36 
Fig. 8: The Authority's RC8 
aerial camera installed in the 
Beaver aircraft. 
  
Jindabyne Reservoir 
This future reservoir will cover an area of 8 miles by 2 miles. Aerial photo- 
graphy was available as follows: 
(i) with Williamson Eagle IX camera, f — 6 inches, photographic scale 
1 : 44,000, taken in March, 1953, as part of the general mapping contract. 
5 stereo models from 2 runs covered the storage area with a flight direction 
East-West. 
(ii) with Williamson Eagle IX camera, f = 6 inches, photographic scale 
1: 18,000, taken in November, 1949, and covering the storage area with 
3 parallel runs of 10-12 photographs each with a flight direction North- 
South. 
The 5 stereo models of the first flight were rigidly controlled by 6 horizontal 
and 8 vertical ground control points each. Using compensation plates for the 
distortion of the Ross 6" lens control points were given out in the A7 at a model 
scale of 1: 15,840 for the low level flight in (ii). With the aid of a Helmert 
Transformation their geodetic co-ordinates were determined according to the 
Least Square conditions for the residual errors in scale and orientation within the 
SMA Grid System. Additional benchmarks which were identified in the field 
provided a check for the orientation of the 30 large scale models. Plotting scale 
was 1: 3,960 (16 inches — 1 mile) with 10 ft. contours for open terrain. 
Lake Eucumbene 
This is the main water storage for the Snowy Mountains Hydro-Electric Scheme 
having a capacity of 3.86 million acre feet and stretching over 22 miles, the greatest 
width being 12 miles. 
In 1957 the area was covered by 9 parallel flight strips, following the main 
extension in NW-SE direction. Photographs were taken at 10,000 ft. above ground 
by a Wild RCS camera fitted with Aviogon, f — 115 mm. lens. The contract specified 
also 3 tie runs across the northern and southern end and across the centre of the 
flight block. In designing the outlay of the tie runs consideration was given to the 
topography of the terrain and to existing trig stations in order to facilitate ground 
control. Each tie run comprising 16 photographs was rigidly controlled in the first 
and last model as well as in the centre. Additional control was available by 
identified trig stations and benchmarks at intermediate distances along the flight strip. 
Each tie run was triangulated twice—in opposite directions. The adjustment for the 
given out pass points followed in principle the graphic method described by J. 
Zarzycki, with the application of Melmert's transformation formula for the controlled 
models. 
Average mean square errors for the arithmetical mean of pass points from two 
observations (forward and backward triangulation) were derived for 
me. = =+ 0.054 mm. my == 0.054 mm. m, = + 0.046 mm. 
at a machine scale of 1: 7,920 (ie. 0.1 mm. = 2.6 feet).