Definition of a ISO-8601/Gregorian TRS

[chris-little]

This is an issue passed from the OGC Naming Authority: Definition of a ISO-8601/Gregorian TRS, and possibly redirecting uom/ISO-8601/0/Gregorian to it #101 .

It is the very common example of using the Gregorian Calendar in ISO8601 notation as a "Coordinate Reference System", albeit with multiple units of measure, non-simple arithmetic, and a non-continuous "coordinate" timeline.

There is extensive discussion as to whether the Gregorian Calendar in ISO8601 notation is a Temporal Reference System (I think YES) or a Temporal Coordinate Reference System (I think NO, according to our conceptual model).

The Calendar is currently in a legacy branch of the Naming Authority registers as a UoM (I think that it is clearly NOT a UoM)

I propose that the NA establish separate TCRS and Calendar sub-branches of a TRS branch, with the Gregorian Calendar as the initial content. Then Chinese, Hindu, Mars, etc calendars can be added as required.

A second option would be to put the Gregorian Calendar in the parent TRS branch as the sole terminal "leaf" reflecting its special status.

Please read the original discussion, then discuss here.

[chris-little]

@ghobona As the OGC Abstract Conceptual Model for Time has been passed by the Technical Committee, and probably soon by the Executive Planning Committee, can we move forward with the Naming Authority framework for Temporal Reference Systems encompassing both Temporal Coordinate Reference Systems and Calendars as separate concepts?
There are some Calendars that we would like to register, via the Temporal Domain Working Group, and also some TCRSs.
The Temporal DWG agreed a 'quality control form' several years ago to ensure that correct and valid properties/atributes are defined.

[jerstlouis]

As @cportele pointed out at the 129th MM in Montreal, it seems that this was already done for the purpose of FG-JSON:

https://www.opengis.net/def/crs/OGC/0/GregorianDateTime

However, the Gregoration Date Time CRS does not make any explicit mention of the UTC time scale as discussed in opengeospatial/NamingAuthority#101