| Ordinal Directions |
Website Links For Cardinal |
Information AboutOrdinal Directions |
| CATEGORIES ABOUT CARDINAL DIRECTION | |
| orientation | |
|
showing the cardinal directions]] In Geography , the four Principal directional indicators are marked as points or arrowheads on a traditional Magnetic Compass Rose . Called cardinal directions, they are North , East , South and West . Though the names may seem arbitrary, there are simple specific means to establish each direction, which should work anywhere on Earth where there is a view of the Sky . North and south are oriented toward the respective Poles of the Earth . The Earth's Rotation defines the orientation of east and west. A Magnetised Ferrous needle, allowed to move freely, aligns itself readily with the Earth's natural Magnetic Field . Upon aligning, the needle points reliably, but only approximately, in the directions we call north and south. This is the very basis of the magnetic compass. By an amazing coincidence the star Polaris is (for practical purposes) permanently pointed to by the earth's axis. We call the end of the Earth's axis that is closest to Polaris the North Pole . The opposite end of the Earth's axis is named the South Pole . Due to the Earth's rotation, the Sun Rises during the Morning in the east and Sets during the Evening in the west. (This definition of east and west is a matter of convention.) With the cardinal points thus defined, by convention Cartographers draw standard Maps with north (N) at the Top , and east (E) at the Right . In turn, maps provide a systematic means to record where places are, and cardinal directions are the foundation of a structure for telling someone how to find those places. North (N) does not have to be at the top. Portable GPS -based Navigation Computer s can be set to Display maps either conventionally (N always up, E always right) or with the Current Instantaneous Direction of Travel , called the Heading , always Up (and whatever direction is +90° from that to the right). The direction of travel required to reach the intended destination is called the Bearing . Since the real World presents numerous obstacles, one must adjust his or her heading accordingly. Upon moving Forward , the bearing will change so that it always points at the destination, thereby giving clues as to which way one should turn. When you are traveling, it can be easier to figure out where your next turn is, and whether to turn left or right, when the direction of travel is always up. The directional names are also routinely and very conveniently associated with the Degrees of rotation in the Unit Circle , a necessary step for navigational calculations (derived from Trigonometry ) and/or for use with Global Positioning Satellite ( GPS ) Receivers . The four cardinal directions correspond to the following Degrees of a compass:
An ordinal, or '''intercardinal''', direction is one of the four intermediate compass directions located halfway between the cardinal directions.
There are also numerous additional intermediate points both named and numbered, a topic well addressed by Boxing The Compass . BEYOND GEOGRAPHY Children are sometimes taught the order of these directions (clockwise, from North) by using a Mnemonic , such as "Naughty '''E'''lephants '''S'''quirt '''W'''ater", "Never '''E'''at '''S'''oggy '''W'''affles"("'''W'''eet-bix" in Australia), or "Never '''E'''at '''S'''hredded '''W'''heat". In Mathematics , ''cardinal directions'' or ''cardinal points'' are the six principal directions or points of the 3D World in a Solid . In the real world there are six cardinal directions not involved with geography which are North , South , East , West , Up and Down . GERMANIC ORIGIN OF NAMES During the Migration Period , the Germanic Languages ' 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.See e.g. Weibull, Lauritz. ''De gamle nordbornas väderstrecksbegrepp''. Scandia 1/1928; Ekblom, R. ''Alfred the Great as Geographer''. Studia Neophilologica 14/1941-2; Ekblom, R. ''Den forntida nordiska orientering och Wulfstans resa till Truso''. Förnvännen. 33/1938; Sköld, Tryggve. ''Isländska väderstreck''. Scripta Islandica. Isländska skällskapet årsbok 16/1965. CARDINAL DIRECTIONS IN WORLD CULTURES Many cultures not descended from European traditions use cardinal directions, but have a number other than four. Typically, a “center” direction is added, for a total of five. Rather than the Western use of direction letters, properties such as Color s are often associated with the various cardinal directions—these are typically the Natural Colors of human perception rather than optical Primary Color s. Some examples are shown here; for more (esp. with regard to American Indian tribes) see Colors of the Four Directions . In many regions of the world, prevalent winds change direction seasonally, and consequently many cultures associate specific named Wind s with cardinal and ordinal directions. The classical Greeks personified these winds as Anemoi . The article on Boxing The Compass contains a more recent list of directional winds from the Mediterranean Sea . Far East
|