The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in

navigation Navigation is a field of study that focuses on the process of monitoring and controlling the motion, movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navig ...

and

cartography Cartography (; from , 'papyrus, sheet of paper, map'; and , 'write') is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an imagined reality) can ...

. A '' compass rose'' is primarily composed of four

cardinal direction The four cardinal directions or cardinal points are the four main compass directions: north (N), south (S), east (E), and west (W). The corresponding azimuths ( clockwise horizontal angle from north) are 0°, 90°, 180°, and 270°. The ...

s—

north 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 (geometry), direction or geography. Etymology T ...

east East 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. Etymology As in other languages, the word is formed from the fact that ea ...

south South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

, 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 Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

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 Colloquialism (also called ''colloquial language'', ''colloquial speech'', ''everyday language'', or ''general parlance'') is the linguistic style used for casual and informal communication. It is the most common form of speech in conversation amo ...

fashion, without having to compute or remember degrees.

Designations

The names of the compass point directions follow these rules:

8-wind compass rose

* The four

s are north (N), east (E), south (S), west (W), at 90° angles on the compass rose. * The four intercardinal (or ordinal) directions are formed by bisecting the above, giving: northeast (NE), southeast (SE), southwest (SW), and northwest (NW). In English and many other tongues, these are compound words. Different

style guide A style guide is a set of standards for the writing, formatting, and design of documents. A book-length style guide is often called a style manual or a manual of style. A short style guide, typically ranging from several to several dozen page ...

s for the four mandate spaces, dashes, or none. ** In Bulgarian, Catalan, Czech, Danish, Dutch, English, Esperanto, French, Galician, German, Greek, Hungarian, Ido, Italian, Japanese (usually), Macedonian, Norwegian (both Bokmal and Nynorsk), Polish, Portuguese, Romanian, Romansch, Russian, Serbian, Croatian, Spanish, Swedish, Ukrainian, and Welsh the part meaning north or south precedes the part meaning east or west.See Wiktionary definitions:

; northeast;

;

southeast The points of the compass are a set of horizontal, Radius, radially arrayed compass directions (or Azimuth#In navigation, azimuths) used in navigation and cartography. A ''compass rose'' is primarily composed of four cardinal directions—north, ...

;

southwest 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— ...

; west;

northwest 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— ...

** In Chinese, Vietnamese, Gaelic, and less commonly Japanese, the part meaning east or west precedes the other. ** In Estonian, Finnish, Breton, the "Italianate system" (see section "Traditional Mediterranean compass points" below), and many South Asian and Southeast Asian languages such as Telugu, the intercardinals have distinct words. * The eight ''principal winds'' (or ''main winds'') are the

set union In set theory, the union (denoted by ∪) of a collection of sets is the set of all elements in the collection. It is one of the fundamental operations through which sets can be combined and related to each other. A refers to a union of ze ...

of the cardinals and intercardinals. Taken in turn, each is 45° from the next. These form the ''8-wind compass rose'', the rose at its usual basic level today.

16-wind compass rose

* The eight ''half-winds'' are the direction 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). The name of each half-wind is constructed by combining the names of the principal winds to either side, with the cardinal wind coming first and the intercardinal wind second. * The eight principal winds and the eight half-winds together form the ''16-wind compass rose'', with each compass point at a ° angle from its two neighbours.

32-wind compass rose

* The sixteen ''quarter-winds'' are the direction points obtained by bisecting the angles between the points on the 16-wind compass rose (above). The quarter-winds are as follows. :* in NE quadrant: north by east (NbE), northeast by north (NEbN), northeast by east (NEbE), and east by north (EbN); :* in SE quadrant: east by south (EbS), southeast by east (SEbE), southeast by south (SEbS), and south by east (SbE); :* in SW quadrant: south by west (SbW), southwest by south (SWbS), southwest by west (SWbW), and west by south (WbS); :* in NW quadrant: west by north (WbN), northwest by west (NWbW), northwest by north (NWbN), and north by west (NbW) * All of the points in the 16-wind compass rose plus the sixteen quarter-winds together form the ''32-wind compass rose''. * If breaking down for study/signalling the subcomponents are called the "principal" followed by the "cardinal" wind/direction. As a

mnemonic A mnemonic device ( ), memory trick or memory device is any learning technique that aids information retention or retrieval in the human memory, often by associating the information with something that is easier to remember. It makes use of e ...

(memory device), minds familiar encode the meaning of "X by Y" as "one small measure ''from'' X ''towards'' Y". It can be noted such measure ('one point') is °. So, for example, "northeast by east" means "one quarter of the gap from NE towards E". 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 ° angle from the next.

Half- and quarter-points

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.E. Chambers. ''Cyclopaedia: or, an Universal Dictionary of Arts and Science'', 5th Ed, 1743, pp. 206–207, "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 32^d part of the circuit, or 11° 15′, from each other; hence 5° ′ is the distance of the half points and 2° ′ is the distance of the quarter points. These fractional points are named by appending, for example, east, east, or east 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, NE is equivalent to NbEN. 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.

Maritime Use

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 °. In the mariner's exercise of "boxing the compass", all thirty-two points of the

compass 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 No ...

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, ° 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.

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 The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

during the

Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of global history. It began with the fall of the Western Roman Empire and ...

(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 Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

terms from around the Mediterranean basin. This Italianate

patois ''Patois'' (, same or ) is speech or language that is considered nonstandard, although the term is not formally defined in linguistics. As such, ''patois'' can refer to pidgins, creoles, dialects or vernaculars, but not commonly to jargon or sl ...

was used to designate the names of the principal winds on the compass rose found in mariners' compasses and

portolan chart Portolan charts are nautical charts, first made in the 13th century in the Mediterranean Sea, Mediterranean basin and later expanded to include other regions. The word ''portolan'' comes from the Italian language, Italian ''portolano'', meaning " ...

s 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. 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" ( 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 degrees where the

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

''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 The Earthly Branches (also called the Terrestrial Branches or the 12-cycle) are a system of twelve ordered symbols used throughout East Asia. They are indigenous to China, and are themselves Chinese characters, corresponding to words with no co ...

, 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-marine-compass

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

References

External links

Wind Rose (archived)
– discusses the origins of the names for compass directions. {{Compass direction Navigational equipment Orientation (geometry) Units of angle de:Himmelsrichtung#Systematik_der_Benennung