IERS Reference MeridianThe IERS Reference Meridian (IRM), also called the International Reference Meridian, is the prime meridian (0° longitude) maintained by the International Earth Rotation and Reference Systems Service (IERS). It passes about 5.3 arcseconds east of George Biddell Airy's 1851 transit circle, and thus it differs slightly from the historical Greenwich Meridian. At the latitude of the Royal Observatory, Greenwich, the difference is 102 metres (335 ft).Prime meridianLine of longitude, at which longitude is defined to be 0°0°Modern IERS Reference Meridian on Earth (interactive map)Countries that touch the equator (red) and that touch the IERS Reference Meridian (blue)A prime meridian is a meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. On a spheroid, a prime meridian and its anti-meridian (the 180th meridian in a 360-degree system) form a great ellipse.
Degree (angle)A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a unit of measurement of a planeangle in which one full rotation is assigned the value of 360 degrees. The unit of angular measure in the International System of Units (SI) is the radian, and one degree is equivalent to π/180 radians. HistoryThe original motivation for choosing the degree as a unit of rotations and angles is unknown.EquatorThe equator is the circle of latitude that divides Earth into the Northern and SouthernHemispheres. It is an imaginary line located at 0 degrees latitude, about 21,639 nautical miles (40,075 kilometres; 24,902 miles) in circumference, located halfway between the North and South Poles. The term can also be used for any other celestial body that is roughly spherical.
AngleIn geometry, an angle is formed by two lines that meet at a point. Each line is called a side of the angle, and the point they share is called the vertex of the angle. The term angle is used to denote both geometric figures and their size or magnitude as associated quantity. Angular measure or measure of angle are sometimes used to distinguish between the measure of the quantity and figure itself.
LongitudeInternational Terrestrial Reference SystemSpatial Reference System Identifier (SRID)Universal Transverse Mercator (UTM)
LatitudeInternational Terrestrial Reference SystemSpatial Reference System Identifier (SRID)Universal Transverse Mercator (UTM)
GeodesyInternational Terrestrial Reference SystemSpatial Reference System Identifier (SRID)Universal Transverse Mercator (UTM)
Locus (mathematics)In geometry, a locus (plural: loci; Latin for 'place, location') is a set of all points (commonly, a line, a line segment, a curve or a surface), whose location satisfies or is determined by one or more specified conditions. The set of the points that satisfy some property is often called the locus of a point satisfying this property.
GeographyCartographyComputer cartographyWeb mappingGeochronologyGeographic information systemDistributed GISInternet GISWeb GISGeologic modellingGeomathematicsGeostatisticsGeovisualizationGlobal Positioning SystemHydrographyMap algebraParticipant observationPhotogrammetryRemote SensingStatistical surveySurveyingLand change modelingEthnographyGeopoeticsInterview (research)Survey (human research)
Coordinate systemIn geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine and standardize the position of the points or other geometric elements on a manifold such as Euclidean space. The coordinates are not interchangeable; they are commonly distinguished by their position in an ordered tuple, or by a label, such as in "the x-coordinate".*As an Amazon Associate I earn from qualifying purchases.