Spread the dividers and place the tips on the courseline. If they will reach, place the
tips of the dividers on the two points (Figure 4.2-18).
Place the straightedge of the plotter against the two points of the dividers (Figure
While keeping the straightedge against the dividers' points, slide the plotter along
the course line until the plotter's grommet is over a meridian (Figure 4.2-18).
NOTE: Greatest accuracy can be obtained by using a meridian exactly halfway
along your course, but using nearby meridians for convenience will still provide
In conclusion, go to the outer two scales and note where the meridian (the one
under the grommet) intersects the scales. There will be a choice of two answers,
choose the one that is nearest the estimate. Be sure to count the marks carefully
and remember the scale increases in a counterclockwise direction (Figure 4.2-18).