190 THE CANADIAN SURVEYOR May, 1960 
This photogrammetric method has been very useful in hydrological laboratory 
work because it is less time-consuming than the electrical methods and it provides the 
most complete information obtainable so far. The accuracy of wave measurements is 
within a few millimeters and the determination of single points can be even more 
precise. It is intended to apply this method over natural water surfaces up to several 
square kilometers in extent. 
Another very interesting application of photogrammetry for similar purposes is 
being carried out by Professor H. L. Cameron, of the Nova Scotia Research Foundation. 
Professor Cameron uses aerial photography to determine wave patterns and to derive 
other important hydrological information for engineering purposes. 
  
A Ao = e MÀ 
~ 5 
> 252 _ = Le 
M WI m A 
T. = E - - 
Eon As 
el Ja . id 
— x Zn -- 
TN 264 ms 
i d M A Te 
AL as m 
2 ™ -— 
— A ET 4 / 
=. > 4 
de A 
_ S. A ae? f 
TIES ; = í 
SS -- ke i 
= s ;) 
= ^ WM = 
S Se ( 
= NS 5 
> = 5 2d 
N ut pH 
Pn - iau 
Zr f 
NE / 
— — = — 
NC 
> 
PAIR NO. l 
Wild Stereometric Camera 
inclined 258 
Plotting Instrument — 
Wild A-7 
Photo Scale — 1:80 
GLACE BAY Plotting Scale — 1:20 
Spot Elevation in Millimetres 
Photogrammetric Research 
PHOTOGRAMMETRIC PLAN N.R.C., Ottawa, Ont. 
120 
Fic. 1. Plot of the water surface in a harbour model. 
SrRUCTURAL DEFORMATIONS 
The National Research Council has used two photogrammetric methods for the 
determination of structural deformations under load. In the first method one photo- 
graph was made without a load and another photograph with the load. When the 
photographs were rotated 90°, deflections appeared as horizontal parallaxes which 
could be measured easily. Figures 2 and 3 illustrate this application. 
The second method used a stereometric camera for a series of stereophotographs 
which were made under different loads and then plotted in a stereoplotter. 
Figure 4 
shows a wood roof truss under loading test.