„1% = 
of increasing the efficiency in briding long distances would be 
achieved. In order to control the cross tilt of the aerotriangu- 
lation strips, short transvers aerotriangulation strips, based on 
the radar profiles, of three or four models might be cut in at 
certain intervals. In this way, it would be possible to determine 
the lateral tilt (not the absolute elevation!) of the terrain with 
a sufficiently high degree of accuracy. 
Ned Hm ZA ee 
On the other hand, the possibility of using the radar 
method as an accurate control of the scale represents a new approach 
to the aerotriangulation method, and the results of our preliminary 
experiments in this connection indicate that it has considerable 
merit. Unfortunately we have not yet had the opportunity of 
carrying out, with first-order autographs, the experiments which 
are necessary for a full investigation of the possibilities offered 
by the radar profile. 
Of the three factors which determine the position of a 
point in space, two - the distance from the initial point and the 
elevation above the reference surface - can quickly be ascertained 
by the radar profile method with a relatively high degree of 
accuracy.and at a great distance. Only the third factor, the | 
azimuth, eludes our grasp to some extent, but even in this case the | 
solution of the problem will probably be found in radar navigatione 
Although I have been able to give you only a brief outline, 
of the radar profile method, and its application, I am sure you will 
realize its significance for photogrammetric mapping. 
Above all, the radar profile represents a substantial 
economy of time. Within a few days it is possible to obtain data 
which would otherwise be available only after many years of pains- 
taking and expensive work in the field. 
Its application offers a possible solution to the problem 
of mapping on small and intermediate scales and particularly to the 
problem of mapping inaccessible areas having insufficient geodetic 
data to overcome the difficulties encountered. Particularly in cases 
where the mapping is based on only a few vertical controls or on 
points determined barometrically in the field, the use of the radar 
profile not only speeds up the mapping process; thus reducing the 
cost, but also increases the general accuracy. 
If we may make a statement on the basis of results 
obtained thus far, it seems no exaggeration to say that the degree of 
accuracy achieved in determining elevations with the radar profile 
is only slightly less than the accuracy of aero-levelling at distance 
as great as 100 kilometers (60 miles), assuming of course that the 
most accurate type of plotting machine and a more elaborate method is 
used. The ratio of the distances bridged, however, would be 2-4:l, 
depending on local conditions. If only second-order apparatus is use 
in aero-levelling (as is very often the rule) the ratio is even more 
favourable to the radar profile method.