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Outline Of Metrology And Measurement
The following is a topical outline of the English language Wikipedia articles on the topic of metrology and measurement. Metrology is the science of measurement and its application. Main articles * Metrology * Measurement Metrology overviews * Dimensional metrology * Forensic metrology * Historical metrology * Smart Metrology * Time metrology * Quantum metrology History * History of measurement * History of the metre Concepts * Quantification (science) * Standard (metrology) * Weights and measures * Unit of measurement Geodesy * Geodesy - the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D. * List of geodesists * History of geodesy * Physical geodesy * International Union of Geodesy and Geophysics * International Association of Geodesy Systems and units * Unit of measurement * System of measurement Systems of measurement * System of measurement * Metric system * Unit prefixes * Metric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metrology
Metrology is the scientific study of measurement. It establishes a common understanding of Unit of measurement, units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in France when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based metric system in 1795, establishing a set of standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure conformity between the countries, the ''International Bureau of Weights and Measures, Bureau International des Poids et Mesures'' (BIPM) was established by the Metre Convention. This has evolved into the International System of Units (SI) as a result of a resolution at the 11th General Conference on Weights and Measures (CGPM) in 1960. Metrology is divided into three basic overlapping activities: * The definition of units of measurement * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mapping (cartography)
Cartography (; from , 'papyrus, sheet of paper, map'; and , 'write') is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an imagined reality) can be modeled in ways that communicate spatial information effectively. The fundamental objectives of traditional cartography are to: * Set the map's agenda and select traits of the object to be mapped. This is the concern of map editing. Traits may be physical, such as roads or land masses, or may be abstract, such as toponyms or political boundaries. * Represent the terrain of the mapped object on flat media. This is the concern of map projections. * Eliminate the mapped object's characteristics that are irrelevant to the map's purpose. This is the concern of generalization. * Reduce the complexity of the characteristics that will be mapped. This is also the concern of generalization. * Orchestrate the elements of the map to best convey its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric System
The metric system is a system of measurement that standardization, standardizes a set of base units and a nomenclature for describing relatively large and small quantities via decimal-based multiplicative unit prefixes. Though the rules governing the metric system have changed over time, the modern definition, the International System of Units (SI), defines the metric prefixes and seven base units: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), Mole (unit), mole (mol), and candela (cd). An SI derived unit is a named combination of base units such as hertz (cycles per second), Newton (unit), newton (kg⋅m/s2), and tesla (unit), tesla (1 kg⋅s−2⋅A−1) and in the case of Celsius a shifted scale from Kelvin. Certain units have been Non-SI units mentioned in the SI#Units officially accepted for use with the SI, officially accepted for use with the SI. Some of these are decimalised, like the litre and electronvolt, and are considered "metric". Others, like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Of Measurement
A system of units of measurement, also known as a system of units or system of measurement, is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and wikt:commerce, commerce. Instances in use include the International System of Units or (the modern form of the metric system), the British imperial system, and the United States customary system. History In antiquity, ''systems of measurement'' were defined locally: the different units might be defined independently according to the length of a king's thumb or the size of his foot, the length of stride, the length of arm, or maybe the weight of water in a keg of specific size, perhaps itself defined in ''hands'' and ''knuckles''. The unifying characteristic is that there was some definition based on some standard. Eventually ''cubits'' and ''yard, strides'' gave way to "customary units" to meet the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Association Of Geodesy
The International Association of Geodesy (IAG) is a constituent association of the International Union of Geodesy and Geophysics focusing on the science which measures and describes the Figure of the Earth, Earth's shape, its rotation and gravity field. History The precursors to the IAG were arc measurement campaigns. The IAG was founded in 1862 as the ''Mitteleuropäische Gradmessung'' (Central European Arc Measurement), later became the ''Europäische Gradmessung'' (European Arc Measurement) in 1867, the ''Internationale Erdmessung'' (''Association Geodésique Internationale'' in French and "International Geodetic Association" in English) in 1886, and took its present name in 1946. In the second half of the 19th century, the creation of the International Geodetic Association marked, following Friedrich Wilhelm Bessel and Friedrich Georg Wilhelm von Struve examples, the systematic adoption of more rigorous methods among them the application of the least squares in geodesy. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Union Of Geodesy And Geophysics
