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Wikipedia dates
Some people have proposed using ISO 8601 for Wikipedia dates. For more of this discussion, see Wikipedia talk:Manual of Style (dates and numbers).
- It appears that it's rapidly becoming a de facto standard (if not yet de jure) at least for dates in Wikipedia citations.
Y10K
- The Long Now foundation suggests that years should be written with five digits (ie 02003 for the year 2003) in order to avoid the Year 10,000 problem.
This is pointless: all it does is push the problem forward a few years to 100,000, and situation already exists for dates in the past (-10,000 and earlier.) May as well accept that the year number can have a varying number of digits -( 18:57 22 Jun 2003 (UTC)
- RFC2550: Y10K and beyond — RFC document published as an April Fools joke in 1999; still it contains many potentially useful ideas.
Without seeing that I assumed they were serious! Brianjd
RFC: Does ISO 8601 use the Gregorian calendar?
Does ISO 8601 use the Gregorian calendar? If so, does this edit by JMJimmy help readers understand that ISO 8601 uses the Gregorian calender, or hinder that understanding? If the Gregorian calendar is used, is the wording as of 7 August 2014 (UT), JMJimmy's wording, or some other wording best? Jc3s5h (talk) 23:17, 9 August 2014 (UTC)
- Procedural note: this question represents only one side in the article. It does not even mention JMJimmy's position. I would suggest to reword it or, even better, remove {{RFC}} tag and use some more lightweight process (WP:3O or WP:DRN instead. — Dmitrij D. Czarkoff (talk•track) 09:07, 10 August 2014 (UTC)
ISO 8601 & Gregorian calendar discussion
As the originator of the RFC, I believe that ISO 8601 does use the Gregorian calendar. I also believe the wording as of 7 August 2014 is better than JMJimmy's version. Omitting hyperlinks and footnotes, the change amounts to this:
The standard uses the Gregorian calendar, which serves as an international standard for civil use.ISO 8601 fixes a reference calendar date to the Gregorian calendar of 20 May 1875 as the date the Convention du Mètre (Metre Convention) was signed in Paris.
This change obscures the fundamental point that ISO 8601 uses the Gregorian calendar, and leaves only a description of the indirect way ISO established a reference date of the calendar without getting into the complexity of the uncertain date of the Incarnation (Christianity) and Dionysius Exiguus' estimate of that date. Jc3s5h (talk) 23:17, 9 August 2014 (UTC)
- Text below was moved from Jc3s5h's talk page.
- I reapplied the changes and I just wanted to explain to you why in more detail. I took a step back and went to find the source. I was able to find a 3rd edition copy and it states in the Scope section: "This International Standard is applicable whenever representation of dates in the Gregorian calendar, times in the 24-hour timekeeping system, time intervals and recurring time intervals or of the formats of these representations are included in information interchange." There are two things which do not support any connection with "civil use". 1) it's limited to information interchange. 2) When parsed it includes more than Gregorian - that's just part of it. ie:
- ...whenever representation of dates in the Gregorian calendar...
- ...whenever representation of times in the 24-hour timekeeping system...
- ...whenever representation of time intervals and recurring time intervals... etc
- This is why the document refers to "local time" and "agreements on information interchange" because it knows that civil calendars are not unified and even within those that are timekeeping is not unified (see BENI time reports). It provides for mechanism (4.2.5.2) which use UTC +/- to convert local time to a standardized time to be formatted with the "Western" Gregorian calendar. Julian or Lunar time can be expressed via this ISO, it simply must be converted to UTC and expressed as "Western" Gregorian. Involving any sort of implication that the ISO has an impact or is impacted by civil use of a particular calendar is not supported by the citation nor the standard. For these reason I strongly believe that discussion of the level of adoption and the details of a particular calendar should be left in their respective articles.
