- tz - lists.iana.org

Another Windows program that uses the TZ database
by ActiveEarth Sales May 26, 2006

May 26, 2006

Dear tz Contributors, My world time clock software, ActiveEarth, also uses the tz database. Would you add a mention of that to your web page? You can see the software here: http://www.activeearth.com <http://www.activeearth.com/> . There is a new release about to come out that will contain the latest tz data. Thank you so much for this excellent resource! Best regards, Thaine Norris President Norris Family Industry

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new ISO 3166-1 entries
by Chuck Soper May 25, 2006

May 25, 2006

I recently read ISO 3166-1 Newsletter No. V-11 (2006-03-29) and noticed three new ISO 3166-1 entries: GUERNSEY; GG ISLE OF MAN;IM JERSEY;JE I found this rule in the Theory file: Include at least one location per time zone rule set per country. One such location is enough. Use ISO 3166 (see the file iso3166.tab) to help decide whether something is a country. However, uninhabited ISO 3166 regions like Bouvet Island do not need locations, since local time is not defined there. For tzdata, should all populated ISO 3166 regions be included? Does this mean that three new TZ zone descriptions should be added to zone.tab and appropriate data files? Or, should Europe/London be used instead? Should iso3166.tab be updated? Chuck

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C#/.NET tz binary reader ...
by Zbigniew Babiej May 24, 2006

May 24, 2006

Dear Sir or Madam, Recently I have posted the C#/.NET version of tz binary reader at http://www.gotdotnet.com/Community/UserSamples/Details.aspx?SampleGuid=0 C9E8F33-7214-4222-B992-D248D107652F I thought that it would be good idea to share this link on your page as well.... Best Regards, Z. Babiej, MarketXS ______________________________ DISCLAIMER: This e-mail message is intended for the addressee(s) or authorized recipient only. If you are not the addressee, or an authorized recipient, you are specifically advised that any use, distribution, publication, copying or repetition of this information is prohibited. If you have received this information in error, please notify us immediately (+31 (0)20 50 25 800) and destroy this message.

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RE: tz list searchable on Google
by Olson, Arthur David (NIH/NCI) [E] May 23, 2006

May 23, 2006

I'm also worried about spam; that's why electronic mail addresses have been purged from the time zone distribution (and most especially from the source data files such as "northamerica" which end up on millions of computers worldwide). The gmane site's archive of stuff that's gone out on the time zone mailing list extends back to July 2004; has tz-linked spam been seen since then? And...if the gmane mailing list archive is a bad thing, is the elsie ftpable mailing list archive also a bad thing (or is security through difficulty of use sufficient)? --ado

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FW: timezones offset from what?
by Olson, Arthur David (NIH/NCI) [E] May 23, 2006

May 23, 2006

Zefram is not on the time zone mailing list; direct replies appropriately. --ado -----Original Message----- From: Zefram [mailto:zefram@fysh.org] Sent: Friday, May 19, 2006 12:30 PM To: tz(a)lecserver.nci.nih.gov Subject: timezones offset from what? I've been doing work on precision timekeeping on computer systems. Naturally I don't use timezones at all inside that code, but there are places where I need to apply timezones when presenting a time to non-specialist humans. Looking through the zoneinfo database and the theory written about it, it struck me that although it deals fantastically with what time offset to use, there's no rigorous treatment of what base time scale to apply the offset to. Then it struck me that a simple treatment of this could solve a couple of other issues with the database. An example of this issue: as the zoneinfo source notes, UK legal time is currently based on mean solar time on the Greenwich meridian. Now that's not even Universal Time any more, since the prime meridian moved (slightly) off the Greenwich meridian. But everyone in the UK in practice sets their clocks based on UTC, as promulgated by the NPL and the BBC. At centisecond timescales, GMT (legal time in the UK), UTC (used in practice), UT1 (which UTC tracks in the long term), and UT2 (used for civil time in the 1950s) are all quite distinct. So I have a suggestion: it would be nice if the zoneinfo database included a field identifying exactly which time scale to apply the offsets to. The database doesn't need to understand how the time scales relate to each other; leave that to the precision horologists. All it needs is a short text string, with values such as "UTC", "UT1", "GMT". Of course, in a lot of cases this information is unavailable, or the distinction wasn't being made, so you'd then give "UT" to be explicitly ambiguous about the exact flavour of Universal Time. This field would also allow the database to handle timezones that are based on something other than UT. Currently the data files for Saudi Arabia attempt to describe apparent solar time in terms of UT, by means of a daily offset change. But it could instead be specified as a fixed offset with a base of apparent solar time on the prime meridian. To understand the zone properly the code would need to calculate the equation of time, but that only needs to be implemented once and it would give a much smoother and more accurate result than the daily UT offset changes do. A system that doesn't do the equation of time would effectively fall back to mean solar time, which is what the Riyadh8X zones do anyway. It's also a way to handle Mars time. Just specify the base to be MTC instead of UT. Ta da. What do you think? -zefram

