Abstract 
  
Some selected problems and trends in mapping of 
scales 1:25,000 and smaller are discussed. The author 
considers growing use of computational methods, the 
Resume 
  
Quelques problémes et tendances en cartographie à 
échelle 1:25,000 ou moindre sont présentés. L'auteur 
envisage l'usage croissant des méthodes analytiques, 
la technique orthophotographique, l'emploi des pho- 
orthophoto mapping technique, use of super-wide- 
angle photographs, color photographs and the ques- 
tion of original plotting versus derivative mapping. 
t is suggested that the I. S. P. consider this last ques- 
tion as a topic for a concerted study. 
tos à objectifs ultra grand angulaires, les photos en 
couleur et la question des levés originales versus car- 
tes dérivées. L'auteur suggére que la S. I. P. considére 
cette derniére question pour un sujet d'étude inter- 
nationale. 
  
Introduction 
  
Any summary review of such a broad field as ‘‘small- 
scale mapping” must necessarily be restricted to main 
topics. The task is not made easier by the fact that 
the meaning of “small-scale mapping” is different in 
various countries, and the maps are often obtained 
in fundamentally different ways. For instance, in 
some European countries, the maps under discussion 
(1:25,000 and smaller scales) are derived from large 
and intermediate scales. They are products of a pu- 
rely cartographic process. Consequently, original 
mapping in smaller scales is restricted to occassional 
projects only. Also, the mapping conditions in these 
countries are unique: great density of ground control 
of excellent quality is combined with complex plani- 
metric contents of the terrain. The mapped areas are 
close to the air bases from which the photographic 
airplanes operate. Visual or instrumental navigation 
is facilitated by existing maps, abundance of distinct 
land marks, and dense network of beckoning stations. 
In contrast, there are still huge territories, ba- 
rely explored, which are difficult to approach because 
of their vastness and adverse climatic conditions. In 
such lands, the mapping operations are different, as 
well as the requirements set forth for the final product. 
Therefore, instead of entering a detailed discus- 
sion requiring the analysis of a great number of se- 
condary factors, I propose to dwell on a few ques- 
tions only, which are, in my opinion, of general im- 
portance. 
Growing use of computational methods 
  
Mapping such territories:as the northern part of 
the American continent, the huge lands of South 
America, Africa, Australia, North and Central Asia, 
usually follows a classical pattern, well established 
since the last war. Only occasionally a less orthodox 
procedure is being used which incorporates new tech- 
niques. Examples of these are projects in Australin 
(intended systematic use of APR data), Bolivia (use 
of superwide-angle photographs) and Canada (com- 
bination of the Aerodist technique with other electro- 
magnetic procedures for determination of control, 
consequent introduction of super-wide-angle photo- 
graphs and numerical methods). 
Development and use of computational methods 
seem to be a more genera! trend that simplifies the 
operations and significantiy improves the quality of 
results. An indication of the general acceptance of 
these methods for aerial triangulation purposes can 
be supported by the number of mapping centres that 
are using computational programs developed by the 
Photogrammetric Research Section of the N. R. C. At 
present, this figure is approaching the hundred mark. 
This is a most impressive number, particularly since 
the Nationa! Research Council is purely a research 
organization and does not make an effort to direct 
practical mapping operations. The wide use of com- 
putational procedures proves the superiority of nu- 
merical methods, particularly in bridging operations, 
and clearly points out the direction of future deve- 
lopment: it is obvious that the period of analogue, 
bridging equipment is nearing its end. Use of such 
equipment in the operations under discussion is neith- 
er economically nor technically justified, and the fact 
that the available analogue equipment continues to 
be used for triangulation does not change this situ- 
ation at all. 
The numerical approach is of particular advant- 
age in the countries that do not have a large number 
of highly skilled technicians or prefer to use their 
trained men in a more efficient way. Persons in char- 
ge of planning and executing large mapping projects 
may like to read a study by Capt. M. E. H. Young 
[1]. This publication contains extremely interesting 
comparative figures obtained from a large block tri- 
angulation carried out under ordinary operational 
conditions. The results are indeed instructive. It may 
be of interest to remark here, that when the efficiency 
of photogrammetric operations is considered, the speed 
and costs are seldom discussed as factors of equal im- 
portance. One svou!d like to hope that in view of the 
urgent needs in the mapping field, the rate of pro- 
duction wil: be given much greater consideration than 
it has received in the past. In many instances, time 
is a much more important factor than cost. Of course,