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v. t. e. A geographic coordinate system ( GCS) is a spherical or geodetic coordinate system for measuring and communicating positions directly on Earth as latitude and longitude. [ 1] It is the simplest, oldest and most widely used of the various spatial reference systems that are in use, and forms the basis for most others.
The World Geodetic System ( WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also describes the associated Earth Gravitational Model (EGM) and World Magnetic Model (WMM).
Ptolemy's map of the Mediterranean superimposed on a modern map, with Greenwich as the reference longitude. Ptolemy, in the 2nd century AD, based his mapping system on estimated distances and directions reported by travellers. Until then, all maps had used a rectangular grid with latitude and longitude as straight lines intersecting at right ...
World map. A world map is a map of most or all of the surface of Earth. World maps, because of their scale, must deal with the problem of projection. Maps rendered in two dimensions by necessity distort the display of the three-dimensional surface of the Earth. While this is true of any map, these distortions reach extremes in a world map.
Longitude ( / ˈlɒndʒɪtjuːd /, AU and UK also / ˈlɒŋɡɪ -/) [ 1][ 2] is a geographic coordinate that specifies the east – west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians are imaginary ...
Latitude is given as an angle that ranges from −90° at the south pole to 90° at the north pole, with 0° at the Equator. Lines of constant latitude, or parallels, run east–west as circles parallel to the equator. Latitude and longitude are used together as a coordinate pair to specify a location on the surface of the Earth.
The Mercator projection of a world map. The angles are untrue for area, especially at high latitudes. Also note increasing distances between the latitudes towards the poles and the parallel lines of longitude. The only true world map is the globe. The Mercator projection comes from a globe inside a cylinder.
Geographic coordinate conversion has applications in cartography, surveying, navigation and geographic information systems . In geodesy, geographic coordinate conversion is defined as translation among different coordinate formats or map projections all referenced to the same geodetic datum. [ 1] A geographic coordinate transformation is a ...