[PATCH] tzdata: Asia/Ha_Noi: Add new timezone
Signed-off-by: Trần Ngọc Quân <vnwildman@gmail.com> --- asia | 20 ++++++++++++++++++++ zone.tab | 1 + 2 files changed, 21 insertions(+) diff --git a/asia b/asia index 0be896b..eb7787b 100644 --- a/asia +++ b/asia @@ -2769,6 +2769,26 @@ Zone Asia/Tashkent 4:37:11 - LMT 1924 May 2 # Vietnam +# From Trần Ngọc Quân (Fri, 03 Oct 2014): +# Hanoi is the capital of Vietnam. +# Currently, official timezone of Vietname is Ha_Noi, not Ho_Chi_Minh. +# References (most of them are in Vietnamese language): +# * http://en.wikipedia.org/wiki/Time_in_Vietnam +# * http://vi.wikipedia.org/wiki/M%C3%BAi_gi%E1%BB%9D +# * http://www.thoigian.com.vn/?mPage=P80D01 +# * [1] http://moj.gov.vn/vbpq/Lists/Vn%20bn%20php%20lut/View_Detail.aspx?ItemID=220... +# Zone NAME GMTOFF RULES FORMAT [UNTIL] +Zone Asia/Ha_Noi 7:06:40 - LMT 1906 Jun 9 + 7:06:20 - SMT 1911 Mar 11 0:01 # Saigon MT? + 7:00 - ICT 1942 Dec 31 23:00 + 8:00 - ICT 1945 Mar 14 23:00 + 9:00 - JST 1945 Sep 02 # Tokyo Standard Time + 7:00 - ICT 1947 Mar 31 23:00 + 8:00 - ICT 1954 Oct 09 23:00 + 7:00 - ICT 1967 Dec 31 23:00 + 7:00 - ICT 2002 Oct 14 # See [1] + 7:00 - ICT + # From Paul Eggert (2013-02-21): # Milne gives 7:16:56 for the meridian of Saigon in 1899, as being # used in Lower Laos, Cambodia, and Annam. But this is quite a ways diff --git a/zone.tab b/zone.tab index 084bb2f..cf87c19 100644 --- a/zone.tab +++ b/zone.tab @@ -428,6 +428,7 @@ VC +1309-06114 America/St_Vincent VE +1030-06656 America/Caracas VG +1827-06437 America/Tortola VI +1821-06456 America/St_Thomas +VN +1054+10600 Asia/Ha_Noi VN +1045+10640 Asia/Ho_Chi_Minh VU -1740+16825 Pacific/Efate WF -1318-17610 Pacific/Wallis -- 2.0.1.427.gc47372d
It doesn't matter what is the capital, or what the official time zone name happens to be - tz database zone names are derived from the name of the city with the biggest population in an area (often country) that uses the same time. For Vietnam, every reference I can find puts Ho Chi Minh City as being more populated than Ha Noi. Hence Ho_Chi_Minh is the name that is used. It is the same reason that we use Shanghai (not Beijing), and New_York (not Washington). Even if Ha Noi's population should overtake Ho Chi Minh City it would take a long time before we would change the name, now it has been selected - eg: For India we still use Kolkata, even though Mumbai and Delhi seem to have gone (way) past it in population count. Kolkata (when we called it Calcutta) was chosen, and remains... Unless you can show that Ha Noi and Ho Chi Minh City have not used the same local time for some period (a few minutes would be enough) since 1970 an additional zone won't be created for it either. (Differences before 1970 could just possibly be used, sometime in the future, so research into actyal time usage back into history is always useful - if backed by good references.) kre
On Fri, 03 Oct 2014, Robert Elz wrote:
Unless you can show that Ha Noi and Ho Chi Minh City have not used the same local time for some period (a few minutes would be enough) since 1970 an additional zone won't be created for it either. (Differences before 1970 could just possibly be used, sometime in the future, so research into actyal time usage back into history is always useful - if backed by good references.)
The Wikipedia page, <https://en.wikipedia.org/wiki/Time_in_Vietnam>, says that they were different. For example, from 1968 to 1975, North Vietnam (Hanoi) was on UTC+07:00, and from 1960 to 1975, South Vietnam (Saigon, or Ho Chi Minh City) was on UTC+08:00. --apb (Alan Barrett)
As it stands right now, the suggested new zone from Trần Ngọc Quân does not differ from Asia/Ho_Chi_Minh after 1970 and should not be added, per the Theory document, as Robert Elz alluded to. Whether a city is a capital or official legal basis for a time zone should not affect our nomenclature. On 3 October 2014 06:39, Alan Barrett <apb@cequrux.com> wrote:
The Wikipedia page, <https://en.wikipedia.org/wiki/Time_in_Vietnam>, says that they were different.
I would note that that page only had one author and does not cite any sources relevant to the data it presents. The second and fourth sources provided in the proposed patch (in Vietnamese) don't seem to support its data; however, the third reference provided, http://www.thoigian.com.vn/?mPage=P80D01, seems somewhat promising, although I don't think it provides nearly as much specificity as the proposed patch. For example, from 1968 to 1975, North Vietnam (Hanoi) was on UTC+07:00, and
from 1960 to 1975, South Vietnam (Saigon, or Ho Chi Minh City) was on UTC+08:00.
