What is the projection of WGS84?
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.
What is a datum projection?
A datum is simply a foundation and reference for spatial measurements. A system of coordinates is then used to describe those measurements relative to the datum, and a projection is the visual representation of those measurements on a different surface.
What is WGS84 map datum?
The World Geodetic System 1984 (WGS84) is a datum featuring coordinates that change with time. WGS84 is defined and maintained by the United States National Geospatial-Intelligence Agency (NGA). It is consistent, to about 1cm, with the International Terrestrial Reference Frame (ITRF).
What projection is NAD 83?
UTM NAD83 is a projected coordinate system that represents physical locations abstracted to a flat, cartesian coordinate system. The UTM NAD83 projection uses the GRS80 ellipsoid and a center-of-the-earth anchor point as its datum, both of which are slightly different than the WGS datum.
Why do we use WGS84?
WGS84: Unifying a Global Ellipsoid Model with GPS The radio waves transmitted by GPS satellites and trilateration enable extremely precise Earth measurements across continents and oceans. Geodesists could create global ellipsoid models because of the enhancement of computing capabilities and GPS technology.
Where is the WGS84 datum used for measurements?
The WGS 84 meridian of zero longitude is the IERS Reference Meridian, 5.3 arc seconds or 102 metres (335 ft) east of the Greenwich meridian at the latitude of the Royal Observatory. The WGS 84 datum surface is an oblate spheroid with equatorial radius a = 6378137 m at the equator and flattening f = 1/298.257223563.
Is WGS84 a datum or coordinate system?
Horizontal datums precisely specify each location on Earth’s surface in latitude and longitude or other coordinate systems. For instance, NAD27, NAD83, and WGS84 are examples of geodetic datums. Using geographic coordinate systems, we can define positions on Earth.
What is Geomatic projection?
A projection represents the irregular three-dimensional surface of the Earth as a flat surface. A map projection is used to transform the locations of features on the Earth’s surface to locations on a two-dimensional plane.
What are NAD 83 and NAD 27?
The North American Datum of 1927 (NAD27) is one of the main three geodetic datums used in North America. This set of horizontal positions formed the basis for the North American Datum of 1983 (NAD83). In 1983, the NAD27 datum was eventually replaced with NAD83.
What four 4 different things comprise WGS84?
Actually, WGS84 stands for World Geodetic System 1984 and comprises of four different things:
- an ellipsoid.
- a horizontal datum.
- a vertical datum.
- a coordinate system.