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What is a geographical coordinate?

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What are the different types of coordinate systems?

2. ### Geographic coordinate system - Wikipedia

en.wikipedia.org/wiki/Geographic_coordinate_system

A geographic coordinate system is a coordinate system associated with positions on Earth. A GCS can give positions: as spherical coordinate system using latitude, longitude, and elevation; as map coordinates projected onto the plane, possibly including elevation; as earth-centered, earth-fixed Cartesian coordinates in 3-space; as a set of numbers, letters or symbols forming a geocode. In geodetic coordinates and map coordinates, the coordinate tuple is decomposed such that one of the numbers rep

• History

The invention of a geographic coordinate system is generally...

• Geodetic datum

In order to be unambiguous about the direction of "vertical"...

3. ### Geographic coordinate system - Simple English Wikipedia, the ...

simple.wikipedia.org/wiki/Geographic_coordinate...

A geographical coordinate system is a coordinate system. This means that every place can be specified by a set of three numbers, called coordinates. A full circle can be divided into 360 degrees (or 360°); this was first done by the Babylonians; Ancient Greeks, like Ptolemy later extended the theory. Today, degrees are divided further.

4. ### Coordinate system - Wikipedia

en.wikipedia.org/wiki/Coordinate_system

In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is significant, and they are sometimes identified by their position in an ordered tuple and sometimes by a letter, as in "the x-coordinate". The coordinates are taken to be real numbers in elementary mathematics, but may be complex numbers or elements of a more a

5. ### Category:Geographic coordinate systems - Wikipedia

en.wikipedia.org/wiki/Category:Geographic...

6. ### Geographic coordinate system - WIKI 2. Wikipedia Republished

wiki2.org/en/Geographic_coordinate_system
• History
• Geographic Latitude and Longitude
• Measuring Height Using Datums
• Map Projection
• Cartesian Coordinates
• Expressing Latitude and Longitude as Linear Units
• Geostationary Coordinates
• on Other Celestial Bodies
• References

The in­ven­tion of a ge­o­graphic co­or­di­nate sys­tem is gen­er­ally cred­ited to Er­atos­thenes of Cyrene, who com­posed his now-lost Ge­og­ra­phy at the Li­brary of Alexan­dria in the 3rd cen­tury BC. A cen­tury later, Hip­parchus of Nicaea im­proved on this sys­tem by de­ter­min­ing lat­i­tude from stel­lar mea­sure­ments rather than solar al­ti­tude and de­ter­min­ing lon­gi­tude by tim­ings of lunar eclipses, rather than dead reck­on­ing. In the 1st or 2nd cen­tury, Mar­i­nus of Tyre com­piled an ex­ten­sive gazetteer and math­e­mat­i­cally-plot­ted world map using co­or­di­nates mea­sured east from a prime merid­ian at the west­ern­most known land, des­ig­nated the For­tu­nate Isles, off the coast of west­ern Africa around the Ca­nary or Cape Verde Is­lands, and mea­sured north or south of the is­land of Rhodes off Asia Minor. Ptolemy cred­ited him with the full adop­tion of lon­gi­tude and lat­i­tude, rather than mea­sur­ing lat­i­tude in terms of the length of the mid­sum­...

The "lat­i­tude" (ab­bre­vi­a­tion: Lat., φ, or phi) of a point on Earth's sur­face is the angle be­tween the equa­to­r­ial plane and the straight line that passes through that point and through (or close to) the cen­ter of the Earth.[n 3] Lines join­ing points of the same lat­i­tude trace cir­cles on the sur­face of Earth called par­al­lels, as they are par­al­lel to the equa­tor and to each other. The north pole is 90° N; the south pole is 90° S. The 0° par­al­lel of lat­i­tude is des­ig­nated the equa­tor, the fun­da­men­tal plane of all ge­o­graphic co­or­di­nate sys­tems. The equa­tor di­vides the globe into North­ern and South­ern Hemi­spheres. The "lon­gi­tude" (ab­bre­vi­a­tion: Long., λ, or lambda) of a point on Earth's sur­face is the angle east or west of a ref­er­ence merid­ian to an­other merid­ian that passes through that point. All merid­i­ans are halves of great el­lipses (often called great cir­cles), which con­verge at the north and south poles. The merid­ian of th...

Complexity of the problem

To com­pletely spec­ify a lo­ca­tion of a topo­graph­i­cal fea­ture on, in, or above Earth, one also has to spec­ify the ver­ti­cal dis­tance from Earth's cen­ter or sur­face. Earth is not a sphere, but an ir­reg­u­lar shape ap­prox­i­mat­ing a bi­ax­ial el­lip­soid. It is nearly spher­i­cal, but has an equa­to­r­ial bulge mak­ing the ra­dius at the equa­tor about 0.3% larger than the ra­dius mea­sured through the poles. The shorter axis ap­prox­i­mately co­in­cides with the axis of ro­ta­tio...

Common baselines

Com­mon height base­lines include 1. The surface of the datum ellipsoid, resulting in an ellipsoidal height 2. The mean sea level as described by the gravity geoid, yielding the orthometric height 3. A vertical datum, yielding a dynamic heightrelative to a known reference height. Along with the lat­i­tude ϕ{\\displaystyle \\phi } and lon­gi­tude λ{\\displaystyle \\lambda }, the height h{\\displaystyle h} pro­vides the three-di­men­sional ge­o­detic coordinates or ge­o­graphic coordinatesfor a loca...

