May, 1960 Commission V 189
of material and the design criteria. The computer calculates the pay quantities and
classifies it in terms of the specifications.
The combination of the photogrammetric plotter and electronic recording and
computing has been used in Canada, on road and railway projects and similar types of
work requiring quantity determination, with considerable success, and the demands
for this type of information are increasing. It is likely that the use of electronic
computer in photogrammetry in general will grow, in particular on the adjustment of
blocks of aerotriangulation strips.
COMMISSION V
NON-TOPOGRAPHIC APPLICATIONS
by U. V. Hezava
Diversification is noticeable in Canadian activity in the field of non-topographic
applications of photogrammetry, although the bulk of practical work in this area still
deals with the application of photogrammetry in measuring pulpwood piles and open
pit mines. This work is carried out by private Canadian photogrammetric firms, and
it is of practical importance, but methods and techniques differ little from those used in
ordinary mapping operations, and are therefore of limited interest for Commission V.
Some other applications are briefly described below.
SALMON GLACIER
Salmon Glacier in northern British Columbia was mapped by the Photogrammetric
Research Section of the National Research Council. This mapping was based on field
surveys carried out during the Second Salmon Glacier Expedition (1957), organized
by the University of Toronto. One entire map was compiled from aerial photographs
taken in 1957. Parts of the Glacier were also plotted from photographs made in 1949,
and the differences between the two maps were studied for changes in the Glacier
during the eight-year period, 1949-1957. "Terrestrial photogrammetry was also exten-
sively used for detailed studies of the Glacier, such as the determination of the velocity
of the ice flow.
HyvpRAULIC INVESTIGATIONS
A photogrammetric method was used to measure exact wave patterns and other
important dimensions on harbour models in the Hydraulics Laboratory of the National
Research Council of Canada. The main difference between the photogrammetric
method and the electrical methods used in the past is that the latter provided data
only for selected points, while photogrammetric measurements can cover the entire
water surface.
In these experiments two versions of stereophotography were used with a Wild
stereometric camera (1.2 m base): (a) vertical photography for precise surface measure-
ments of limited water areas around critical points such as the head of the break-
water, and (P) horizontal photography for complete coverage of a harbour model.
For vertical photography permanganate was added as colorant to the water in the
harbour model and sometimes cork powder was spread over the water to bring out
surface detail in the photographs. This was not necessary for horizontal photography.
Proper illumination of the water surface is important because it is essential for adequate
contrast in the photographs for the identification and measurement of wave forms with
the required accuracy.