Plotting

PLOTTING

This section discusses the equipment and techniques used in plotting.

PLOTTING EQUIPMENT

The dividers (Figure 4.2-13) are used primarily for measuring distances. A secondary use

(when combined with the plotter) is to measure courses.

Figure 4.2-13 Dividers

The plotter (Figure 4.2-14) is a combination protractor and straightedge. It is used to aid in

drawing course lines and measuring direction. The parts of the plotter include the

straightedge itself, the grommet (center hole of the protractor section), and the scales on

the protractor outer edge. The scales run from 0 to 180 on the top of the outer scale, and

from 180 to 360 on the bottom of the outer scale. The number line on the plotter is

reversed (i.e. the numbers increase to the left and decrease to the right). There is also an

inner scale (called the north/south scale) which will be helpful in measuring course lines

that run close to the north-south axis of the chart. Do not use the distance scales on the

straightedge, as they are not accurate. The dividers will be used to measure distances.

4.6-32