Points of the compass

Last updated

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 directionsnorth, 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). [1]


Compass points 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. [2]


The names of the compass point directions follow these rules:

8-wind compass rose

8-wind compass rose Compass rose en 08p.svg
8-wind compass rose

16-wind compass rose

32-wind compass rose

32-point compass rose Brosen windrose Full.svg
32-point compass rose

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+14° angle from the next.

In the mariner's exercise of boxing the compass, all thirty-two points of the compass are named in clockwise order. [6]

Half- and quarter-points

Compass rose from "American Practical Navigator" 1916 Bowditch1916p15CompassRose.png
Compass rose from "American Practical Navigator" 1916

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. [7] 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." [8] The Royal Navy used the additional "rule that quarter points were never read from a point beginning and ending with the same letter." [9]

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

128 compass directions

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.

Traditional Mediterranean compass points

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 (with no obvious connection to the twelve classical compass winds of the ancient Greeks and Romans). 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, which was principally composed of Genoese (Ligurian), mixed with Venetian, Sicilian, Provençal, Catalan, Greek and Arabic terms from around the Mediterranean basin.

32-wind compass with traditional names (and traditional colour code) 32-point compass (traditional winds).svg
32-wind compass with traditional names (and traditional colour code)

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

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.

Each half-wind name is simply a combination of the two principal winds that it bisects, with the shortest name usually placed first, for example: 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" (pronounced  [ˈkwarto di X ˈvɛrso Y] [10] [11] [12] one quarter from X towards Y), or "X al Y" (X to Y) or "X per Y" (X by Y). There are no irregularities to trip over; the closest principal wind always comes first, the more distant one second, for example: north-by-east is "Quarto di Tramontana verso Greco"; and northeast-by-north is "Quarto di Greco verso Tramontana".

The table below shows how the 32 compass points are named. Each point has an angular range of 11+14 degrees where the azimuth midpoint is the horizontal angular direction (clockwise from north) of the given compass bearing; minimum is the lower (counterclockwise) angular limit of the compass point; and maximum is the upper (clockwise) angular limit of the compass point.

Chinese compass points

Navigation texts dating from the Yuan, Ming, and Qing dynasties in China use a 24-pointed compass with named directions. These are based on the twelve Earthly Branches, which also form the basis of the Chinese zodiac. When a single direction is specified, it may be prefaced by the character (meaning single) or .

Ming Dynasty 24-pointed compass Ming-marine-compass.jpg
Ming Dynasty 24-pointed compass

Headings mid-way in-between are compounds as in English. For instance, 癸子 refers to the direction halfway between point and point , or 7+12°. This technique is referred to as a double-needle (雙針) compass.

PointOrdinal NameAngle
north0° or 360°

See also

Related Research Articles

<span class="mw-page-title-main">Compass</span> Instrument used for navigation and orientation

A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north. Other methods may be used, including gyroscopes, magnetometers, and GPS receivers.

Azimuth Angle between a reference plane and a point

An azimuth is an angular measurement in a spherical coordinate system. The vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane; the angle between the projected vector and a reference vector on the reference plane is called the azimuth.

North One of the four cardinal directions

North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. North is a noun, adjective, or adverb indicating direction or geography.

East One of the four cardinal directions

East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth.

Cardinal direction Directions of north, east, south and west

The four cardinal directions, or cardinal points, are the four main compass directions: north, east, south, and west, commonly denoted by their initials N, E, S, and W respectively. Relative to north, the directions east, south, and west are at 90 degree intervals in the clockwise direction.

Bearing (angle) In navigation, horizontal angle between the direction of an object and another object

In navigation, bearing is the horizontal angle between the direction of an object and another object, or between it and that of true north.

Compass rose Figure on a compass, map, nautical chart

A compass rose, sometimes called a wind rose, rose of the winds or compass star, is a figure on a compass, map, nautical chart, or monument used to display the orientation of the cardinal directions and their intermediate points. It is also the term for the graduated markings found on the traditional magnetic compass. Today, a form of compass rose is found on, or featured in, almost all navigation systems, including nautical charts, non-directional beacons (NDB), VHF omnidirectional range (VOR) systems, global-positioning systems (GPS), and similar equipment.

Cardinal mark Sea mark indicating where safe water is near to a hazard

A cardinal mark is a sea mark used in maritime pilotage to indicate the position of a hazard and the direction of safe water.

<span class="mw-page-title-main">Section (United States land surveying)</span> One square mile

In U.S. land surveying under the Public Land Survey System (PLSS), a section is an area nominally one square mile, containing 640 acres, with 36 sections making up one survey township on a rectangular grid.

Course (navigation) Cardinal direction for steering

In navigation, the course of a watercraft or aircraft is the cardinal direction in which the craft is to be steered. The course is to be distinguished from the heading, which is the compass direction in which the craft's bow or nose is pointed.

Railroad directions are used to describe train directions on rail systems. The terms used may be derived from such sources as compass directions, altitude directions, or other directions. However, the railroad directions frequently vary from the actual directions, so that, for example, a "northbound" train may really be headed west over some segments of its trip, or a train going "down" may actually be increasing its elevation. Railroad directions are often specific to system, country, or region.

Day beacon Unlighted nautical sea mark

A day beacon is an unlighted nautical sea mark. A signboard identifying it is called a day mark. Day beacons typically mark channels whose key points are marked by lighted buoys. They may also mark smaller navigable routes in their entirety. They are the most common navigation aid in shallow water, as they are relatively inexpensive to install and maintain. Navigation around them is similar to that around other navigation aids.

