North Vietnam 1970 to 1975 - Asia/Hanoi belongs into main file
(Corrected subject line) The backzone file contains the zone Asia/Hanoi It should go into the main file for Asia. There exists no doubt that in all of what was North Vietnam between at least 1970 and 1975 the timezone was 7h east, and not 8h east as in South Vietnam. There may be unclear borders, but most of North Vietnam, including its capital, was not unclear at all. I find it a discrimination of former North Vietnam to not have it represented correctly, at least for the post-1970 period. What Paul Eggert writes in the comments is a poor excuse. From Paul Eggert (2019-02-19): # # The Ho Chi Minh entry suffices for most purposes as it agrees with all of # Vietnam since 1975-06-13. Presumably clocks often changed in south Vietnam # in the early 1970s as locations changed hands during the war; however the # details are unknown and would likely be too voluminous for this database. # # For timestamps in north Vietnam back to 1970 (the tzdb cutoff), # use Asia/Bangkok; see the VN entries in the file zone1970.tab. # For timestamps before 1970, see Asia/Hanoi in the file 'backzone'.
I want to explain why I find the the comment # For timestamps in north Vietnam back to 1970 (the tzdb cutoff), # use Asia/Bangkok; not sufficient. I have found that most users of time zone database in Vietnam select the Vietnamese city Ho Chi Minh city as their time zone reference. Nobody in heir right mind will select Asia/Bankok, as this is in Thailand and not in Vietnam. The public geonames.org database assigns the zone Asia/Ho_Chi_Minh for all location in country VN (Vietnam). This indicates that the comment above is not followed. The result are incorrect timestamps for half of Vietnam for the years 1970-1975, ie. after the tzdb cutoff. These common errors would be avoided if Asia/Hanoi was present in the main database. On 28.06.20 14:06, Alois Treindl wrote:
(Corrected subject line)
The backzone file contains the zone Asia/Hanoi
It should go into the main file for Asia.
There exists no doubt that in all of what was North Vietnam between at least 1970 and 1975 the timezone was 7h east, and not 8h east as in South Vietnam.
There may be unclear borders, but most of North Vietnam, including its capital, was not unclear at all.
I find it a discrimination of former North Vietnam to not have it represented correctly, at least for the post-1970 period.
What Paul Eggert writes in the comments is a poor excuse. From Paul Eggert (2019-02-19): # # The Ho Chi Minh entry suffices for most purposes as it agrees with all of # Vietnam since 1975-06-13. Presumably clocks often changed in south Vietnam # in the early 1970s as locations changed hands during the war; however the # details are unknown and would likely be too voluminous for this database. # # For timestamps in north Vietnam back to 1970 (the tzdb cutoff), # use Asia/Bangkok; see the VN entries in the file zone1970.tab. # For timestamps before 1970, see Asia/Hanoi in the file 'backzone'.
Ho Chi Minh is a big city in Vietnam, and it is true that people often use the Asia/Ho_Chi_Minh time zone for all locations in Vietnam. # For timestamps in north Vietnam back to 1970 (the tzdb cutoff),
# use Asia/Bangkok; see the VN entries in the file zone1970.tab.
Should we replace that Asia/Bangkok to Asia/Ho_Chi_Minh in the comment? Most timezones contain the name of the capital of the country. Example: Europe/Paris, Europe/London, Asia/Beijing, ... is it ok if we get Asia/Hanoi back? My opinion is that it's okay to be mainfile. On Sun, Jun 28, 2020 at 9:42 PM Alois Treindl <alois@astro.ch> wrote:
I want to explain why I find the the comment
# For timestamps in north Vietnam back to 1970 (the tzdb cutoff), # use Asia/Bangkok;
not sufficient.
I have found that most users of time zone database in Vietnam select the Vietnamese city Ho Chi Minh city as their time zone reference.
Nobody in heir right mind will select Asia/Bankok, as this is in Thailand and not in Vietnam.
The public geonames.org database assigns the zone Asia/Ho_Chi_Minh for all location in country VN (Vietnam). This indicates that the comment above is not followed.
The result are incorrect timestamps for half of Vietnam for the years 1970-1975, ie. after the tzdb cutoff.
These common errors would be avoided if Asia/Hanoi was present in the main database. On 28.06.20 14:06, Alois Treindl wrote:
(Corrected subject line)
The backzone file contains the zone Asia/Hanoi
It should go into the main file for Asia.
There exists no doubt that in all of what was North Vietnam between at least 1970 and 1975 the timezone was 7h east, and not 8h east as in South Vietnam.
There may be unclear borders, but most of North Vietnam, including its capital, was not unclear at all.
I find it a discrimination of former North Vietnam to not have it represented correctly, at least for the post-1970 period.
