Cardinal direction

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

The four ordinal directions or intercardinal directions are northeast (NE), southeast (SE), southwest (SW), and northwest (NW). The corresponding azimuths are 45°, 135°, 225°, and 315°.

The intermediate direction of every pair of neighboring cardinal and intercardinal directions is called a secondary intercardinal direction. These eight shortest points in the compass rose shown to the right are:

West-northwest (WNW)
North-northwest (NNW)
North-northeast (NNE)
East-northeast (ENE)
East-southeast (ESE)
South-southeast (SSE)
South-southwest (SSW)
West-southwest (WSW)

Points between the cardinal directions form the points of the compass. Arbitrary horizontal directions may be indicated by their azimuth angle value.

Determination

Direction determination refers to the ways in which a cardinal direction or compass point can be determined in navigation and wayfinding. The most direct method is using a compass (magnetic compass or gyrocompass), but indirect methods exist, based on the Sun path (unaided or by using a watch or sundial), the stars, and satellite navigation.^[1]

Additional points

Azimuth v t e	Cardinal direction	Intercardinal direction	Secondary intercardinal direction	Tertiary intercardinal direction
0°	North
11¼°				NbE
22½°			NNE
33¾°				NEbN
45°		NE
56¼°				NEbE
67½°			ENE
78¾°				EbN
90°	East
101¼°				EbS
112½°			ESE
123¾°				SEbE
135°		SE
146¼°				SEbS
157½°			SSE
168¾°				SbE
180°	South
191¼°				SbW
202½°			SSW
213¾°				SWbS
225°		SW
236¼°				SWbW
247½°			WSW
258¾°				WbS
270°	West
281¼°				WbN
292½°			WNW
303¾°				NWbW
315°		NW
326¼°				NWbN
337½°			NNW
348¾°				NbW

Azimuth

The directional names are routinely associated with azimuths, the angle of rotation (in degrees) in the unit circle over the horizontal plane. It is a necessary step for navigational calculations (derived from trigonometry) and for use with Global Positioning System (GPS) receivers. The four cardinal directions correspond to the following degrees of a compass:

North (N): 0° = 360°
East (E): 90°
South (S): 180°
West (W): 270°

Intercardinal directions

The intercardinal (intermediate, or, historically, ordinal^[2]) directions are the four intermediate compass directions located halfway between each pair of cardinal directions.

Northeast (NE), 45°, halfway between north and east, is the opposite of southwest.
Southeast (SE), 135°, halfway between south and east, is the opposite of northwest.
Southwest (SW), 225°, halfway between south and west, is the opposite of northeast.
Northwest (NW), 315°, halfway between north and west, is the opposite of southeast.

Subintercardinal directions

The eight above listed directional names have been further compounded known as secondary intercardinal directions, resulting in a total of 16 named points evenly spaced around the compass. But there exist even tertiary intercardinal directions, resulting in a total of 32 named points evenly spaced around the compass: north (N), north by east (NbE), north-northeast (NNE), northeast by north (NEbN), northeast (NE), northeast by east (NEbE), east-northeast (ENE), east by north (EbN), east (E), etc.

Beyond geography

Cardinal directions or cardinal points may sometimes be extended to include vertical position (elevation, altitude, depth): north and south, east and west, up and down; or mathematically the six directions of the x-, y-, and z-axes in three-dimensional Cartesian coordinates. Topographic maps include elevation, typically via contour lines. Alternatively, elevation angle may be combined with cardinal direction (or, more generally, arbitrary azimuth angle) to form a local spherical coordinate system.

In astronomy

In astronomy, the cardinal points of an astronomical star as seen in the sky are four points defined by the directions toward which the celestial poles lie relative to the center of the disk of the object in the sky.^[3]^[4] A line (a great circle on the celestial sphere) from the center of the disk to the North celestial pole will intersect the edge of the body (the "limb") at the North point. The North point will then be the point on the limb that is closest to the North celestial pole. Similarly, a line from the center to the South celestial pole will define the South point by its intersection with the limb. The points at right angles to the North and South points are the East and West points. Going around the disk clockwise from the North point, one encounters in order the West point, the South point, and then the East point. This is opposite to the order on a terrestrial map because one is looking up instead of down.

Similarly, when describing the location of one astronomical object relative to another, "north" means closer to the North celestial pole, "east" means at a higher right ascension, "south" means closer to the South celestial pole, and "west" means at a lower right ascension. If one is looking at two stars that are below the North Star, for example, the one that is "east" will actually be further to the left.

Germanic origin of names

During the Migration Period, the Germanic names for the cardinal directions entered the Romance languages, where they replaced the Latin names borealis (or septentrionalis) with north, australis (or meridionalis) with south, occidentalis with west and orientalis with east. It is possible that some northern people used the Germanic names for the intermediate directions. Medieval Scandinavian orientation would thus have involved a 45 degree rotation of cardinal directions.^[5]

north (Proto-Germanic *norþ-) from the proto-Indo-European *nórto-s 'submerged' from the root *ner- 'left, below, to the left of the rising sun' whence comes the Ancient Greek name Nereus.^[6]
east (*aus-t-) from the word for dawn. The proto-Indo-European form is *austo-s from the root *aues- 'shine (red)'.^[7] See Ēostre.
south (*sunþ-), derived from proto-Indo-European *sú-n-to-s from the root *seu- 'seethe, boil'.^[8] Cognate with this root is the word Sun, thus "the region of the Sun".
west (*wes-t-) from a word for "evening". The proto-Indo-European form is *uestos from the root *ues- 'shine (red)',^[9] itself a form of *aues-.^[7] Cognate with the root are the Latin words vesper and vesta and the Ancient Greek Hestia, Hesperus and Hesperides.

Cultural variations

In many regions of the world, prevalent winds change direction seasonally, and consequently many cultures associate specific named winds with cardinal and intercardinal directions. For example, classical Greek culture characterized these winds as Anemoi.

In pre-modern Europe more generally, between eight and 32 points of the compass – cardinal and intercardinal directions – were given names. These often corresponded to the directional winds of the Mediterranean Sea (for example, southeast was linked to the Sirocco, a wind from the Sahara).

Particular colors are associated in some traditions with the cardinal points. These are typically "natural colors" of human perception rather than optical primary colors.^[vague]

Many cultures, especially in Asia, include the center as a fifth cardinal point.

Northern Eurasia

Northern Eurasia	N	E	S	W	C	Source
Slavic					—	^[10]
China

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