Editing Projected coordinate system (section)

{{Short description|Cartesian geographic coordinate system}}
{{distinguish-redirect|Easting and northing|East north up}}
{{Broader|Spatial reference system}}
[[File:Utm-latlon grid en.svg|thumb|Layout of a UTM coordinate system.]]
{{Geodesy}}

A '''projected coordinate system'''{{snd}}also called a '''projected coordinate reference system''', '''planar coordinate system''', or '''grid reference system'''{{snd}}is a type of [[spatial reference system]] that represents locations on [[Earth]] using [[Cartesian coordinate system|Cartesian coordinates]] (''x'', ''y'') on a planar surface created by a particular [[map projection]].<ref name="chang2016">{{cite book |last1=Chang |first1=Kang-tsung |title=Introduction to Geographic Information Systems |date=2016 |publisher=McGraw-Hill |isbn=978-1-259-92964-9 |page=34 |edition=9th}}</ref> 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.<ref name="ogc as">{{Cite web|url=https://docs.ogc.org/as/18-005r5/18-005r5.html|title=OGC Abstract Specification Topic 2: Referencing by coordinates Corrigendum|website=Open Geospatial Consortium|access-date=2018-12-25}}</ref> 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 domains such as the military that encode coordinates as alphanumeric ''grid references''. However, the term ''projected coordinate system'' has recently become predominant to clearly differentiate it from other types of [[spatial reference system]]. The term is used in international standards such as the  [[EPSG code|EPSG]] and ISO 19111 (also published by the [[Open Geospatial Consortium]] as Abstract Specification 2), and in most [[geographic information system]] software.<ref name="epsg">{{cite web |title=Using the EPSG geodetic parameter dataset, Guidance Note 7-1 | url=https://epsg.org/guidance-notes.html |website=EPSG Geodetic Parameter Dataset |publisher=Geomatic Solutions |access-date=15 December 2021}}</ref><ref name="ogc as"/>