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Geodesy Organizations
Geodesy or geodetics is the science of measuring and representing the Figure of the Earth, geometry, Gravity of Earth, gravity, and Earth's rotation, spatial orientation of the Earth in Relative change, temporally varying Three-dimensional space, 3D. It is called planetary geodesy when studying other astronomical body, astronomical bodies, such as planets or Natural satellite, circumplanetary systems. Geodynamics, Geodynamical phenomena, including crust (geology), crustal motion, tides, and polar motion, can be studied by designing global and national Geodetic control network, control networks, applying space geodesy and terrestrial geodetic techniques, and relying on Geodetic datum, datums and coordinate systems. Geodetic job titles include geodesist and geodetic surveyor. History Geodesy began in pre-scientific Classical antiquity, antiquity, so the very word geodesy comes from the Ancient Greek word or ''geodaisia'' (literally, "division of Earth"). Early ideas about t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Motion
Polar motion of the Earth is the motion of the Earth's rotation, Earth's rotational axis relative to its Earth's crust, crust. This is measured with respect to a reference frame in which the solid Earth is fixed (a so-called ''Earth-centered, Earth-fixed'' or ECEF reference frame). This variation is a few meters on the surface of the Earth. Analysis Polar motion is defined relative to a conventionally defined reference axis, the CIO (Conventional International Origin), being the pole's average location over the year 1900. It consists of three major components: a free oscillation called Chandler wobble with a period of about 435 days, an annual oscillation, and an irregular drift in the direction of the 80th Meridian (geography), meridian west, which has lately been less extremely west. Causes The slow drift, about 20 m since 1900, is partly due to motions in the Earth's core and mantle, and partly to the redistribution of water mass as the Greenland ice sheet melts, and to iso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surveying
Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Plane (mathematics), two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of Point (geometry), points and the Euclidean distance, distances and angles between them. These points are usually on the surface of the Earth, and they are often used to establish maps and boundaries for ownership, locations, such as the designated positions of structural components for construction or the surface location of subsurface features, or other purposes required by government or civil law, such as property sales. A professional in land surveying is called a land surveyor. Surveyors work with elements of geodesy, geometry, trigonometry, regression analysis, physics, engineering, metrology, programming languages, and the law. They use equipment, such as total stations, robotic total stations, theodolites, Satellite navigation, GNSS receivers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomatics
Geomatics is defined in the ISO/TC 211 series of standards as the "discipline concerned with the collection, distribution, storage, analysis, processing, presentation of geographic data or geographic information". Under another definition, it consists of products, services and tools involved in the collection, integration and management of geographic (geospatial) data. Surveying engineering was the widely used name for geomatic(s) engineering in the past. Geomatics was placed by the UNESCO Encyclopedia of Life Support Systems under the branch of technical geography. History and etymology The term was proposed in French ("géomatique") at the end of the 1960s by scientist Bernard Dubuisson to reflect at the time recent changes in the jobs of surveyor and photogrammetrist. The term was first employed in a French Ministry of Public Works memorandum dated 1 June 1971 instituting a "standing committee of geomatics" in the government. The term was popularised in English by Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geospatial Information
Geographic data and information is defined in the ISO/TC 211 series of standards as data and information having an implicit or explicit association with a location relative to Earth (a geographic location or geographic position). It is also called geospatial data and information, georeferenced data and information, as well as geodata and geoinformation. Location information (known by the many names mentioned here) is stored in a geographic information system (GIS). There are also many different types of geodata, including vector files, raster files, geographic databases, web files, and multi-temporal data. Spatial data or spatial information is broader class of data whose geometry is relevant but it is not necessarily georeferenced, such as in computer-aided design (CAD), see geometric modeling. Fields of study Geographic data and information are the subject of a number of overlapping fields of study, mainly: * Geocomputation * Geographic information science ** Geogra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Language