- Additional comments:
- I never indicated that the ISO does not use the Gregorian calendar. It does without question. Section 3.2.1 The Gregorian calendar details this. What it avoids is any connection with any particular civil time other than for the conversion of local civil time into a standard time (using western Gregorian) for the purposes of information interchange. JMJimmy (talk) 23:34, 9 August 2014 (UTC)
- I'm having a hard time following this. The Gregorian calendar does not concern itself with time of day. "Civil calendar" is a calendar used for general secular use in a particular place. "Civil time" is the time-of-day used for general secular use in a particular place. They are almost separate ideas, except that the civil time determines when the transition occurs from one civil calendar day to the next. ISO 8601 allows local time, which is agreed to among the communicating parties or is implied by context, but which is not specified by the standard other than consisting of 24 hours in a day, 60 minutes in an hour, and 59 to 61 seconds in a minute. Alternatively, UTC can be used, or a combination of UTC and a time zone offset. Jc3s5h (talk) 23:46, 9 August 2014 (UTC)
- Addressing your assertion that "This change obscures the fundamental point that ISO 8601 uses the Gregorian calendar". If you feel that text does not adequately address Section 3.2.1 then it can be adjusted. My issue isn't with the reference to the Gregorian calendar - it's with the connection between the ISO and civil use. In fact I would encourage further detail on the use of Gregorian within the standard as the article is currently not clear that it uses a specific form of Gregorian (for those who don't know, Gregorian has numerous forms which are not compatible with this ISO unless first converted to UTC) These details would be great to include, but the moment you bring in "civil use" it then becomes about the calendar itself and not the standard. JMJimmy (talk) 23:55, 9 August 2014 (UTC)
- Clarification, this is the part I have a problem with: "which serves as an international standard for civil use.". I just removed the whole line because I thought it was clear enough by the paragraph below that it used Gregorian. Further to your last comment all calendars concern themselves with time to the extent that it is required to determine the change in date. When you bring in "civil use" it gives the impression that a) there is an actual standard (there's not, just a de facto use) b) that Gregorian is universally the same world wide, which it is not. 7% of the countries worldwide use a different civil calendar or modified Gregorian, it does not prevent them from converting to UTC and expressing in the specific Gregorian format discussed in the standard for the purposes of information interchange. JMJimmy (talk) 00:21, 10 August 2014 (UTC)
- There is exactly one Gregorian calendar for civil use. Its features include a sequence of days named January 1 through December 31 in the familiar sequence, the use of the year naming convention called AD or CE, and a rule for calculating leap years. Some things that are not defined by the Gregorian calendar include how time of day is measured or described, what time of day marks the end of one day and the start of another, and what date marks the first day of the calendar year. If a local calendar deviates from the Gregorian calendar, it isn't the Gregorian calendar, even if it's close.
- There is also a lunar Gregorian calendar, which uses an arithmetic rule to estimate the phase of the moon, and is used in computing the date of Easter in several Christian denominations. This is the part of the Gregorian calendar that is not for civil use, it is for religious use.
