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Grid Reference
A projected coordinate system, also known as a projected coordinate reference system, a planar coordinate system, or grid reference system, is a type of spatial reference system that represents locations on the Earth using cartesian coordinates (''x'',''y'') on a planar surface created by a particular map projection. Each projected coordinate system, such as "Universal Transverse Mercator WGS 84 Zone 26N," is defined by a choice of map projection (with specific parameters), a choice of geodetic datum to bind the coordinate system to real locations on the earth, an origin point, and a choice of unit of measure. Hundreds of projected coordinate systems have been specified for various purposes in various regions. When the first standardized coordinate systems were created during the 20th Century, such as the Universal Transverse Mercator, State Plane Coordinate System, and British National Grid, they were commonly called ''grid systems''; the term is still common in some domai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordnance Survey National Grid
The Ordnance Survey National Grid reference system (OSGB) (also known as British National Grid (BNG)) is a system of geographic grid references used in Great Britain, distinct from latitude and longitude. The Ordnance Survey (OS) devised the national grid reference system, and it is heavily used in their survey data, and in maps based on those surveys, whether published by the Ordnance Survey or by commercial map producers. Grid references are also commonly quoted in other publications and data sources, such as guide books and government planning documents. A number of different systems exist that can provide grid references for locations within the British Isles: this article describes the system created solely for Great Britain and its outlying islands (including the Isle of Man); the Irish grid reference system was a similar system created by the Ordnance Survey of Ireland and the Ordnance Survey of Northern Ireland for the island of Ireland. The Universal Transverse Merc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meter
The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefixed forms are also used relatively frequently. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in a vacuum in of a second. After the 2019 rede ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Navigation
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few centimetres to metres) using time signals transmitted along a line of sight by radio from satellites. The system can be used for providing position, navigation or for tracking the position of something fitted with a receiver (satellite tracking). The signals also allow the electronic receiver to calculate the current local time to a high precision, which allows time synchronisation. These uses are collectively known as Positioning, Navigation and Timing (PNT). One set of critical vulnerabilities in satellite communications are the signals that govern positioning, navigation and timing (PNT). Failure to properly secure these transmissions could not only disrupt satellite networks but wreak havoc on a host of dependent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geographic Information Systems
A geographic information system (GIS) is a type of database containing geographic data (that is, descriptions of phenomena for which location is relevant), combined with software tools for managing, analyzing, and visualizing those data. In a broader sense, one may consider such a system to also include human users and support staff, procedures and workflows, body of knowledge of relevant concepts and methods, and institutional organizations. The uncounted plural, ''geographic information systems'', also abbreviated GIS, is the most common term for the industry and profession concerned with these systems. It is roughly synonymous with geoinformatics and part of the broader geospatial field, which also includes GPS, remote sensing, etc. Geographic information science, the academic discipline that studies these systems and their underlying geographic principles, may also be abbreviated as GIS, but the unambiguous GIScience is more common. GIScience is often considered a subdi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Grid Reference System
The Military Grid Reference System (MGRS) Datums, Ellipsoids, Grids, and Grid Reference Systems is the geocoordinate standard used by militaries for locating points on Earth. The MGRS is derived from the Universal Transverse Mercator (UTM) grid system and the Universal Polar Stereographic (UPS) grid system, but uses a different labeling convention. The MGRS is used as [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wehrmacht
The ''Wehrmacht'' (, ) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the ''Heer'' (army), the '' Kriegsmarine'' (navy) and the ''Luftwaffe'' (air force). The designation "''Wehrmacht''" replaced the previously used term and was the manifestation of the Nazi regime's efforts to rearm Germany to a greater extent than the Treaty of Versailles permitted. After the Nazi rise to power in 1933, one of Adolf Hitler's most overt and audacious moves was to establish the ''Wehrmacht'', a modern offensively-capable armed force, fulfilling the Nazi régime's long-term goals of regaining lost territory as well as gaining new territory and dominating its neighbours. This required the reinstatement of conscription and massive investment and defense spending on the arms industry. The ''Wehrmacht'' formed the heart of Germany's politico-military power. In the early part of the Second World War, the ''Wehrmacht'' employed combined arms tactics (close- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universal Transverse Mercator Coordinate System
The Universal Transverse Mercator (UTM) is a map projection system for assigning coordinates to locations on the surface of the Earth. Like the traditional method of latitude and longitude, it is a horizontal position representation, which means it ignores altitude and treats the earth as a perfect ellipsoid. However, it differs from global latitude/longitude in that it divides earth into 60 zones and projects each to the plane as a basis for its coordinates. Specifying a location means specifying the zone and the ''x'', ''y'' coordinate in that plane. The projection from spheroid to a UTM zone is some parameterization of the transverse Mercator projection. The parameters vary by nation or region or mapping system. Most zones in UTM span 6 degrees of longitude, and each has a designated central meridian. The scale factor at the central meridian is specified to be 0.9996 of true scale for most UTM systems in use. History The National Oceanic and Atmospheric Administration (NOAA) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theater Of War
In warfare, a theater or theatre is an area in which important military events occur or are in progress. A theater can include the entirety of the airspace, land and sea area that is or that may potentially become involved in war operations. Theater of war In his book ''On War'', Carl von Clausewitz defines the term ''Kriegstheater'' (translating the older, 17th-century Latin term ''theatrum belli'') as one that: Theater of operations ''Theater of operations'' (TO) is a sub-area within a theater of war. The boundary of a TO is defined by the commander who is orchestrating or providing support for specific combat operations within the TO. Theater of operations is divided into strategic directions or military regions depending on whether it is a war or peacetime. The United States Armed Forces split into Unified Combatant Commands (regions) that are assigned to a particular theater of military operations. A strategic direction is a group of armies also known as a task (fie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Army Map Service
The Army Map Service (AMS) was the military cartography, cartographic agency of the United States Department of Defense from 1941 to 1968, subordinated to the United States Army Corps of Engineers. On September 1, 1968, the AMS was redesignated the U.S. Army Topographic Command (USATC) and continued as an independent organization until January 1, 1972, when it was merged into the new Defense Mapping Agency (DMA) and redesignated as the DMA Topographic Center (DMATC). On October 1, 1996, DMA was folded into the National Imagery and Mapping Agency (NIMA), which was redesignated as the National Geospatial-Intelligence Agency (NGA) in 2003. The major task of the Army Map Service was the compilation, publication and distribution of military topographic maps and related products required by the Armed Forces of the United States. The AMS was also involved in the preparation of extraterrestrial maps of satellite and planetary bodies; the preparation of national intelligence studies; the es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, massa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
