Re: [tz] timezone change for antarctica\casey [SEC=UNCLASSIFIED]
| Can we now assume, do you think, that Casey will be switching back and forth between +0800 and +1100 in accordance with Australian summer time shifts for the forseeable future (that 3 hour offset change will break assumptions made in some code I expect!) The TZ changes, particularly at Casey, are highly variable, they are based around resupply and flights. They will rarely line up with DST changes, this year there were early flights (leaving tomorrow) and an early insertion of ground crew into Wilkins | What's useful to know is when it was first founded/settled, what times were in use locally, when they altered (as accurately as possible) and what the prediction is for the future. I will endeavour to go through the database and pull out the TZ changes, should be able to get 3-4 years. Regarding predictions, sometimes there are only a couple of days notice on changes much to the anguish of a few wintering expiditioners. All changes are visible live on the external site (it's the same database) ___________________________________________________________________________ Australian Antarctic Division - Commonwealth of Australia IMPORTANT: This transmission is intended for the addressee only. If you are not the intended recipient, you are notified that use or dissemination of this communication is strictly prohibited by Commonwealth law. If you have received this transmission in error, please notify the sender immediately by e-mail or by telephoning +61 3 6232 3209 and DELETE the message. Visit our web site at http://www.antarctica.gov.au/ ___________________________________________________________________________
Date: Fri, 30 Oct 2015 05:01:39 +0000 From: Michael Chinn <Michael.Chinn@aad.gov.au> Message-ID: <b269372e88e94074996dbfd2b611cec1@KGS-EX02.AAD.GOV.AU> | The TZ changes, particularly at Casey, are highly variable, Oh. | they are based around resupply and flights. I assume in that case that someone plans them in advance ... given the logistics, probably a fair time (months?) in advance ? | I will endeavour to go through the database and pull out the TZ changes, | should be able to get 3-4 years. Ideally we're looking to go back to at least 1970 (or whenever it was established, if more recent than that) - and even earlier if applicable and possible. But it does not have to be all at once. | Regarding predictions, sometimes there are only a couple of days | notice on changes much to the anguish of a few wintering expiditioners. Oh. | All changes are visible live on the external site (it's the same database) That just tells us the current time, and so, unless continually monitored (which I doubt anyone here really has the resources to do) isn't suitable for much more than verifying (or not) that the current data is correct, and at best, would only ever tell us that we should have changed the zone already. To be really useful, we need to know (however far in advance is possible) when the next change is coming, before it occurs. Ideally more than 2 days! kre
If the zones are volatile, wouldn't it make more sense for someone in the Antarctic scientific community to maintain a private distribution for Antarctica? tzdb could pull from it periodically, such as before each otherwise-scheduled release. But I'd be disappointed if a short-notice Antarctic zone change forced a new public tzdb version. For example, it's not quite the same scenario as the recent Turkey update.
From: kre@munnari.OZ.AU To: Michael.Chinn@aad.gov.au Date: Fri, 30 Oct 2015 12:31:43 +0700 CC: tz@iana.org Subject: Re: [tz] timezone change for antarctica\casey [SEC=UNCLASSIFIED]
Date: Fri, 30 Oct 2015 05:01:39 +0000 From: Michael Chinn <Michael.Chinn@aad.gov.au> Message-ID: <b269372e88e94074996dbfd2b611cec1@KGS-EX02.AAD.GOV.AU>
| The TZ changes, particularly at Casey, are highly variable,
Oh.
| they are based around resupply and flights.
I assume in that case that someone plans them in advance ... given the logistics, probably a fair time (months?) in advance ?
| I will endeavour to go through the database and pull out the TZ changes, | should be able to get 3-4 years.
Ideally we're looking to go back to at least 1970 (or whenever it was established, if more recent than that) - and even earlier if applicable and possible.
But it does not have to be all at once.
| Regarding predictions, sometimes there are only a couple of days | notice on changes much to the anguish of a few wintering expiditioners.
Oh.
| All changes are visible live on the external site (it's the same database)
That just tells us the current time, and so, unless continually monitored (which I doubt anyone here really has the resources to do) isn't suitable for much more than verifying (or not) that the current data is correct, and at best, would only ever tell us that we should have changed the zone already.