English is a West Germanic language that developed in early medieval England and has since become a English as a lingua franca, global lingua franca. The namesake of the language is the Angles (tribe), Angles, one of the Germanic peoples that Anglo-Saxon settlement of Britain, migrated to Britain after its End of Roman rule in Britain, Roman occupiers left. English is the list of languages by total number of speakers, most spoken language in the world, primarily due to the global influences of the former British Empire (succeeded by the Commonwealth of Nations) and the United States. English is the list of languages by number of native speakers, third-most spoken native language, after Mandarin Chinese and Spanish language, Spanish; it is also the most widely learned second language in the world, with more second-language speakers than native speakers. English is either the official language or one of the official languages in list of countries and territories where English ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polaris
Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris (Latinisation of names, Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an apparent magnitude that fluctuates around 1.98, it is the brightest star in the constellation and is readily visible to the naked eye at night. The position of the star lies less than angular distance, 1° away from the north celestial pole, making it the current northern pole star. The stable position of the star in the northern celestial hemisphere, Northern Sky makes it useful for celestial navigation, navigation. As the closest Cepheid variable its distance is used as part of the cosmic distance ladder. The revised ''Hipparcos'' stellar parallax gives a distance to Polaris of about , while the successor mission Gaia (spacecraft), ''Gaia'' gives a distance of about . Although appearing to the naked eye as a single point of light, Polar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firmament
In ancient near eastern cosmology, the firmament means a celestial barrier that separates the heavenly waters above from the Earth below. In biblical cosmology, the firmament ( ''rāqīaʿ'') is the vast solid dome created by God during the Genesis creation narrative to separate the primal sea into upper and lower portions so that the dry land could appear. The concept was adopted into the subsequent Classical and Medieval models of heavenly spheres, but was dropped with advances in astronomy in the 16th and 17th centuries. Today it is known as a synonym for ''sky'' or ''heaven''. Etymology Firmament In English, the word "firmament" is recorded as early as 1250, in the '' Middle English Story of Genesis and Exodus''. It later appeared in the King James Bible. The same word is found in French and German Bible translations, all from Latin '' firmamentum'' (a firm object), used in the Vulgate (4th century). This in turn is a calque of the Greek (), also meaning a solid o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flat Earth
Flat Earth is an archaic and scientifically disproven conception of the Figure of the Earth, Earth's shape as a Plane (geometry), plane or Disk (mathematics), disk. Many ancient cultures, notably in the cosmology in the ancient Near East, ancient Near East, subscribed to a flat-Earth cosmography. The model has undergone a modern flat Earth beliefs, recent resurgence as a conspiracy theory in the 21st century. The idea of a spherical Earth appeared in ancient Greek philosophy with Pythagoras (6th century BC). However, the Early Greek cosmology, early Greek cosmological view of a flat Earth persisted among most Pre-Socratic philosophy, pre-Socratics (6th–5th century BC). In the early 4th century BC, Plato wrote about a spherical Earth. By about 330 BC, his former student Aristotle had provided strong empirical evidence for a spherical Earth. Knowledge of the Earth's global shape gradually began to spread beyond the Hellenistic period, Hellenistic world. By the early period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek Dark Ages, Dark Ages (), the Archaic Greece, Archaic or Homeric Greek, Homeric period (), and the Classical Greece, Classical period (). Ancient Greek was the language of Homer and of fifth-century Athens, fifth-century Athenian historians, playwrights, and Ancient Greek philosophy, philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Homeric Greek, Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Antiquity
Classical antiquity, also known as the classical era, classical period, classical age, or simply antiquity, is the period of cultural History of Europe, European history between the 8th century BC and the 5th century AD comprising the interwoven civilizations of ancient Greece and ancient Rome, Rome known together as the Greco-Roman world, centered on the Mediterranean Basin. It is the period during which ancient Greece and Rome flourished and had major influence throughout much of Europe, North Africa, and West Asia. Classical antiquity was succeeded by the period now known as late antiquity. Conventionally, it is often considered to begin with the earliest recorded Homeric Greek, Epic Greek poetry of Homer (8th–7th centuries BC) and end with the fall of the Western Roman Empire in 476 AD. Such a wide span of history and territory covers many disparate cultures and periods. ''Classical antiquity'' may also refer to an idealized vision among later people of what was, in Ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordinate System
In 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". The coordinates are taken to be real numbers in elementary mathematics, but may be complex numbers or elements of a more abstract system such as a commutative ring. The use of a coordinate system allows problems in geometry to be translated into problems about numbers and ''vice versa''; this is the basis of analytic geometry. Common coordinate systems Number line The simplest example of a coordinate system is the identification of points on a line with real numbers using the '' number line''. In this system, an arbitrary point ''O'' (the ''origin'') is chosen on a given line. The coordinate o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