If this is true, then Asia/Ho_Chi_Minh needs to be updated, in which case a new zone for North Vietnam is *indeed* needed to accurately reflect the pre-unification differences. Per Theory, this zone would probably be called Asia/Hanoi as "Hanoi" is more common in English than "Ha Noi". -- Tim Parenti
Thank you for this new information. Since Hanoi and Ho Chi Minh City disagree for time stamps as late as 1975, we need to add a Zone for Hanoi. The real jewel here is the indirect reference to the authoritative source"Lịch Việt Nam: thế kỉ XX–XXI (1901–2100) & Niên Biểu Lịch Sử Việt Nam" (2014) <http://bookaholic.vn/lich-viet-nam-the-ki-xx-xxi-1901-2100-va-bien-bieu-lich...>. I'd like to verify the information from this source if possible. For example, if I'm reading the website correctly the 1906 transition was on July 1, not June 9, but I'd like to check that against the book. I have requested a copy of the book from my library; it has a 2005 edition, which should suffice for our needs. This underscores the unreliability of our old source Shanks. We already knew Shanks was wrong for large swaths of the world in the 20th century. Even so, it's surprisingly bad for a U.S. source like Shanks to get South Vietnam wrong in 1973. Wasn't Shanks reading the newspapers?
On 03/10/14 19:08, Paul Eggert wrote:
This underscores the unreliability of our old source Shanks. We already knew Shanks was wrong for large swaths of the world in the 20th century. Even so, it's surprisingly bad for a U.S. source like Shanks to get South Vietnam wrong in 1973. Wasn't Shanks reading the newspapers?
What it does demonstrate is that now we are getting more people involved, the better documented provenance is starting to be uncovered? -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk
On Oct 3, 2014, at 12:02 PM, Lester Caine <lester@lsces.co.uk> wrote:
On 03/10/14 19:08, Paul Eggert wrote:
This underscores the unreliability of our old source Shanks. We already knew Shanks was wrong for large swaths of the world in the 20th century. Even so, it's surprisingly bad for a U.S. source like Shanks to get South Vietnam wrong in 1973. Wasn't Shanks reading the newspapers?
What it does demonstrate is that now we are getting more people involved, the better documented provenance is starting to be uncovered?
...and that, as Paul has repeatedly said, much of the current historical data in the tz database is bogus.
On 03/10/14 20:41, Guy Harris wrote:
This underscores the unreliability of our old source Shanks. We already
knew Shanks was wrong for large swaths of the world in the 20th century. Even so, it's surprisingly bad for a U.S. source like Shanks to get South Vietnam wrong in 1973. Wasn't Shanks reading the newspapers?
What it does demonstrate is that now we are getting more people involved, the better documented provenance is starting to be uncovered? ...and that, as Paul has repeatedly said, much of the current historical data in the tz database is bogus.
I'd not disagree with that ... but hiding proven valid data away in backzone is not the way to improve the quality. There is as much uncorroborated data still in main database as has been ring fenced in backzone as suspect. If we spend time researching material only for it to be a lottery if it is included or not what is the point of bothering? -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk
On 04/10/2014 01:08, Paul Eggert wrote:
The real jewel here is the indirect reference to the authoritative source"Lịch Việt Nam: thế kỉ XX–XXI (1901–2100) & Niên Biểu Lịch Sử Việt Nam" (2014) <http://bookaholic.vn/lich-viet-nam-the-ki-xx-xxi-1901-2100-va-bien-bieu-lich...>. I'd like to verify the information from this source if possible. For example, if I'm reading the website correctly the 1906 transition was on July 1, not June 9, Yes, you right but I'd like to check that against the book. I have requested a copy of the book from my library; it has a 2005 edition, which should suffice for our needs.
You just compare date on this book with <http://www.thoigian.com.vn/?mPage=P80D01>. Unfortunately, the library near me don't have this book. "National Library of Vietnam" has three book of 2005 edition, but I'm not in Hanoi now. So you have to verify it by yourself. If every thing is OK, I will change both Hanoi and Ho Chi Minh city. If you can't read it, I will try to find people who can help us. -- Trần Ngọc Quân.
On 2014-10-03 19:25, Trần Ngọc Quân wrote:
On 04/10/2014 01:08, Paul Eggert wrote:
The real jewel here is the indirect reference to the authoritative source"Lịch Việt Nam: thế kỉ XX–XXI (1901–2100) & Niên Biểu Lịch Sử Việt Nam" (2014) <http://bookaholic.vn/lich-viet-nam-the-ki-xx-xxi-1901-2100-va-bien-bieu-lich...>. I'd like to verify the information from this source if possible. For example, if I'm reading the website correctly the 1906 transition was on July 1, not June 9, Yes, you right but I'd like to check that against the book. I have requested a copy of the book from my library; it has a 2005 edition, which should suffice for our needs.
You just compare date on this book with <http://www.thoigian.com.vn/?mPage=P80D01>. Unfortunately, the library near me don't have this book. "National Library of Vietnam" has three book of 2005 edition, but I'm not in Hanoi now. So you have to verify it by yourself. If every thing is OK, I will change both Hanoi and Ho Chi Minh city. If you can't read it, I will try to find people who can help us.