Datums

In order to be un­am­bigu­ous about the di­rec­tion of "ver­ti­cal" and the "sur­face" above which they are mea­sur­ing, map-mak­ers choose a ref­er­ence el­lip­soid with a given ori­gin and ori­en­ta­tion that best fits their need for the area they are map­ping. They then choose the most ap­pro­pri­ate map­ping of the spher­i­cal co­or­di­nate sys­tem onto that el­lip­soid, called a ter­res­trial ref­er­ence sys­tem or ge­o­detic datum. Da­tums may be global, mean­ing that they rep­re­sent t...

To es­tab­lish the po­si­tion of a ge­o­graphic lo­ca­tion on a map, a map pro­jec­tion is used to con­vert ge­o­detic co­or­di­nates to two-di­men­sional co­or­di­nates on a map; it pro­jects the datum el­lip­soidal co­or­di­nates and height onto a flat sur­face of a map. The datum, along with a map pro­jec­tion ap­plied to a grid of ref­er­ence lo­ca­tions, es­tab­lishes a grid system for plot­ting lo­ca­tions. Com­mon map pro­jec­tions in cur­rent use in­clude the Uni­ver­sal Trans­verse Mer­ca­tor (UTM), the Mil­i­tary Grid Ref­er­ence Sys­tem (MGRS), the United States Na­tional Grid (USNG), the Global Area Ref­er­ence Sys­tem (GARS) and the World Ge­o­graphic Ref­er­ence Sys­tem (GEO­REF).Co­or­di­nates on a map are usu­ally in terms nor­thing N and east­ingE off­sets rel­a­tive to a spec­i­fied ori­gin. Map pro­jec­tion for­mu­las de­pend in the geom­e­try of the pro­jec­tion as well as pa­ra­me­ters de­pen­dent on the par­tic­u­lar lo­ca­tion at which the map is pro­jected. T...

Every point that is ex­pressed in el­lip­soidal co­or­di­nates can be ex­pressed as an rec­ti­lin­ear x y z (Carte­sian) co­or­di­nate. Carte­sian co­or­di­nates sim­plify many math­e­mat­i­cal cal­cu­la­tions. The Carte­sian sys­tems of dif­fer­ent da­tums are not equivalent.

On the GRS80 or WGS84 spher­oid at sea level at the equa­tor, one lat­i­tu­di­nal sec­ond mea­sures 30.715 me­tres, one lat­i­tu­di­nal minute is 1843 me­tres and one lat­i­tu­di­nal de­gree is 110.6 kilo­me­tres. The cir­cles of lon­gi­tude, merid­i­ans, meet at the ge­o­graph­i­cal poles, with the west-east width of a sec­ond nat­u­rally de­creas­ing as lat­i­tude in­creases. On the equa­tor at sea level, one lon­gi­tu­di­nal sec­ond mea­sures 30.92 me­tres, a lon­gi­tu­di­nal minute is 1855 me­tres and a lon­gi­tu­di­nal de­gree is 111.3 kilo­me­tres. At 30° a lon­gi­tu­di­nal sec­ond is 26.76 me­tres, at Green­wich (51°28′38″N) 19.22 me­tres, and at 60° it is 15.42 me­tres. On the WGS84 spher­oid, the length in me­ters of a de­gree of lat­i­tude at lat­i­tude φ (that is, the dis­tance along a north–south line from lat­i­tude (φ − 0.5) de­grees to (φ + 0.5) de­grees) is about 1. 111132.92−559.82cos⁡2φ+1.175cos⁡4φ−0.0023cos⁡6φ{\\displaystyle 111132.92-559.82\\,\\cos 2\\varphi +1.175\\,...

Geo­sta­tion­ary satel­lites (e.g., tele­vi­sion satel­lites) are over the equa­tor at a spe­cific point on Earth, so their po­si­tion re­lated to Earth is ex­pressed in lon­gi­tude de­grees only. Their lat­i­tudeis al­ways zero (or ap­prox­i­mately so), that is, over the equa­tor.

Sim­i­lar co­or­di­nate sys­tems are de­fined for other ce­les­tial bod­ies such as: 1. A similarly well-defined system based on the reference ellipsoid for Mars. 2. Selenographic coordinates for the Moon

Portions of this article are from Jason Harris' "Astroinfo" which is distributed with KStars, a desktop planetarium for Linux/KDE. See The KDE Education Project - KStars

7. ### Geographic coordinate system - WikiMili, The Best Wikipedia ...

wikimili.com/en/Geographic_coordinate_system

A geographic coordinate system is a coordinate system that enables every location on Earth to be specified by a set of numbers, letters or symbols. [note 1] The coordinates are often chosen such that one of the numbers represents a vertical position and two or three of the numbers represent a horizontal position; alternatively, a geographic position may be expressed in a combined three-dimensional Cartesian vector.

8. ### Geographic coordinate seestem - Wikipedia

sco.wikipedia.org/wiki/Geographic_coordinate_system

The circles parallel tae the equator is lines o constant latitude, or parallels. The graticule determines the latitude an longitude o poseetion on the surface. A geographic coordinate seestem is a coordinate seestem that enables ilka location on the Yird tae be specified bi a set o nummers or letters. The coordinates are aften chosen sae that ane o the nummers represents vertical poseetion, an twa or three o the nummers represent horizontal poseetion.

9. ### Geographic coordinate conversion - Wikipedia

en.wikipedia.org/wiki/Geographic_coordinate...