<span class="mw-page-title-main">Wind rose</span> Graphic tool used by meteorologists

A wind rose is a graphic tool used by meteorologists to give a succinct view of how wind speed and direction are typically distributed at a particular location. Historically, wind roses were predecessors of the compass rose, as there was no differentiation between a cardinal direction and the wind which blew from such a direction. Using a polar coordinate system of gridding, the frequency of winds over a time period is plotted by wind direction, with colour bands showing wind speed ranges. The direction of the longest spoke shows the wind direction with the greatest frequency.

Traverse board

The traverse board is a tool formerly used in dead reckoning navigation to easily record the speeds and directions sailed during a watch. Even crew members who could not read or write could use the traverse board.

Winds of Provence

The winds of Provence, the region of southeast France along the Mediterranean from the Alps to the mouth of the Rhone River, are an important feature of Provençal life, and each one has a traditional local name, in the Provençal language.

Classical compass winds Historical wind directions

In the ancient Mediterranean world, the classical compass winds were names for the points of geographic direction and orientation, in association with the winds as conceived of by the ancient Greeks and Romans. Ancient wind roses typically had twelve winds and thus twelve points of orientation, sometimes reduced to eight or increased to twenty-four.

<span class="mw-page-title-main">Rule of marteloio</span>

The rule of marteloio is a medieval technique of navigational computation that uses compass direction, distance and a simple trigonometric table known as the toleta de marteloio. The rule told mariners how to plot the traverse between two different navigation courses by means of resolving triangles with the help of the Toleta and basic arithmetic.

Heading (navigation) Compass direction

In navigation, the heading of a vessel or aircraft is the compass direction in which the craft's bow or nose is pointed. Note that the heading may not necessarily be the direction that the vehicle actually travels, which is known as its course or track. Any difference between the heading and course is due to the motion of the underlying medium, the air or water, or other effects like skidding or slipping. The difference is known as the drift, and can be determined by the wind triangle. At least seven ways to measure the heading of a vehicle have been described.

Prismatic compass Navigation and surveying instrument to measure magnetic bearing

A prismatic compass is a navigation and surveying instrument which is extensively used to find out the bearing of the traversing and included angles between them, waypoints and direction. Compass surveying is a type of surveying in which the directions of surveying lines are determined with a magnetic compass, and the length of the surveying lines are measured with a tape or chain or laser range finder. The compass is generally used to run a traverse line. The compass calculates bearings of lines with respect to magnetic needle. The included angles can then be calculated using suitable formulas in case of clockwise and anti-clockwise traverse respectively. For each survey line in the traverse, surveyors take two bearings that is fore bearing and back bearing which should exactly differ by 180° if local attraction is negligible. The name Prismatic compass is given to it because it essentially consists of a prism which is used for taking observations more accurately.

Rhumbline network Navigational aid drawn on early portolan charts

A rhumbline network, more properly called, a windrose network, or sometimes also called harbour-finding chart, compass chart, or rhumb chart, is a navigational aid drawn on early portolan charts dating from the medieval to early modern period. This network is like a web forming a grid on the map.


  1. Evans, Frederick John, ed. (1859). "Notes on the Magnetism of Ships". Pamphlets on British shipping. 1785–1861. p. 8 (p. 433 of PDF). ISBN   0-217-85167-3. A deviation table having been formed by any of the processes now so generally understood, either on the thirty-two points of the compass, the sixteen intermediate, or the eight principal points
  2. Boardman, David (1983). Graphicacy and Geography Teaching. p. 41. In particular they should learn that wind direction is always stated as the direction from which, and not to which, the wind is blowing. Once children have grasped these eight points they can learn the full sixteen points of the compass.
  3. 1 2 See Wiktionary definitions: north; northeast; east; southeast; south; southwest; west; northwest
  4. Webb Aintablian, Xanthe (June 28, 2018). "An Overview and History of the Compass". thoughtco.com. Dotdash. Archived from the original on July 6, 2018.
  5. Lee, Robert E. (2011). "Compass Rose". University of Washington. Archived from the original on February 21, 2015.
  6. George Payn Quackenbos A Natural Philosophy: Embracing the Most Recent Discoveries 1860 "Mentioning the mariner's compass: the points of the compass in their order is called boxing the compass. — The compass box is suspended within a larger box by means of two brass hoops, or gimbals as they are called, supported at opposite ..."
  7. E. Chambers Cyclopaedia: or, an Universal Dictionary of Arts and Science, 5th Ed, 1743, pp. 206–7, "Points of the Compass, or Horizon, &c., in Geography and Navigation, are the points of division when the whole circle, quite around, is divided into 32 equal parts. These points are therefore at the distance of the 32d part of the circuit, or 11°15′, from each other; hence 5°37+1/2′ is the distance of the half points and 2°48+3/4′ is the distance of the quarter points.
  8. Bowditch, Nathaniel (1916). American Practical Navigator: An Epitome of Navigation and Nautical Astronomy. United States Hydrographic Office. p.  15.
  9. Kemp, Peter, ed. (1988). "Box the Compass". The Oxford Companion to Ships and the Sea. Oxford University Press. p.  103. ISBN   0-19-282084-2.
  10. "quarto". WordReference.com. Retrieved December 2, 2018. English translation: fourth, quarter
  11. "di". WordReference.com. Retrieved December 2, 2018. English translation: of, from...
  12. "verso". WordReference.com. Retrieved December 2, 2018. English translation: towards, toward, close to, near to