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Need to update Kansas City, MO
by Kevin DeCapite Feb. 25, 2018

Feb. 25, 2018

I would like to propose a change to the database to account for Kansas City, Missouri, USA as having not observed DST between 1946 - 1965. Please see the source book referenced in the link (page 87 in the actual printed pages, standard PDF is the best way to view it): https://archive.org/details/time-changes-in-usa-1966 <https://archive.org/details/time-changes-in-usa-1966> I can also confirm the accuracy of at least this piece of information through testimony. What are the procedures for formally proposing, reviewing & accepting/rejecting such changes? Thank you. --- Kevin DeCapite kevin(a)decapite.net 562.355.8222

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AP & WFLA-TV: Florida House OKs bill asking to skip Daylight Saving Time
by Vance, Frank Feb. 24, 2018

Feb. 24, 2018

http://wfla.com/2018/02/14/florida-house-oks-bill-asking-to-skip-daylight-s… "The [Florida] House voted 103-11 to approve the bill to ask Congress to let Florida remain in Daylight Saving Time all year, meaning while the rest of the Eastern United States sets their clocks back in the fall, Florida wouldn't." Regards, F

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SGT abbreviation is missing from the IANA tz database
by Lu, Can Feb. 21, 2018

Feb. 21, 2018

Hi Paul, Hope you're well. By way of introduction, this is Can, working as a software developer in BAML. We noticed that Asia/Singapore had its SGT abbreviation dropped in tzdb 2017, and the reason being is that the zone abbreviation doesn't correspond to any real-world usage. But it's actually not entirely true, SGT is very commonly used in Singapore and it's also a standard abbreviation for Singapore time. Please refer to: https://en.wikipedia.org/wiki/List_of_time_zone_abbreviations and https://en.wikipedia.org/wiki/List_of_time_zone_abbreviations Wondering if it's possible to add SGT back to IANA db as I believe this change will cause breaks to other libraries rely on it. (We're using pytz for python development). I am happy to discuss and appreciate any thoughts you may have on it. Thanks, Can ---------------------------------------------------------------------- This message, and any attachments, is for the intended recipient(s) only, may contain information that is privileged, confidential and/or proprietary and subject to important terms and conditions available at http://www.bankofamerica.com/emaildisclaimer. If you are not the intended recipient, please delete this message.

4 4

[PROPOSED] Parallelize the main part of 'make to2050new.tzs'
by Paul Eggert Feb. 21, 2018

