GREAT BRITAIN- 1. 
VIII International Congress of photogrammetry, 1956 
BRITISH NATIONAL REPORT 
1. INTRODUCTION 
(INTRODUCTION) 
(vorwort) ' 
Topographical surveys have been carried out by the 
Ordnance Survey in Great Britain, by the Directorate of 
Colonial Surveys in British Colonial Territories, and by 
a small number of private companies both in Great Britain 
and overseas# Air photo methods have also been used for 
geophysical surveys, and for surveys of natural resources. 
2. SURVEY OPERATIONS 
" (TRAVAUX CADASTRAUX ET TOPOGRAPHIQUfiS) 
(VSRMES5UNGSARBEITEN) 
The Ordnance Survey has continued to make photo- 
¿grammetric surveys of urban areas at 1/1250 scale (12); 
to survey contours at 25 ft. vertical interval; and to 
use various photogrammetrie methods for revision of the 
one-inch to one mile map, and for surveys of tide lines. 
The Department has just begun a survey of the Highlands of 
Scotland at 1/10,5&0. Plying is done by the Plying Unit 
of the Ministry of Transport and Civil Aviation. Very 
careful organisation is needed to exploit fully the very 
few days of good photographic weather that occur each year. 
The aircraft used are the de Havilland Dove and Percival 
Prince. Navigation is assisted by tracking on the Decca 
system (5). The Department employes its own camera 
operator, and uses Williamson catoeras with Ross lenses and 
the 7/ild R.C.5 with the Avipgon. Film is used throughout 
(infra-red for tidal surveys) and a reseau is always 
employed in the Williamson cameras. Contact scales are 
1/3,000-1/5,000, 1/20,000-1/24,000, and 1/40,000. The 
Department does its own processing. Small scale photo 
graphy is also provided by the Royal Air Force. 
Photogrammetrie equipment includes the Thorapson-Watts 
plotter, the Cambridge Stereocomparator, and Wild A3 and