Rough facts in the linked passage via Google translate cleaned up (especially random month/day switches): On 01.07.1906 When completed construction Observatory Phu Lien, Indochina government decree dated 09.06.1906 (Official Gazette dated 18.06.1906 Indochina) fixed now legal for all countries of Indochina under the meridian passing through Phu Lien (104°17'17" east of Paris) from 0 hours on 01.07.1906. On 01.05.1911 After France signed the Treaty of international time zones, according to a decree dated 06.04.1911 (Indo Gazette on 13.4.1911-page 803) taken under the provisions of the new time zone 7 hours (from meridian line passing through Greenwich) for all countries of Indochina starting at 0 hours on 1.5.1911. On 01.01.1943 The French government issued a decree dated 23.12.1942 (Official Gazette dated 30.12.1942 Indochina) link Indochina in 8 time zone and the clock is so advanced by 60 minutes at 23 hours on 31.12.1942. On 14.03.1945 On 09.03.1945 Japanese invaded and forced French Indochina to the time zone of Tokyo (Japan) ie ninth time zone so time officially was advanced quickly on again 1 hour at 23 hours on 14.03.1945 . On 02.09.1945 After the August Revolution Provisional Government of Vietnam Democratic Republic claims made 7 hour time zone official (Ordinance No. year / SL of the Ministry of Internal Affairs). On 01.04.1947 According to the decree dated 28.3.1947 of the colonial government (Official Gazette dated 14.10.1947 Indochina), then in the occupied areas in Vietnam, Laos and Cambodia is now officially eighth time zone from date 1.4.1947. But in the liberated areas remains seventh time zone and after the Geneva Agreement for liberated areas in the north also time zone 7 (Hanoi and Hai Phong from the end of months 10.1954 5.1955); Laos separately return to seventh time zone on 15.4.1955. On 01.07.1955 South Vietnam back to seventh time zone from 0 hours on 01.07.1955. On 01.01.1960 Saigon government decree dated 30.12.1959 No. 362-TTP rules now official time zone South Vietnam is eighth, promptly advancing the clock by 1 hour from 23hours night of 31.12.1959 (ie, 0 hours on 1.1.1960) On 31.12.1967 The Government of the Democratic Republic of Vietnam in Decision 121 / CP dated 8.8.1967 confirmed the country's official time is seventh time zone from 0 hours on 1.1.1968. On 13.06.1975 After the South was completely liberated, the provisional revolutionary government issued a formal decision and went back to the seventh hour time zone in Saigon returning again to 1 hour later. (According Calendar Vietnam XX-XXI century, author Master Tran Tien Binh, state board schedule) -- Take care. Thanks, Brian Inglis
Brian Inglis wrote:
On 01.07.1906 When completed construction Observatory Phu Lien, Indochina government decree dated 09.06.1906 (Official Gazette dated 18.06.1906 Indochina) fixed now legal for all countries of Indochina under the meridian passing through Phu Lien (104°17'17" east of Paris) from 0 hours on 01.07.1906.
Yes, thanks, I'm working my way through that web page. For that paragraph, I assume "east of Paris" means east of Paris Mean Time, which was legally 00:09:21 east of Greenwich, and since 104°17′17″ works out to 06:57:09.1333..., that would make Phù Liễn Mean Time legally 07:06:30.1333.... An alternate interpretation would be that it refers to François Arago's definition of the Paris Meridian; in that case Phù Liễn Mean Time would be the temporal equivalent of 2°20′14.03″ + 104°17′17″ east, which would be 07:06:29.33333.... Luckily both values round to 07:06:30, so we can use this rounded value under either interpretation. By the way, if Google Maps and <http://kml.inovmapping.com/Ph-Lin-Observatory> are to believed the observatory is a bit east of both values, at roughly 07:06:31; but perhaps they moved the observatory since 1906, and anyway the legal definition is close enough. I assume the abbreviation should be PLMT for Phù Liễn Mean Time.
Attached are two patches which are a WIP "starting point" for this change. Obviously, we need to check the rest of the dates more thoroughly and include translated commentary where necessary, and so they will certainly still need some further iteration. There are still a few things that bother me about this. Specifically, ICT referring to different UT offsets for several periods. Perhaps, prior to reunification, NICT and SICT should be used for "North/South Indochina Time"? In any case, I think this WIP patchset gets us closer to where we'll ultimately be headed with this change. These patches are on my 2014-10-vietnam-wip-1 branch on Github and can be reviewed in the browser at https://github.com/timparenti/tz-experimental/compare/eggert:master...timpar... -- Tim Parenti On 4 Oct 2014 14:09, Paul Eggert wrote:
Brian Inglis wrote:
On 01.07.1906 When completed construction Observatory Phu Lien, Indochina government decree dated 09.06.1906 (Official Gazette dated 18.06.1906 Indochina) fixed now legal for all countries of Indochina under the meridian passing through Phu Lien (104°17'17" east of Paris) from 0 hours on 01.07.1906.
Yes, thanks, I'm working my way through that web page. For that paragraph, I assume "east of Paris" means east of Paris Mean Time, which was legally 00:09:21 east of Greenwich, and since 104°17′17″ works out to 06:57:09.1333..., that would make Phù Liễn Mean Time legally 07:06:30.1333.... An alternate interpretation would be that it refers to François Arago's definition of the Paris Meridian; in that case Phù Liễn Mean Time would be the temporal equivalent of 2°20′14.03″ + 104°17′17″ east, which would be 07:06:29.33333.... Luckily both values round to 07:06:30, so we can use this rounded value under either interpretation.
By the way, if Google Maps and <http://kml.inovmapping.com/Ph-Lin-Observatory> are to believed the observatory is a bit east of both values, at roughly 07:06:31; but perhaps they moved the observatory since 1906, and anyway the legal definition is close enough.
I assume the abbreviation should be PLMT for Phù Liễn Mean Time.
