Guidebook.pdf.
Soil and Water Conservation Society (2003). Enhancing LESA: Ideas for Improving the Use and Capabilities of the Land Evaluation and Site Assessment System Report. Ankeny, Iowa: Soil and Water Conservation Society. Retrieved June 1, 2008, from www.swcs.org/documents/LESA_Report_112904155120.pdf.
Steiner, F. R. (1994). "Introduction." In Steiner, F. R., J. R. Pease, and R. E. Coughlin (Eds.), A Decade with LESA: The Evolution of Land Evaluation and Site Assessment (pp. 13–19). Ankeny, Iowa: Soil and Water Conservation Society.
Tomlin, C. D. (1990). Geographic Information Systems and Cartographic Modeling. Englewood Cliffs, New Jersey: Prentice-Hall, Inc.
Tulloch, D. L., J. Hasse, J. Myers, P. Parks, and R. Lathrop (2003). "The Challenge of Automating Public Farmland Preservation Techniques." Landscape and Urban Planning, 63(1): pp. 33–48.
Williams, T. H. Lee (1985). "Implementing LESA on a Geographic Information System: A Case Study." Photogrammetric Engineering and Remote Sensing, 51(12): pp. 1923–1932.
Wright, L. E.; W. Zitzmann, K. Young, and R. Googins (1983). "LESAAgricultural Land Evaluation and Site Assessment." Journal of Soil and Water Conservation, 38(2): pp. 82–86.