Points of the compass

The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each separated by 90 degrees, and secondarily divided by four ordinal (intercardinal) directions—northeast, southeast, southwest, and northwest—each located halfway between two cardinal directions. Some disciplines such as meteorology and navigation further divide the compass with additional azimuths. Within European tradition, a fully defined compass has 32 "points" (and any finer subdivisions are described in fractions of points).

Compass points or compass directions are valuable in that they allow a user to refer to a specific azimuth in a colloquial fashion, without having to compute or remember degrees.

The names of the compass point directions follow these rules:

In summary, the 32-wind compass rose comes from the eight principal winds, eight half-winds, and sixteen quarter-winds combined, with each compass point at an 11+1⁄4° angle from the next.

By the middle of the 18th century, the 32-point system had been further extended by using half- and quarter-points to give a total of 128 directions. These fractional points are named by appending, for example, ⁠1/4⁠east, ⁠1/2⁠east, or ⁠3/4⁠east to the name of one of the 32 points. Each of the 96 fractional points can be named in two ways, depending on which of the two adjoining whole points is used, for example, N⁠3/4⁠E is equivalent to NbE⁠1/4⁠N. Either form is easily understood, but alternative conventions as to correct usage developed in different countries and organisations. "It is the custom in the United States Navy to box from north and south toward east and west, with the exception that divisions adjacent to a cardinal or inter-cardinal point are always referred to that point." The Royal Navy used the additional "rule that quarter points were never read from a point beginning and ending with the same letter."

Compass roses very rarely named the fractional points and only showed small, unlabelled markers as a guide for helmsmen.

Prior to the modern three-figure method of describing directions (using the 360° of a circle), the 32-point compass was used for directions on most ships, especially among European crews. The smallest unit of measure recognized was 'one point', 1/32 of a circle, or 11+1⁄4°. In the mariner's exercise of "boxing the compass", all thirty-two points of the compass are named in clockwise order. This exercise became more significant as navigation improved and the half- and quarter-point system increased the number of directions to include in the 'boxing'. Points remained the standard unit until switching to the three-figure degree method. These points were also used for relative measurement, so that an obstacle might be noted as 'two points off the starboard bow', meaning two points clockwise of straight ahead, 22+1⁄2° This relative measurement may still be used in shorthand on modern ships, especially for handoffs between outgoing and incoming helmsmen, as the loss of granularity is less significant than the brevity and simplicity of the summary.

The table below shows how each of the 128 directions are named. The first two columns give the number of points and degrees clockwise from north. The third gives the equivalent bearing to the nearest degree from north or south towards east or west. The "CW" column gives the fractional-point bearings increasing in the clockwise direction and "CCW" counterclockwise. The final three columns show three common naming conventions: No "by" avoids the use of "by" with fractional points. Colour coding shows whether each of the three naming systems matches the "CW" or "CCW" column.