Course Angles

When working out mathematical navigation problems, the angles you find are not courses but course angles. Course Angles reference a cardinal direction, North, East, South or West, have an angle, and then a direction to go towards.

For example this course angle of \(N 24° E\) starts North, and then is 24° to the East. To convert this to a true course in this case is \(0° + 24° = 024°\).

That’s an easy one, so lets try south now. A course angle of \(S 52° W\) starts South, and then is 52° to the West. To convert to a true course in this case is \(180° + 52° = 232°\).

Lets show the rest of the quadrants:

\[\begin{split}N 24° E = 0° + 24° &= 024° \\ S 52° E = 180° - 52° &= 128° \\ S 45° W = 180° + 45° &= 225° \\ N 42° W = 360° - 42° &= 318°\end{split}\]

In the case of SE and NW, the course angle is subtracted from the cardinal direction rather than added. Generally course angles are expressed in terms of North and South as their first cardinal direction, but at times you may see course angles that are East/West cardinal:

\[\begin{split}E 24° N = 90° - 24° &= 066° \\ E 34° S = 90° + 34° &= 124° \\ W 42° S = 270° - 42° &= 228° \\ W 72° N = 270° + 72° &= 342°\end{split}\]

The main thing to remember is that the first direction is your reference point, and then from there you add or subtract based on which direction around the compass you need to go towards the second direction.