Figure 4-21.Number of flight lines nomograph.
is 1/10,000, the distance between flight lines drawn on
the chart is 64,800
1/20,000, or 3.24 inches. Since it
is difficult to measure the flight-line distances
accurately, a multi-finger divider should be used (fig.
To use the multi-finger divider, first multiply the
distance between flight lines by the number of fingers
on the divider. This will give you the total flight-line
plot width. Using a ruler, place the first divider finger
on zero and the last divider finger on the mark
corresponding to the total flight-line plot width. The
individual fingers of the divider automatically space
themselves to the correct distance for each flight line.
The multi-finger divider may then be used to lay out the
INTERVAL BETWEEN EXPOSURES
You must convert the aircraft ground speed to feet
per second to determine the exposure interval or
frequency between frames. The conversion factor for
Figure 4-22.Multi-finger divider.