4 
E 
| 
8 
P 
8 
q 
f 
8 
  
   
D 2 a) 5) c) d) e) f) Nil. 
g) Air photographs are used in the compilation of Archaeological 
maps. 
h) 2) 4) Nil 
C a) This return refers ONLY to the Ordnance Survey and NOT to other 
organisations. 
b) About 150 employed on the Ordnance Survey. 
c) The air triangulation work with Stereo-comparators is thought 
to be of a hitherto unprecedented accuracy. 
d) The photogrammetric work of the Ordnance Survey forms only 
a small part of the activities of the Department; it is not designed to meet 
any particular demand, but only to fulfil a programme. 
€) f) 9) h) Insufficient data exists to give accurate statistics at 
present. 
1) The Cambridge Stereo-comparator is made by the Cambridge 
Instrument Company. 
D a) No. 
b) It 1s too early to say, but most of these questions refer more 
closely to countries less well developed than Great Britain. 
Chessington, 28 th November, 1951.