2 
that of civil engineers etc. is not such that the 3rd condition is automatically fulfilled. 
In particular in the English speaking world the standard of the survey profession is still 
under discussion. We see there in some cases, that, in order to guarantee the higher 
officials a position equivalent to that of civil engineers, not the demands on their training 
in geodesy, cartography and photogrammetry (and their basic Sciences) are raised but 
only civil engineers are entitled to these positions in cartographic services. This although 
their education is specialised in a direction which is of little use in a survey organisation. 
Only along this line it is possible to obtain a satisfactory social position and the necessary 
prestige of the survey officials among their collegues in other services. In such cases the 
weak spot lies in the education which is then transferred from the university to the 
services as far as professional knowledge is concerned. For our subject "planning" 
however, we find that then in general the 3rd condition is fulfilled and survey officials 
deal on equal footing with their collegues. 
2. Subjects of planning in aerial survey. 
In LT.C.-publication Nr. AB 1 I mentioned the outline of a programme. Here I will 
make some further remarks about it. 
a. General topographic maps. 
Different countries have different series of scales. We mention the following. 
As in general a constant size of the sheets is preferred the scales are many times 
reduced in geometrical series 1 : 25,000; 1 : 50,000; 1 : 100,000 and 1 : 200,000. The usual 
procedure is then to obtain the small scale map by reduction and generalisation from the 
larger scale. Photogrammetry, however, enables us, as I will show further, to produce 
the map 1:100,000 and smaller directly in an economic way from air photographs. The 
advantage is that this makes the map series independent of each other. There exist many 
areas on earth however, for which a large scale map is not needed at all and for which a 
map 1 : 100,000 would be entirely sufficient. In other cases like in the U.S.S.R. it is the 
basic small scale topographie map which Russia has finished for the entire country 
including Asia. In parts of French Africa and of the British Commonwealth also a scale 
1 : 100,000 is used, but then as largest scale. 
In the Nato-countries the scale 1 : 250,000 has been accepted for a general map and 
not the 1 : 200,000, which fits in with the system of the 1 : 100,000 and which existed 
already in some European countries. The result of this N.A.T.O. policy is that everywhere 
in Asiatic and African countries in which the U.S.A. assists with the production of maps, 
this map scale is also accepted. It may be that for military purposes the scale 1 : 250,000 
is satisfactory lent, I believe that for general planning, for the production of geological 
and of agricultural maps the scale 1 : 100,000 is to be preferred. This will in particular 
be true if the manuscripts for these maps are made in a scale of 1 : 50,000, thus making 
it possible to provide the users, when necessary, with maps 1:50,000 and even with 
enlargements 1 : 25,000. 
Since the production of medium scale topographic maps from airphotographs is 
hardly anywhere considered a problem any longer, we will pay more attention in this 
article to the production of small scale maps, also because this has more influence on 
the general carthographic planning. 
b. Use of airphotographs for geological mapping. 
The air photograph is not only to be used for the construction of the map, but photo- 
interpretation too, gives data about the geology. Since in 1935-37 the *Bataafsche Petro- 
leum Maatschappij" (Member of the Shell Group) carried out for the first time in history 
the photogeological interpretation of 100,000 km? in New Guinee, hardly any oil explora- 
tion has been carried out without this method. It may be that for this subject research