- I now see one, and only one, distinction between the Gregorian calendar for civil use and the ISO version of the Gregorian calendar. ISO 8601 insists that the first day of the calendar year is January 1. This is not a requirement of the Gregorian calendar, although our Gregorian calendar article indicates most European countries adopted January 1 as the beginning of the calendar year before, or at the same time as, adopting the Gregorian calendar. If such a distinction needs to be mentioned at all, I think it belongs in a footnote. Jc3s5h (talk) 00:48, 10 August 2014 (UTC)
- The easiest way I can show you that there are multiple calendars is: Microsoft's calendar dll those are fairly minor differences, part of the need for the ISO in question, Thai solar calendar is a version of Gregorian as is the Japanese calendar that info can be found in the wiki article here: Gregorian_calendar#Present_situation JMJimmy (talk) 02:03, 10 August 2014 (UTC)
- The Microsoft stuff is just different spellings of the month names and minor punctuation changes. That doesn't constitute a different calendar. As for the rest, a modified Gregorian calendar isn't the Gregorian calendar. When "Gregorian calendar" is written in an English language article, I think everyone has knows it isn't the Thai solar calendar. Jc3s5h (talk) 02:51, 10 August 2014 (UTC)
- I looked back into the page's history to see when this change was made. From Jan 2006 to Oct 2010 the text read that it was a de facto standard for international trade. Your edit changed the meaning to fit the source instead of sourcing the meaning. That is not a bad thing per se, just in this instance your source didn't relate to ISO and resulted in synth. I don't know where you're getting your info but you've made some assertions which are not supported by fact. ISO does not insist the 1st of January as being the calendar year. A calendar year is defined in the ISO as "cyclic time interval in a calendar which is required for one revolution of the Earth around the Sun and approximated to an integral number of calendar days NOTE 1 A calendar year is often also referred to as year. NOTE 2 Unless otherwise specified the term designates in this International Standard a calendar year in the Gregorian calendar.". In the standard it also states that it "...does not cover dates and times where words are used in the representation and dates..." and specifies the extent of the definition of the Gregorian calendar (it doesn't have all elements of it). This is what allows Japanese/Thai Gregorian style to interact with the ISO. Japan by example, could express a date as "平成二十六年 2014-08-09" and the ISO would ignore the language portion and only use the Gregorian compatible. As a programmer I've learned you have to be careful because in rare instances a date will be expressed as Heisei 26-2014-08-90 or Jan 1 26(2014), which could be interpreted as 2014-26-01. The point is, there's no reason to be imprecise about it by bringing in issues of civil use. The standard is explicit as to what it does use so why not stay true to that? JMJimmy (talk) 03:35, 10 August 2014 (UTC)
- The Microsoft stuff is just different spellings of the month names and minor punctuation changes. That doesn't constitute a different calendar. As for the rest, a modified Gregorian calendar isn't the Gregorian calendar. When "Gregorian calendar" is written in an English language article, I think everyone has knows it isn't the Thai solar calendar. Jc3s5h (talk) 02:51, 10 August 2014 (UTC)
- The easiest way I can show you that there are multiple calendars is: Microsoft's calendar dll those are fairly minor differences, part of the need for the ISO in question, Thai solar calendar is a version of Gregorian as is the Japanese calendar that info can be found in the wiki article here: Gregorian_calendar#Present_situation JMJimmy (talk) 02:03, 10 August 2014 (UTC)
- I now see one, and only one, distinction between the Gregorian calendar for civil use and the ISO version of the Gregorian calendar. ISO 8601 insists that the first day of the calendar year is January 1. This is not a requirement of the Gregorian calendar, although our Gregorian calendar article indicates most European countries adopted January 1 as the beginning of the calendar year before, or at the same time as, adopting the Gregorian calendar. If such a distinction needs to be mentioned at all, I think it belongs in a footnote. Jc3s5h (talk) 00:48, 10 August 2014 (UTC)
I have made a change to the article to replace the incomprehensible sentence involving the signing of the treaty of the meter with a definition of the Gregorian calender taken right from the standard. Jc3s5h (talk) 04:02, 10 August 2014 (UTC)
- I rewrote the section. The definition you used included a note "In this International Standard the term Gregorian calendar is used to refer to the time scale described in 3.2.1. " establishing the distinct separation of the standard from the definition supplied for that part. I also restored much of the deleted information as it was important. I tried to re-word it in a clearer way as you were right, it was awkward and confusing. The portion regarding the date chosen for the reference point should probably be expanded further as it's a very important distinction. It established a reference point with no religious significance to any religion. Instead they chose one with a both a scientific significance and a standardization significance. This made it easier for non-Christian states/companies/people to adopt the standard. I remember reading the history somewhere but I'm not up to researching/properly citing it at the moment (too many projects on the go). Cheers. JMJimmy (talk) 06:47, 10 August 2014 (UTC)
oh... side note, info on Alternate Format is missing if you (or anyone) feels up to tackling that JMJimmy (talk) 06:52, 10 August 2014 (UTC)
"expresses the term Gregorian calendar ..."