Feb. 21, 2018

This improves real-time performance of 'make -j4 to2050new.tzs' by a factor of about 3.5 (from 120 s to 34 s) on my old 4-core desktop, which runs Fedora 27 x86-64 atop an AMD Phenom II X4 910e. * Makefile (ZDS): New macro. ($(ZDS)): New rule. All targets are phony. ($(TZS_NEW)): Use it in a submake that is parallelized by GNU make -j. (check_links): Depend on tzdata.zi, fixing a dependency bug. * NEWS: Mention this. --- Makefile | 29 ++++++++++++++++++++--------- NEWS | 4 ++++ 2 files changed, 24 insertions(+), 9 deletions(-) diff --git a/Makefile b/Makefile index fc15c3e..835f34b 100644 --- a/Makefile +++ b/Makefile @@ -640,19 +640,29 @@ posix_packrat: zones: $(REDO) +# dummy.zd is not a real file; it is mentioned here only so that the +# top-level 'make' does not have a syntax error. +ZDS = dummy.zd +# Rule used only by submakes invoked by the $(TZS_NEW) rule. +# It is separate so that GNU 'make -j' can run instances in parallel. +$(ZDS): zdump + ./zdump -i -c $(TZS_YEAR) '$(wd)/'$$(expr $@ : '$.*$.zd') >$@ + $(TZS_NEW): tzdata.zi zdump zic - mkdir -p tzs.dir + rm -fr tzs.dir + mkdir tzs.dir $(zic) -d tzs.dir tzdata.zi $(AWK) '/^L/{print "Link\t" $$2 "\t" $$3}' \ tzdata.zi | LC_ALL=C sort >$@.out wd=`pwd` && \ - zones=`$(AWK) -v wd="$$wd" \ - '/^Z/{print wd "/tzs.dir/" $$2}' tzdata.zi \ - | LC_ALL=C sort` && \ - ./zdump -i -c $(TZS_YEAR) $$zones >>$@.out - sed 's,^TZ=".*tzs\.dir/,TZ=",' $@.out >$@.sed.out - rm -fr tzs.dir $@.out - mv $@.sed.out $@ + set x `$(AWK) '/^Z/{print "tzs.dir/" $$2 ".zd"}' tzdata.zi \ + | LC_ALL=C sort -t . -k 2,2` && \ + shift && \ + ZDS=$$* && \ + $(MAKE) wd="$$wd" TZS_YEAR=$(TZS_YEAR) ZDS="$$ZDS" $$ZDS && \ + sed 's,^TZ=".*tzs\.dir/,TZ=",' $$ZDS >>$@.out + rm -fr tzs.dir + mv $@.out $@ # If $(TZS) does not already exist (e.g., old-format tarballs), create it. # If it exists but 'make check_tzs' fails, a maintainer should inspect the @@ -730,7 +740,7 @@ check_sorted: backward backzone iso3166.tab zone.tab zone1970.tab $(AWK) '/^[^#]/ $(CHECK_CC_LIST)' zone1970.tab | \ LC_ALL=C sort -cu -check_links: checklinks.awk $(TDATA_TO_CHECK) +check_links: checklinks.awk $(TDATA_TO_CHECK) tzdata.zi $(AWK) -f checklinks.awk $(TDATA_TO_CHECK) $(AWK) -f checklinks.awk tzdata.zi @@ -964,3 +974,4 @@ zic.o: private.h tzfile.h version.h .PHONY: public right_only right_posix signatures signatures_version .PHONY: tarballs tarballs_version typecheck .PHONY: zonenames zones +.PHONY: $(ZDS) diff --git a/NEWS b/NEWS index 3d18e89..1d2827e 100644 --- a/NEWS +++ b/NEWS @@ -79,6 +79,10 @@ Unreleased, experimental changes already can use vanguard.zi; in this respect, current tzcode is bleeding-edge. + The Makefile should now be safe for parallelized builds, and 'make + -j to2050new.tzs' is now much faster on a multiprocoessor host + with GNU Make. + When built with -DSUPPRESS_TZDIR, the tzcode library no longer prepends TZDIR/ to file names that do not begin with '/'. This is not recommended for general use, due to its security implications. -- 2.14.3

1 0

timezone history of Uruguay
by Jeremie Bonjour Feb. 20, 2018

Feb. 20, 2018

I submitted this information because it is not correct on the iana. org website. Greetings! Source: http://www.armada.mil.uy/ContenidosPDFs/sohma/web/almanaque/almanaque_2018.… Army Force of Uruguay http://www.armada.mil.uy .:Armada Nacional - Marina de Uruguay:.<http://www.armada.mil.uy/> www.armada.mil.uy Embarcación demorada La Armada Nacional, a través del Centro Coordinador de Búsqueda y Rescate en el Mar (MRCC), está realizando la búsqueda de un pesquero ... Almanac 2018, page 38 [cid:4e5339c0-4b51-4184-b33a-ad63059bec3a] Saludos. Jeremie Bonjour (+598) 093 81 21 71

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Sol 5000 for Opportunity
by Tim Parenti Feb. 18, 2018

