The practical training is not aimed at 
attaining proficiency, but a working knowledge 
level. It clears a threshold, which is 
normally associated with flying and aerial 
photography. 
Since 1978 nearly 200 exercise flights 
have been executed, training about 200 
students. More than 90 % of the participants 
proved to be able to produce very acceptable 
photographs, particularly in the second 
exercise flight. An important factor is the 
use of automatic exposure (shutter priority) 
single lens reflex cameras with a motor drive, 
allowing full concentration on detecting and 
photographing the target areas. 
A relative small number of participants 
applied this training in their work situation. 
Major problems are the security clearances in 
many countries, and possibly resistance 
against new tasks considered to be alien to 
the traditional planning organization. 
The ITC Urban Survey departmental staff 
applied the technique to provide up-to-date 
data for a number of research projects in the 
Netherlands, Cyprus, Kenya, Sri Lanka, 
Suriname, and Tanzania. In a few cases it was 
allowed to take off an aircraft door, 
providing less constraints in camera pointing. 
In these cases hand-held, near-vertical 
photography was realized too (Fig.3). 
7 
AIR PHOTOS, MAPS, AND GEO-INFORMATION SYSTEMS FOR URBAN PLANNERS 
An environment in which the map producer 
and consumer (i.c. the urban planner in a 
developing country) are closely linked, is 
very desirable as it can ensure the so much 
needed specific products and fast production. 
Such a situation could be created when the 
data acquisition (aerial photography, ground 
control measurements, and additional data 
collection), photo interpretation, and mapping 
are executed by and within the urban planning 
organization. 
Such an in-house mini-survey department 
should not imitate large, specialized survey 
organizations, but concentrate on what is 
essential to its own organization: fast 
production of aerial photographs, air photo 
interpretations, field checks, field 
measurements, and maps. The investments, the 
running costs, as well as the required skills 
of operators, should be limited to suit that 
purpose, so that this mini-survey department 
can be run on the basis of the regular budget 
of the organization. 
In such a context, ultralight or light 
airplanes adapted to aerial photography, and 
small format cameras can play an essential 
role to provide low-cost and up-to-date air 
photos of project areas. Moreover, appropiate 
low-cost, approximate mapping methods and 
techniques have to be introduced to make such 
a system feasible. 
Existing services as an in-house 
photographic laboratory, ground survey team, 
mapping office, and draftsmen, of course 
should be utilized and integrated into such a 
system. External commercial services can 
provide, for instance, additional map printing 
facilities. 
The quality of a thematic map is to a very 
large extent determined by the theaatic 
accuracy: the correct classification of 
objects and elements. Also, when considering 
the way maps are used in a planning 
environment, the importance of the metric 
accuracy is quite relative. In many cases 
sketchmaps (without geodetic control) will be 
acceptable. For specific applications, mostly 
at the engineering level (implementation of 
infrastructure constructions) an approximate 
map may be upgraded by local measurements 
through a precision method as a ground survey. 
The geo-information system part already 
appears to be fairly well developed: systems 
that at least claim to be good are abundant on 
the commercial and semi-commercial markets. 
The essential link with the front end, the air 
photo and map data acquisition part, however, 
still seems to be weak, as long as low-cost 
mapping systems are considered (for cities in 
developing countries). The experiences with 
low-cost aerial photography systems in 
projects supported by ITC in China, India, and 
Indonesia, demonstrate the feasibility of such 
systems to deliver the required photos 
economically and timely. 
The main problem now seems to be the 
conceptual (not the technical) development of 
a low-cost mapping technique from small format 
aerial photography. As on one hand the 
precision requirements are not very high, and 
on the other hand low-cost mapping systems are 
feasible (even including microcomputer based 
analytical plotters), prospects are favorable 
(Warner,1989). Such a decentralized system, if 
well designed, could also provide important 
inputs into an information system for urban 
planning and management. 
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