ABSTRACT
Previous chapters have considered how detailed urban morphologies might be revealed using satellite technology. The focus has been upon quite general-purpose technical solutions to technical problems, and has been couched largely within the physical domain of the built environment. This Chapter addresses the applicability of some of this technical work to the derivation of summary indicators of urban shape and form . In so doing, we are minded to begin by stating two important considerations. The fir t i that cities are socio-economic systems, and hence 'urban analysis' is at least as much about human activity patterns Uourneys to work, recreation , shopping behaviour, residential differentiation, etc.) as it is about the built environment. The built environment is a frozen artefact of the concatenation of past and contemporary urban processes (see also Batty and Howes, Chapter 10 this volume), and reveals but one facet of the functioning of urban ystems. The econd derive directly from this, and is that the power of even the most sophisticated optical satellite sensors to discriminate detailed urban land-use categories is severely limited (see also Donnay et al., Chapter 1 this volume). The Orb View 3 (Orbimage), QuickBird I (Earth Watch) and IKON OS 1 (Space Imaging) satellite sensors will provide unprecedented spatial information about the Earth's surface, at a level of detail (I m-5m) more closely associated with aerial photography. Even at these fine scales, however, it will not be pos ible unambiguously to identify, say, small workshops amidst residential areas from an analysis of their spatial form alone. In any case, a much more time-and cost-effective route is likely to involve interfacing of socio-economic information with data pertaining to the socio-economic/unction of the built form. There is thus a clear substantive and methodological rationale for integrating socio-economic information with satellite imagery.