Tim Parenti wrote:
... ICT referring to different UT offsets for several periods. Perhaps, prior to reunification, NICT and SICT should be used for "North/South Indochina Time"?
It wasn't North vs South. The new data say that French Indochina mostly used UT+7, but sometimes all of French Indochina used UT+8, sometimes just South Vietnam, sometimes more of a hodgepodge. I had independently run into this problem and thought of using the abbreviation "IDT" (short for InDochina Time) for UT+8 in Indochina to help clear this up. There's a bigger problem, though. The new data also tell us that our entries for Laos and Cambodia are almost entirely bogus. We already knew that, and I had slated them for 'backzone' anyway, so now's a good time to do that. As a corollary, although we clearly need to fix Asia/Ho_Chi_Minh, we don't need a separate Zone for Asia/Hanoi as it is identical to Asia/Bangkok since 1970. This will give us a simpler fix and an easier-to-maintain result. A proposed pair of patches is attached. The first moves the bogus data for Cambodia and Laos to 'backzone'. The second fixes Asia/Ho_Chi_Minh and adds a line to zone1970.tab so that users in Vietnam now have two choices, one for each half of the country.
On 05/10/2014 07:32, Paul Eggert wrote:
Tim Parenti wrote:
... ICT referring to different UT offsets for several periods. Perhaps, prior to reunification, NICT and SICT should be used for "North/South Indochina Time"?
It wasn't North vs South. The new data say that French Indochina mostly used UT+7, but sometimes all of French Indochina used UT+8, sometimes just South Vietnam, sometimes more of a hodgepodge. I had independently run into this problem and thought of using the abbreviation "IDT" (short for InDochina Time) for UT+8 in Indochina to help clear this up. I agree with you.
There's a bigger problem, though. The new data also tell us that our entries for Laos and Cambodia are almost entirely bogus. We already knew that, and I had slated them for 'backzone' anyway, so now's a good time to do that. As a corollary, although we clearly need to fix Asia/Ho_Chi_Minh, we don't need a separate Zone for Asia/Hanoi as it is identical to Asia/Bangkok since 1970. This will give us a simpler fix and an easier-to-maintain result.
A proposed pair of patches is attached. The first moves the bogus data for Cambodia and Laos to 'backzone'. The second fixes Asia/Ho_Chi_Minh and adds a line to zone1970.tab so that users in Vietnam now have two choices, one for each half of the country.
About second patch: +Zone Asia/Ho_Chi_Minh 7:06:40 - LMT 1906 Jul 1 + 7:06:30 - PLMT 1911 May 1 + 7:00 - ICT 1942 Dec 31 23:00 + 8:00 - IDT 1945 Mar 14 23:00 + 9:00 - JST 1945 Sep 2 + 7:00 - ICT 1947 Apr 1 + 8:00 - IDT 1955 Jul 1 + 7:00 - ICT 1959 Dec 31 23:00 + 8:00 - IDT 1975 Jun 13 7:00 - ICT This is Hanoi, not Ho Chi Minh City. I find an other book about this topic: Name: Lịch âm dương Việt Nam 1900-2010 Author: Nguyễn Văn Chung Publisher: Nhà xuất bản văn hóa dân tộc Edition: 2001 - It confirms the date `1906 Jul 1'. So I think this date is correct. - It said Phù Liễn is 104°17’17” East. But I think `east of Paris' is correct. In Google map, it is: 20°47'05.1"N+106°38'22.0"E Unfortunately, It don't show any other information that we need. Some photos about Phù Liễn: * <http://www.panoramio.com/photo/22547402> * <http://www.panoramio.com/photo/57154621> -- Trần Ngọc Quân.
Trần Ngọc Quân wrote:
I find an other book about this topic:
Yes, there are a lot of books on Vietnamese dates and times! All in Vietnamese, unfortunately for me. The book by Trần Ngọc Quân appears to be one of the most authoritative. Dershowitz and Reingold cites its 2005 edition in their book Calendrical Calculations (3rd ed.) <http://emr.cs.iit.edu/home/reingold/calendar-book/third-edition/>. They also cite the 2000 edition of a calendrical book by L T Lân and personal communications from Hồ Ngọc Đức -- none of which agree exactly, unfortunately.
This is Hanoi, not Ho Chi Minh City.
We need to correct the Asia/Ho_Chi_Minh entry regardless of what we do about Hanoi, and that is what the patch does. As I pointed out in my most recent email, it appears to be unnecessary to add an entry for Hanoi, since Hanoi does not have a unique time zone history since 1970. In contrast, Ho Chi Minh City (now that its data are corrected) does have a unique time zone history since 1970 and therefore needs a distinct Zone. I had planned to replace the Ho Chi Minh City zone with a link on the grounds that it was redundant, but this new information means we need to keep it.
On 05/10/2014 10:22, Paul Eggert wrote:
Trần Ngọc Quân wrote:
I find an other book about this topic:
Yes, there are a lot of books on Vietnamese dates and times! All in Vietnamese, unfortunately for me. The book by Trần Ngọc Quân appears to be one of the most authoritative. Dershowitz and Reingold cites its 2005 edition in their book Calendrical Calculations (3rd ed.) <http://emr.cs.iit.edu/home/reingold/calendar-book/third-edition/>. They also cite the 2000 edition of a calendrical book by L T Lân Dr. Lê thành Lân I find his email, but it I'm not sure he still use it. But I will try to contact. lethanhlan@yahoo.de <mailto:lethanhlan@yahoo.de> and personal communications from Hồ Ngọc Đức -- none of which agree exactly, unfortunately. I will try to contact Hồ Ngọc Đức.