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Corrections to latitudes/longitudes in zone.tab
by Andy McDonald May 23, 2006

May 23, 2006

Hi, A very very minor point, but I've run across a few inaccurate latitudes/longitudes in tz's zone.tab (2006g and earlier): Corrected lat/long zone.tab lat/long America/Argentina/Tucuman: -0265000, -0651300 -0312400, -0641100 America/Inuvik: +0682200, -1334400 +0682500, -1133000 America/Rainy_River: +0484300, -0943400 +0484300, -0942900 America/Rankin_Inlet +0624800, -0920500 +0624500, -0921000 America/Scoresbysund: +0703000, -0215800 +0703000, -0221500 (Tucuman's latitude and longitude in zone.tab are those of America/Argentina/Cordoba.) The corrected values come from playing with my Firefox extension (http://www.stemhaus.com/firefox/foxclocks/) and Google Earth, and are of course entirely subjective. Regards, Andy McDonald

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timezones offset from what?
by Zefram May 19, 2006

May 19, 2006

I've been doing work on precision timekeeping on computer systems. Naturally I don't use timezones at all inside that code, but there are places where I need to apply timezones when presenting a time to non-specialist humans. Looking through the zoneinfo database and the theory written about it, it struck me that although it deals fantastically with what time offset to use, there's no rigorous treatment of what base time scale to apply the offset to. Then it struck me that a simple treatment of this could solve a couple of other issues with the database. An example of this issue: as the zoneinfo source notes, UK legal time is currently based on mean solar time on the Greenwich meridian. Now that's not even Universal Time any more, since the prime meridian moved (slightly) off the Greenwich meridian. But everyone in the UK in practice sets their clocks based on UTC, as promulgated by the NPL and the BBC. At centisecond timescales, GMT (legal time in the UK), UTC (used in practice), UT1 (which UTC tracks in the long term), and UT2 (used for civil time in the 1950s) are all quite distinct. So I have a suggestion: it would be nice if the zoneinfo database included a field identifying exactly which time scale to apply the offsets to. The database doesn't need to understand how the time scales relate to each other; leave that to the precision horologists. All it needs is a short text string, with values such as "UTC", "UT1", "GMT". Of course, in a lot of cases this information is unavailable, or the distinction wasn't being made, so you'd then give "UT" to be explicitly ambiguous about the exact flavour of Universal Time. This field would also allow the database to handle timezones that are based on something other than UT. Currently the data files for Saudi Arabia attempt to describe apparent solar time in terms of UT, by means of a daily offset change. But it could instead be specified as a fixed offset with a base of apparent solar time on the prime meridian. To understand the zone properly the code would need to calculate the equation of time, but that only needs to be implemented once and it would give a much smoother and more accurate result than the daily UT offset changes do. A system that doesn't do the equation of time would effectively fall back to mean solar time, which is what the Riyadh8X zones do anyway. It's also a way to handle Mars time. Just specify the base to be MTC instead of UT. Ta da. What do you think? -zefram

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Correction
by Behdad Elahipanah May 17, 2006

May 17, 2006

Tehran's (Iran) current UTC/GMT Offset is: +3:30 hours with no daylight saving time at the moment Please correct it in your database.