Feb. 18, 2018

Today, 16 February 2018, at 01:26:20.092 UTC, it is 01:01:06 Coordinated Mars Time on Mars Sol Date 51235, which corresponds to midnight HLST (hybrid local solar time) at the beginning of mission sol 5000 for the Opportunity (MER-B) rover at its mission reference longitude. The sol will last, of course, for 24 hours 39 minutes 35.244 seconds, ending on 17 February 2018 at 02:05:55.336 UTC. Curiosity will observe its mission sol 2000 next month, reckoned in mean solar time at its landing site, from 2018-03-22 13:24:49.020 UTC to 2018-03-23 14:04:24.264 UTC. -- Tim Parenti

5 7

apply Portuguese decree of 1911-05-30
by Michael H Deckers Feb. 17, 2018

Feb. 17, 2018

The decree [http://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf] of 1911-05-30, mentioned for Europe/Lisbon prescribes time zone time scales for continental Portugal, Madeira, Azores, Cabo Verde, Guinea-Bissau, São Tomé, Angola, and Moçambique. It is currently not applied to all of these locations, and its article 5 is not correctly applied: " Art. 5.º Estas disposições entrarão em vigor no instante em que, segundo o artigo 2.º, começar o dia civil 1 de [j]aneiro de 1912, devendo então todos os relogios ser adeantados ou atrasados convenientemente, conforme as alineas seguintes:"... -- These dispositions shall enter into force at the instant at which, -- according to the 2nd article, the civil day January 1, 1912 begins, -- all clocks therefore having to be advanced or set back correspondingly, -- conforming with the following sections:.... (Article 2 specifies the various time zone time scales GMT + 00 h, GMT - 02 h, etc to be used in Portugal from 1912-01-01 onward.) The following proposals contain the necessary corrections. I have also tried to indicate exactly which data are implied by the source. I see this as a small step to make the tzdb data traceable to its sources, and thus to clarify the uncertainty of tzdb data (when they are estimated, or derived from less reliable sources). The format of these indications can certainly be improved. +# [pt 1911] decree https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf of 1911-05-30 # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Atlantic/Azores -1:42:40 - LMT 1884 # Ponta Delgada - -1:54:32 - HMT 1912-01-01 # Horta Mean Time +# [pt 1911] specifies UNTIL date, time & new GMTOFF: + -1:54:32 - HMT 1912-01-01 02:00u # Horta Mean Time -2:00 Port -02/-01 1942 Apr 25 22:00s # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Atlantic/Madeira -1:07:36 - LMT 1884 # Funchal - -1:07:36 - FMT 1912-01-01 # Funchal Mean Time +# [pt 1911] specifies UNTIL date, time & new GMTOFF: + -1:07:36 - FMT 1912-01-01 01:00u # Funchal Mean Time -1:00 Port -01/+00 1942 Apr 25 22:00s # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Europe/Lisbon -0:36:45 - LMT 1884 - -0:36:45 - LMT 1912 Jan 1 # Lisbon Mean Time +# [pt 1911] specifies UNTIL date, time & unrounded old (-00:36:44.68) and new GMTOFF: + -0:36:45 - LMT 1912 Jan 1 00:00u # Lisbon Mean Time 0:00 Port WE%sT 1966 Apr 3 2:00 The correction for Europe/Lisbon is an example where I think that Paul Eggert's proposal for GMTOFF values with fractional seconds would be helpful. [pt 1911] specifies Cabo Verde to use UT - 02 h since 1912-01-01 02:00Z. Currently, tzdb has a switch to UT - 02 h in 1907 without source (Shanks by default). This switch would precede the one in [pt 1911] which appears to be unlikely (admittedly, we know from Guernsey on 1913-06-18 that such conclusions may be wrong). # Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Atlantic/Cape_Verde -1:34:04 - LMT 1907 # Praia +# [pt 1911] specifies UNTIL date, time & new GMTOFF: +# Ignore [Shanks] specifying UNTIL year 1907, no date, no time. +Zone Atlantic/Cape_Verde -1:34:04 - LMT 1912-01-01 02:00u # Praia -2:00 - -02 1942 Sep # Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Africa/Bissau -1:02:20 - LMT 1912 Jan 1 +# [pt 1911] specifies UNTIL date, time & new GMTOFF: +Zone Africa/Bissau -1:02:20 - LMT 1912 Jan 1 01:00u # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Africa/Sao_Tome 0:26:56 - LMT 1884 - -0:36:32 - LMT 1912 # Lisbon Mean Time +# [pt 1911] specifies UNTIL date, time & new GMTOFF: + -0:36:32 - LMT 1912-01-01 00:00u # Lisbon Mean Time 0:00 - GMT 2018 Jan 1 01:00 Note that Lisbon Mean Time as in [pt 1911] and in [Milne 1899] differs from the GMTOFF given here for it (from Shanks?). # Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Asia/Macau 7:34:20 - LMT 1912 Jan 1 +# [pt 1911] specifies UNTIL date, time & new GMTOFF: +Zone Asia/Macau 7:34:20 - LMT 1911-12-31 16:00u 8:00 Macau C%sT In backzone: # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Africa/Luanda 0:52:56 - LMT 1892 - 0:52:04 - LMT 1912 Jan 1 +# [pt 1911] specifies UNTIL date, time & new GMTOFF: + 0:52:04 - LMT 1911-12-31 23:00u 1:00 - WAT The decree specifies that Goa (Panaji) and Timor (Aisa/Dili) should keep the time scale of the adjacent colonies. Michael Deckers.