I disagree with this wording (as at this version):
The standard expresses the term Gregorian calendar to mean a, possibly infinite, time scale of adjoining calendar years and having several additional properties.
I don't think "expresses" is the correct word. 8601 expresses specific dates (from the Gregorian calendar) and times, durations and intervals - eg search the standard for "express" for numerous examples of that usage of the word. But it does not "express the term Gregorian calendar to mean..." - that phrase just does not make any sense. 8601 simply uses the Gregorian calendar, or possibly "expresses dates from the Gregorian calendar". I propose that this would be better:
The standard uses the Gregorian calendar, which provides ...
or, possibly:
The standard expresses dates from the Gregorian calendar, which provides ...
The second half of the sentence (as it currently stands) is, to my mind, unnecessarily convoluted. The wording is clearly a re-arrangement of the standard's 3.2.1 (apparently to avoid copyright violation) - it would probably be better to simply quote the standard thus:
The standard uses the Gregorian calendar, which provides "a, potentially infinite, series of contiguous calendar years",[1] with several additional properties.
I think a direct attributed quote in this context is fair use, and doesn't violate WP:QUOTE. Because this is in the Dates section, "time scale" is not necessary here, so I've removed it to keep the quote short. However, if you think it really matters:
The standard uses the Gregorian calendar, which "provides a time scale consisting of a, potentially infinite, series of contiguous calendar years",[1] with several additional properties.
(I think the shorter version is sufficient.)
Mitch Ames (talk) 09:43, 10 August 2014 (UTC)
- Given what you said, I agree that "expresses" is the wrong term.
- "uses" is not appropriate as "Gregorian calendar" is not being used it's being defined for use.
- "expresses dates" or "expresses dates from" also changes the meaning to indicate that "Gregorian calendar" is representative of a formula to express dates or fails to attribute the defining characteristics to the Gregorian calendar term.
- "time scale" must be kept otherwise it's meaningless.
- My concern with direct quoting is that there is already a significant amount of it in the text which is both an issue of policy (also if it's "fair use" it should be on wikisource) and copyright. That's why I attempted, and think it's important, to reword/reorder where rewording was not possible to create unique text that does not lose the meaning of the original.
- The sentence, expanded or otherwise, is intended to include these elements: 1) The standard is defining a specific version of the term "Gregorian calendar" (not that it merely states*) 2) That the term "Gregorian calendar" is a time scale 3) The time scale could be infinite 4) The time scale is comprised of adjoining years (adjoining has much the same meaning as "series of contiguous") 5) The time scale has reference point 6) The years have 52-53 weeks 7) The years are continuous and sequential (this language is hard to avoid) 8) The years are comprised of 365 or 366 days 9) Each year contains 12 months 10) Each month individually has a number of days 11) Those days are detailed in the standard
- If expanded into something more verbose, the separation must not cause any attributes described in 1-10 to be lost, changed, or improperly attributed. It should also not cause any confusion between the term being defined and the traditional term. (*I avoided the use of "define" so that it would not be easily confused with the "definitions" section which defines the basic traditional meaning for the term) JMJimmy (talk) 12:03, 10 August 2014 (UTC)
- I found the word! Delineates - to portray in words; describe or outline with precision. I'm more excited about this than I should be as I'm a little delirious from insomnia. I made a full pass over it (not sure if that was the smartest thing to do in my state) that I think cleans up a number of the issues with it (not all I'm sure) JMJimmy (talk) 19:30, 10 August 2014 (UTC)
The ISO has no authority to define the Gregorian calendar. If they purport to, they're idiots and we should not say in Wikipedia that the standard defines the Gregorian calendar. What they could do is describe that/those version(s) of the Gregorian calendar that are representable with the notation they define in their standard. Jc3s5h (talk) 12:23, 10 August 2014 (UTC)
- They are defining it for the standard and the standard alone. It has no bearing no the civil use of the Gregorian calendar whatsoever. It's a common practice in standards. They take a term that has a common understanding of what something is, use elements that will allow popular adoption of the standard (often that are shared among similar concepts), this allows for the standardization. By defining the term or the elements of the term used in the standard they are preventing any external changes from affecting the internal workings of the standard. ie: if Gregorian is reformed, outside ISO's control, in order to fix some short coming and it was not separately defined in the 8601 standard they could have a huge mess to fix. That mess may require complete abandonment of the standard or conflicting interpretations which could lead to disasters. If it is separate then they can do a controlled update or transition (if desired) to incorporate the reforms. JMJimmy (talk) 12:44, 10 August 2014 (UTC)
I have many points of disagreement with the version that Mitch Ames objects to (as at this version):
- It's too long.
