GREAT BRITAIN 4.
and its* research division holds current Government
contracts in connection with design, development and air
testing of air cameras.
Hunting Aerosurveys Ltd, have undertaken topographical
and engineering surveys for Local Authorities and
Nationalised undertakings in the United Kingdom, and
mapping for several foreign Governments. Mapping scales
have varied from 40 feet to 1 inch (1/480) to 1/50,000, and
contour intervals from 2 ft. (J metre) to 20 metres. The
Company has also undertaken a considerable amount of aerial
photography for the Directorate of Colonial Surveys in
Africa and the West Indies. A wide variety of aircraft is
used, including the Dakota, Percival Prince, de Havilland
Dove and Rapide. For cameras, the Company uses the
Williamson Eagle, and Wild R.C,5> the latter with both
Aviotar and Aviogon lenses. Ground control for the
Company 5 s own surveys is usually provided by their own
surveyors, though in E. Africa this was furnished by the
local Survey Department# Equipment includes the Wild A5>
A6 and a8, also Multiplex.
In addition the Company undertakes field work, supple
mented by aerial photos, for surveys of natural resources
(3); contracts have been received from Iraq and Jordan.
It also conducts extensive exploratory surveys using
airborne magnetometers and scintillometers.
3. DEVELOPMENT OF EQUIPMENT
(PEVSLQEPSMBNT DU MATERIEL)
(ENTWICKELUNG VON AUSRUSTUNG)
In recent years there has been a distinct movement
towards the greater employment of precision plotting equip
ment, and two firms have developed new instruments.
Hilger and Watts Ltd, have produced the Thompson-Watts
plotter (10, 17)» to the design of professor E.H. Thompson.
This is a precise instrument based on the Forro principle,
for aerial triangulation and for plotting at all scales.
The Williamson Manufacturing Co., Ltd, have produced their
"L.S.P. M plotter for large and medium scale plotting
(15» 18). Both instruments will be on view in the
Exposition.
Although some aerial triangulation is done by plotting
