29 
THE AUTHORITY'S PHOTOGRAMMETRIC ACTIVITIES 
A. Equipment 
In realising future demands for large scale plans, the Authority acquired its 
first WILD phototheodolite late in 1951, when the scope of the General Mapping 
had not been finally decided. 
, In 1953 a Universal Stereo Plotting machine of latest design was purchased. 
This machine, an Autograph WILD A7, was the first of its kind to be landed in 
Australia. Prior to this, phototheodolite surveys had been plotted on a WILD AS 
at the Department of Lands and Surveys in Melbourne. 
These first phototheodolite plans, with their more accurate detail, and the 
fact that stereo pairs of photographs were available for office investigations led 
to the purchase of a second phototheodolite in 1953. 
. In 1957 river channel investigations extended beyond the area covered by the 
4 inch — 1 mile maps. A ZEISS Stereotope was used for this medium scale plotting 
from low altitude photography. 
Soon after the Authority had commenced to operate its own aircraft, a de 
Havilland “Beaver,” an order was placed for a modern WILD RCS aerial camera 
which was installed in January, 1959. This camera will carry out all future aerial 
photography required by the Authority. 
In summary the photogrammetric equipment consists of: 
Cameras 
2 Precision phototheodolites (Wild) 
1 Aerial Survey Camera RC8 with Aviotar and Aviogon lens (Wild) 
1 Aerial Camera F 24 (ex RAAF) 
1 Stereo Camera for short range photogrammetry (SMA). 
Plotting Instruments and Office Equipment 
I Stereo Autograph A7 (Wild) 
1 Stereotope (Zeiss) 
1 Stereo Comparograph (Fairchild) 
1 Mirror Stereoscope with Parallax Bar (Wild) 
2 Old Delft Scanning Stereoscopes. 
For Li Surveys associated with Airphoto control the following instruments are 
available: 
3 Field outfits for aerial photograph interpretation (Zeiss) 
1 Tellurometer 
1 Automatic Level (Zeiss) 
T2 theodolites with 2 meter subtense bars (Wild). 
With this photogrammetric equipment, it is believed that the Authority became 
one of the first engineering organisations in the world to undertake all stages of 
photogrammetric mapping. 
B. Terrestrial Photogrammetry 
For the general description of the phototheodolite the reader is referred to 
textbooks and previous publications listed in the bibliography. 
A few characteristic points may be mentioned however. The information 
available from the field work by using the combination of a theodolite and camera 
offers two outstanding advantages when compared with the problem of finding 
the orientation of aerial photographs. These are 
1. The co-ordinates and height of the camera station on the ground are 
known. 
2. The grid bearing of the camera axis which is equivalent to the Y-tilt of 
an aerial photograph (i.e. in the line of flight) can be determined 
accurately with the theodolite. 
And considering the remaining two unknown properties of absolute orientation 
of an aerial camera (i.e. rotation about axis and lateral tilt) we find that 
3. The swing of the terrestrial camera is made zero by levelling the camera 
mount with the aid of bubbles, and 
4. The tilt of the camera axis against a horizontal plane can be read on 
a scale, the range of which is between 4 6°18’ and — 25°12’. 
Compared with manual survey practice and plans derived by classical methods, 
it was found that phototheodolite surveys offered the following advantages: 
1. Expensive fieldwork is greatly reduced, 
2. Photographs present an immeasurable source of information for the 
delineation of topographical and geological detail which can be shown 
on a plan,