Fragmentation profiles for real and simulated landscapes

When a natural landscape is represented by a series of categorical raster m aps of varying resolution, a multiresolution characterization of spatial pa ttern can be obtained in which entropy is computed at each resolution condi tional on the next coarser resolution. The series of entropy values is plot ted as a function of resolution, resulting in a multiresolution profile of fragmentation pattern in the landscape. If a categorical raster map is available at a single resolution only, a ser ies of degraded maps at increasingly coarser resolutions is generated and t he fragmentation profile is computed for this series. An algorithm has been developed for obtaining the profile directly from the single resolution ma p without having to generate and store the coarser resolution maps. A hierarchical stochastic model is described for simulating categorical ras ter maps and the fragmentation profile of the generating process is obtaine d in terms of the model parameters. These "process" profiles provide benchm arks for assessing empirical profiles obtained from raster maps of actual l andscapes. Methods of the paper are applied to several watersheds of Pennsy lvania using landcover maps derived from satellite imagery. These examples indicate that characteristic landscape types induce characteristic features in their fragmentation profiles.