Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
There have been no further comments for three weeks and sufficient support has been expressed, so this change is therefore accepted according to the rules. I have merged https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/pull/331__;!!G2kpM7uM-TzIFchu!iwe0XIZ6ul3z7d-ZjVbAISgJVUGywNtc0FN05WOY8srcs4N8FQriKsqgDvba2hZyH6HU9RnFhDQ$ . Thanks to all contributors to the discussion, especially @Dave-Allured, who raised this issue. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-885458535__;Iw!!G2kpM7uM-TzIFchu!iwe0XIZ6ul3z7d-ZjVbAISgJVUGywNtc0FN05WOY8srcs4N8FQriKsqgDvba2hZyH6HU6Yq8AgA$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
Closed #319. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*event-5059621829__;Iw!!G2kpM7uM-TzIFchu!l8DVQGMeUPL6S4HfoIGN5xAkU64yoHPeZEz1fQG-lXuPsrXQhLhhuJCXuzbABUJMzSrcbQpnH5M$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
Thanks to @JonathanGregory for putting together the pull request that will close this issue (as well as #298). This PR (#331) should be merged on 23rd July, three weeks from today, if no concerns are raised. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-872927915__;Iw!!G2kpM7uM-TzIFchu!iU8v3DdSzkFgSkYgdrZ-nkjj7qw8Zuq8tL4eJAmZf5hWE91zqd6Uz0bI525va7Wrne2UCtmTz5c$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
The changes agreed here will now be incorporated into the wider-ranging changes of #298 "_Interpretation of negative years in the units attribute_" (https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/298*issuecomment-865916396__;Iw!!G2kpM7uM-TzIFchu!k-Kq_1wJy9S3G6mQUOEwR-RCXcAoqqcXRPpJR54HjdMSfpy8EyQhNFgcG2vgLehVbKYpWFBuPRo$ ). This not only makes it easier to write up the PR for #298, but will also avoid merge conflicts that are likely to occur if these two issues are treated separately. The PR for #298 will also add @Dave-Allured to the CF authors in recognition of his raising the issue and the work he has done on it (unless he would prefer not) (https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/298*issuecomment-866802285__;Iw!!G2kpM7uM-TzIFchu!k-Kq_1wJy9S3G6mQUOEwR-RCXcAoqqcXRPpJR54HjdMSfpy8EyQhNFgcG2vgLehVbKYpPfHCdqI$ ). Therefore, when #298 is closed, this issue may be closed as well. Thanks everyone. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-867464512__;Iw!!G2kpM7uM-TzIFchu!k-Kq_1wJy9S3G6mQUOEwR-RCXcAoqqcXRPpJR54HjdMSfpy8EyQhNFgcG2vgLehVbKYp_emvoDQ$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
It looks like a consensus solution has emerged: * The `gregorian` calendar is deprecated. * The default calendar is redefined as `standard` alone. * The `noleap` and `all_leap` calendars are both redefined to be modifications of the proleptic gregorian calendar. Does that sound right? @Dave-Allured, would you like to put together a pull request for these changes? Thanks all, David -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-865102656__;Iw!!G2kpM7uM-TzIFchu!mv2bmQEWjMp8I6ET-gdmaXeN7EIjVSfe--Vp8GeYu70XSh7OMJn4RlLT5zo__I2Ru90VMK5q3DQ$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
A `strict_gregorian` calendar would be one which is Gregorian and *must not* be used before 1582 i.e. that would be an error, whereas `proleptic_gregorian` can be used both before and after 1582 without error or warning - that is the point of it. However, I am not in favour of `strict_gregorian`. I raised the possibility in case there was a use-case for it, but no-one's described one. Hence I'm happy if we drop it. I agree with @davidhassell's summary, with the addition of @zklaus that we redefine the default as `standard` alone. Jonathan -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-865082652__;Iw!!G2kpM7uM-TzIFchu!jQ1KVcNdhlzUmswOIOJcJbdEIMug_J-YV1C3REngqnVixVMYBSOUOuaLWKwmNlAHw3dke5rnyFA$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