What Paul Eggert writes in the comments is a poor excuse. From Paul Eggert (2019-02-19): # # The Ho Chi Minh entry suffices for most purposes as it agrees with all of # Vietnam since 1975-06-13. Presumably clocks often changed in south Vietnam # in the early 1970s as locations changed hands during the war; however the # details are unknown and would likely be too voluminous for this database. # # For timestamps in north Vietnam back to 1970 (the tzdb cutoff), # use Asia/Bangkok; see the VN entries in the file zone1970.tab. # For timestamps before 1970, see Asia/Hanoi in the file 'backzone'.
On 6/28/20 12:57 PM, pierreneter wrote:
# For timestamps in north Vietnam back to 1970 (the tzdb cutoff),
# use Asia/Bangkok; see the VN entries in the file zone1970.tab.
Should we replace that Asia/Bangkok to Asia/Ho_Chi_Minh in the comment?
No, as that would be mishandle timestamps in much of south Vietnam from 1970 to 1975-06-13. That being said, perhaps the comment could be improved to make things clearer; suggestions are welcome.
On 6/28/20 7:42 AM, Alois Treindl wrote:
The public geonames.org database assigns the zone Asia/Ho_Chi_Minh for all location in country VN (Vietnam). This indicates that the comment above is not followed.
That's a problem with the geonames.org database, and I suggest reporting the bug to them. The bug should be reported regardless of whether we change tzdb since geonames.org should work with what we have now as well as with what we might have in the future. You can point them at the zone1970.tab file to help explain the situation. A little background here. We don't have the resources to create entries for every location in this part of southeast Asia, with different transition times for when locations changed hands between North and South Vietnam during the 1970-1975 conflict. So we approximate by using Ho Chi Minh as the representative for clocks in south Vietnam, and Bangkok as the representative for clocks in Thailand, Cambodia, Laos and north Vietnam. We have links from Asia/Bangkok to Asia/Phnom_Penh and Asia/Vientiane for backward-compatibility purposes only, as the names Asia/Phnom_Penh and Asia/Vientiane would not exist according to today's guidelines. There's no need for a backward-compatibility link for Asia/Hanoi since that name never existed in tzdb. These are all technical reasons, not political ones.
I don't agree. I think the capital of North Vietnam, Asia/Hanoi should be present in the main file, and used. Geonames.org will and should not use zones which exist only in backzone and will not be compiled by default into binary TZ distributions. They will and should not use the capital of another country, Bangkok, for parts of Vietnam. In my opinion the case is clear: Hanoi belongs into main file, to cover the 1970-1975 period correctly. On 28.06.20 23:12, Paul Eggert wrote:
On 6/28/20 7:42 AM, Alois Treindl wrote:
The public geonames.org database assigns the zone Asia/Ho_Chi_Minh for all location in country VN (Vietnam). This indicates that the comment above is not followed. That's a problem with the geonames.org database, and I suggest reporting the bug to them. The bug should be reported regardless of whether we change tzdb since geonames.org should work with what we have now as well as with what we might have in the future. You can point them at the zone1970.tab file to help explain the situation.
A little background here. We don't have the resources to create entries for every location in this part of southeast Asia, with different transition times for when locations changed hands between North and South Vietnam during the 1970-1975 conflict. So we approximate by using Ho Chi Minh as the representative for clocks in south Vietnam, and Bangkok as the representative for clocks in Thailand, Cambodia, Laos and north Vietnam. We have links from Asia/Bangkok to Asia/Phnom_Penh and Asia/Vientiane for backward-compatibility purposes only, as the names Asia/Phnom_Penh and Asia/Vientiane would not exist according to today's guidelines. There's no need for a backward-compatibility link for Asia/Hanoi since that name never existed in tzdb. These are all technical reasons, not political ones.
On 2020-06-28 15:22, Alois Treindl wrote:
On 28.06.20 23:12, Paul Eggert wrote:
On 6/28/20 7:42 AM, Alois Treindl wrote:
The public geonames.org database assigns the zone Asia/Ho_Chi_Minh for all location in country VN (Vietnam). This indicates that the comment above is not followed.
That's a problem with the geonames.org database, and I suggest reporting the bug to them. The bug should be reported regardless of whether we change tzdb since geonames.org should work with what we have now as well as with what we might have in the future. You can point them at the zone1970.tab file to help explain the situation.
A little background here. We don't have the resources to create entries for every location in this part of southeast Asia, with different transition times for when locations changed hands between North and South Vietnam during the 1970-1975 conflict. So we approximate by using Ho Chi Minh as the representative for clocks in south Vietnam, and Bangkok as the representative for clocks in Thailand, Cambodia, Laos and north Vietnam. We have links from Asia/Bangkok to Asia/Phnom_Penh and Asia/Vientiane for backward-compatibility purposes only, as the names Asia/Phnom_Penh and Asia/Vientiane would not exist according to today's guidelines. There's no need for a backward-compatibility link for Asia/Hanoi since that name never existed in tzdb. These are all technical reasons, not political ones.
