d. This same Fort Sill model was compiled at an output scale
of 1/25,000 with a contour interval of 40 feet and at an output
scale of 1/12,500 with a contour interval of 20 feet. In other
words the outputs were enlarged two and four times respectively
during compilation on the UNAMACE. Compilation times were 80
and 105 minutes respectively. Visual comparison of contours
among the three different scaled outputs shows general similarity.
A portion of the 4X enlargement is shown in Figure 19. It is
evident that there is some degradation in orthophoto quality
because the printout raster line spot density is less per unit
area of output.
e. Experiments have been conducted in mosaicking models
together as a direct output of the UNAMACE. One quarter of a
1/50,000 15-minute quadrangle with 40 foot contours composed of
six models and a 22-model mosaic at 1/100,000 scale with 100 foot
contours have been compiled. The orthophoto and line drop outputs
were prepared in approximately eight hours in both cases. Figures
20 and 21 show the resulting contoured orthophotograph for the
1/50,000 scale and the corresponding line drop output with super-
imposed contours for a portion of the mosaic.
f. Inspection of the mosaic shows that there are no
observable discontinuities in imagery between models and that the
contour continuity is well within half an interval. Comparator
measurements of eleven control points show that their mean error
is 25 microns. The time for preparing this six model mosaic
(exclusive of photographic processing) is divided into the following
sub-operation times:
Initial and intermediate set-up 86 minutes
Adverse area selection 29 H
Symbol printout 23 H
Automatic compilation 326 "
Drafting contours from 240 "
line drop
TOTAL 704 minutes or 11
hours 44 minutes
In this example the compilation time is approximately double that
of a typical operation because a longer print time was used in an
effort to improve the quality of the orthophotograph. Approximately
50 manual interventions were required for this entire compilation
in those areas of extremely high relief or dark shadows.
The above test results are typical of what has been obtained
thus far. As refined and improved computer programs become avail-
able and as experience is gained in the operation of this instru-
ment, it can be expected that time for the compilation and resultant
errors will decrease.
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