I agree with @taylor13. As I hinted at earlier I can see no specific reason for having a specific `strict_gregorian` calendar (whatever it might called). And in addition to what arguments Karl might think of for not having it, I think that the the [comment](https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-860835466__;Iw!!G2kpM7uM-TzIFchu!h4iml-CU5W6Hr_Eg8bjwjCIxoINWzj3c2YiAHK7Q83BVyxAPCxsVodPxLd1xu7Ma1h7GzWKuMos$ ) by @chris-little indirectly points in the same direction,. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-862735004__;Iw!!G2kpM7uM-TzIFchu!h4iml-CU5W6Hr_Eg8bjwjCIxoINWzj3c2YiAHK7Q83BVyxAPCxsVodPxLd1xu7Ma1h7Gi-WZVSc$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
>From the above, it's not clear to me whether or not a strict_gregorian >calenadar is or is not being proposed. I think it would be a mistake to >include it, and I don't think "strict" is optimal as a descriptor. I'll >provide reasoning if it *is* in fact being proposed here. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-861791064__;Iw!!G2kpM7uM-TzIFchu!nINKR-TFegRuvtKBI-1-3_JziB4JNF5kAeww-KpoZdW6WJVad5oOcMOPtMa-SUq9uTbz718jJvw$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
Good point, @zklaus. I think that all this applies only to `gregorian`, i.e. the `standard` calendar (= Mixed Gregorian/Julian calendar as defined by Udunits) remains unchanged by this proposal. In that case, we need to be clear that the default calendar has changed to `standard`, rather than "gregorian" _or_ "standard". -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-861555997__;Iw!!G2kpM7uM-TzIFchu!iIiIuSfdawEtthT4JEE6hUyfQqxU4qXXVSjZTKAyPb2H-7pR48wXUe8lO_34MrbFNZFsCopoEog$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
> It seems like there is support for deprecating `gregorian`. When the > Gregorian calendar is intended for dates after 1582, we could introduce a new > calendar (e.g. `strict_gregorian`), or else use the existing > `proleptic_calendar`, which is the same as Gregorian for dates after 1582. To be clear, does this refer only to the `gregorian` calendar or also to the `standard` calendar? -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-861551964__;Iw!!G2kpM7uM-TzIFchu!i-pPNfAeOajtnQBRIdBwYvQBB08F-MoKnYwjtjFR2feP5uVl3IzNLitdBKTfman6zJXunCaUWrY$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
@davidhassell Thank you for this summary,which I think captures it all. Referencing the proleptic_gregorian calendar instead of the gregorian, as you suggest in your fourth point, provides an elegant and easy way to update calendar definitions (section 4.4.1, and possibly elsewhere). -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-860958900__;Iw!!G2kpM7uM-TzIFchu!nnvFNhcAvrYSVw9lWdCbMw7gN-_SDVy-R4e0sNdwP8nYL70zGh38syN6sZdtyt9SiO3kDnG4IT0$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
@davidhassell To strengthen your argument in the 5th bullet, many countries/communities did not switch to Gregorian, and therefore continued with the Julian calendar as late as 1923, and may have annotated their observations or data that way. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-860835466__;Iw!!G2kpM7uM-TzIFchu!gBvxdAR3L4R0sicmn8c-nEODWFztHHQn3nQQor5U2OfNky4l2K9uPilEn8Jhu1dWDYv-8epHoUE$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
Hello, Here's my summary of where we are with this issue. Please say if you think that I've misrepresented/misunderstood anything. * The initial proposal was to redefine `gregorian` to have a distinct meaning from `standard`, namely, `gregorian` would include the restriction that prohibits date/times no earlier than 1582 October 15 00:00:00 (https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issue-849497317__;Iw!!G2kpM7uM-TzIFchu!lnk2LRqS4xALuyIsHijmF35cygt9HoYTrPF2y34HyE1gbjMD4L5q51mEhZRBhLu-kXAdqrLLsnw$ ). * Such a split was deemed undesirable as it would mean that something which is presently legal would become illegal, and thus the change would potentially break existing software (https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-812838600__;Iw!!G2kpM7uM-TzIFchu!lnk2LRqS4xALuyIsHijmF35cygt9HoYTrPF2y34HyE1gbjMD4L5q51mEhZRBhLu-kXAdRBtkpVU$ , https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-812862492__;Iw!!G2kpM7uM-TzIFchu!lnk2LRqS4xALuyIsHijmF35cygt9HoYTrPF2y34HyE1gbjMD4L5q51mEhZRBhLu-kXAdyST388w$ ). * If there is a need for a Gregorian calendar which can only be used from 1582, we could introduce a new one for that purpose e.g. `strict_gregorian.