I don't agree. I think the capital of North Vietnam, Asia/Hanoi should be present in the main file, and used. Geonames.org will and should not use zones which exist only in backzone and will not be compiled by default into binary TZ distributions.> They will and should not use the capital of another country, Bangkok, for parts of Vietnam.> In my opinion the case is clear: Hanoi belongs into main file, to cover the 1970-1975 period correctly.
Searching for Vietnam time, I see sites stating that Vietnam follows Indochina Time, so this view does not appear too controversial in the region. I agree from the design point of view that countries should have their own independent time zones, as what they do is so unpredictable, and should not be allowed to affect any other country, so allowing a little judicious duplication would be in order, where there is no political commonality but only geographical proximity or coincidence in decision making. Perhaps the needs of historical communities diverge from those served by the tzdb project over the issue of differences before 1970. You could take the experimental github repo, which has history from 1984, or the tar releases from 1993, and cherry pick which patches to choose to apply, as Oracle does to improve backward compatibility for its major DB product and Java. There is absolutely nothing stopping you from creating and distributing your own patches to tzdata sources, additional source files of rules, zones, and links, or scripts to patch, build, copy, or link files to meet your historical community's needs. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in IEC units and prefixes, physical quantities in SI.]
On 29.06.20 06:10, Brian Inglis wrote:
Searching for Vietnam time, I see sites stating that Vietnam follows Indochina Time, so this view does not appear too controversial in the region. I agree from the design point of view that countries should have their own independent time zones, as what they do is so unpredictable, and should not be allowed to affect any other country, so allowing a little judicious duplication would be in order, where there is no political commonality but only geographical proximity or coincidence in decision making.
I noticed also that timeanddate.com represents Hanoi incorrectly for the period 1970-1975. See attached screenshot. Timeanddate.com is usually a good site for time zone history after 1970, and often goes beyond of what tzdb offers. But here they neither included backzone nor the comment which advises to follow Asia/Bangkok for half of Vietnam. That problem would easily be fixed if Asia/Hanoi were moved from backzone to file asia. All sites following the main distribution of tzdb would update. Nobody can really be expected to study the comments, to get exect timestamps for after 1970.
I see we have a lot of discussion about this. Present and in the past https://mm.icann.org/pipermail/tz/2019-February/thread.html#27530 https://github.com/moment/moment-timezone/issues/653 https://unicode-org.atlassian.net/browse/CLDR-11977 ... Whether we have a standard or will create a standard to create tz list? And Paul Eggert told me why this particular list was made: https://data.iana.org/time-zones/theory.html#naming ("the naming conventions attempt to strike a balance among the following goals") but through the discussions I found, I feel that they are very confusing because they think Asia/Hanoi still exists, and I don't know why Hanoi is in the backzone. I will learn more about this because the tz list is really confusing. On Tue, Jun 30, 2020 at 5:45 PM Michael H Deckers via tz <tz@iana.org> wrote:
On 2020-06-30 09:20, Alois Treindl wrote:
That problem would easily be fixed if Asia/Hanoi were moved from backzone to file asia.
...or if Asia/Hanoi were made a link to Asia/Bangkok (as Asia/Vientiane and Asia/Phnom_Penh already are).
Michael Deckers.
Thank you for bringing this to our attention (and Paul Eggert for a heads up!) Previously we did map all of Vietnam to the Asia/Ho_Chi_Minh zone, which is why Hanoi showed this. We have now mapped Hanoi and a few other places to Asia/Hanoi instead, so we hope it should now be correct. Locations we show that are Geonames based might still show the wrong historical data. We will look into a workaround for that, but it can take some time to get corrected. Best regards, Steffen Thorsen - timeanddate.com On 6/30/2020 11:20 AM, Alois Treindl wrote:
On 29.06.20 06:10, Brian Inglis wrote:
Searching for Vietnam time, I see sites stating that Vietnam follows Indochina Time, so this view does not appear too controversial in the region. I agree from the design point of view that countries should have their own independent time zones, as what they do is so unpredictable, and should not be allowed to affect any other country, so allowing a little judicious duplication would be in order, where there is no political commonality but only geographical proximity or coincidence in decision making.
I noticed also that timeanddate.com represents Hanoi incorrectly for the period 1970-1975. See attached screenshot.
Timeanddate.com is usually a good site for time zone history after 1970, and often goes beyond of what tzdb offers. But here they neither included backzone nor the comment which advises to follow Asia/Bangkok for half of Vietnam.