This is Hanoi, not Ho Chi Minh City.
We need to correct the Asia/Ho_Chi_Minh entry regardless of what we do about Hanoi, and that is what the patch does. As I pointed out in my most recent email, it appears to be unnecessary to add an entry for Hanoi, since Hanoi does not have a unique time zone history since 1970. In contrast, Ho Chi Minh City (now that its data are corrected) does have a unique time zone history since 1970 and therefore needs a distinct Zone.
I had planned to replace the Ho Chi Minh City zone with a link on the grounds that it was redundant, but this new information means we need to keep it. I find other document about time zone in Vietnam (an archive on website). Note: date format is dd/mm/yyyy. It is translated by google with some fix:
Previously,withthenationalstageorapart ofthe countryusingdifferent time zones: - From01/01/1943:Vietnamaccording toGMT +8(1hourearlierthannormal). -From01/04/1945:VietnamGMT+9,2 hoursearlierthanstandard time. -From01/04/1947,theFrench colonialistsoccupiedGMT+8. -In the South,from01/07/1955accordingto GMT+7.To01/01/1960,thetime zoneofsouthernGMT+8. -In the north,according toDecision No.121/CPsigned on08/08/1967byCouncil ofGovernment,from08/08/1967accordingto GMT+7. -From02/08/1976,the countrystandardtime zoneGMT+7. We seem have to find more document for both Vietnam and Lao, Cambodia. I hope I reply soon. -- Trần Ngọc Quân.
Hello Paul Eggert,
On 05/10/2014 10:22, Paul Eggert wrote:
Trần Ngọc Quân wrote: Dr. Lê thành Lân I find his email, but it I'm not sure he still use it. But I will try to contact. lethanhlan@yahoo.de <mailto:lethanhlan@yahoo.de> I will try to contact Hồ Ngọc Đức. Unfortunately, I can't contact both of them. We need to correct the Asia/Ho_Chi_Minh entry regardless of what we do about Hanoi, and that is what the patch does. Of cause, Asia/Ho_Chi_Minh properly need to fix. As I pointed out in my most recent email, it appears to be unnecessary to add an entry for Hanoi, since Hanoi does not have a unique time zone history since 1970. In contrast, Ho Chi Minh City (now that its data are corrected) does have a unique time zone history since 1970 and therefore needs a distinct Zone. Wiki [1] point out Hanoi and Ho Chi Minh timezone diff from 1970 - 1975: Hanoi used GMT +7 while Ho Chi Minh used GMT +8. So I sure timezone in Hanoi is unique. You decide add or not by yourself. I read carefully both [1] and [2]. They are the same content. I think they are the best document. So you can use [1].
Paul Eggert, please make new patch. I will review. About Cambodia and Lao, I recommend remove them. They can use Asia/Bangkok instead. Unique timezone for them will create when we have enough document. [1] http://en.wikipedia.org/wiki/Time_in_Vietnam [2] http://www.thoigian.com.vn/?mPage=P80D01 -- Trần Ngọc Quân.
Trần Ngọc Quân wrote:
About Cambodia and Lao, I recommend remove them. They can use Asia/Bangkok instead.
As can north Vietnam, which was the point of the 2nd patch in: http://mm.icann.org/pipermail/tz/2014-October/021669.html See its two lines with the string "VN". With the patch installed, you can run the command "tzselect" to see these two lines in action.
Even though we believe that north Vietnam can be handled by Asia/Bangkok, given this new source of reliable historical data, shouldn't we put that somewhere, e.g. in backzone? We should keep these data around in case we discover changes to one of the other merged zones that means the assumptions under which they were merged is no longer accurate. I realize that including this as an actual Zone in backzone would chip away a bit at the firmness of the 1970 cutoff, and there has already been much debate over whether or not that would be a Good Thing, which I do not wish to rehash. But I feel that having a second-class area like backzone makes loosening this cutoff a bit more necessary in cases like this, so that good data like these can be preserved in case we need them again, whether within our current scope or the scope this project takes on in the future. So maybe we should keep this "extra" information about north Vietnam in comments? -- Tim Parenti On 10 October 2014 00:12, Paul Eggert <eggert@cs.ucla.edu> wrote:
Trần Ngọc Quân wrote:
About Cambodia and Lao, I recommend remove them. They can use
Asia/Bangkok instead.
As can north Vietnam, which was the point of the 2nd patch in:
http://mm.icann.org/pipermail/tz/2014-October/021669.html
See its two lines with the string "VN". With the patch installed, you can run the command "tzselect" to see these two lines in action.
Copied to tzdist list as I feel this starts to fill in the gaps! On 11/10/14 06:46, Tim Parenti wrote:
I realize that including this as an actual Zone in backzone would chip away a bit at the firmness of the 1970 cutoff, and there has already been much debate over whether or not that would be a Good Thing, which I do not wish to rehash. But I feel that having a second-class area like backzone makes loosening this cutoff a bit more necessary in cases like this, so that good data like these can be preserved in case we need them again, whether within our current scope or the scope this project takes on in the future.