`, if there is a use case for it (https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-812838600__;Iw!!G2kpM7uM-TzIFchu!lnk2LRqS4xALuyIsHijmF35cygt9HoYTrPF2y34HyE1gbjMD4L5q51mEhZRBhLu-kXAdRBtkpVU$ ). However, the existing `proleptic_gregorian` could be used for the same purpose (https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-813937985__;Iw!!G2kpM7uM-TzIFchu!lnk2LRqS4xALuyIsHijmF35cygt9HoYTrPF2y34HyE1gbjMD4L5q51mEhZRBhLu-kXAdwSkMICY$ ). * The definitions of other calendars refer that to the "Gregorian" calendar, i.e. `noleap` and `all_leap`, should be reviewed - presumable to refer to the "Proleptic Gregorian" calendar (my comment)? * There is no use case for deprecating the `julian` calendar use for dates after 1582, because there are probably some models with simplified calendars defined in which leap years invariably occur every 4 years (https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-812871576__;Iw!!G2kpM7uM-TzIFchu!lnk2LRqS4xALuyIsHijmF35cygt9HoYTrPF2y34HyE1gbjMD4L5q51mEhZRBhLu-kXAdAY-HSFs$ ). It seems like there is support for deprecating `gregorian`. When the Gregorian calendar is intended for dates after 1582, we could introduce a new calendar (e.g. `strict_gregorian`), or else use the existing `proleptic_calendar`, which is the same as Gregorian for dates after 1582. The `noleap` and `all_leap` calendars could be updated in a backwards-compatible fashion to refer to the proleptic Gregorian calendar (see comment on the `julian` calendar). David -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-860641932__;Iw!!G2kpM7uM-TzIFchu!lnk2LRqS4xALuyIsHijmF35cygt9HoYTrPF2y34HyE1gbjMD4L5q51mEhZRBhLu-kXAdt3p1toQ$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
I very much support this proposal. Equating `gregorian` with `mixed gregorian/julian` has always been a CF oddity to my mind. And I agree with Jonathan and KarI that existing datasets should not be invalidated. Jonathan asks the question whether we need a `strict_gregorian` calendar as replacement; the only though not very strong use case I can think of right now is to clearly show that the "old `gregorian`" is indeed deprecated. For all practical purposes the `proleptic-gregorian` calendar can be used instead of a `strict_gregorian`. This might be a separate issue, but I raise here for reference: If `gregorian` is deprecated we should review how the `365_day` and `366_day` calendars are described in [Section 4.4.1](https://urldefense.us/v3/__http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html*calendar__;Iw!!G2kpM7uM-TzIFchu!ib1vsvS76xM7owzrpL0XJPNH7QXhJFp9222Hi8F9zGPFJ9kiiELM-kH33cKBbTD62jfdJ9qYM5I$ ). What does it mean that a calendar is "Gregorian calendar without leap years" and "Gregorian calendar with every year being a leap year", presumably the system of varying month lengths? -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-813937985__;Iw!!G2kpM7uM-TzIFchu!ib1vsvS76xM7owzrpL0XJPNH7QXhJFp9222Hi8F9zGPFJ9kiiELM-kH33cKBbTD62jfdgfTrr8s$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
And while we're at it, what about the ``julian`` calendar? Should we, for consistency, deprecate its use for dates after 1582? Perhaps not, since there are probably some models with simplified calendars defined in which leap years invariably occur every 4 years. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-812871576__;Iw!!G2kpM7uM-TzIFchu!nqZ0atA_Un02PuTJsXZm1G8YV3EWXSm9cO7L8sHea6nIeHSxsPTV9qKKIgvrqS9N143XPM6b_xw$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
