It may be asked: What is photogrammetry and what is remote sensing? While you as experts
need no ex planation of the meaning of these terms, the average intelligent persons, policy-makers
in Africa among them, do. Photogrammetry has been defined as ‘‘the ensemble of scientific
artistic ana technical studies and operations that come into play after the results of direct obser-
vations or the exploitation of an existing documentation, aiming at the elaboration and prepara-
tion of maps, plans and other forms of expression, as well as in its utilization”. Remote Sensing
on the other hand, may be defined as the science and art of obtaining information about an ob-
ject, area or phenomenon through the analysis of data acquired by a device that is not in contact
with the object, area or phenomenon under investigation.
These two definitions bring out areas of complementarity between the two disciplines, even
though the device for acquiring the scientific data and their analysis may be different. The data
analysis process, in both cases, involve using various viewing and interpretation devices to analyse
pictorial data, and/or computers to analyse numerical sensor data. The analyst extracts informa-
tion about the type, extent, location and the condition of the various resources over which the
sensor data were collected. The ultimate objective is, generally, to present the information in the
form of maps, tables, and reports which are usually presented to users for application in decision-
making. By this means, photogrammetry and remote sensing can make significant contributions
to effective planning, judicious exploitation and rational utilization of natural resources.
Here we may raise some pertinent questions. To what extent are these tools being used by
Africans to plan, explore and exploit the natural resources in Africa? To what extent are they
used in monitoring the weather situation, the desertification process and as tools for enabling
the African governments and people to be in a state of preparedness for any climatically-induced
state of emergency? What efforts are being made to transfer these technologies to African experts
whose responsibilities it is to provide scientific data for use by African planners and decision-
makers? Assuming that such scientific data are available to policy and decision-markers, how
much use is actually being made of them in decision-making on the development of the natural
resources? We are fortunate that the spectrum of the assigned activities of Commission V1 of the
Society is sufficiently wide to enable it to focus on these and other pertinent questions.
Since one of the main end-products of these two sister-disciplines is the presentation of scien-
tific data collected, treated and analysed in the form of maps, tables, etc, it is relevant to have a
quick bird's eye-view of the mapping situation at the medium scales in Africa, particularly the
1:50,000 and 1:250,000 series, which are immensely useful for the planning of regional devetop-
ment projects from the stage of exploration to that of exploitation.
In the early phase of the African mapping programme during the colonial period, priority
was given to the production of reconnaissance maps. A survey of natural resources carried out by
the Economic Commission for Africa in early 1960 revealed that, up to 1949, only 45 per cent
of the surface of the African continent was covered by maps, mostly of a reconnaissance standard.
Later, the same areas were supplied with more accurate maps at scales of 1:50,000 and
1:75,000 and, to a limited extent, with maps at scales 1:200,000 and 1:250,000. Thus the early
phase of the African mapping programme was sporadic rather than systematic and covered only a
fraction of the continent's land surface. Besides, it was the perceived or actual needs of the colo-
nial administrations rather than the development needs of the people and countries of Africa that
determined the nature and content of the mapping programme.
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