The orthophoto maps found considerable interest in Canada, particularly at large scales for special projects, 
such as route location and resources inventories. However, at this time, the use of orthophoto maps is still 
comparatively limited. 
In September of 1967, The Canadian Institute of Surveying, together with Working Group IV-3, organized 
in Ottawa an international symposium on orthophoto maps and photo maps. Different Canadian governmental 
agencies, as well as universities and private companies, have participated in tests and experiments carried out 
by COMMISSION IV. 
COMMISSION V 
Non-Topographical Photogrammetry 
Reporter: M. C. van Wijk, Photogrammetric Research Section, National Research Council. 
Photogrammetry is being increasingly applied to scientific and engineering projects that have little or no 
relation to topographical mapping. Much of the work is carried out at research institutes and universities. 
In underground mining, Chrzanowski and Masry, of the University of New Brunswick, have developed 
a photogrammetric technique for measuring tunnel profiles. The described method can be used for volume 
determination in underground excavations, for deformation measurements and for the determination of tunnel 
dimensions. An accuracy of ±1 per cent of the cross-sectional areas was achieved. 
The suitability of stereo photogrammetry in mine surveying was also investigated at the University of 
New Brunswick (23). Volumes were determined from photographs taken with a standard stereometric camera. 
Results from these experiments indicated distinct advantages of photogrammetry over conventional surveying 
techniques. 
Another application of photogrammetry, which is directly related to Canada’s resources, is the measure 
ment of forest inventories from aerial photographs. For this purpose, single cameras, as well as large base 
stereometric cameras, are used. A study of the accuracy of the single camera method was carried out at the 
National Research Council (24). A new radar altimeter was developed for the determination of the flying 
height of the aircraft at the moment of exposure (25). Maximum errors, in the determination of normal flying 
heights for forestry inventory purposes, do not exceed 1.5 m. 
Short-range photogrammetry was used at the National Research Council to determine the geometrical 
characteristics of the aircraft models used in wind tunnel experiments. A study has been undertaken to establish 
whether photogrammetry can replace the precise, but time-consuming, mechanical calibration techniques. 
A precise photogrammetric camera was especially developed for this purpose. The system was tested by 
photographing an accurately calibrated wing model. A total of 70 points were located along three profiles. 
The NRC-Monocomparator was used for the measurements and the photogrammetric coordinates of the 
control points were determined by analytical methods. From the discrepancies of the given and the photo 
grammetric coordinates, standard errors of 30 microns were found for the position and height. 
Other applications of short-range photogrammetry were studied at Laval University (26). A detailed plot 
of the front face of the parliament building in Quebec was made from photographs taken with a phototheodolite 
camera. Photogrammetric methods were also used to determine the fish density in lakes by using underwater 
photography. In psychological studies, photogrammetry was used to measure a person’s face at various 
emotional stages. 
Photogrammetry has proven to be very suitable for the measurement of movement. The technique was 
applied to measuring velocities of snow masses in an avalanche (27). Various stages of a snow avalanche were 
measured at the National Research Council from a series of terrestrial photographs that were taken with two 
synchronized photogrammetric cameras. 
At the University of Waterloo, a photogrammetric technique was used to measure particle velocities and 
turbulence components in an airflow. Photographs were made through an observation window in the wall of a 
10 cm vertical pipe, using a 340 mm principal-distance camera. A beamsplitter, consisting of surface-coated 
plane mirrors, was installed symmetrically with the lens. The area of interest was thus projected on the photo 
graphic plate with respect to two projection centres. A pair of simultaneously exposed photographs was ob 
tained, therefore, on one single photographic plate. Two consecutive exposures were made at an interval of 
10- 4 sec. using two electronic flash units. The individual particle velocities were expressed as a function of the 
radial distance from the centre of the pipe. The stereo-photogrammetric method was also used for determining 
the concentration of particles across the pipe. 
Movements of the ice cover, caused by temperature variations and the water current, were measured by 
stereo photogrammetry to assist a research project carried out at the National Research Council. The pressures 
on bridge piers, caused by ice movements, present a substantial problem in the designing of bridges which 
overspan wide water surfaces. Using a phototheodolite, ice was photographed at regular intervals from a 
platform that was attached to a selected bridge. Targets on the ice and the bridge pier served as reference points. 
The Photogrammetric Research Section of the National Research Council was asked to assist in the 
investigation of an airplane crash, which occurred at the Ottawa Airport. By chance, the crash was photo