May, 1960 Commission Il 177 
Sensitometric control of film processing has become quite general. Sensitometric 
step wedge exposures are printed on most rolls of survey film before processing except 
where field conditions or other circumstances make the use of a sensitometer impractical. 
For making paper prints and contact diapositives the use of photo-electrically 
controlled dodging printers such as the LogEtronic or Cintel has increased greatly. 
The most common navigational device is an open-line sight that may be fitted with 
adjustable drift wires to define the position of adjacent flight lines. As a refinement 
of this, experimental tests have been made with a Polaroid Land camera mounted to 
photograph the next flight line and fitted with special fiducial marks to indicate the 
position of the line. Capital Air Survey uses a special slide-rule for determining the 
angle of bank required to establish the desired line separation under prevailing condi- 
tions of drift and speed. The principle is similar to the French Institut Géographique 
National system. 
COMMISSION 11 
PLOTTING INSTRUMENTS AND METHODS 
by R. A. STEWART 
The period 1956-60 has been one of increased development and productivity with 
regard to plotting instruments and methods of plotting. 
The Surveys and Mapping Branch, Department of Mines and Technical Surveys, 
and the Army Survey Establishment, Department of National Defence, have increased 
both quality and quantity of output of the national topographic series of maps. This 
increase has been due in large part to improvements in plotting instrument accessories 
and methods. 
Canadian mapping is produced at scales of 1:50,000, in areas of economic import- 
ance, and 1:250,000 over the entire country, including the Arctic Archipelago. In 
addition, the Army Survey Establishment has produced 1:25,000 mapping of military 
training areas. The Surveys and Mapping Branch also produces special large-scale 
engineering plots for other departments of the federal government. 
The National Research Council of Canada has been engaged in the development 
of faster, more accurate instruments and methods of plotting. Two significant develop- 
ments of N.R.C., the Straight Line Plotter and the Analytical Plotter, are summarized 
in this report. 
Several provincial government departments have added plotting instruments to 
their mapping divisions and have shown an increase in output of topographical plotting. 
Foremost among these is the Surveys and Mapping Branch of the Department of Lands 
and Forests, British Columbia, which produces a major part of the topographical 
plotting in that province. 
Ten commercial firms, located in municipalities from the Atlantic to the Pacific 
Oceans, are engaged in plotting large-scale engineering plans for private enterprise, 
and for some governmental agencies. 
Third-order plotting instruments are employed to turn out the bulk of the national 
mapping. Extensive areas of Canada are not yet mapped at scales larger than 1:500,000, 
so third-order plotters will continue to be employed for some considerable time. 
Multiplex is used to compile 1:50,000 maps from photographs taken at altitudes of up 
to 7000 metres. Compilation for 1:250,000 mapping is carried out by Wernstedt-Mahan 
and Multiplex plotters with photography taken at 9000 metres.