COMMISSION IV 
PHOTOGRAMMETRIC MAPPING 
by B. F. ENGLER 
During the period 1956 to 1960, the use of photogrammetry as applied to mapping 
in Canada has continued to develop at an increasing rate each year. Although there 
are no very radical changes in the basic techniques or methods, there has been a 
definite trend towards the use of high-performance cameras of minimum distortion 
together with a more general use and acceptance of electronic computers à and recording 
devices in the mapping operation. 
The bulk of mapping may be roughly divided into two main scale groups, the 
small-scale mapping and large-scale maps and plans. 
The greater part of the small-scale work, 1:25,000 or smaller, is undertaken by 
the provincial or federal governments, while most of the work at the larger scales is 
carried out by privately-owned commercial mapping organizations. 
Many of the problems that the two broad scale groups have had to meet have led 
to the development of new methods and techniques. The application of these tech- 
niques and methods is considered under the general headings of the two scale groups. 
SMALL-SCALE MAPPING 
At present, the greater volume of topographical mapping in Canada is carried out 
by the provincial and federal mapping organizations, and the greater part of this work 
is confined to s.ales of 1:25,000, 1:50,000, and 1:250,000. The volume of work at these 
scales has been steadily increasing, and developments during the past year indicate that 
demand will continue to increase, in particular, the requirements for additional maps 
of urban areas at the scale of 1:25,000. 
For comparative purposes, Table I gives the coverages of topographical mapping 
from 1956 to 1959. The area of the coverage is given in square miles. 
  
  
  
  
TABLE I 
Year 1:25,000 1:50,000 | 1:250,000 
1955-56 1200 80,825 | 101,785 
1956-57 2166 81,890 | 192,165 
1957-58 360 99,905 | 172,600 
1958-59 1269 107,965 | 175,134 
= - e HELL ts récit SEE [ 
1959-60 Data not yet available 
  
Topographical mapping at the scale of 1:250,000 has been progressing steadily 
farther into northern Canada with each year. The problems raised by the shorter 
summer seasons and unpredictable w eather conditions when field surv ey and aerial 
photography are considered, combined w ith the ever-increasing distances over which 
transportation is required, have led to great interest in methods that reduce the require- 
ments for ground surveys. 
Up to 1958, Shoran- controlled photography was perhaps the most important single 
tool in use to keep the ground survey to a minimum. Shoran-controlled photography, 
flown in a grid pattern, w ith the grid spacing at approximately 30 km, has been flown 
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