5. When placing a parallel under the grommet, read the course from the inner north/south
1. Locate the point of interest.
2. Estimate the Direction
3. Place a pencil on the point of interest and slide the straightedge of the plotter up against
4. Place the grommet of the plotter over the nearest meridian sliding the grommet up and
down the meridian until the desired direction is read under the outer scale.
Note: Estimating the direction First, will maintain individual focus when selecting the angle
from the proper plotter scale.
If a direction line runs generally north and south, it may be difficult, if not impossible, to
slide the plotter along the direction line until a meridian falls under the plotter's grommet.
The north/south scale (the innermost scale on the plotter) can be used in this situation.
The procedures are the same in that the plotter's straight edge is kept on the point of
interest, but now a parallel is placed under the plotter's grommet. Then, follow that parallel
out to the inner north/south scale to read the answer (Figure 4.2-21). Again, there is a
choice of two answers; so it is imperative to estimate the general course direction before
Note: The plotter outer scale is applicable when using meridians whereas the inner scale is
applicable when using parallels.