See 
Application of Shoran to Establish 
Horizontal Control For Photogrammetric 
Mapping of Inaccessible Areas 
DR. J. M. ZARZYCKI, P. ENG., 
CHIEF TOPOGRAPHICAL ENGINEER, 
CANADIAN AERO SERVICE LIMITED, OTTAWA, CANADA 
INTRODUCTION: 
The tremendous developments of the 
last few years in the field of electronics 
have influenced the science of photogram- 
metry appreciably. Electronic instruments 
developed during the war, mainly for navi- 
gational purposes, have been improved and 
new instruments designed, to give the 
photogrammetrist an independent means 
of establishing the position of the nadir 
point of each individual aerial photograph 
at the moment of exposure, plus the cor- 
responding ground elevation. 
Shoran and its modified version, Hiran, 
give the horizontal position while the 
radar altimeter measures and continuously 
records the distance from the airplane to 
the ground. 
It is evident that this additional and 
independent information is of great help 
in conducting aerotriangulation in inacces- 
sible areas. Furthermore, the use of these 
electronic instruments has opened a wide 
field for development of new methods of 
extending control for photogrammetric 
mapping and has permitted the photogram- 
metrist to extend and to revise his present 
aerotriangulation techniques. 
Every new tool or technique must justify 
itself from the points of view of accuracy 
and economy. The most accurate and 
theoretically brilliant method will not leave 
the doors of a research institute and find 
any practical applications if it is not eco- 
nomical. On the other hand, a cheap and 
fast technique which does not give the 
required accuracy will never be accepted 
by responsible photogrammetrists. Shoran's 
rapid acceptance is gratifying proof that 
it fails on neither count. 
In Canada, Shoran is being used not 
only by the Geodetic Survey of Canada to 
establish the primary net of geodetic con- 
trol points, but also used by a private 
mapping organization to establish secon- 
dary horizontal control for photogram- 
metric mapping of Canada's Northland. 
This survey is being conducted for the 
Army Survey Establishment. 
The first operation of this kind in 
Canada was conducted in the summer and 
fall of 1952 by specialists of Spartan Air 
Services Limited and Canadian Aero Ser- 
vice Limited. Since 1952 Shoran operations 
have been carried out during the opera- 
tional season of each year. From 1952 to 
1955 a total of 500,000 square miles have 
been covered by Shoran control. At this 
a