Uncertainty Assessment of Land Use/cover Maps: User Beware!
Bryan C. Pijanowski*, Kimberly D. Robinson and James Plourde
Department of Forestry and Natural Resources Purdue University West Lafayette, Indiana 47906 USA
Abstract: We compare land use/cover maps developed by local government and those developed by state agencies for two locations in the Upper Midwest USA. A map comparison rubric is presented that includes the examination of (1) amount of land use/cover class in each map; (2) the percent map agreement using a cross-tabulation; and (3) patch metrics that include the number of patches, patch shape and arrangement of patches in a landscape. We compare several of these statistics across 4 different cell size aggregations. We find that there is more difference in methods used to derive land use maps than there is 20-30 years of change represented in maps developed using the same method. The implications of this work are significant if decision makers and modelers rely on these maps for planning and simulation. Furthermore, this analysis throws into question what the "truth" land use map might be or even how it might be created. We argue that methods need to be developed that incorporate land use map errors into the decision making process and scientific research that uses these maps.
Keywords: land use maps; uncertainty; classification methods.