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Below is an example of a datum shift operation in WKT 2 format. Contrarily to an equivalent description in WKT 1 format, the WKT 2 description specifies the source and target coordinate reference systems, together with the domain of validity and the accuracy (in metres) that we can expect from this operation:
The standard style for OpenStreetMap, like most Web maps, uses the Web Mercator projection. Web Mercator, Google Web Mercator, Spherical Mercator, WGS 84 Web Mercator [1] 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 ...
A geodetic datum or geodetic system (also: geodetic reference datum, geodetic reference system, or geodetic reference frame, or terrestrial reference frame) is a global datum reference or reference frame for unambiguously representing the position of locations on Earth by means of either geodetic coordinates (and related vertical coordinates) or geocentric coordinates. [1]
The NAD83 map datum is sufficiently close to WGS84 for initial use. It is best to double check on a mapping site such as WikiMapia. It is best to double check on a mapping site such as WikiMapia. Cordinates obtained in China from commercial sources (Google, Bing, Baidu, etc.) may be obfuscated with GCJ-02 or BD-09 .
The WGS 84 datum surface is an oblate spheroid with equatorial radius a = 6 378 137 m at the equator and flattening f = 1 ⁄ 298.257 223 563. The refined value of the WGS 84 gravitational constant (mass of Earth's atmosphere included) is GM = 3.986 004 418 × 10 14 m 3 /s 2. The angular velocity of the Earth is defined to be ω = 72.921 15 × ...
Map datum must be WGS84 if possible (except for off-Earth bodies). Avoid excessive precision (0.0001° is <11 m, 1″ is <31 m). Maintain consistency of decimal places or minutes/seconds between latitude and longitude.
The precursor version XGM2016 (X stands for experimental) was released in 2016 up to degree and order (d/o) 719. [13] XGM2019e was released in 2020 up to spheroidal d/o 5399 (that corresponds to a spatial resolution of 2′ which is ~4 km) and spherical d/o 5540 with a different spheroidal harmonic construction followed by conversion back into ...
The difference between the latest as of 2006 WGS 84 (frame realisation G1150) and the latest ITRF2000 is only a few centimeters and RMS difference of one centimeter per component. [1] The ITRS and ITRF solutions are maintained by the International Earth Rotation and Reference Systems Service . Practical navigation systems are in general ...