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K.L.M. Aerial Surveys: 
1 Wild A 5 
2 Stereoplotters A 6 
1 Wild Rectifier. 
Military Topographical Service: 
1 Wild Stereoplotter A 6 
2 De Koningh Rectifiers. 
Topographic Maps. 
The methods did not change very much; the 1:25,000 maps of the 
Netherlands are, for the flat area, obtained by rectifying single photographs 
on a scale of 1 : 16,667. Stereophotogrammetry by means of the Wild À 6 is 
only applied to a very small hilly region in the southern area of the country 
with a scale of the manuscript 1 : 10,000. 
For the topographic maps the contour line interval is 25 metres. Altitudes 
are determined by normal ground survey, except for the area plotted in the 
A 6. The Netherlands topographic map is based on the first, second and third 
order triangulation and levelling of the country. The accuracy obtained for 
this topographic map of the Netherlands is indicated by a mean square error 
in a position of 2.5 metres when applying the rectifying method. By the method 
of restitution of pairs in the A 6, the mean square error in the position is 
between 1 and 2 metres and between 0.6 and 1.0 metre in altitude. 
Besides this production of military topographic maps by the Military 
Topographical Service in Delft, we would mention the production of small 
scale topographic maps of tropical regions carried out by the Survey Dept. of 
the Ministry of Public Works and K.L.M. Aerial Surveys. In Chapter III 
details of the triangulation have been indicated. The restitution in Wild A 6 
does not need any further detailed description. 
Re-allotment and Cadastral Survey. 
During the last four years no important progress has been made in the 
application of photogrammetry to cadastral survey proper. Of more importance 
is the work carried out in connection with re-allotment. In this country the 
re-allotment of about 1,000,000 hectares is urgent. This problem can only be 
solved within a reasonable time if photogrammetry is applied. During the 
years of German occupation a method was developed, using the available 
1:20,000 photographs made on behalf of the Topographical Service for the 
1:2,500 map. From these photographs 1:2,500 maps have been plotted 
by means of the stereoplanigraph and the Wild A 5. All this work has been 
7