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Irish Transverse Mercator
Irish Transverse Mercator (ITM) is the geographic coordinate system for Ireland. It was implemented jointly by the Ordnance Survey Ireland (OSi) and the Ordnance Survey of Northern Ireland (OSNI) in 2001. The name is derived from the Transverse Mercator projection it uses and the fact that it is optimised for the island of Ireland. History The older Irish grid reference system required GPS measurements to be "translated" (using co-ordinate transformations). The more precise the GPS measurements were, the more the translation process introduced inaccuracies. While the existing UTM co-ordinate system partly fulfilled the requirement for direct GPS compatibility it had some drawbacks, including varying levels of distortion across the island due to the central meridian being at the west coast of Ireland. The new system needed to satisfy various criteria: GPS compatibility, map distortion for the whole island of Ireland had to be minimal, it was to be conformal and backward c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITM Example 2007-06-05
ITM may stand for: Education * ITM Global School, an English medium co-educational day school in Gwalior, Madhya Pradesh, India * ITM Law School, one of the professional graduate schools of ITM University * ITM-IFM, Mumbai, India * Institut Teknologi Mara, a public university in Shah Alam, Selangor, Malaysia * Institute for Information, Telecommunication and Media Law, educational organization in Münster, Germany * Institute of Tropical Medicine Antwerp, research and training in tropical medicine, Belgium * Information technology management * International Tourism Management Music * In This Moment, a female-led metalcore band * Irish traditional music * ''In the Meantime'' (Alessia Cara album) Other * Independent Timber Merchants, a New Zealand building supplies and hardware retailer * ITM Cup, a rugby union professional competition for New Zealand unions * ITM Power, manufactures integrated hydrogen energy solutions * ITM Stadium, in Whangarei, New Zealand * Indiana Transport ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Axis
A Cartesian coordinate system (, ) in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in the same unit of length. Each reference coordinate line is called a ''coordinate axis'' or just ''axis'' (plural ''axes'') of the system, and the point where they meet is its '' origin'', at ordered pair . The coordinates can also be defined as the positions of the perpendicular projections of the point onto the two axes, expressed as signed distances from the origin. One can use the same principle to specify the position of any point in three-dimensional space by three Cartesian coordinates, its signed distances to three mutually perpendicular planes (or, equivalently, by its perpendicular projection onto three mutually perpendicular lines). In general, ''n'' Cartesian coordinates (an element of real ''n''-space) specify the point ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography Of Ireland
:Ireland is an island in Northwestern Europe in the north Atlantic Ocean. The island lies on the European continental shelf, part of the Eurasian Plate. The island's main geographical features include low central plains surrounded by coastal mountains. The highest peak is Carrauntoohil ( ga, Corrán Tuathail), which is above sea level. The western coastline is rugged, with many islands, peninsulas, headlands and bays. The island is bisected by the River Shannon, which at with a estuary is the longest river in Ireland and flows south from County Cavan in Ulster to meet the Atlantic just south of Limerick. There are a number of sizeable lakes along Ireland's rivers, of which Lough Neagh is the largest. Politically, the island consists of the Republic of Ireland, with jurisdiction over about five-sixths of the island, and Northern Ireland, a constituent country of the United Kingdom, with jurisdiction over the remaining sixth. Located west of the island of Great Britain, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geographic Coordinate Systems
The geographic coordinate system (GCS) is a spherical or ellipsoidal coordinate system for measuring and communicating positions directly on the Earth as latitude and longitude. 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. Although latitude and longitude form a coordinate tuple like a cartesian coordinate system, the geographic coordinate system is not cartesian because the measurements are angles and are not on a planar surface. A full GCS specification, such as those listed in the EPSG and ISO 19111 standards, also includes a choice of geodetic datum (including an Earth ellipsoid), as different datums will yield different latitude and longitude values for the same location. History 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spatial Reference System
A spatial reference system (SRS) or coordinate reference system (CRS) is a framework used to precisely measure locations on the surface of the Earth as coordinates. It is thus the application of the abstract mathematics of coordinate systems and analytic geometry to geographic space. A particular SRS specification (for example, "Universal Transverse Mercator WGS 84 Zone 16N") comprises a choice of Earth ellipsoid, horizontal datum, map projection (except in the geographic coordinate system), origin point, and unit of measure. Thousands of coordinate systems have been specified for use around the world or in specific regions and for various purposes, necessitating transformations between different SRS. Although they date to the Hellenic Period, spatial reference systems are now a crucial basis for the sciences and technologies of Geoinformatics, including cartography, geographic information systems, surveying, remote sensing, and civil engineering. This has led to their standar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ETRS89
