AUTOMATIC STEREOPLOTTING 
IN SMALL- AND LARGE-SCALE MAPPING 
Results of Automatic Relative Orientation, 
Elevation Readings, Profiling, and Contouring 
ABSTRACT 
An automatic stereoplotting device (called Auscor 
or Stereomat) invented by G. L. Hobrough of Hunting Survey 
Corporation was studied for its performance in various 
mapping operations. It was found that the device measured 
vertical parallaxes and performed semiautomatic relative 
orientations more accurately than an experienced human 
operator. The spot elevations measured by the device on 
1:50,000 photographs had a mean square errorof t1.8 meters. 
The profiling and contouring speed of the device is 4 to 10 
times faster than a human operator and the accuracy of the 
contours, although affected by vegetation and artificial ob- 
jects, is remarkably good. The device had no failure during 
the tests, maintained its stereocontact consistently, and was 
found easy to operate.