166 WORKING GROUP 5, INTRODUCTION 
discussion on the subject of administrative plan- 
ning and census taking in rural areas and the 
application of aerial photo interpretation to 
these problems of rural administration and 
management. 
In spite of some of the gaps which we see in 
our coverage and in our reporting, we do feel 
that there are certain trends which we can pin- 
point at this time. It seems to me that photo 
interpretation studies of urban areas, including 
the industrial complexes and rural fringes, are 
now concerned more than ever before with 
human problems of expanding population and 
social economic integration. It seems to me this 
underlying concern with integration and devel- 
opment planning is a core concept which ties 
in the interests of urban, rural and industrial as 
well as regional elements. 
Our survey shows that photo interpretation is 
playing an increasingly active role in all of this 
by providing supporting studies with new adap- 
tations directly related to socio-economic prob- 
lems. A few brief examples and further elabora- 
tion may serve to underscore this conclusion, 
characterising recent trends in this broadening 
field of photo interpretation. 
As diverse as they may appear to be, the 
technical papers which Working Group 5 is 
presenting do have one common denominator. 
In each case the authors are concerned with 
some phase of a social problem related to grow- 
ing aerial complexes. The ecological aspects of 
human behaviour, restricted and conditioned by 
urban traffic patterns, reflects a very real prob- 
lem, having implications in the daily lives of 
millions of people in cities all over the world. 
The health and safety of urban dwellers is the 
basic concern underlying the special project 
relating photo interpretation to medical research 
on radiation effects. This work also has wide- 
spread human implications and international 
interest. 
Finally, there is a growing interest in devel- 
oping and refining methods for using photo 
interpretation for collecting data on urban pop- 
ulations and social structures. This kind of 
endeavour is a recognition of the increasing need 
for more planning information and systematic 
studies regarding the increasing urban popul- 
ations. 
In all of these efforts the state of the art in 
photo interpretation is being advanced to a more 
refined technology to be applied to problems 
beyond the traditional studies of physical struc- 
tures. As it long has been a working method in 
several other fields, photo interpretation is now 
rapidly becoming a study medium for the social 
scientist concerned with urban and regional 
analysis. 
As a supplementary source of data — and in 
some cases as an adequate alternative to costly 
field surveys — photo interpretation may provide 
information on ecological organisation, the or- 
ganisation of the natural areas of the city, pop- 
ulation size and density distributions, land use 
characteristics, human settlements, social eco- 
nomics sub-areas, housing problems, health and 
welfare, transportation, requirements and pat- 
terns of development, growth and change of the 
urban area. Photo interpretation is playing this 
new role because of the fact that when real 
complexes are considered as social-physical 
systems, it is possible to develop relationships 
through which the more elusive social data can 
be derived from the more obvious physical, 
spatial, structural information on the air photo- 
graphs. 
As indicated previously, we feel that we have 
not given a complete coverage of the activities in 
urban photo interpretation, but we do feel that 
we have focussed on one area where there is 
developing a most important new trend and 
application in our field. 
One of the papers to which I have already 
referred is that authored, prepared and the work 
completed by Dr Dubuisson, who I am sure 
needs no introduction to you at this time. In 
selecting and inviting Dr Dubuisson to present 
his paper I feel that this problem of urban traf- 
fic, although an old problem, is so important 
to so many people and also that the technical 
developments and the innovations which have 
come about through the work of Dr Dubuisson 
and Mr Burger are significant to say the least. 
At this time I am very pleased to present Dr 
Dubuisson, who will give his paper on photo 
interpretation studies of urban traffic problems. 
Dr Dubuisson then presents his paper.