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surveys in the inner part of towns. Aerial photography can play a key role in 
making a survey feasible at all. Many of the practical problems of a survey in 
a city centre can be efficiently solved". Land use, being a key term in the 
language of urban planning, does not have a clear meaning. On the contrary, 
its meaning is becoming more and more ambiguous and we endow the term 
“land use" with more and more connotations (Guttenberg 1959). In an effort 
to replace the broad term land use with others that are more precise, Gutten- 
berg proposes to identify and define the individual components or dimensions 
of land use. The result is a set of parallel classifications, each based on a single 
dimension (a “multiple” land use classification system): 
i general site development (eg, undeveloped land, developed land without 
structure, developed land with permanent building); 
ii site adaptation, as represented by building type or other special site 
facility (cf *artefact"); 
iii ^ actual use, ie the type of activity on the premises; 
iv economic "over-use", ie the type of economic function performed by 
the enterprise conducting the activity; 
V activity characteristics—size, rhythm, realm, and material impact. 
By making each dimension the basis of a distinct land use classification, a 
systematic connection between the interests or concerns of planning and the 
form in which land use data are to be collected and organised is made possible. 
Other dimensions can still be added, for example ownership and building 
conditions. The basic areal unit in the system is the parcel. 
Guttenberg's proposal has not found wide acceptance in planning 
practice. In fact, standardisation and clear, precise definition of land use is 
still an under-developed area. In an attempt to stimulate discussion around 
this subject, the ITC recently made a land use map of Enschede, in the 
Netherlands. At the same time, however, efficient inventory methods and 
cartographic representation techniques of the highly complex urban system 
were investigated. The land use dimension selected for inventory and presen- 
tation was the actual use (the type of activity) in existence. The term land use 
is in this case therefore not fully correct, as not only information on activities 
at the ground floor level, but also on the upper floors was collected and 
mapped (partly by 3-dimensional representation). As the planners' interest 
generally is not limited to the use of the ground floor levels, it is preferable