RC-025063, for detailed instructions.
fraction of this chart, or its linear scale, provides
important information. The amount of area to be
that one unit of measure on the map is equal to 10,000
of the same units on the ground.
provided, then the altitude and focal length must be
determined to get the required scale. The scale of a
photographic mosaic map is calculated as follows:
the photograph equals 10,000 inches on the ground.
so it overlaps both the preceding photograph and the
following photograph. The amount of overlap on each
overlap ensures that the strip contains no blank areas
area of each print is used. Only the central area is used
because the middle areas of all vertical photographs are
the area of truest reproduction of terrain. (See fig.
practical purposes, when the aircraft is directly over the
mountain, a perfect reproduction of the mountain is
obtained. Pictures taken before and after the one
directly over the mountain show the near side of the
mountain clearly, but very little, if any, of the far side.
This is caused by the different camera positions in
respect to the subject.
edges of prints when these distortions of the terrain are
present. Therefore, the outer area (toward the edges of
the print) is discarded and the inner 40 percent of each
print is used. Another important reason for using only
the center area of the prints is that stereoscopic
measurement associated with either contour mapping or
photographic interpretation requires the highest degree
in each negative. For example, a 5-
negative, multiply the ground coverage by 0.40. For
example, using the IFGA formula, you have determined
that the ground coverage for each negative is 9,000 feet.
The usable GGF in each negative is 3,600 feet (9,000
strip. The aircraft must fly a number of side-by-side
strips to get complete coverage so none of the area is
Advanced Photography Course