Modeling population density with night-time satellite imagery and GIS

Abstract

Night-time satellite imagery, as provided by the Defense Meteorological Satellite Program's Operational Linescan System (DMSP OLS), shows promise as a proxy measurement of urban extent. Earlier efforts have shown that the areas of contiguous saturated DMSP OLS images show strong correlations with the total population living in those areas. This paper describes efforts at modeling the population density within the urban areas identified within the continental United States. These efforts build upon the previous efforts of Clark, Berry, Nordbeck, Tobler and others to describe the variation of population density within cities. The method described herein differs from the aforementioned theories because it operates from the edges of the urban areas rather than attempting to identify a “center” of the urban cluster. By measuring distance from the edge rather than the distance from the center this method allows for the “multiple nuclei” of urban clustering that have clearly manifested as a result of the conurbation of urban centers within the U.S.A. This paper describes the methods used to allocate population to one, two, three, five, and ten square kilometer pixels for the continental U.S.A. Several urban population decay functions are applied and evaluated. In addition, an empirical urban population density decay function is derived for all the urban clusters defined by the DMSP imagery.