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[PATCH 1/2] Improve use of non-ASCII symbols in commentary
by Paul Eggert Feb. 16, 2018

Feb. 16, 2018

From: Paul Eggert <eggert(a)Penguin.CS.UCLA.EDU> Go back to using °, ±, etc. in commentary. This was prompted by my recent minor cleanup change of “34°” to “34 degrees” for Uruguay commentary. As it happens, this cleanup wasn't really needed for XEmacs, and it's annoying to have to use longwinded workarounds for common symbols. * Makefile (UNUSUAL_OK_CHARSET): New macro. (OK_CHAR): Use it. (check_character_set): Check Makefile seperately, since its UNUSUAL_OK_CHARSET can be a non-SAFE_LINE now. * NEWS: Mention this. --- Makefile | 22 +++++++++++++++------- NEWS | 6 +++++- asia | 11 +++++------ australasia | 4 ++-- backzone | 6 +++--- europe | 14 +++++++------- northamerica | 5 ++--- southamerica | 2 +- zone1970.tab | 2 +- 9 files changed, 41 insertions(+), 31 deletions(-) diff --git a/Makefile b/Makefile index 47acbbd..fc15c3e 100644 --- a/Makefile +++ b/Makefile @@ -408,13 +408,19 @@ SAFE_CHARSET3= 'abcdefghijklmnopqrstuvwxyz{|}~' SAFE_CHARSET= $(SAFE_CHARSET1)$(SAFE_CHARSET2)$(SAFE_CHARSET3) SAFE_CHAR= '[]'$(SAFE_CHARSET)'-]' +# Non-ASCII non-letters that OK_CHAR allows, as these characters are +# useful in commentary. XEmacs 21.5.34 displays them correctly, +# presumably because they are Latin-1. +UNUSUAL_OK_CHARSET= °±½¾× + # OK_CHAR matches any character allowed in the distributed files. -# This is the same as SAFE_CHAR, except that multibyte letters are -# also allowed so that commentary can contain people's names and quote -# non-English sources. For non-letters the sources are limited to -# ASCII renderings for the convenience of maintainers whose text editors -# mishandle UTF-8 by default (e.g., XEmacs 21.4.22). -OK_CHAR= '[][:alpha:]'$(SAFE_CHARSET)'-]' +# This is the same as SAFE_CHAR, except that UNUSUAL_OK_CHARSET and +# multibyte letters are also allowed so that commentary can contain a +# few safe symbols and people's names and can quote non-English sources. +# Other non-letters are limited to ASCII renderings for the +# convenience of maintainers using XEmacs 21.5.34, which by default +# mishandles Unicode characters U+0100 and greater. +OK_CHAR= '[][:alpha:]$(UNUSUAL_OK_CHARSET)'$(SAFE_CHARSET)'-]' # SAFE_LINE matches a line of safe characters. # SAFE_SHARP_LINE is similar, except any OK character can follow '#'; @@ -689,8 +695,10 @@ check_character_set: $(ENCHILADA) sharp='#' && \ ! grep -Env $(SAFE_LINE) $(MANS) date.1 $(MANTXTS) \ $(MISC) $(SOURCES) $(WEB_PAGES) \ - CONTRIBUTING LICENSE Makefile README \ + CONTRIBUTING LICENSE README \ version tzdata.zi && \ + ! grep -Env $(SAFE_LINE)'|^UNUSUAL_OK_CHARSET='$(OK_CHAR)'*$$' \ + Makefile && \ ! grep -Env $(SAFE_SHARP_LINE) $(TDATA_TO_CHECK) backzone \ leapseconds yearistype.sh zone.tab && \ ! grep -Env $(OK_LINE) $(ENCHILADA); \ diff --git a/NEWS b/NEWS