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 movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...
and
cartography
Cartography (; from grc, χάρτης , "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 ...
. A
compass rose is primarily composed of four
cardinal directions—
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 or geography.
Etymology
The word ''no ...
,
east,
south, and
west
West or Occident is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth.
Etymology
The word "west" is a Germanic word passed into some ...
—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 a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did no ...
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 are valuable in that they allow a user to refer to a specific azimuth in a
colloquial
Colloquialism (), also called colloquial language, everyday language or general parlance, is the linguistic style used for casual (informal) communication. It is the most common functional style of speech, the idiom normally employed in convers ...
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
cardinal directions 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 guides 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, Romansch, Russian, Serbian, Croatian, Spanish, Swedish, Ukrainian and Welsh the part meaning north or south precedes the part meaning east or west.
[See ]Wiktionary
Wiktionary ( , , rhyming with "dictionary") is a multilingual, web-based project to create a free content dictionary of terms (including words, phrases, proverbs, linguistic reconstructions, etc.) in all natural languages and in a number ...
definitions: 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 or geography.
Etymology
The word ''no ...
; northeast
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 sepa ...
; east; southeast; south; southwest; west
West or Occident is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth.
Etymology
The word "west" is a Germanic word passed into some ...
; northwest
** In Chinese, Vietnamese, Gaelic and less commonly in Japanese, the part meaning east or west precedes the other.
** In Estonian, Finnish, the "Italianate system", and 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: (in first quadrant) north by east (NbE), northeast by north (NEbN), northeast by east (NEbE), and east by north (EbN); (in second quadrant) east by south (EbS), southeast by east (SEbE), southeast by south (SEbS), and south by east (SbE); (in third quadrant) south by west (SbW), southwest by south (SWbS), southwest by west (SWbW), and west by south (WbS); (in fourth 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, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding.
Mnemonics make use of elaborative encoding, retrieval cues, and image ...
(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 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.
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 ...
are named in clockwise
Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite ...
order.
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. 206–7, "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° ′ 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.
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
Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite ...
direction and "CCW" counterclockwise
Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite s ...
. 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 north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
during the Middle Ages
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
(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
Venetian often means from or related to:
* Venice, a city in Italy
* Veneto, a region of Italy
* Republic of Venice (697–1797), a historical nation in that area
Venetian and the like may also refer to:
* Venetian language, a Romance language s ...
, Sicilian, Provençal
Provençal may refer to:
*Of Provence, a region of France
* Provençal dialect, a dialect of the Occitan language, spoken in the southeast of France
*''Provençal'', meaning the whole Occitan language
*Franco-Provençal language, a distinct Roman ...
, Catalan
Catalan may refer to:
Catalonia
From, or related to Catalonia:
* Catalan language, a Romance language
* Catalans, an ethnic group formed by the people from, or with origins in, Northern or southern Catalonia
Places
* 13178 Catalan, asteroid ...
, Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
and Arabic
Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walte ...
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 mariners' 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.
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 ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north.
Mathematicall ...
''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 .
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.
See also
* Bearing (navigation)
* Course (navigation)
* Heading (navigation)
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 ''cours ...
* TVMDC
* Wind rose
References
External links
Wind Rose (archived)
– discusses the origins of the names for compass directions.
{{Compass direction
Navigational equipment
Orientation (geometry)
Units of angle