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Kirov on GMT+4?
by Jesper Norgaard Welen May 16, 2006

May 16, 2006

The Kirov timezone according to the tz database is GMT+3. As you will remember in an earlier mail I could not find any mention of the timezone directly in the page of the Kirovskaya oblast' in http://www.gov-vyatka.ru/ however this page pointed to another page http://www.gismeteo.ru/weather/towns/27196.htm that has sunrise and sunset times indicating that Kirov is on GMT+3. Now I have found a page that points to this same page, but explicitly defines Kirov as being on GMT+4: >From main page http://map.rin.ru selecting Kirovskaya obl. http://map.rin.ru/cgi-bin/main.pl?Region=kirov you can see just below the link to the www.gismeteo.ru link that it specifies explicitly GMT+4 The other links confirm what we think for other oblast's in the area: Samarskaya oblast' on GMT+4: http://map.rin.ru/cgi-bin/main.pl?Region=samara Udmurtskaya oblast' on GMT+4: http://map.rin.ru/cgi-bin/main.pl?Region=udmurt Volgogradskaya oblast' on GMT+3: http://map.rin.ru/cgi-bin/main.pl?Region=volga Astrakhanskaya oblast' on GMT+3: http://map.rin.ru/cgi-bin/main.pl?Region=astrah Saratovskaya oblast' on GMT+3: http://map.rin.ru/cgi-bin/main.pl?Region=saratov Komi republic on GMT+3: http://map.rin.ru/cgi-bin/main.pl?Region=komi This page has a summary of time differences from Moscow time, and shows Kirov as being on Moscow time, e.g. GMT+3: http://www.bereg.ru/sprav_info/inform/time.shtml As we know from an earlier email from Paul Eggert, Shanks & Pottenger (2003) has Kirov on GMT+4. I'm afraid Kirov is a difficult case. I have changed it myself in World Time Explorer 4 times from between GMT+4 and GMT+3: February 23, 2000 GMT+4 to GMT+3 January 21, 2001 GMT+3 to GMT+4 June 18, 2001 GMT+4 to GMT+3 October 2, 2002 GMT+3 to GMT+4 Each time I was convinced I had found a better source. So who are we to believe? We have still not found any official russian page that gives the GMT offset explicitly. - Jesper Jesper Nørgaard Welen Email: jnorgard(a)Prodigy.Net.mx Project Leader (Líder de Proyecto) Software CIMMYT - Centro Internacional de Mejoramiento de Maíz y Trigo Dirección: CIMMYT Int. c/o Jesper Nørgaard Km. 45, Carretera México-Veracruz El Batán Texcoco, Edo. de México CP 56130 MEXICO Tel.: +52 (55) 58-04-20-04 ext. 1374 Fax: +52 (55) 58-04-75-58 Tel. Casa: 53-10-05-95 ó 53-10-97-78 Download the free program World Time Explorer, I made: http://www.worldtimeexplorer.com/index.html

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FW: Finnish summer time (DST) rule
by Olson, Arthur David (NIH/NCI) [E] May 15, 2006

May 15, 2006

Jukka A. Ukkonen is not on the time zone mailing list; direct replies appropriately. --ado -----Original Message----- From: Jukka A. Ukkonen [mailto:jau@iki.fi] Sent: Friday, May 12, 2006 1:57 AM To: tz(a)lecserver.nci.nih.gov Subject: Finnish summer time (DST) rule Greetings from Kirkkonummi (32km from Helsinki), The correct DST rule (in POSIX TZ syntax) for Finland has been at least since 2002 EET-02:00EEST-03:00,M3.5.0/03:00,M10.5.0/04:00 Notice that in there the zone change times are represented in the local time of the zone which is current at the moment when the change shall take place - i.e. both local times actually refer to 01:00 GMT. I guess Finland used this rule already several years before the common EU directive officially harmonized the DST rules all around EU from 2002 onwards. The EU directive can be found here... http://europa.eu.int/eur-lex/pri/en/oj/dat/2001/l_031/l_03120010202en002 10022.pdf I will let you know, if I find more precise info about when Finland actually adopted the current DST rule. Cheers, // jau .--- ..- -.- -.- .- .- .-.-.- ..- -.- -.- --- -. . -. / Jukka A. Ukkonen, Oxit Ltd, Finland /__ M.Sc. (sw-eng & cs) (Phone) +358-500-606-671 / Internet: Jukka.Ukkonen(a)Oxit.Fi (Home) +358-9-6215-280 / Internet: jau(a)iki.fi v .--- .- ..- ...-.- .. -.- .. .-.-.- ..-. .. + + + + My opinions are mine and mine alone, not my employers. + + + +

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