- "Calendar dates prior to 1875-05-20 are still compatible with the ISO back to 1582-10-15"? This is meaningless.
- "Dates prior to 1582-10-15 are accomplished by the use of the proleptic Gregorian calendar and should only be used by mutual agreement." This is an inaccurate description of the standard, caused by only looking at the page this is paraphrased from, and not the whole standard. Page 13 states that year "values in the range [0000] through [1582] shall only be used by mutual agreement of the partners in information interchange."
- "The propleptic reference point year is '0000', which has 366 days." The standard doesn't say that. It just says 0000 is a leap year. I have no idea what "proleptic reference point year" means.
- "While the standard does not expressly forbid the use of alternate calendars they should not be used for exchange purposes." The standard says over and over that it uses the Gregorian calendar. The standard also specifies those aspects that may be varied by mutual agreement, and the Gregorian calendar there is no mention of being allowed to change to a different calendar by mutual agreement. So the calendar does exclude non-Gregorain calendars, although it does not use the word "forbid".
- "Dates from alternate calendars, if first converted to Gregorian UTC for expression, can be formatted using the standard as exampled by the Jet Propulsion Laboratory." This whole statement is unnecessary; of course dates can be converted from other calendars to the Gregorian calendar (if enough information has been preserved about the other calendar). Obviously after the date is converted to Gregorian, it can be expressed in the ISO 8601 format. If an example of a website that expresses a Gregorian date in ISO 8601 format is needed, put it in "External links". Also, the phrase "Gregorian UTC" is not a customary English or technical phrase; it just rams together two words that address different concepts.
Jc3s5h (talk) 13:00, 10 August 2014 (UTC)
- Addressing points in relation to the order listed in above comment
- Length is very very short considering the full text it's summarizing is over 2 pages long.
- It is not meaningless, it's establishing that a) the reference point is not defining an epoch or era b) due to a the calculations remain the same, but only until 1582-10-15 which is also not an epoch or era but is the end of the time scale
- It is not inaccurate as it encompasses what you stated (0000 - 1582-10-15) but also considers section 3.5 which allows for dates before 0000. Regardless of range any date prior to 1582-10-15 must use the proleptic Gregorian calendar and be by agreement. This is established clearly in section 3.2.1
- proleptic - defined so in terms of the standard the time scale is from 1582-10-15 to possible infinity. Proleptic Gregorian calendar is therefore prior to 1582-10-15. Because it exists outside of the defined time scale it's a time scale in its own right. As a result it needs a fixed reference point otherwise you cannot calculate anything properly. You can't use the post 1582 reference point because dates where calculated differently. (they dropped 10 days when adopting Gregorian). Hence, the proleptic reference year is 0000 and all other dates in the time scale can be calculated from that reference point. As to the standard "just saying it's a leap year" - a leap year always has 366 days.
- Perhaps the wording can be changed here to be clearer. The intent is to establish that Gregorian incompatible calendars can be converted to Gregorian UTC and then expressed using the standards in Gregorian. It is NOT meant to indicate that Julian can be used directly with the ISO. Many have taken it to mean that other calendars are not allowed to be converted at all. To visualize it some think only this is allowed: "Gregorian → ← Gregorian". "Julian → ← Gregorian" is NEVER allowed. This is allowed: "Julian → Conversion to Gregorian UTC → Gregorian → ← Gregorian → Conversion to UTC → Julian" but only by agreement because, if the conversion is not accurate, it can cause problems. The JPL calculator does the latter example.
