|
Web Mercator
Web Mercator, Google Web Mercator, Spherical Mercator, WGS 84 Web Mercator or WGS 84/Pseudo-Mercator is a variant of the Mercator map projection and is the de facto standard for Web mapping applications. It rose to prominence when Google Maps adopted it in 2005. It is used by virtually all major online map providers, including Google Maps, CARTO, Mapbox, Bing Maps, OpenStreetMap, Mapquest, Esri, and many others. Its official EPSG identifier is EPSG:3857, although others have been used historically. Properties Web Mercator is a slight variant of the Mercator projection, one used primarily in Web-based mapping programs. It uses the same formulas as the standard Mercator as used for small-scale maps. However, the Web Mercator uses the spherical formulas at all scales whereas large-scale Mercator maps normally use the ellipsoidal form of the projection. The discrepancy is imperceptible at the global scale but causes maps of local areas to deviate slightly from true ellipsoid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Web Maps Mercator Projection SW
Web most often refers to: * Spider web, a silken structure created by the animal * World Wide Web or the Web, an Internet-based hypertext system Web, WEB, or the Web may also refer to: Computing * WEB, a literate programming system created by Donald Knuth * GNOME Web, a Web browser * Web.com, a web-design company * Webs (web hosting), a Web hosting and website building service * Web hosting service Engineering * Web (manufacturing), continuous sheets of material passed over rollers ** Web, a roll of paper in offset printing * Web, the vertical element of an I-beam or a rail profile * Web, the interior beams of a truss Films * ''Web'' (2013 film), a documentary * ''Webs'' (film), a 2003 science-fiction movie * ''The Web'' (film), a 1947 film noir * Charlotte's Web (2006 film) Literature * ''Web'' (comics), an MLJ comicbook character (created 1942) * ''Web'' (novel), by John Wyndham (1979) * The Web (series), a science fiction series (1997–1999) * World English Bible, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conformal Map Projection
In cartography, a conformal map projection is one in which every angle between two curves that cross each other on Earth (a sphere or an ellipsoid) is preserved in the image of the projection; that is, the projection is a conformal map in the mathematical sense. For example, if two roads cross each other at a 39° angle, their images on a map with a conformal projection cross at a 39° angle. Properties A conformal projection can be defined as one that is locally conformal at every point on the map, albeit possibly with Mathematical singularity, singular points where conformality fails. Thus, every small figure is nearly similar to its image on the map. The projection preserves the ratio of two lengths in the small domain. All of the projection's Tissot's indicatrices are circles. Conformal projections preserve only small figures. Large figures are distorted by even conformal projections. In a conformal projection, any small figure is similar to the image, but the ratio of sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geographic Coordinate Systems
A geographic coordinate system (GCS) is a spherical or geodetic coordinate system for measuring and communicating positions directly on Earth as latitude and longitude. It is the simplest, oldest, and most widely used type 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 BC. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Well-known Text Representation Of Coordinate Reference Systems
Well-known text representation of coordinate reference systems (WKT or WKT-CRS) is a text markup language for representing spatial reference systems and transformations between spatial reference systems. The formats were originally defined by the Open Geospatial Consortium (OGC) and described in their '' Simple Feature Access'' and ''Well-known text representation of coordinate reference systems'' specifications. The current standard definition is ISO 19162:2019. This supersedes ISO 19162:2015. Version history This WKT format was initially defined by the Open Geospatial Consortium (OGC) in 1999, then extended in 2001. This format, also defined in ISO 19125-1:2004, is sometime known as "WKT 1". Later, evolution of the Coordinate Reference System conceptual model, new requirements and inconsistencies in implementation of WKT 1 format between different software have encouraged the revision of that format. The updated "Well-known text representation of coordinate reference systems" s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geodesy
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] |
Leet
Leet (or "1337"), also known as eleet or leetspeak, or simply hacker speech, is a system of modified spellings used primarily on the Internet. It often uses character replacements in ways that play on the similarity of their glyphs via reflection or other resemblance. Additionally, it modifies certain words on the basis of a system of suffixes and alternative meanings. There are many dialects or linguistic varieties in different online communities. The term "leet" is derived from the word '' elite'', used as an adjective to describe skill or accomplishment, especially in the fields of online gaming and computer hacking. The leet lexicon includes spellings of the word as ''1337'' or ''leet''. History Leet originated within bulletin board systems (BBS) in the 1980s,Mitchell.An Explanation of l33t Speak. where having "elite" status on a BBS allowed a user access to file folders, games, and special chat rooms. The Cult of the Dead Cow hacker collective has been credited ... [...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 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, Geodetic datum, 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 geographic coordinate conversion, transformations between different SRS. Although they date to the Hellenistic 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 civ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EPSG Registry
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, originated by a member of the European Petroleum Survey Group (EPSG) in 1985. Each entity is assigned an EPSG code between 1024 and 32767, along with a standard machine-readable well-known text (WKT) representation. The dataset is 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 some also support SRIDs issued by other organizations (such as Esri). Common EPSG codes * EPSG:4326 - WGS 84 datum ensemble for 2D (latitude, longitude) coordinates with 2 meter accuracy, used by the Global Positioning System among others. * EPSG:3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WGS84
The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also describes the associated Earth Gravitational Model (EGM) and World Magnetic Model (WMM). The standard is published and maintained by the United States National Geospatial-Intelligence Agency. History Efforts to supplement the various national surveying systems began in the 19th century with F.R. Helmert's book (''Mathematical and Physical Theories of Physical Geodesy''). Austria and Germany founded the (Central Bureau of International Geodesy), and a series of global ellipsoids of the Earth were derived (e.g., Helmert 1906, Hayford 1910 and 1924). A unified geodetic system for the whole world became essential in the 1950s for several reasons: * International space science and the beginning of astronautics. * The lack of inter-continental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gudermannian Function
In mathematics, the Gudermannian function relates a hyperbolic angle measure \psi to a circular angle measure \phi called the ''gudermannian'' of \psi and denoted \operatorname\psi. The Gudermannian function reveals a close relationship between the circular functions and hyperbolic functions. It was introduced in the 1760s by Johann Heinrich Lambert, and later named for Christoph Gudermann who also described the relationship between circular and hyperbolic functions in 1830. The gudermannian is sometimes called the hyperbolic amplitude as a limiting case of the Jacobi elliptic amplitude \operatorname(\psi, m) when parameter m=1. The real Gudermannian function is typically defined for -\infty < \psi < \infty to be the integral of the hyperbolic secant : The real inverse Gudermannian function can be defined for |
Geodetic Latitude
Geodetic coordinates are a type of curvilinear orthogonal coordinate system used in geodesy based on a ''reference ellipsoid''. They include geodetic latitude (north/south) , ''longitude'' (east/west) , and ellipsoidal height (also known as geodetic height). The triad is also known as Earth ellipsoidal coordinates (not to be confused with '' ellipsoidal-harmonic coordinates''). Definitions Longitude measures the rotational angle between the zero meridian and the measured point. By convention for the Earth, Moon and Sun, it is expressed in degrees ranging from −180° to +180°. For other bodies a range of 0° to 360° is used. For this purpose, it is necessary to identify a ''zero meridian'', which for Earth is usually the Prime Meridian. For other bodies a fixed surface feature is usually referenced, which for Mars is the meridian passing through the crater Airy-0. It is possible for many different coordinate systems to be defined upon the same reference ellipsoid. Geode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