I agree with Jonathan that we should avoid making changes that make illegal something that is currently legal in C. I would therefore favor his suggestion to deprecate ``gregorian`` when dates precede 1582. Users who want to use the gregorian algorithm to compute dates before 1582 should instead use the ``standard`` calendar for that purpose (if I've interpreted the proposal correctly). -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-812862492__;Iw!!G2kpM7uM-TzIFchu!jF_cRg9r_QMsGSMHL_d1RcyIYcL6-dajkVF8P8SQXcIMzrh0WmwHpDpy0oi0VPmIFf_-LnrJ4ks$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
Re: [CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
I agree with the desirability of distinguishing the default mixed Julian/Gregorian calendar from the Gregorian. It does not make sense to call dates "Gregorian" when they are earlier than the invention of the Gregorian calendar and don't conform to the Gregorian calendar rules. Redefining `gregorian` to have a distinct meaning from `standard` (=default), as @Dave-Allured proposes, would achieve that aim, but it would be backward-incompatible. It wouldn't invalidate any existing data, but it would mean that something which is presently legal would become illegal, and thus the change would potentially break existing software which doesn't check the version of the CF convention. This is not disastrous, but we don't usually make such changes to the convention. Hence I would prefer to deprecate `gregorian`, meaning that the CF checker would produce a warning if it was used in future. If there is a need for a Gregorian calendar which can only be used from 1582, we should introduce a new one for that purpose e.g. `strict_gregorian`. Is there a use-case for it? Jonathan -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319*issuecomment-812838600__;Iw!!G2kpM7uM-TzIFchu!m5KFxdY7J6KrX5fkGeDuC3kA02pREoL_evAITV59eCcnPR2pSZVb06a6zXPPjRNfaDWSpq4eR6Q$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
[CF-metadata] [cf-convention/cf-conventions] Restrict "gregorian" label to only dates in the Gregorian calendar (#319)
# Summary of Proposal When using specifically the `gregorian` calendar attribute with time coordinates, restrict the time range to only dates in the real-world Gregorian calendar. That is, date/times no earlier than 1582 October 15 00:00:00. Usage for dates earlier than the Julian/Gregorian crossover of 1582 October 15 is deprecated but not prohibited, because of possible usage in existing data sets. The initial proposal is to add this restriction to the `gregorian` label, but leave the `standard` and CF default (unspecified) calendars unchanged. Until now, `gregorian` and `standard` were both synonyms for the default mixed Julian/Gregorian calendar as defined by UDUNITS, and in common usage with netCDF since the 1990's. This proposal would split `gregorian` and `standard` into two separate calendar definitions in [CF section 4.4.1](https://urldefense.us/v3/__https://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html*calendar__;Iw!!G2kpM7uM-TzIFchu!iBErcBI6ZCO_WSyPGeut17gWLz8v9vAkoS-pe-fxHgHknladMXlS1qLRmN-VWcV2sw3FoOO-cq0$ ). This is a recurring request, such as in issues #148 and #298, and at other times. Reference: [Wikipedia article "Gregorian calendar"](https://urldefense.us/v3/__https://en.wikipedia.org/wiki/Gregorian_calendar__;!!G2kpM7uM-TzIFchu!iBErcBI6ZCO_WSyPGeut17gWLz8v9vAkoS-pe-fxHgHknladMXlS1qLRmN-VWcV2sw3Fdhh9bdU$ ) # Details Same as in the proposal for #298, this restriction on dates would apply to both the reference date/time string, and to encoded date/time values. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/319__;!!G2kpM7uM-TzIFchu!iBErcBI6ZCO_WSyPGeut17gWLz8v9vAkoS-pe-fxHgHknladMXlS1qLRmN-VWcV2sw3FaxvXD5Q$ This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