That the 'second class' area has 'first class' material simply because the date of change pre-dates 1970 is the whole problem. There is substantial pre-1970 data in the 'first class' area but no indication if that actually applies to the linked aliases! The discussion on the tzdist list is about 'truncation' and I've only just realised that it is just for every alias that the TZ data is only valid from 1970. Of cause the 'primary' set of data is perfectly valid back to it's start date. Personally I feel where a current alias has got first class data back to an earlier time then it should always be included in the base set. Since in most cases it IS just an extra start rule prior to another generic data set then there is little extra data. Where it becomes a problem is when the data set for an ID is always fully expanded such as on the tzdist current protocol. 'Secondary' ID's which just have a small data set prior to a more generic one post some later date are the problem. In many cases it is the start of 'DST' which forms a smaller set of 'variable' data and around 2/3rds of ID's never hit that point. I was originally looking for a flag between LMT and the start of a timezone, but the real point here is using the 'common' event time as the end marker of 'aliases' so that the handling of say Europe/UK/Oxford would have fine detail prior to Europe/UK and in this case Europe/UK/London is the 'master' for Europe/UK. Europe/Isle_of_Man/Castle_Rushen then folds down to Europe/Isle_of_Man which picks up Europe/UK at the start of DST changes rather than the start of London/GMT or 1970, both of which are wrong. It *IS* the use of an arbitrary location to identify a set of timezone data which is the whole problem of making this scale well back in time? A 'DST' data set SHOULD be a region rather than a location and a location simply has a date on which they started using that data set. In tzdist the conversion of an alias to a set of data actually needs to be a two stage process of which only the second stage is currently being developed. The TZID for Europe/London provides a set of timezone data which is accurate from 1916 and while not fully verified, all other UK locations adopted that and used that from 1916. (There are some gaps in later provenance on DST changes). Prior to 1916 there are a number of other common points such as the adoption on GMT in different areas culminating in the eventual standardisation by around 1884. Some locations like counties in Idaho are a list of changes between two of the 5 American main data sets. Most locations are a lot easier, either only having a single date for the start of the international GMT adoption, or perhaps two or three dates with a local pre GMT standard followed by the GMT change all well before 1970. 'GMT' is essentially just a fixed set of 24 offsets which is all that the large majority of locations reference and which is fine tuned by UTC in 1972, so stage one is to identify the history for a location, which can be simple if all one is interested in is post 1970 or so. This will either just give a fixed offset, or identify a dataset to use. Where I don't think the current tzdist model scales is where a large number of historic ID's only vary by a single start date. The system does not need to duplicate all the following data. -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk
On 12/10/2014 01:58, Paul Eggert wrote:
Tim Parenti wrote:
given this new source of reliable historical data, shouldn't we put that somewhere, e.g. in backzone?
Sure, why not? Proposed patch attached. There is an incorrect date here. Please see below:
$ git diff diff --git a/backzone b/backzone index 70a526f..44f010c 100644 --- a/backzone +++ b/backzone @@ -333,7 +333,7 @@ Link Asia/Chongqing Asia/Chungking # Vietnam # From Paul Eggert (2014-10-11): # See Asia/Ho_Chi_Minh for the source for this data. -# Trần's book is quoting as saying the 1954-55 transition to 07:00 +# Trần's book is quoting as saying the 1954-1955 transition to 07:00 # was at the end of October 1954 in Hanoi. Zone Asia/Hanoi 7:03:24 - LMT 1906 Jul 1 7:06:30 - PLMT 1911 May 1 @@ -341,7 +341,7 @@ Zone Asia/Hanoi 7:03:24 - LMT 1906 Jul 1 8:00 - IDT 1945 Mar 14 23:00 9:00 - JST 1945 Sep 2 7:00 - ICT 1947 Apr 1 - 8:00 - IDT 1954 Nov 1 + 8:00 - IDT 1954 Nov 10 7:00 - ICT # China -- Trần Ngọc Quân.
Trần Ngọc Quân wrote:
- 8:00 - IDT 1954 Nov 1 + 8:00 - IDT 1954 Nov 10
Thanks, but where did the "10" come from? Is there a source that we can cite? The cited web page <http://www.thoigian.com.vn/?mPage=P80D01> says this: "Ngày 1/4/1947. Theo nghị định ngày 28/3/1947 của chính quyền thực dân (Công báo Đông Dương ngày 14/10/1947) thì trong các vùng bị tạm chiếm ở Việt Nam, ở Lào và Campuchia giờ chính thức là múi giờ 8 kể từ ngày 1/4/1947. Tuy nhiên trong các vùng giải phóng vẫn giữ múi giờ 7 và sau Hiệp định giơnevơ các vùng giải phóng ở miền bắc cũng theo múi giờ 7 (Hà nội từ 10/1954 và Hải phòng cuối tháng 5/1955); riêng Lào trở lại múi giờ 7 vào ngày 15/4/1955." I don't read Vietnamese, but I've read Brian Inglis's translation <http://mm.icann.org/pipermail/tz/2014-October/021654.html>, and if I understand it correctly the parenthesized text can be translated as "Hanoi from the end of October 1954 and Haiphong from the end of May 1955", which would mean a transition from UT+8 to UT+7 at 1954-10-31 24:00 or (equivalently) at 1954-11-01 00:00. Perhaps the translation is incorrect, or perhaps I'm reading it incorrectly, but I'd like to know the details.
