As Lo pointed out in Chapter 7, there was considerable optimism a generation ago over the potential of using remote sensing for population estimation. Although Brugioni (1983) went so far as to predict that the US Census would be rendered obsolete, Lo (1986), in a more considered and pragmatic assessment, distinguished four approaches to population estima­ tion from remotely sensed imagery: counts of dwelling units, measurement of areas of urbanization, measurement of areas of different land use and automated digital image analysis.