- Mostly addressed in previous comment. The "obvious" to you is not obvious to others, when someone who doesn't find it obvious reads "Julian calendar is incompatible with ISO 8061" they can it take to mean it can never be used in any way. Most wouldn't but someone who doesn't understand properly can make that leap and start to spread it. (like how wikihoaxes propogate) Regarding the "Gregorian UTC", this is not a "jamming together" of two words. UTC does not require the Gregorian calendar for input. 20140810 as Julian UTC would be 50430-07-14 12:00:00 where a Gregorian UTC would be 2014-08-10 00:00:00. As to the "example of Gregorian date as ISO", that's not what the demo does, it's Julian/UT/UT7. JMJimmy (talk) 15:31, 10 August 2014 (UTC)
- "Dates prior to 1582-10-15 are accomplished by the use of the proleptic Gregorian calendar and should only be used by mutual agreement" does reflect one page of the standard, but it is misleading because all years in the range 0000 to and including 1582 require mutual agreement, as explained in the "Years" section of the article. We shouldn't lay traps for readers by making statements that, in a hyper-technical sense, are true, but require careful perusal of the entire article to find important exceptions.
- I didn't follow at first, but I see what you're saying. Agreed and should be changed to reflect that. JMJimmy (talk) 18:50, 10 August 2014 (UTC)
- About the paragraph
As a result of the consecutive date requirements, usage of the Julian calendar and other incompatible calendars would be contrary to the standard. While the standard does not expressly forbid the use of alternate calendars they should not be used for exchange purposes. Dates from alternate calendars, if first converted to Gregorian UTC for expression, can be formatted using the standard as exampled by the Jet Propulsion Laboratory here.
- Apparently you are concerned some readers might think standard purports to banish all non-Gregorian calendars in all spheres of life. You seem to feel that to avoid that misperception, we need to explain that the restriction only means that it is wrong to simply rearrange "Isaac Newton was born 25 December 1642" to "Isaac Newton was born 1642-12-25" and assert that statement complies with ISO 8601. I thought it was obvious that the ISO was only proposing a notation for expressing Gregorian calendar dates, and that other notations for Gregorian calender dates, as well as other calendars, would continue in use in parallel with ISO 8601.
- Here's why, comments appear like this: "for the official standard that one must only use it for Gregorian calendar dates". Someone who does not know better could read that, think it means that excludes using other calendars, checks the wiki to see if it's true and be none the wiser. They wouldn't know that the person meant the post-calculated input and formatting. The person who stated that, was you. (I honestly did not seek out a comment from you, it just showed up when I googled "must be gregorian" "iso 8601") There are many examples of similar ambiguities just on wikipedia Wikipedia_talk:Manual_of_Style/Dates_and_numbers/Archive_144 Wikipedia_talk:Manual_of_Style_(dates_and_numbers)/Archive_D6#Non-Gregorian_calendars. I think it's prudent to make it clear, though I do agree that my wording is not ideal. JMJimmy (talk) 18:50, 10 August 2014 (UTC)
- The standard, in section 3.2.1, states "The use of this calendar for dates preceding the introduction of the Gregorian calendar (also called the proleptic Gregorian calendar) should only be by agreement of the partners in information interchange." So far as the standard is concerned, the proleptic Gregorian calender is just a subset of the Gregorian calendar. Since the standard only uses the Gregorian calendar, there is no discontinuity or change in calculation rules at 1582-10-15T00:00, nor is there any discontinuity or change in calculation rules at 0000-01-01T00:00. Jc3s5h (talk) 16:32, 10 August 2014 (UTC)
- I think we're both almost right on this one lol. You're right that it's sequential and the method of calculation change I stated (re: 10 days) is wrong, not quite sure where my head was at. That said, while it conforms to all the rules in 3.2.1, it is still a new "instance" of a Gregorian calendar and each instance must have a reference point within its time scale. JMJimmy (talk) 18:50, 10 August 2014 (UTC)
Jet Propulsion Laboratory link is a bad example
I propose that the the JPL example (the subject of these edits [1][2][3]) should be deleted - or replaced with a better example - because:
- The JPL Time Conversion Tool does not mention ISO 8601 at all
- None of the seven lines denoting date/time in Equivalent Times (or 13 instances if "=" separates two instances) comply with 8601, because "A.D." is not ISO-8601 compliant.
