For bulk processing, video data are recorded on video (magnetic) tape and afterwards 
undergo preliminary processing, An electron beam recorder receives signals from the video tape, 
corrects the signals for various distortions, and records the images on 70-mm film, The 70-mm 
film images are developed, inspected for cloud cover and quality, and then logged and filed, 
Upon request, precision processing is performed on selected image data, The 70-mm 
film images produced in bulk processing are reproduced on a format of 9 by 9 inches, In the re- 
production process, additional corrections for image displacements are applied to improve metric 
quality. 
In special processing, image data of particular interest produced in either bulk proces- 
sing or precision processing are edited, corrected, and reproduced in digital form on magnetic 
tape, printed copy, or punched cards, 
With this automated system, data can be made available to the user within 24 hours after 
being obtained by instruments on board the space vehicle, 
Aerotriangulation 
Semianalytical Aerotriangulation - Semianalytical aerotriangulation is currently the most 
popular means of establishing horizontal and vertical pass points for stereomodels, and the inde- 
pendent model method is the most popular of the semianalytical methods, In this method, relati- 
vely inexpensive non-bridging stereoplotters can be used for obtaining instrument coordinates of 
pass points. The perspective centers of the two projectors of the stereoplotter are determined, 
and these centers, along with the pass points measured in the terrain model, are used to join each 
successive stereomodel to the previous model, thereby generating a strip with all coordinates 
expressed in the coordinate system of the first stereomodel. 
  
Of the two computer programs most commonly used for generating strips by successive 
joining of independent stereomodels, one was prepared by Kern Instruments, Inc., and the other 
was prepared by the National Research Council of Canada (NRC). Also prepared by NRC is a 
computer program for fitting strips to each other and to ground control in a cycling routine, For 
a block being adjusted, each strip in turn is fitted to ground control and to a previously adjusted 
adjoining strip. The process is repeated over the block until a stable solution is reached. 
USGS has prepared an IBM 360/65 computer program for adjusting a block of strips by 
simultaneously fitting adjoining strips to each other and to ground control, Either a horizontal 
only or a combined horizontal and vertical adjustment can be specified. A similar version of this 
program has been prepared for an IBM 1130 computer with a memory of 8k bytes. 
Fully Analytical Aerotriangulation - A computer program for fully analytical aerotrian- 
gulation has been prepared in FORTRAN IV by NRC for use on IBM System/360 computers having 
relatively small memories, The first program transforms comparator coordinates to photograph 
coordinates and corrects the coordinates of each image for systematic displacements. The second 
program forms stereomodels mathematically by enforcing the condition that for each pair of cor- 
responding rays, the point of intersection and the perspective centers of the two photographs for- 
ming a stereomodel alllie in a plane. A strip is generated by forming an equation for each point 
common to two stereomodels, enforcing an equal slant-range distance from the perspective center 
of the middle photograph to the point as computed from each stereomodel. The third program is 
the same cycling-routine program used in semianalytical aerotriangulation for adjusting strips 
to each other and to ground control. 
  
The National Ocean Survey (NOS) has also developed a set of separate computer programs 
for fully analytical aerotriangulation that can be used, if required, on computers of modest size, 
However, a relatively large computer is needed for a large block adjustment, The program of the 
set that generates strip coordinates mathematically forms stereomodels by enforcing the colli- 
nearity condition, that the perspective center of a photograph, the image of a point, and the point 
itself must all lie on a straight line, If a block solution is desired, the collinearity condition is 
enforced in a resection problem to determine geocentric coordinates for exposure stations and to 
determine camera orientation parameters, 
The direct geodetic constraint method has been programed for the IBM System /360 by 
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