It resulted in an instrument called the Stereoplotter, Projection 
AP14 in late 1963. A Gamble/Balplex Plotter was modified with a 
photomultiplier in each projector head and with a high-resolution 
flying spot scanner replacing the usual tracing table. The model 
was oriented with the photomultiplier tubes moved out of position 
and the flying spot being manually positioned on the tube face by 
an operator-controlled joy stick. After orientation, the photo- 
multiplier tubes were rotated into position and automatic searching 
and plotting of the contours began. The flying spot scanner tube 
was placed at a specified elevation in the model where the scanning 
raster performed a preprogrammed search until image coincidence 
indicated a contour. At this point the search mode was interrupted 
and the contour was automatically traced out. The contour was traced 
to the edges of the tube face and the search mode resumed until all contours 
at that elevation on the area of the tube face were completed. The 
operator then reset the elevation of the tube face successively for 
each additional contour. The contour manuscript was obtained by 
photographing with a copy camera the beam of a display CRT which 
moved in synchronism with the DC position of the scanner beam's 
center as it sequentially traced the contours. "C" factors in 
excess of 500 were attained with this instrument in areas of moderate 
detail and slope. Printing speeds of 5 to 15 inches per second were 
attained and contours were detected and traced in areas having slopes 
between 6° and 60°. Since the tube face covered only a part of the 
model area and had to be horizontally indexed to adjacent positions, 
full exploitation of this principle required either the use of a 
larger tube face or a tube having sufficiently high resolution to 
permit reducing the size of the stereomodel to that of the tube face. 
This development is significant in that it represented a successful 
attempt to modify a conventional stereoplotter for automation in 
such a manner that the plotting speed was not limited by the mechanical 
inertia of the tracing table. 
19. Historically, computer controlled plotters have their 
inception in a series of contracts with Paul Rosenberg Associates 
of Mt. Vernon, New York, by ERDL, Fort Belvoir, Virginia, dating 
back to 1953. Initially, information theory was applied to the 
problem of automating the photogrammetric process. Automatic 
recognition and discrimination between images of individual features 
were also studied. These studies were culminated in a breadboard 
piece of hardware in 1960 which was based upon integrating flying 
spot scanners and electronic correlation with a digital computer 
of computation and control. The digital computer exerted logical 
control over the scanning and printing process, utilizing elevation 
estimation as a function of correlation and measurement of instantaneous 
displacement of the scanning carriage. The success of this approach 
experimentally resulted in a contract in 1960 with Ramo-Wooldridge 
Corporation,Canoga Park, California, by U. S. Army Engineer Geodesy, 
Intelligence and Mapping Research and Development Agency, (GIMRADA), 
(Now designated U. S. Army Engineer Topographic Laboratories, USAETL) 
for developing the Autómatic Map Compilation System, which was designed 
from the start as a completely automatic instrument for the high 
speed compilation controlled electronic scanning and correlation devices. 
This equipment, which was the forerunner of the Universal Automatic 
Mapping Equipment (UNAMACE), was delivered to GIMRADA in December 1963, 
and is still in use at GIMRADA as a test bed. Principle elements of 
this equipment are a PB250 digital computer, a single scanning and