Measuring Distances

Figure 4.2-21 Plotting North/South Direction

Measuring Distances

In navigation, the standard for distance measurement is the nautical mile. On Lambert

conformal projections one nautical mile equals one minute of arc measured along any

great circle. All lines of longitude (meridians) are great circles; therefore, one-degree (60

minutes) measured along a meridian equals 60 nautical miles. It is important to understand

that this is NOT a degree of longitude, but actually a degree of latitude. Degrees of latitude

are marked on the longitude lines. Never measure distance along a parallel. On Lambert

Conformal charts a course line is a segment of a great circle. To find the distance of the

course, compare it's length to an equal length of another great circle (any meridian).

(Figure 4.2-22)

4.6-41