On 2014-10-12 09:16, Paul Eggert wrote:
Trần Ngọc Quân wrote:
- 8:00 - IDT 1954 Nov 1 + 8:00 - IDT 1954 Nov 10
Thanks, but where did the "10" come from? Is there a source that we can cite? The cited web page <http://www.thoigian.com.vn/?mPage=P80D01> says this:
"Ngày 1/4/1947. Theo nghị định ngày 28/3/1947 của chính quyền thực dân (Công báo Đông Dương ngày 14/10/1947) thì trong các vùng bị tạm chiếm ở Việt Nam, ở Lào và Campuchia giờ chính thức là múi giờ 8 kể từ ngày 1/4/1947. Tuy nhiên trong các vùng giải phóng vẫn giữ múi giờ 7 và sau Hiệp định giơnevơ các vùng giải phóng ở miền bắc cũng theo múi giờ 7 (Hà nội từ 10/1954 và Hải phòng cuối tháng 5/1955); riêng Lào trở lại múi giờ 7 vào ngày 15/4/1955."
I don't read Vietnamese, but I've read Brian Inglis's translation <http://mm.icann.org/pipermail/tz/2014-October/021654.html>, and if I understand it correctly the parenthesized text can be translated as "Hanoi from the end of October 1954 and Haiphong from the end of May 1955", which would mean a transition from UT+8 to UT+7 at 1954-10-31 24:00 or (equivalently) at 1954-11-01 00:00. Perhaps the translation is incorrect, or perhaps I'm reading it incorrectly, but I'd like to know the details.
Perhaps confusion of the OP by the tzdata use of the English month 11 abbreviation Nov for November, in representing "the end of the month of 10/1954" i.e 31.10.1954 24.00 as the equivalent 01.11.1954 00.00. -- Take care. Thanks, Brian Inglis
On 12/10/2014 22:16, Paul Eggert wrote:
Trần Ngọc Quân wrote:
- 8:00 - IDT 1954 Nov 1 + 8:00 - IDT 1954 Nov 10
Thanks, but where did the "10" come from? "1954 Nov 10" is the day that "Government of the Democratic Republic of Vietnam" returned Hanoi. Is there a source that we can cite? The cited web page <http://www.thoigian.com.vn/?mPage=P80D01> says this:
"Ngày 1/4/1947. Theo nghị định ngày 28/3/1947 của chính quyền thực dân (Công báo Đông Dương ngày 14/10/1947) thì trong các vùng bị tạm chiếm ở Việt Nam, ở Lào và Campuchia giờ chính thức là múi giờ 8 kể từ ngày 1/4/1947. Tuy nhiên trong các vùng giải phóng vẫn giữ múi giờ 7 và sau Hiệp định giơnevơ các vùng giải phóng ở miền bắc cũng theo múi giờ 7 (Hà nội từ 10/1954 và Hải phòng cuối tháng 5/1955); riêng Lào trở lại múi giờ 7 vào ngày 15/4/1955."
"Hanoi from the end of October 1954 and Haiphong from the end of May 1955", Yes, It don't specify day. Must translate "since" or "from begin of" not "from the end of". I've contacted Dr. Lân yesterday. And I will confirm all information with him. Thanks,
-- Trần Ngọc Quân.
On 2014-10-12 18:29, Trần Ngọc Quân wrote:
On 12/10/2014 22:16, Paul Eggert wrote:
Trần Ngọc Quân wrote:
- 8:00 - IDT 1954 Nov 1 + 8:00 - IDT 1954 Nov 10
Thanks, but where did the "10" come from? "1954 Nov 10" is the day that "Government of the Democratic Republic of Vietnam" returned Hanoi. Is there a source that we can cite? The cited web page <http://www.thoigian.com.vn/?mPage=P80D01> says this:
"Ngày 1/4/1947. Theo nghị định ngày 28/3/1947 của chính quyền thực dân (Công báo Đông Dương ngày 14/10/1947) thì trong các vùng bị tạm chiếm ở Việt Nam, ở Lào và Campuchia giờ chính thức là múi giờ 8 kể từ ngày 1/4/1947. Tuy nhiên trong các vùng giải phóng vẫn giữ múi giờ 7 và sau Hiệp định giơnevơ các vùng giải phóng ở miền bắc cũng theo múi giờ 7 (Hà nội từ 10/1954 và Hải phòng cuối tháng 5/1955); riêng Lào trở lại múi giờ 7 vào ngày 15/4/1955."
"Hanoi from the end of October 1954 and Haiphong from the end of May 1955", Yes, It don't specify day. Must translate "since" or "from begin of" not "from the end of". I've contacted Dr. Lân yesterday. And I will confirm all information with him.
The translation would need to be: (Hanoi after 10/1954 and Hai Phong from the end of the month 5/1955.) but would that not require "sau" (after), rather than "từ" (from or "since"), or else "từ đầu" ("from the beginning of" or 'from the start of'), which would exclude 10.11.1954 (10 November 1954). -- Take care. Thanks, Brian Inglis
On 13/10/2014 11:21, Brian Inglis wrote:
On 2014-10-12 18:29, Trần Ngọc Quân wrote:
On 12/10/2014 22:16, Paul Eggert wrote:
Trần Ngọc Quân wrote:
- 8:00 - IDT 1954 Nov 1 + 8:00 - IDT 1954 Nov 10
Thanks, but where did the "10" come from? "1954 Nov 10" is the day that "Government of the Democratic Republic of Vietnam" returned Hanoi. Is there a source that we can cite? The cited web page <http://www.thoigian.com.vn/?mPage=P80D01> says this:
"Ngày 1/4/1947. Theo nghị định ngày 28/3/1947 của chính quyền thực dân (Công báo Đông Dương ngày 14/10/1947) thì trong các vùng bị tạm chiếm ở Việt Nam, ở Lào và Campuchia giờ chính thức là múi giờ 8 kể từ ngày 1/4/1947. Tuy nhiên trong các vùng giải phóng vẫn giữ múi giờ 7 và sau Hiệp định giơnevơ các vùng giải phóng ở miền bắc cũng theo múi giờ 7 (Hà nội từ 10/1954 và Hải phòng cuối tháng 5/1955); riêng Lào trở lại múi giờ 7 vào ngày 15/4/1955."
