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Authalic Latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. 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. On its own, the term "latitude" normally refers to the ''geodetic latitude'' as defined below. Briefly, the geodetic latitude of a point is the angle formed between the vector perpendicular (or ''normal'') to the ellipsoidal surface from the point, and the plane of the equator. Background Two levels of abstraction are employed in the definitions of latitude and longitude. In the first step the physical surface is modeled by the geoid, a surface which approximates the mean sea level over the ocean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Division Of The Earth Into Gauss-Krueger Zones - Globe
Division or divider may refer to: Mathematics * Division (mathematics), the inverse of multiplication *Division algorithm, a method for computing the result of mathematical division Military * Division (military), a formation typically consisting of 10,000 to 25,000 troops ** Divizion, a subunit in some militaries *Division (naval), a collection of warships Science *Cell division, the process in which biological cells multiply * Continental divide, the geographical term for separation between watersheds * Division (biology), used differently in botany and zoology *Division (botany), a taxonomic rank for plants or fungi, equivalent to phylum in zoology *Division (horticulture), a method of vegetative plant propagation, or the plants created by using this method * Division, a medical/surgical operation involving cutting and separation, see ICD-10 Procedure Coding System Technology *Beam compass, a compass with a beam and sliding sockets for drawing and dividing circles larger than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geodesy
Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivalent measurements for other planets (known as '' planetary geodesy''). Geodynamical phenomena, including crustal motion, tides and polar motion, can be studied by designing global and national control networks, applying space geodesy and terrestrial geodetic techniques and relying on datums and coordinate systems. The job title is geodesist or geodetic surveyor. History Definition The word geodesy comes from the Ancient Greek word ''geodaisia'' (literally, "division of Earth"). It is primarily concerned with positioning within the temporally varying gravitational field. Geodesy in the German-speaking world is divided into "higher geodesy" ( or ), which is concerned with measuring Earth on the global scale, and "practical geodes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Figure Of The Earth
Figure of the Earth is a Jargon, term of art in geodesy that refers to the size and shape used to model Earth. The size and shape it refers to depend on context, including the precision needed for the model. A Spherical Earth, sphere is a well-known historical approximation of the figure of the Earth that is satisfactory for many purposes. Several models with greater accuracy (including Earth ellipsoid, ellipsoid) have been developed so that Geographic coordinate system, coordinate systems can serve the precise needs of navigation, surveying, cadastre, land use, and various other concerns. Motivation Earth's Topography, topographic surface is apparent with its variety of land forms and water areas. This topographic surface is generally the concern of topographers, Hydrography, hydrographers, and Geophysics, geophysicists. While it is the surface on which Earth measurements are made, mathematically modeling it while taking the irregularities into account would be extremely compl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theodolite
A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position. These angles can be measured with accuracies down to microradians or seconds of arc. From these readings a plan can be drawn, or objects can be positioned in accordance with an existing plan. The modern theodolite has evolved into what is known as a total station where angles and distances are measured electronically, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meridian Altitude
Meridian altitude is a method of celestial navigation to calculate an observer's latitude. It notes the altitude angle of an astronomical object above the horizon at culmination. Principle Meridian altitude is the simplest calculation of celestial navigation, in which an observer determines his latitude by measuring the altitude of an astronomical object at the time of its meridian contact. A meridian contact is the moment when the object contacts the observer's meridian, i.e. the imaginary line running north–south and through the zenith, nadir, and celestial poles. This is usually done with the equinox Sun at solar noon to determine the observer's latitude, but can be done with any celestial object. Solar noon is the time when the Sun contacts the meridian. Imagine that the equinox Sun is overhead (at the zenith) at a point on the Equator (latitude 0°), and Observer A is standing at this point – the subsolar point. If he were to measure the height of the Sun above the hor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celestial Navigation
Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space (or on the surface of the Earth) without having to rely solely on estimated positional calculations, commonly known as "dead reckoning", made in the absence of satellite navigation or other similar modern electronic or digital positioning means. Celestial navigation uses "sights", or timed angular measurements, taken typically between a celestial body (e.g. the Sun, the Moon, a planet, or a star) and the visible horizon. Celestial navigation can also take advantage of measurements between celestial bodies without reference to the Earth horizon, such as when the Moon and other selected bodies are used in the practice called "lunars" or lunar distance method, used for determining precise time when time is unknown. Celestial navigation by taking sights of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Latitude
The Greeks studied the results of the measurements of latitude by the explorer Pytheas who voyaged to Britain and beyond, as far as the Arctic Circle (observing the midnight sun), in 325 BC. They used several methods to measure latitude, including the height of the Sun above the horizon at midday, measured using a gnōmōn (a word that originally meant an interpreter or judge); the length of the day at the summer solstice, and the elevation of the Sun at winter solstice. The Greek Marinus of Tyre (AD 70–130) was the first to assign a latitude and longitude to every place on his maps. From the late 9th century CE, the Arabian Kamal was used in equatorial regions, to measure the height of Polaris above the horizon. This instrument could only be used in latitudes where Polaris is close to the horizon. The mariner's astrolabe which gives the angle of the Sun from the horizon at noon, or the angle of a known star at night, was used from around the 15th to the 17th centur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetographic Latitude
A planetary coordinate system is a generalization of the geographic coordinate system and the geocentric coordinate system for planets other than Earth. Similar coordinate systems are defined for other solid celestial bodies, such as in the ''selenographic coordinates'' for the Moon. The coordinate systems for almost all of the solid bodies in the Solar System were established by Merton E. Davies of the Rand Corporation, including Mercury, Venus, Mars, the four Galilean moons of Jupiter, and Triton, the largest moon of Neptune. Longitude The longitude systems of most of those bodies with observable rigid surfaces have been defined by references to a surface feature such as a crater. The north pole is that pole of rotation that lies on the north side of the invariable plane of the solar system (near the ecliptic). The location of the prime meridian as well as the position of the body's north pole on the celestial sphere may vary with time due to precession of the axis of rotat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Normal
In geometry, a normal is an object such as a line, ray, or vector that is perpendicular to a given object. For example, the normal line to a plane curve at a given point is the (infinite) line perpendicular to the tangent line to the curve at the point. A normal vector may have length one (a unit vector) or its length may represent the curvature of the object (a ''curvature vector''); its algebraic sign may indicate sides (interior or exterior). In three dimensions, a surface normal, or simply normal, to a surface at point P is a vector perpendicular to the tangent plane of the surface at P. The word "normal" is also used as an adjective: a line ''normal'' to a plane, the ''normal'' component of a force, the normal vector, etc. The concept of normality generalizes to orthogonality (right angles). The concept has been generalized to differentiable manifolds of arbitrary dimension embedded in a Euclidean space. The normal vector space or normal space of a manifold at point P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Needles
The Needles is a row of three stacks of chalk that rise about out of the sea off the western extremity of the Isle of Wight in the English Channel, United Kingdom, close to Alum Bay and Scratchell's Bay, and part of Totland, the westernmost civil parish of the Isle of Wight. The Needles Lighthouse stands at the outer, western end of the formation. Built in 1859, it has been automated since 1994. The waters and adjoining seabed form part of the Needles Marine Conservation Zone and the Needles along with the shore and heath above are part of the Headon Warren and West High Down Site of Special Scientific Interest. The formation takes its name from a fourth needle-shaped pillar called Lot's Wife, which collapsed in a storm in 1764. The remaining rocks are not at all needle-like, but the name has stuck. The Needles were featured on the BBC Two TV programme ''Seven Natural Wonders'' (2005) as one of the wonders of Southern England. During Storm Eunice on 18 February 2022, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decimal Degrees
Decimal degrees (DD) is a notation for expressing latitude and longitude geographic coordinates as decimal fractions of a degree. DD are used in many geographic information systems (GIS), web mapping applications such as OpenStreetMap, and GPS devices. Decimal degrees are an alternative to using sexagesimal degrees (degrees, minutes, and seconds - ''DMS notation''). As with latitude and longitude, the values are bounded by ±90° and ±180° respectively. Positive latitudes are north of the equator, negative latitudes are south of the equator. Positive longitudes are east of the Prime Meridian; negative longitudes are west of the Prime Meridian. Latitude and longitude are usually expressed in that sequence, latitude before longitude. The abbreviation dLL has been used in the scientific literature with locations in texts being identified as a tuple within square brackets, for example 4.5798,-3.5820 The appropriate decimal places are used. Precision The radius of the semi-major a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
