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Planning and Constructing Great-Circle Tracks, Continued
Track
Construction
Use the following step action table to construct a great-circle track:
Step
Action
1.
Plot the departure and arrival points on the gnomonic chart
projection.
2.
Draw a line between the two points (see fig. 12-1).
3.
Inspect the track to make sure that is does not cross any
dangers. Redraw if necessary.
4.
5.
6.
7.
Note: If the track must be redrawn, always do so on the
gnomonic chart. This will have less impact on overall mileage
than navigating around dangers on a Mercator chart.
Select convenient points to use to transfer the track to small
scale Mercator charts. Normally these points should be about
300 nmi apart; refer again to figure 12-1.
Label the points beginning with the letter A.
Extract and record the latitude and longitude of each point.
This information can be used later for the movement report
(MOVREP).
Transfer the points to small scale Mercator charts (fig. 12-2) to
show the entire transit.
Transfer the points to larger scale Mercator charts that cover
about one leg of the transit each.
8.
9.
Example: Transfer points A and B on the first Mercator chart
selected; transfer points B and C on the second Mercator chart
selected; and so on.
Label the track with course and distance for that leg.
Go to steps 7 and 8 until all legs of the track have been
transferred and labeled.
Now the last stage is to lay out PIM. Move on to page 5.
12-3
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