https://www.opengis.net/def/crs/OGC/0/GregorianDateTime DateTime in Gregorian calendar This definition was derived from the example E.4.1 in OGC Abstract Specification in Topic 2 "Definition of a Temporal CRS in which axis quantity is DateTime" (https://docs.ogc.org/as/18-005r4/18-005r4.html#118). Since GML 3.2 implements an older model for coordinate reference systems, the information in Topic 2 has been mapped to the XML schema of GML 3.2. A Well-Known-Text or PROJJSON representation would support encoding the CRS definition according to the current version of Topic 2. 1582-10-15 Date/time as defined in ISO 8601. DateTime DateTime. Axis: T. Orientation: future. dateTime T future gregorian Gregorian calendar The Gregorian calendar has a reference point that assigns 20 May 1875 to the calendar day that the “Convention du Mètre” was signed in Paris. 1875-05-20T00:00:00Z