The European Terrestrial Reference System 1989 (ETRS89) is an ECEF (Earth-Centered, Earth-Fixed) geodetic Cartesian reference frame, in which the Eurasian Plate as a whole is static. The coordinates and maps in Europe based on ETRS89 are not subject to change due to the continental drift. The development of ETRS89 is related to the global ITRS geodetic datum, in which the representation of the continental drift is balanced in such a way that the total apparent angular momentum of continental plates is about 0. ETRS89 was officially born at the 1990 Florence meeting of EUREF, following its Resolution 1, which recommends that the terrestrial reference system to be adopted by EUREF will be coincident with ITRS at the epoch 1989.0 and fixed to the stable part of the Eurasian Plate. According to the resolution, this system was named European Terrestrial Reference System 89 (ETRS89). Since then ETRS89 and ITRS diverge due to the continental drift at a speed about 2.5 cm per y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EPSG
EPSG Geodetic Parameter Dataset (also EPSG registry) is a public registry of geodetic datums, spatial reference systems, Earth ellipsoids, coordinate transformations and related units of measurement A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a mul .... Originally created by European Petroleum Survey Group (EPSG). Each entity is assigned an EPSG code between 1024-32767, along with a standard machine-readable well-known text (WKT) representation. The dataset is actively maintained by the IOGP Geomatics Committee. Most geographic information systems (GIS) and GIS libraries use EPSG codes as Spatial Reference System Identifiers (SRIDs) and EPSG definition data for identifying coordinate reference systems, projections, and performing transformations between these systems, while som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malin Head
Malin Head ( ga, Cionn Mhálanna) is the most northerly point of mainland Ireland, located in the townland of Ardmalin on the Inishowen peninsula in County Donegal. The head's northernmost point is called Dunalderagh at latitude 55.38ºN. It is about 16 km (10 mi) north of the village of Malin. The island of Inishtrahull is further north, about 10 km (6 mi) northeast of the headland. Malin Head gives its name to the Malin sea area. There is a weather station on the head, which is one of 22 such stations whose reports are broadcast as part of the BBC Shipping Forecast. A tower built in 1805 is on Altnadarrow, also known locally as the Tower Hill. Ptolemy's ''Geography'' (2nd century AD) described a point called Βορειον (''Boreion'', "the northern") which probably referred to Malin Head. Locality To the northeast Inistrahull Island can be seen. The first lighthouse on the island was put into operation in 1813, and the light flashes every 30 second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordnance Datum
In the British Isles, an ordnance datum or OD is a vertical datum used by an ordnance survey as the basis for deriving altitudes on maps. A spot height may be expressed as AOD for "above ordnance datum". Usually mean sea level (MSL) is used for the datum. In particular: * In Great Britain, OD for the Ordnance Survey is ODN (Ordnance Datum Newlyn), defined as the MSL as recorded by the tidal gauge at Newlyn in Cornwall between 1915 and 1921. **Prior to 1921, OD was defined as MSL as recorded in the Victoria Dock, Liverpool, during a short period in 1844 (ODL). * In Northern Ireland, OD for the Ordnance Survey of Northern Ireland is Belfast Ordnance Datum, the MSL at Clarendon Dock, Belfast, between 1951 and 1956. * In the Republic of Ireland, OD for the Ordnance Survey of Ireland is Malin Ordnance Datum: the MSL at Portmoor Pier, Malin Head, County Donegal, between 1960 and 1969. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scale (map)
The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. This simple concept is complicated by the curvature of the Earth's surface, which forces scale to vary across a map. Because of this variation, the concept of scale becomes meaningful in two distinct ways. The first way is the ratio of the size of the generating globe to the size of the Earth. The generating globe is a conceptual model to which the Earth is shrunk and from which the map is projected. The ratio of the Earth's size to the generating globe's size is called the nominal scale (= principal scale = representative fraction). Many maps state the nominal scale and may even display a bar scale (sometimes merely called a 'scale') to represent it. The second distinct concept of scale applies to the variation in scale across a map. It is the ratio of the mapped point's scale to the nominal scale. In this case 'scale' means the scale factor (= point scale = particular scal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRS80
The Geodetic Reference System 1980 (GRS 80) is a geodetic reference system consisting of a global reference ellipsoid and a normal gravity model. Background Geodesy is the scientific discipline that deals with the measurement and representation of the earth, its gravitational field and geodynamic phenomena (polar motion, earth tides, and crustal motion) in three-dimensional, time-varying space. The geoid is essentially the figure of the Earth abstracted from its topographic features. It is an idealized equilibrium surface of sea water, the mean sea level surface in the absence of currents, air pressure variations etc. and continued under the continental masses. The geoid, unlike the ellipsoid, is irregular and too complicated to serve as the computational surface on which to solve geometrical problems like point positioning. The geometrical separation between it and the reference ellipsoid is called the geoidal undulation, or more usually the geoid-ellipsoid separation, ''N''. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reference Ellipsoid
An Earth ellipsoid or Earth spheroid is a mathematical figure approximating the Earth's form, used as a reference frame for computations in geodesy, astronomy, and the geosciences. Various different ellipsoids have been used as approximations. It is a spheroid (an ellipsoid of revolution) whose minor axis (shorter diameter), which connects the geographical North Pole and South Pole, is approximately aligned with the Earth's axis of rotation. The ellipsoid is defined by the ''equatorial axis'' (''a'') and the ''polar axis'' (''b''); their radial difference is slightly more than 21 km, or 0.335% of ''a'' (which is not quite 6,400 km). Many methods exist for determination of the axes of an Earth ellipsoid, ranging from meridian arcs up to modern satellite geodesy or the analysis and interconnection of continental geodetic networks. Amongst the different set of data used in national surveys are several of special importance: the Bessel ellipsoid of 1841, the internatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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