The International Union of Geodesy and Geophysics (IUGG; , UGGI) is an international non-governmental organization dedicated to the scientific study of Earth and its space environment using geophysical and geodetic techniques. The IUGG is a member of the International Science Council (ISC), which is composed of international scholarly and scientific institutions and national academies of sciences. History The IUGG was established in Brussels, Belgium in 1919. Objectives IUGG's objectives are the promotion and coordination of studies related to Earth's physical, chemical and mathematical representation. This includes geometrical shape, internal structure, gravity and magnetic fields, seismicity, volcanism, hydrologic cycle, glaciers, oceans, atmosphere, ionosphere, and magnetosphere of Earth. It also includes solar, lunar and planetary studies. Some areas within its scope are environmental preservation, reduction of the effects of natural hazards, and mineral resour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Geodesy
Physical geodesy is the study of the physical properties of Earth's gravity and its potential field (the geopotential), with a view to their application in geodesy. Measurement procedure Traditional geodetic instruments such as theodolites rely on the gravity field for orienting their vertical axis along the local plumb line or local vertical direction with the aid of a spirit level. After that, vertical angles (zenith angles or, alternatively, elevation angles) are obtained with respect to this local vertical, and horizontal angles in the plane of the local horizon, perpendicular to the vertical. Levelling instruments again are used to obtain geopotential differences between points on the Earth's surface. These can then be expressed as "height" differences by conversion to metric units. Units Gravity is commonly measured in units of m·s−2 (metres per second squared). This also can be expressed (multiplying by the gravitational constant G in order to change units) as newto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Geodesy
The history of geodesy ( /dʒiːˈɒdɪsi/) began during antiquity and ultimately blossomed during the Age of Enlightenment. Many early conceptions of the Earth held it to be flat, with the heavens being a physical dome spanning over it. Early arguments for a spherical Earth pointed to various more subtle empirical observations, including how lunar eclipses were seen as circular shadows, as well as the fact that Polaris is seen lower in the sky as one travels southward. Hellenic world Initial developments Though the earliest written mention of a spherical Earth comes from ancient Greek sources, there is no account of how the sphericity of Earth was discovered, or if it was initially simply a guess.James Evans, (1998), ''The History and Practice of Ancient Astronomy'', page 47, Oxford University Press A plausible explanation given by the historian Otto E. Neugebauer is that it was "the experience of travellers that suggested such an explanation for the variation in the observa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Geodesists
This is a list of geodesists, people who made notable contributions to geodesy, whether or not geodesy was their primary field. These include historical figures who laid the foundations for the field of geodesy. Geodesists before 1900 (arranged by date) * Pythagoras 580–490 BC (ancient Greece) * Eratosthenes 276–194 BC (ancient Greece) * Hipparchus 190–120 BC (ancient Greece) * Posidonius 135–51 BC (ancient Greece) * Menelaus of Alexandria AD 70–140 (ancient Greece) * Claudius Ptolemy AD 83–168 Roman Empire (Roman Egypt) * Al-Ma'mun 786–833 (Iraq/Mesopotamia) * Abu Rayhan Biruni 973–1048 (Iran/Samanid Dynasty) * Muhammad al-Idrisi 1100–1166 (Arabia/Sicily) * Regiomontanus 1436–1476 (Germany/Austria) * Abel Foullon 1513–1563 or 1565 (France) * Pedro Nunes 1502–1578 (Portugal) * Gerhard Mercator 1512–1594 (Belgium/Germany) * Snellius (Willebrord Snel van Royen) 1580–1626 (Netherlands) * Christiaan Huygens 16 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three Dimensional Space
In geometry, a three-dimensional space (3D space, 3-space or, rarely, tri-dimensional space) is a mathematical space in which three values (''coordinates'') are required to determine the position of a point. Most commonly, it is the three-dimensional Euclidean space, that is, the Euclidean space of dimension three, which models physical space. More general three-dimensional spaces are called ''3-manifolds''. The term may also refer colloquially to a subset of space, a ''three-dimensional region'' (or 3D domain), a '' solid figure''. Technically, a tuple of numbers can be understood as the Cartesian coordinates of a location in a -dimensional Euclidean space. The set of these -tuples is commonly denoted \R^n, and can be identified to the pair formed by a -dimensional Euclidean space and a Cartesian coordinate system. When , this space is called the three-dimensional Euclidean space (or simply "Euclidean space" when the context is clear). In classical physics, it serves as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Change
In any quantitative science, the terms relative change and relative difference are used to compare two quantities while taking into account the "sizes" of the things being compared, i.e. dividing by a ''standard'' or ''reference'' or ''starting'' value. The comparison is expressed as a ratio and is a unitless number. By multiplying these ratios by 100 they can be expressed as percentages so the terms percentage change, percent(age) difference, or relative percentage difference are also commonly used. The terms "change" and "difference" are used interchangeably. Relative change is often used as a quantitative indicator of quality assurance and quality control for repeated measurements where the outcomes are expected to be the same. A special case of percent change (relative change expressed as a percentage) called '' percent error'' occurs in measuring situations where the reference value is the accepted or actual value (perhaps theoretically determined) and the value being comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering Water distribution on Earth, 70.8% of Earth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere. Most of Earth's land is at least somewhat humid and covered by vegetation, while large Ice sheet, sheets of ice at Polar regions of Earth, Earth's polar polar desert, deserts retain more water than Earth's groundwater, lakes, rivers, and Water vapor#In Earth's atmosphere, atmospheric water combined. Earth's crust consists of slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's outer core, Earth has a liquid outer core that generates a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