"Hanoi from the end of October 1954 and Haiphong from the end of May 1955", Yes, It don't specify day. Must translate "since" or "from begin of" not "from the end of". I've contacted Dr. Lân yesterday. And I will confirm all information with him.
The translation would need to be: (Hanoi after 10/1954 and Hai Phong from the end of the month 5/1955.) but would that not require "sau" (after), rather than "từ" (from or "since"), or else "từ đầu" ("from the beginning of" or 'from the start of'), which would exclude 10.11.1954 (10 November 1954). Not "after", You translate Hai Phong ok From origin document, It mean "Hanoi apply GMT +7 since October 1954" (Maybe 1st of October 1954, or one of day of this month). About 10 or 11, I will confirm later. And also need to verify 2nd or 3th of September 1945. I have a question: # Zone NAME GMTOFF RULES FORMAT [UNTIL] So if time not specify, like: 8:00 - IDT 1954 Nov 10 So IDT timezone end in 23:59 1954 Nov 10 or end of the previous day (9)? I read zic(1), and think it mean 1954 Nov 10 00:01? Is it true?
-- Trần Ngọc Quân.
On 2014-10-13 01:16, Trần Ngọc Quân wrote:
On 13/10/2014 11:21, Brian Inglis wrote:
On 2014-10-12 18:29, Trần Ngọc Quân wrote:
On 12/10/2014 22:16, Paul Eggert wrote:
Trần Ngọc Quân wrote:
- 8:00 - IDT 1954 Nov 1 + 8:00 - IDT 1954 Nov 10
Thanks, but where did the "10" come from? "1954 Nov 10" is the day that "Government of the Democratic Republic of Vietnam" returned Hanoi. Is there a source that we can cite? The cited web page <http://www.thoigian.com.vn/?mPage=P80D01> says this:
"Ngày 1/4/1947. Theo nghị định ngày 28/3/1947 của chính quyền thực dân (Công báo Đông Dương ngày 14/10/1947) thì trong các vùng bị tạm chiếm ở Việt Nam, ở Lào và Campuchia giờ chính thức là múi giờ 8 kể từ ngày 1/4/1947. Tuy nhiên trong các vùng giải phóng vẫn giữ múi giờ 7 và sau Hiệp định giơnevơ các vùng giải phóng ở miền bắc cũng theo múi giờ 7 (Hà nội từ 10/1954 và Hải phòng cuối tháng 5/1955); riêng Lào trở lại múi giờ 7 vào ngày 15/4/1955."
"Hanoi from the end of October 1954 and Haiphong from the end of May 1955", Yes, It don't specify day. Must translate "since" or "from begin of" not "from the end of". I've contacted Dr. Lân yesterday. And I will confirm all information with him.
The translation would need to be: (Hanoi after 10/1954 and Hai Phong from the end of the month 5/1955.) but would that not require "sau" (after), rather than "từ" (from or "since"), or else "từ đầu" ("from the beginning of" or 'from the start of'), which would exclude 10.11.1954 (10 November 1954). Not "after", You translate Hai Phong ok From origin document, It mean "Hanoi apply GMT +7 since October 1954" (Maybe 1st of October 1954, or one of day of this month). About 10 or 11, I will confirm later. And also need to verify 2nd or 3th of September 1945. I have a question: # Zone NAME GMTOFF RULES FORMAT [UNTIL] So if time not specify, like: 8:00 - IDT 1954 Nov 10 So IDT timezone end in 23:59 1954 Nov 10 or end of the previous day (9)? I read zic(1), and think it mean 1954 Nov 10 00:01? Is it true?
If it was "one day of this month" then that would imply some date in October 1954, and exclude 10th November 1954. In original rule 1954-10-31 24:00:00 local time == 1954-11-01 00:00:00 local time; in revised rule 1954-11-09 24:00:00 local time == 1954-11-10 00:00:00 local time. -- Take care. Thanks, Brian Inglis
On 13 October 2014 10:56, Brian Inglis <Brian.Inglis@systematicsw.ab.ca> wrote:
If it was "one day of this month" then that would imply some date in October 1954, and exclude 10th November 1954.
The way I'm reading the translations that have been going around, it seems Hanoi had UT+7 since *some time* in October 1954, so the only thing we know somewhat definitively is that it at least happened before the start of 1 November 1954. I think the current rule reflects that, but lacking other sources, perhaps the uncertainty should be noted. -- Tim Parenti
Trần Ngọc Quân wrote:
So if time not specify, like: 8:00 - IDT 1954 Nov 10 So IDT timezone end in 23:59 1954 Nov 10 or end of the previous day (9)? I read zic(1), and think it mean 1954 Nov 10 00:01?
Omitted times default to 00:00:00. The style is to specify the time as 00:00 if the time is known to be 00:00, and to omit the time if it's not known.
participants (8)
-
Alan Barrett -
Brian Inglis -
Guy Harris -
Lester Caine -
Paul Eggert -
Robert Elz -
Tim Parenti -
Trần Ngọc Quân