index b83cce9..1e2cfdf 100644 --- a/NEWS +++ b/NEWS @@ -108,6 +108,10 @@ Unreleased, experimental changes with links to many relevant legal documents. (Thanks to Tim Parenti.) + Commentary now uses some non-ASCII characters with Unicode value + less than U+0100, as they can be useful and should work even with + older editors such as XEmacs. + Release 2018c - 2018-01-22 23:00:44 -0800 @@ -1009,7 +1013,7 @@ Release 2016b - 2016-03-12 17:30:14 -0800 Comments in zone tables have been improved. (Thanks to J William Piggott.) tzselect again limits its menu comments so that menus fit on a - 24x80 alphanumeric display. + 24×80 alphanumeric display. A new web page tz-how-to.html. (Thanks to Bill Seymour.) diff --git a/asia b/asia index 63d2fb0..5c2fc50 100644 --- a/asia +++ b/asia @@ -1478,8 +1478,7 @@ Rule Japan 1950 1951 - May Sat>=1 24:00 1:00 D # From Hideyuki Suzuki (1998-11-09): # 'Tokyo' usually stands for the former location of Tokyo Astronomical -# Observatory: 139 degrees 44' 40.90" E (9h 18m 58.727s), -# 35 degrees 39' 16.0" N. +# Observatory: 139° 44' 40.90" E (9h 18m 58.727s), 35° 39' 16.0" N. # This data is from 'Rika Nenpyou (Chronological Scientific Tables) 1996' # edited by National Astronomical Observatory of Japan.... # JST (Japan Standard Time) has been used since 1888-01-01 00:00 (JST). @@ -1487,10 +1486,10 @@ Rule Japan 1950 1951 - May Sat>=1 24:00 1:00 D # From Hideyuki Suzuki (1998-11-16): # The ordinance No. 51 (1886) established "standard time" in Japan, -# which stands for the time on 135 degrees E. +# which stands for the time on 135° E. # In the ordinance No. 167 (1895), "standard time" was renamed to "central # standard time". And the same ordinance also established "western standard -# time", which stands for the time on 120 degrees E.... But "western standard +# time", which stands for the time on 120° E.... But "western standard # time" was abolished in the ordinance No. 529 (1937). In the ordinance No. # 167, there is no mention regarding for what place western standard time is # standard.... @@ -3097,9 +3096,9 @@ Zone Asia/Tashkent 4:37:11 - LMT 1924 May 2 # and is the basis for the information below. # # The 1906 transition was effective July 1 and standardized Indochina to -# Phù Liễn Observatory, legally 104 deg. 17'17" east of Paris. +# Phù Liễn Observatory, legally 104° 17' 17" east of Paris. # It's unclear whether this meant legal Paris Mean Time (00:09:21) or -# the Paris Meridian (2 deg. 20'14.03" E); the former yields 07:06:30.1333... +# the Paris Meridian (2° 20' 14.03" E); the former yields 07:06:30.1333... # and the latter 07:06:29.333... so either way it rounds to 07:06:30, # which is used below even though the modern-day Phù Liễn Observatory # is closer to 07:06:31. Abbreviate Phù Liễn Mean Time as PLMT. diff --git a/australasia b/australasia index 4f96458..c7c0ea7 100644 --- a/australasia +++ b/australasia @@ -1610,7 +1610,7 @@ Zone Pacific/Wallis 12:15:20 - LMT 1901 # From Howie Phelps (1999-11-10), who talked to a Pitcairner via shortwave: # Betty Christian told me yesterday that their local time is the same as -# Pacific Standard Time. They used to be 1/2 hour different from us here in +# Pacific Standard Time. They used to be ½ hour different from us here in # Sacramento but it was changed a couple of years ago. @@ -1649,7 +1649,7 @@ Zone Pacific/Wallis 12:15:20 - LMT 1901 # 12 hours and 20 minutes ahead of GMT. When New Zealand adjusted its # standard time in 1940s, Tonga had the choice of subtracting from its # local time to come on the same standard time as New Zealand or of -# advancing its time to maintain the differential of 13 degrees +# advancing its time to maintain the differential of 13° # (approximately 50 minutes ahead of New Zealand time). # # Because His Majesty King Tāufaʻāhau Tupou IV, then Crown Prince diff --git a/backzone b/backzone index cc724aa..2071110 100644 --- a/backzone +++ b/backzone @@ -409,7 +409,7 @@ Zone Asia/Bahrain 3:22:20 - LMT 1920 # Manamah # From Paul Eggert (2014-08-21): # In tomorrow's The Hindu, Nitya Menon reports that India had two civil time # zones starting in 1884, one in Bombay and one in Calcutta, and that railways -# used a third time zone based on Madras time (80 deg. 18'30" E). Also, +# used a third time zone based on Madras time (80° 18' 30" E). Also, # in 1881 Bombay briefly switched to Madras time, but switched back. See: # http://www.thehindu.com/news/cities/chennai/madras-375-when-madras-clocked-… #Zone Asia/Chennai [not enough info to complete] @@ -532,7 +532,7 @@ Zone Europe/Belfast -0:23:40 - LMT 1880 Aug 2 # Data from Joseph S. Myers # https://mm.icann.org/pipermail/tz/2013-September/019883.html # References to be added -# LMT is for Town Church, St. Peter Port, 49 degrees 27'17"N 2 degrees 32'10"W +# LMT is for Town Church, St. Peter Port, 49° 27' 17" N, 2° 32' 10" W. Zone Europe/Guernsey -0:10:09 - LMT 1913 Jun 18 0:00 GB-Eire %s 1940 Jul 2 1:00 C-Eur CE%sT 1945 May 8 @@ -566,7 +566,7 @@ Zone Europe/Isle_of_Man -0:17:55 - LMT 1883 Mar 30 0:00s # Data from Joseph S. Myers # https://mm.icann.org/pipermail/tz/2013-September/019883.html # References to be added -# LMT is for Parish Church, St. Helier, 49 degrees 11'0.57"N 2 degrees 6'24.33"W +# LMT is for Parish Church, St. Helier, 49° 11' 0.57" N, 2° 6' 24.33" W. Zone Europe/Jersey -0:08:26 - LMT 1898 Jun 11 16:00u 0:00 GB-Eire %s 1940 Jul 2 1:00 C-Eur CE%sT 1945 May 8 diff --git a/europe b/europe index 8aab26e..6bbb49d 100644 --- a/europe +++ b/europe @@ -117,8 +117,8 @@ # along the towpath within a few yards of it.' # # I have a one inch to one mile map of London and my estimate of the stone's -# position is 51 degrees 28' 30" N, 0 degrees 18' 45" W. The longitude should -# be within about +-2". The Ordnance Survey grid reference is TQ172761. +# position is 51° 28' 30" N, 0° 18' 