The points of the compass, specifically on the compass rose, mark divisions of a compass into the four cardinal directionsnorth, south, east, and west — and often into subdivisions as well. The number of points may be only the four cardinal points, or the eight principal points adding the intercardinal (or ordinal) directions northeast (NE), southeast (SE), southwest (SW), and northwest (NW). In meteorological usage further intermediate points are added to give the sixteen points of a wind compass. Finally, at the most complete in European tradition, are found the full thirty-two points of the mariner's compass. In ancient China 24 points of the compass were used, measuring fifteen degrees between points.

In the mariner's exercise of boxing the compass, all thirty-two points of the compass are named in clockwise order. The names of intermediate points are formed by the initials of the cardinal directions and their intermediate ordinal directions, and are very handy to refer to a heading (or course or azimuth) in a general or colloquial fashion, without having to resort to computing or recalling degrees. For most applications, the minor points have been superseded by degrees measured clockwise from North.

Compass point names

The names of the compass directions follow the 32-point wind compass rose follow these rules:

  • The cardinal directions are north (N), east (E), south (S), west (W), at 90° angles on the compass rose.
  • The ordinal (or intercardinal) directions are northeast (NE), southeast (SE), southwest (SW) and northwest (NW), formed by bisecting the angle of the cardinal winds. The name is merely a combination of the cardinals it bisects.
  • The eight principal winds (or main winds) are the cardinals and ordinals considered together, that is N, NE, E, SE, S, SW, W, NW. Each principal wind is 45° from its neighbour. The principal winds form the basic eight-wind compass rose.

16-wind compass rose

  • The eight half-winds are the points obtained by bisecting the angles between the principal winds. The half-winds are north-northeast (NNE), east-northeast (ENE), east-southeast (ESE), south-southeast (SSE), south-southwest (SSW), west-southwest (WSW), west-northwest (WNW) and north-northwest (NNW). Notice that the name is constructed simply by combining the names of the principal winds to either side, with the cardinal wind coming first, the ordinal wind second. The eight principal winds and the eight half-winds together yield a 16-wind compass rose, with each compass point at a 22 12° angle from the next.

32-wind compass points

All of the above named points plus the sixteen quarter winds listed in the next paragraph define the 32 points of the wind compass rose.

  • The sixteen quarter winds are the direction points obtained by bisecting the angles between the points on a 16-wind compass rose. The sixteen quarter-winds are north by east (NbE), northeast by north (NEbN), northeast by east (NEbE), east by north (EbN) in the first quadrant, east by south (EbS), southeast by east (SEbE), southeast by south (SEbS), south by east (SbE) in the second quadrant, south by west (SbW), southwest by south (SWbS), southwest by west (SWbW), west by south (WbS) in the third quadrant, and finally west by north (WbN), northwest by west (NWbW), northwest by north (NWbN) and north by west (NbW) in the fourth quadrant.[2][3]

The name of a quarter-wind is "X by Y", where X is a principal wind and Y is a cardinal wind. As a mnemonic device, it is useful to think of "X by Y" as a shortcut for the phrase "one quarter wind from X towards Y", where a "quarter" is 11 14°, X is the nearest principal wind, and Y the next (more distant) cardinal wind. So "northeast by east" means "one quarter from NE towards E", "southwest by south" means "one quarter from SW towards S". The eight principal winds, eight half-winds and sixteen quarter winds together yield a 32-wind compass rose, with each compass direction point at 11 14° angle from the next.

The title of the Alfred Hitchcock 1959 movie, North by Northwest, is actually not a direction point on the 32-wind compass, but the film contains a reference to Northwest Airlines. Similarly, the names of the two film festivals South by Southwest and North by Northeast are not 32-wind compass points; a quarter wind whose name contains both a cardinal and an ordinal direction is named with the ordinal direction first.

Traditional names

The traditional compass rose of eight winds (and its 16-wind and 32-wind derivatives) was invented by seafarers in the Mediterranean Sea during the Middle Ages (the ancient Greco-Roman 12 classical compass winds have little to do with them). The traditional mariner's wind names were expressed in Italian – or, more precisely, the Italianate Mediterranean lingua franca common among sailors in the 13th and 14th centuries, that was principally composed of Genoese (Ligurian), mixed with Venetian, Sicilian, Provençal, Catalan, Greek and Arabic terms from around the Mediterranean basin.

