180 THE CANADIAN SURVEYOR May, 1960 
factor equivalent to Z are used as input to the computer. Using this data and a number 
of predetermined parameters corresponding to the orientation elements, distortion 
characteristics, etc., the computer derives the values by which the photographs must be 
shifted. Servo systems bring the photographs to their correct positions. The operator 
can then decide what changes should be made in the input to obtain the required 
results. The computations and shifts take place at such speeds that the motions 
resulting from continuous changes in the input co-ordinates appear continuous to the 
operator. 
À prototype is now being built with the following tentative design characteristics: 
Size of Photographs: 9” X 9” maximum 
Focal Length: 1” :to-12” 
Distortion: Any experimental curve up to = 200 microns. 
Magnification: 10 times. 
Inclinations: Maximum tip or tilt, = 10°. 
Speed: 250 solutions per second. 
Output: Digital and analog. 
GAMBLE PLOTTER 
Production records tabulated over the past three years show that the Gamble 
Plotter increases compilation output by 25% over the regular Multiplex or Balplex 
methods. In addition, the Gamble Plotter produces contours with better continuity 
than does conventional Multiplex or Balplex compilation. The Gamble Plotter was 
exhibited at the 1956 Congress of the LS.P. at Stockholm. 
STEREOMAT 
A new semi-automatic contouring technique called Auscor has been developed by 
the Hunting Survey Corporation Limited. This technique is incorporated in 
the Stereomat Plotter, which is being manufactured by another firm under contract. 
A prototype of the Stereomat was demonstrated at the 1959 Convention of the 
American Society of Photogrammetry in Washington. Delivery of the first produc- 
tion model was scheduled for February 1960. 
The Stereomat will perform automatic profiling and semi-automatic contouring. 
Any type of anaglyphic projection plotter may be connected to the automatic scanning 
correlator. The plotter can also be equipped to supply x, y, and z co-ordinate output 
on magnetic tape. Contouring and profiling speeds depend upon the rate of change 
of relief in the model. On level terrain the scanning spot travels at a rate of 8 inches 
per second. Tests made with the prototype have shown that x and y parallaxes can 
be removed to 0.02 mm. Automatic relative orientation is accomplished in about 5 
minutes. 
Reports on achievements of these new plotters should be available in the near 
future. It is expected that they will prove to be noteworthy contributions to the 
advancement of photogrammetric plotting. 
REFERENCES 
Helava, U. V. "Use of Infrared Oblique Photographs in Aerial Triangulation." 
Photogrammetria, 1955-56, No. 4, pp. 230-235. 
— Use of Oblique Photographs to Control the Bend of Aerial Triangula- 
tion. National Research Council of Canada, NRC-5396, September 1959.