That problem would easily be fixed if Asia/Hanoi were moved from backzone to file asia. All sites following the main distribution of tzdb would update. Nobody can really be expected to study the comments, to get exect timestamps for after 1970.
Sorry for my curiosity, if Asia/Bangkok represents areas with a time zone of +7, then why was Asia/Ho_Chi_Minh created? On Mon, Jun 29, 2020 at 4:12 AM Paul Eggert <eggert@cs.ucla.edu> wrote:
On 6/28/20 7:42 AM, Alois Treindl wrote:
The public geonames.org database assigns the zone Asia/Ho_Chi_Minh for all location in country VN (Vietnam). This indicates that the comment above is not followed.
That's a problem with the geonames.org database, and I suggest reporting the bug to them. The bug should be reported regardless of whether we change tzdb since geonames.org should work with what we have now as well as with what we might have in the future. You can point them at the zone1970.tab file to help explain the situation.
A little background here. We don't have the resources to create entries for every location in this part of southeast Asia, with different transition times for when locations changed hands between North and South Vietnam during the 1970-1975 conflict. So we approximate by using Ho Chi Minh as the representative for clocks in south Vietnam, and Bangkok as the representative for clocks in Thailand, Cambodia, Laos and north Vietnam. We have links from Asia/Bangkok to Asia/Phnom_Penh and Asia/Vientiane for backward-compatibility purposes only, as the names Asia/Phnom_Penh and Asia/Vientiane would not exist according to today's guidelines. There's no need for a backward-compatibility link for Asia/Hanoi since that name never existed in tzdb. These are all technical reasons, not political ones.
And I wonder based on geographic area reasons, not political reasons. On Mon, Jun 29, 2020 at 6:17 AM pierreneter <pierreneter@gmail.com> wrote:
Sorry for my curiosity, if Asia/Bangkok represents areas with a time zone of +7, then why was Asia/Ho_Chi_Minh created?
On Mon, Jun 29, 2020 at 4:12 AM Paul Eggert <eggert@cs.ucla.edu> wrote:
On 6/28/20 7:42 AM, Alois Treindl wrote:
The public geonames.org database assigns the zone Asia/Ho_Chi_Minh for all location in country VN (Vietnam). This indicates that the comment above is not followed.
That's a problem with the geonames.org database, and I suggest reporting the bug to them. The bug should be reported regardless of whether we change tzdb since geonames.org should work with what we have now as well as with what we might have in the future. You can point them at the zone1970.tab file to help explain the situation.
A little background here. We don't have the resources to create entries for every location in this part of southeast Asia, with different transition times for when locations changed hands between North and South Vietnam during the 1970-1975 conflict. So we approximate by using Ho Chi Minh as the representative for clocks in south Vietnam, and Bangkok as the representative for clocks in Thailand, Cambodia, Laos and north Vietnam. We have links from Asia/Bangkok to Asia/Phnom_Penh and Asia/Vientiane for backward-compatibility purposes only, as the names Asia/Phnom_Penh and Asia/Vientiane would not exist according to today's guidelines. There's no need for a backward-compatibility link for Asia/Hanoi since that name never existed in tzdb. These are all technical reasons, not political ones.
On 6/28/20 4:17 PM, pierreneter wrote:
if Asia/Bangkok represents areas with a time zone of +7, then why was Asia/Ho_Chi_Minh created?
Among other things Asia/Ho_Chi_Minh differs from Asia/Bangkok for timestamps from 1959 to 1975, when south Vietnam was at +08 while the rest of the region was at +07. tzdb identifies timezones where clocks have agreed since 1970, and since these regions disagreed from 1970 to 1975 they need distinct identifiers. For more, see <https://data.iana.org/time-zones/theory.html#naming>.
Thanks for making that information clear to me. This document is very useful for explaining why things are formed. On Mon, Jun 29, 2020 at 7:42 AM Paul Eggert <eggert@cs.ucla.edu> wrote:
On 6/28/20 4:17 PM, pierreneter wrote:
if Asia/Bangkok represents areas with a time zone of +7, then why was Asia/Ho_Chi_Minh created?
Among other things Asia/Ho_Chi_Minh differs from Asia/Bangkok for timestamps from 1959 to 1975, when south Vietnam was at +08 while the rest of the region was at +07. tzdb identifies timezones where clocks have agreed since 1970, and since these regions disagreed from 1970 to 1975 they need distinct identifiers. For more, see <https://data.iana.org/time-zones/theory.html#naming>.
participants (6)
-
Alois Treindl -
Brian Inglis -
Michael H Deckers -
Paul Eggert -
pierreneter -
Steffen Thorsen