Even taking only parts of each line (and allowing the space delimiter instead of 8601's "T") for each time zone there are six representations, eg:
- A.D. 2014-Aug-11 11:52:41.00 = A.D. 2014-Aug-11.4949190
- A.D. 2014-08-11 11:52:41.00 = A.D. 2014-08-11.4949190
- A.D. 2014--223 11:52:41.00 = A.D. 2014--223.4949190
of which only one date and three times (in bold above) comply with 8601.
If we must say that "you can convert from other calendars to Gregorian and then represent with ISO 8601" (and I agree with Jc3s5h that this is unnecessary), we should provide an example that is clearly and explicitly ISO 8601 compliant. Mitch Ames (talk) 12:47, 11 August 2014 (UTC)
- That's true it does use multiple conversions and styles so it could be confusing. JMJimmy (talk) 14:36, 11 August 2014 (UTC)
- The paragraph containing the JPL example fails to bring out the central purpose of the standard. The standard is all about information interchange. It only applies at the moment information is interchanged from one partner to another (whether those partners be nineteen different mega-corporation, or two bits of software I wrote myself). It does not address how to do a calendar conversion (from, for example, an Arabic calendar or Unix time) nor it does it address how to convert the format from, for example, "this eleventh day of August in the Year of the Lord two thousand fourteen" to "2014-08-14". All is addresses is what the format must be at the moment the information is interchanged. The whole paragraph, if it is to be kept, needs to be rewritten. Jc3s5h (talk) 15:36, 11 August 2014 (UTC)
- It's not intended to bring out the purpose of the standard, it's intended to dispel a misunderstanding about the standard. JMJimmy (talk) 16:17, 11 August 2014 (UTC)
- The majority of editors commenting in the RFC say the paragraph is not needed. The misunderstanding has not been clearly stated. No reliable source has been cited to prove the misunderstanding exists. I'm therefore removing the paragraph. Jc3s5h (talk) 16:39, 11 August 2014 (UTC)
Strong objection to "Gregorian UTC"
At this moment the phrase "Gregorian UTC" does not appear in the article. Nevertheless, I need to express not only my strong objection to the phrase, but also the thought process that would lead anyone to write such a phrase. The standard may be used, if desired, to only express the calendar date without conveying the time of day. In such a case, UTC is irrelevant to the statement of data in ISO 8601 format. (How the person stating the date figured out the date, and whether that process involved UTC, is outside the scope of the standard.)
Also, the standard may be used to express the time and date in local time, without any statement, within the ISO 8601 formatted text, of how that local time relates to UTC. For example, we could rewrite a sentence from the article First Battle of Bull Run:
On 1861-07-21T02:30, McDowell sent the divisions of Hunter and Heintzelman (about 12,000 men) from Centreville, marching southwest on the Warrenton Turnpike and then turning northwest toward Sudley Springs.
This is a perfectly valid representation, even though the time is the local mean time of Manassas, Virginia, at a time when neither UTC nor time zones existed.
It is wrong to make any statement that a time must be in UTC, or convertible to UTC, in order to use the ISO 8601 format. Jc3s5h (talk) 17:02, 11 August 2014 (UTC)
- It is used it is also used as UTC (Gregorian) it's not common to express UTC as non-Gregorian, however, it is can be done. The terms are used by the likes of: Harvard Ohio State, Jet Propulsion Labratory. Here's an explanation from the ESA Space Trajectory Analysis software docs:
There are several possible formats to express time and date. Having a feature in the AM allowing the conversion between some of them, will allow not only the comparison of data with other sources, but also the adjustment to a particular user’s need. For this reason it was decided to provide time in the following formats: Gregorian UTC, Gregorian LCL, Julian UTC, Julian LCL, Time from Epoch (seconds, minutes, hours, or days), Mission Elapsed Time, YYDDD, Modified Julian Date (MJD), and Julian Date (JD) [9]. Since the time in STA is saved in the MJD format, all the necessary conversions should consider it as the starting point.