This Italianate patois was used to designate the names of the principal winds on the compass rose found in mariner compasses and portolan charts of the 14th and 15th centuries. The "traditional" names of the eight principal winds are:

  • (N) – Tramontana
  • (NE) – Greco (or Bora in some Venetian sources)
  • (E) – Levante (sometimes Oriente)
  • (SE) – Scirocco (or Exaloc in Catalan)
  • (S) – Ostro (or Mezzogiorno in Venetian)
  • (SW) – Libeccio (or Garbino, Eissalot in Provençal)
  • (W) – Ponente (or Zephyrus in Greek)
  • (NW) – Maestro (or Mistral in Provençal)

Local spelling variations are far more numerous than listed, e.g. Tramutana, Gregale, Grecho, Sirocco, Xaloc, Lebeg, Libezo, Leveche, Mezzodi, Migjorn, Magistro, Mestre, etc. Traditional compass roses will typically have the initials T, G, L, S, O, L, P, and M on the main points. Portolan charts also colour-coded the compass winds: black for the eight principal winds, green for the eight half-winds and red for the sixteen quarter-winds.

In the English compass, all wind names are constructed on the basis of the cardinal four names (N, E, S, W). In the traditional compass, one needs to memorize eight basic names – one for each of the eight principal winds (N, NE, E, SE, S, SW, W, NW.) While there are more names to memorize, the payoff is that the name construction rules for the 32-wind compass are more straightforward. The half-winds are just a combination of the two principal winds it bisects, with the shortest name usually coming first (e.g. NNE is "Greco-Tramontana", ENE is "Greco-Levante", SSE is "Ostro-Scirocco", etc.). The quarter winds are expressed with an Italian phrase, "Quarto di X verso Y" (one quarter from X towards Y, pronounced [ˈkwarto di ˈiks ˈvɛrso ˈipsilon][4][5][6]) or "X al Y" (X to Y) or "X per Y" (X by Y). There are no irregularities to trip over: the nearest principal wind always comes first, the more distant one second, e.g. North-by-east is "Quarto di Tramontana verso Greco", northeast-by-north "Quarto di Greco verso Tramontana". The names are perfectly symmetric.

32 cardinal points

#Compass pointAbbreviationTraditional wind pointMinimumMiddle
2North by eastNbEQuarto di Tramontana verso Greco5.63°11.25°16.87°
4Northeast by northNEbNQuarto di Greco verso Tramontana28.13°33.75°39.37°
6Northeast by eastNEbEQuarto di Greco verso Levante50.63°56.25°61.87°
8East by northEbNQuarto di Levante verso Greco73.13°78.75°84.37°
10East by southEbSQuarto di Levante verso Scirocco95.63°101.25°106.87°
12Southeast by eastSEbEQuarto di Scirocco verso Levante118.13°123.75°129.37°
14Southeast by southSEbSQuarto di Scirocco verso Ostro140.63°146.25°151.87°
16South by eastSbEQuarto di Ostro verso Scirocco163.13°168.75°174.37°
18South by westSbWQuarto di Ostro verso Libeccio185.63°191.25°196.87°
20Southwest by southSWbSQuarto di Libeccio verso Ostro208.13°213.75°219.37°
22Southwest by westSWbWQuarto di Libeccio verso Ponente230.63°236.25°241.87°
24West by southWbSQuarto di Ponente verso Libeccio253.13°258.75°264.37°
26West by northWbNQuarto di Ponente verso Maestro275.63°281.25°286.87°
28Northwest by westNWbWQuarto di Maestro verso Ponente298.13°303.75°309.37°
30Northwest by northNWbNQuarto di Maestro verso Tramontana320.63°326.25°331.87°
32North by westNbWQuarto di Tramontana verso Maestro343.13°348.75°354.37°

Half- and quarter-points

By at least the middle of the eighteenth century the 32-point system had been further extended with the use of 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 of which of the two adjoining whole points is used, for example, N3/4E is equivalent to NbE1/4N. Either form is easily understood but differing conventions as to correct usage developed in different countries and organisations.

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" counter clockwise. The final three columns show three common naming conventions: No "by" avoids the use of "by" with fractional points; "USN" the system used by US Navy; and "RN" the Royal Navy. The colour coding illustrates where each of the three naming systems matches the "CW" and "CCW" columns.

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