Sensing cities remotely is difficult - very difficult! It is tricky enough to interpret the intricate interplay of artificial structures, economic activity, government policies, land tenure, social class, culture and the biosphere, typical of all cities, from on the ground let alone from the sky or space (Brugioni 1983). Cities are complex enough, providing many challenges for planners, civil engineers, environmentalists, government agencies, sociolo­ gists, demographers, economists, psychologists and political scientists with­ out adding remote sensing scientists to the list. Complex and at times conflicting decisions by private individuals, commerce and government policies shape not only human behaviour but also the arrangement of physical structures and intervening natural surfaces. Whether the decisions are on where to locate new out-of-town retail outlets, the building of residential estates, the mapping of school catchment zones, the renovation of city parks, the expansion of transport infrastructure, how to reduce air pollution or simply what households grow in their gardens, cities will always be characterized by heterogeneous, convoluted and unpredictable land patterns.