4 
his photographs sufficient controlpoints to enable him to carry out an easy transfer of 
his details with some approximate plotting instruments. 
We will discuss this in the next section. 
e. Air photography for engineering projects. 
This subject covers a wide variety of applications of air-photographs to mostly 
cartographie work, sometimes in combination with photo-interpretation. For the national 
cartographie planning only projects covering larger areas must be considered for the air 
photography programme. There we meet the projects for agriculture, such as irrigation, 
leaching of excessive salt, land use, soil conservation, re-allotment etc. For many of these 
agricultural projects the photographie coverage 1 : 20,000 required for soil survey can 
also be used for the maps and photo-mosaics necessary for these projects. 
It may be that the small areas for large-scale mapping which is also an important 
task in this category are not important for the flying programme. Yet the planning must 
take them into account for the restitution, since this type of work will occupy many in- 
strument hours. The planner must know that he cannot expect for each machine a greater 
production per year than 500-600 models for large scale mapping, working in two shifts. 
Also with this photogrammetric work it must be decided in how far special photographs 
must be taken or whether the large scale coverage 1 : 20,000 is available and satisfactory. 
Maps in the scale 1 : 2500 can be plotted from the 1 : 20,000 with graphical precision if 
precise plotters are used. 
All these considerations must be taken into account for national cartographic planning. 
f. Airphotographs for the general administration of a country. 
The first important subject is the cadastral survey for the land register. It belongs 
to the national administration since it guarantees the legal rights on immovable proper- 
ties. In most countries this service has a kind of private life, isolated from other carto- 
graphie services although there are important and favourable exceptions such as Austria. 
In that case it gets its share in the national planning. It is not surprising that photo- 
grammetry has made its most succesful progress in those countries in which there is 
some relation between the general large-scale photography and the cadastral service 
where the latter takes an active part in the cartography of the country. 
In addition to this real photogrammetric application we see here also the use of 
airphotographs for all kinds of sociological and economical studies regarding the popu- 
lation of a country and its way of life (see Nr. 5 of the B series of I.T.C.-publications). 
We can place all this under the heading geographical airphoto-interpretation, which 
science is only in its first stages of development. It will nevertheless be the subject of a 
new course which the I.T.C. will start in January 1961 under the title Aerial survey and 
regional planning. 
) 
3. An aerial survey programme for unmapped countries. 
a. General I will give here an example of the planning of an overall survey of a 
country in which so far no general topographic map of a reasonable quality exists. Let 
us assume that furthermore economic development takes place and that geologists, soil 
specialists and foresters need their base maps in different scales such as 1 : 100,000, 
1 : 50,000, 1 :25,000 and 1:10,000. We believe that all these base maps can be derived 
from the same photography, taken for the map 1 : 100,000 for which a manuscript is made 
in the scale 1 : 50,000. 
Moreover there will be a need for maps for engineering projects. For certain areas 
even large scale maps for highway construction, cadastral and city surveying are 
required. 
Regarding planning, the latter projects will only ask for reservation of a certain