From publications in this field (Table 2), it becomes apparent that 
even in the USA, where the morphology of cities is generally not very 
complex, results obtained will not impress real users very much. 
The data lack a lot in both thematic resolution and accuracy. 
For certain specific applications, however, delineation of urban areas 
by digital classification may be competitive with other methods. Such 
applications include the indication of urban areas on small-scale maps 
(1:100,000 and 1:250,000 map series, DANTHINE et al, 1978), delineation 
of census tracts at the urban periphery (CORNER, 1976; CHRISTENSON & 
LACHOWSKI, 1976), and information at the national scale on the amount 
of urban land (CARTER et al, 1977). Depending on accuracy and consis- 
tency, such delineations may also be used to estimate urban populations 
in developing countries, and to define the area for airphoto coverage, 
but the problems of such an approach are many and they should not be 
underestimated. 
Considering these different aspects, a limited research project was 
defined at ITC, mainly for obtaining case-study material for the 
Urban Survey courses, but with an eye on the potential applications 
mentioned above. Four objectives were defined: 
1) to become acquainted with techniques and procedures for digital 
classification of multispectral images; 
2) to form an idea of the possible potential of future satellite 
data with higher spatial resolution; 
3) to test claims by others on accuracy and number of different 
urban classes obtainable; 
4) to assess the potential of the present Landsat data for developing 
countries to monitor their urban development.