To be really useful, we need to know (however far in advance is possible) when the next change is coming, before it occurs. Ideally more than 2 days!
kre
On Oct 30, 2015, at 1:13 PM, Matt Johnson <mj1856@hotmail.com> wrote:
If the zones are volatile, wouldn't it make more sense for someone in the Antarctic scientific community to maintain a private distribution for Antarctica?
tzdb could pull from it periodically, such as before each otherwise-scheduled release. But I'd be disappointed if a short-notice Antarctic zone change forced a new public tzdb version. For example, it's not quite the same scenario as the recent Turkey update.
I very strongly disagree. It would be a VERY bad precedent for the TZ project to decide that some changes are more equal than others. There are some countries whose TZ information are not all that relevant to me. But I expect them to relevant to others. I track all TZ changes and import them when they appear. Sometimes they are out of the way places, other times they are not, but the effort is small in each case. If some organizations feel that importing each TZ change as it occurs is too much trouble, they are perfectly free to filter the changes before doing the import, and skipping the import if it isn't interesting enough by their standards. But that MUST be a decision made at the receiving end; it cannot be made at the data source end. paul
On 10/30/2015 10:39 AM, Paul_Koning@dell.com wrote:
It would be a VERY bad precedent for the TZ project to decide that some changes are more equal than others.
Although we try to incorporate all changes, there are limits to what we can do quickly. It's not just me personally -- it's also the hassle of everybody who tries to track the tz database and generate new releases. It'd be nice to have a reliable history of Casey's time zone, but I'm not sure it's worth cutting a new release merely because they have bad weather and their supply aircraft is overdue. As I understand it, Wilkins Aerodrome is not year-round and so doesn't make our cut.
True, Wilkins does have semi-permanent structures but is only manned October-April. ________________________________________ From: Paul Eggert <eggert@cs.ucla.edu> Sent: Saturday, 31 October 2015 8:28 AM To: Paul_Koning@dell.com; mj1856@hotmail.com Cc: tz@iana.org; Michael Chinn; kre@munnari.oz.au Subject: Re: [tz] timezone change for antarctica\casey [SEC=UNCLASSIFIED] On 10/30/2015 10:39 AM, Paul_Koning@dell.com wrote:
It would be a VERY bad precedent for the TZ project to decide that some changes are more equal than others.
Although we try to incorporate all changes, there are limits to what we can do quickly. It's not just me personally -- it's also the hassle of everybody who tries to track the tz database and generate new releases. It'd be nice to have a reliable history of Casey's time zone, but I'm not sure it's worth cutting a new release merely because they have bad weather and their supply aircraft is overdue. As I understand it, Wilkins Aerodrome is not year-round and so doesn't make our cut. ___________________________________________________________________________ Australian Antarctic Division - Commonwealth of Australia IMPORTANT: This transmission is intended for the addressee only. If you are not the intended recipient, you are notified that use or dissemination of this communication is strictly prohibited by Commonwealth law. If you have received this transmission in error, please notify the sender immediately by e-mail or by telephoning +61 3 6232 3209 and DELETE the message. Visit our web site at http://www.antarctica.gov.au/ ___________________________________________________________________________
On Fri, Oct 30, 2015 at 1:13 PM, Matt Johnson <mj1856@hotmail.com> wrote:
If the zones are volatile, wouldn't it make more sense for someone in the Antarctic scientific community to maintain a private distribution for Antarctica?
tzdb could pull from it periodically, such as before each otherwise-scheduled release. But I'd be disappointed if a short-notice Antarctic zone change forced a new public tzdb version. For example, it's not quite the same scenario as the recent Turkey update.
I'm not sure that is desirable for a lot of people. The database shouldn't get involved in the politics of the distribution. Downstream users of the database can determine if a new version warrants faster/slower deployment by looking at the changelog. e.g. North Korea's timezone decisions don't really warrant any emergency action because they have no bearing on our product, but Turkey's do. The only thing we ask is that updates be released in a timely manner and it is up to Paul to decide when to cut the release to balance # of releases vs time remaining until planned change(s).
participants (6)
-
Andrew Paprocki -
Matt Johnson -
Michael Chinn -
Paul Eggert -
Paul_Koning＠dell.com -
Robert Elz