Continuum-based classification of remotely sensed imagery to describe urban sprawl on a watershed scale

Remote sensed imagery can both describe urban sprawl on a watershed scale and provide essential information for modeling the impact of sprawl on watercourses. This paper looks at six watersheds in greater Cleveland, OH: two urban; two rural; and two undergoing rapid urbanization. Thematic Mapper imagery from 1984, 1988, 1994, to 1999 was classified into functional classes describing each watershed in terms of the position of each pixel along continua of [1] percentage permeability and [2] canopy cover. Because the functional classes represent positions along independent continua rather than thematic land-cover classes, they can easily be compared from image to image, and they provide quantitative estimates of parameters at 30-m resolution suitable for spatial simulation models. The imagery classified in this way makes it possible to observe the progress of urban sprawl both within these watersheds and over a study area which extends from the inner city to its rural surroundings.