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below:
a. Autoplot System. The task of the Autoplot system is to prepare map
bases, as well as to carry out projection line scribing, geodetic and pass-point
plotting, point symbolizing, and border format labeling. Basic design require
ments of the system include high precision, relatively low cost, and compatibility
with existing instrumentation. The incorporation of analytical and semianalytical
techniques of aerotriangulation has made the system possible. Characteristics of
the Autoplot system are as follows:
(1) It consists of a magnetic-tape-controlled logic unit for generating
commands to the drive motors for the X and Y axes and each position is plotted
in incremental format.
(2) The system’s magnetic-tape input is generated from basic data
H processed on a centrally located IBM 360/model 65 system computer and written
in Fortran IV language. Subroutines generate instructions for printing alphameric
characters; for providing conversion between geographic coordinates and plane
coordinates; and for providing printouts of transformation parameters.
b. The Stereo Image Alternator (SIA). Several developments have been
initiated to improve the direct viewing capabilities of double-projection stereo-
plotters. One such economical device, namely, the Stereo Image Alternator (SIA)
has been introduced to overcome the shortcomings of the large number of Kelsh
and ER 55 stereoplotters in operation. The disadvantages of the anaglyphic -type
instruments include incompatibility with color photographs; unequal sharpness
of the red and the blue filtered images; possible appearance of ghost images and
incomplete separations of the filtered image; and the low light intensity in the
projected model due to filtering. The SIA, basically, consists of rotating cylin
drical shutters (both in the viewing and in the projection field). These are syn
chronized in such a way that each eye sees only the image from the corresponding
projector. Small motors impart a rotation of 90° to the motor shaft and operate
|| synchronously at relatively high speeds; it is to be noted that a rate of 60 flashes
per second will produce a steady image for most individuals.
