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vation, in these countries land use inventories and land use mapping on a 
basis of aerial photographs could be the only efficient solution. Whereas in 
industrialised countries they might be only a possible alternative, or a supple- 
mentary method. 
3.3 Urban Information Systems 
Methods and objectives of urban planning have undergone profound 
changes in the last two decades. Modern urban (and regional) planning moved 
from static “end state” planning towards a number of different new concepts, 
all of them having in common, however, the fact that they see planning as a 
continuous process that needs regular information on how a planning area 
performs (monitoring). This change has created a demand for a new structure 
of urban information. New procedures are to be found for data collecting, 
data processing and data storage, able to supply the necessary input for the 
new planning methods. The increasing use of mathematical models is putting 
additional claims on the description, frequency and spatial resolution of an 
increasing number of basic data. 
The usual answer to this new demand is a proposal to create an “urban 
information system” that would serve not only planning objectives, but would 
also be useful in management and administration. Experience shows that 
management problems, even more than planning needs, are often the proper 
incentive to the building of a modern data base, especially in areas where it 
can be helpful to collect real estate taxes (Shillstone 1975). 
Since data banks are expensive, their multi-purpose character is much 
stressed in the fund-finding period, but when it comes to actual operation, 
management and administration—showing accountable benefits— will receive 
more attention than planning, so that sometimes it is advisable to postpone 
spatial referencing until a later stage (Spicer 1975). It explains why there is 
still not much known about the way in which planning offices use these 
information systems. This in turn makes the design of an efficient data base 
difficult, since it should provide for all possible questions, even those not yet 
thought of in the present situation (Butzbach and Tizianel 1972).