- While it's not specifically mentioned in the ISO, it's obviously important to be precise in the fact that, just because you have a UTC date, it does not mean that UTC date is in Gregorian. The same logic applies for ISO 8601 formatted dates - it cannot be assumed they refer to a Gregorian date - the links to the archives above discuss that extensively and that is why Wikipedia didn't adopt ISO8601. Please do not delete content that is under discussion when consensus has not been reached. Consensus was reached on the example and that has been removed. I strongly believe that this text is important for clarity and accuracy. (for clarity, I am not opposed to any sort of rewrite just opposed to it being removed/losing any accuracy) JMJimmy (talk) 20:58, 11 August 2014 (UTC)
False paragraph
The paragraph demanded by JMJimmy is false and I will point out the reasons sentence by sentence. Frist, the whole paragraph:
As a result of the consecutive date requirements, usage of the Julian calendar and other incompatible calendars would be contrary to the standard. While the standard does not expressly forbid conversion of incompatible calendars, such conversions must not be used for exchange purposes unless agreed to. If it is agreed to, the incompatible calendar should first converted to Gregorian UTC and formatted using the standard.
First sentence: "As a result of the consecutive date requirements, usage of the Julian calendar and other incompatible calendars would be contrary to the standard." For one thing, the consecutive date requirement is not the reason the Julian calendar or other incompatible calendars are contrary to the standard; they are contrary to the standard because the standard says to use only the Gregorian calendar (with the proleptic Gregorian calendar treated as a subset of the Gregorian calendar). Furthermore, if someone decided to ignore the Gregorian requirement and use the Julian calendar for both ancient and modern dates, there would be no violation of the consecutive date requirement.
Second sentence: "While the standard does not expressly forbid conversion of incompatible calendars, such conversions must not be used for exchange purposes unless agreed to." All the standard requires is that dates purported to obey the standard must be in the Gregorian calendar (as restricted within the standard) and written in the format specified in the standard. The standard does not require one information exchange partner to ask another information partner for permission to convert, for example, a Unix time to a Gregorian date before presenting it to the receiving information exchange partner.
Third sentence: "If it is agreed to, the incompatible calendar should first converted to Gregorian UTC and formatted using the standard." The phrase "If it is agreed to" is shown to be false in the discussion of the second sentence. "Converted to Gregorian UTC" is false because the standard does not require that days begin and end at midnight UTC, the standard does not require the use of UTC, and the standard does allow the use of local time without making any statement about how to convert that time to UTC time. Indeed, local time is allowed even if it is impossible to convert to UTC, such as events that occurred before UTC was established. Jc3s5h (talk) 21:03, 11 August 2014 (UTC)
Clauses or sections
The article currently uses both "clause" and "section" to denote numbered clauses/sections of the standard, but ideally we would use only the one term. I was of the view that ISO used the term "clause" in its standards - eg ISO/IEC 7816 does - but searching through 8601 I find no use of the term "clause" and two usages of "section" (in 4.4.3 and 4.4.5, but referring to other numberer sections).
Should replace "clause" with "section" in our article, where referring to sections of 8601? Mitch Ames (talk) 08:54, 10 August 2014 (UTC)
- Clause refers to a group of sections. Section refers to a specific section within a clause. ie: "Clause 4" is everything from 4 to 4.5.4. While section 4.2.4 applies to that specific point. JMJimmy (talk) 09:07, 10 August 2014 (UTC)
- fixed them all JMJimmy (talk) 09:14, 10 August 2014 (UTC)