45" W. The longitude should +# be within about ±2". The Ordnance Survey grid reference is TQ172761. # # [This yields GMTOFF = -0:01:15 for London LMT in the 18th century.] @@ -158,7 +158,7 @@ # after-hours daylight in which to pursue his research. # In 1895 he presented a paper to the Wellington Philosophical Society # that proposed a two-hour daylight-saving shift. See: -# Hudson GV. On seasonal time-adjustment in countries south of lat. 30 deg. +# Hudson GV. On seasonal time-adjustment in countries south of lat. 30°. # Transactions and Proceedings of the New Zealand Institute. 1895;28:734 # http://rsnz.natlib.govt.nz/volume/rsnz_28/rsnz_28_00_006110.html # Although some interest was expressed in New Zealand, his proposal @@ -2594,13 +2594,13 @@ Zone Europe/Kaliningrad 1:22:00 - LMT 1893 Apr # From Vladimir Karpinsky (2014-07-08): # LMT in Moscow (before Jul 3, 1916) is 2:30:17, that was defined by Moscow -# Observatory (coordinates: 55 deg. 45'29.70", 37 deg. 34'05.30").... +# Observatory (coordinates: 55° 45' 29.70", 37° 34' 05.30").... # LMT in Moscow since Jul 3, 1916 is 2:31:01 as a result of new standard. # (The info is from the book by Byalokoz ... p. 18.) # The time in St. Petersburg as capital of Russia was defined by # Pulkov observatory, near St. Petersburg. In 1916 LMT Moscow # was synchronized with LMT St. Petersburg (+30 minutes), (Pulkov observatory -# coordinates: 59 deg. 46'18.70", 30 deg. 19'40.70") so 30 deg. 19'40.70" > +# coordinates: 59° 46' 18.70", 30° 19' 40.70") so 30° 19' 40.70" > # 2h01m18.7s = 2:01:19. LMT Moscow = LMT St.Petersburg + 30m 2:01:19 + 0:30 = # 2:31:19 ... # @@ -3429,7 +3429,7 @@ Zone Atlantic/Canary -1:01:36 - LMT 1922 Mar # Las Palmas de Gran C. # three degrees, or twelve minutes of time, to the west of the # meridian of the Observatory of Stockholm". The law is dated 1878-05-31. # -# The observatory at that time had the meridian 18 degrees 03' 30" +# The observatory at that time had the meridian 18° 03' 30" # eastern longitude = 01:12:14 in time. Less 12 minutes gives the # national standard time as 01:00:14 ahead of GMT.... # @@ -3533,7 +3533,7 @@ Zone Europe/Stockholm 1:12:12 - LMT 1879 Jan 1 # From Alois Treindl (2013-09-11): # The Federal regulations say # https://www.admin.ch/opc/de/classified-compilation/20071096/index.html -# ... the meridian for Bern mean time ... is 7 degrees 26' 22.50". +# ... the meridian for Bern mean time ... is 7° 26' 22.50". # Expressed in time, it is 0h29m45.5s. # From Pierre-Yves Berger (2013-09-11): diff --git a/northamerica b/northamerica index dabca97..f4e38f8 100644 --- a/northamerica +++ b/northamerica @@ -424,8 +424,7 @@ Zone America/North_Dakota/New_Salem -6:45:39 - LMT 1883 Nov 18 12:14:21 # ...according to the Census Bureau, the largest city is Beulah (although # it's commonly referred to as Beulah-Hazen, with Hazen being the next # largest city in Mercer County). Google Maps places Beulah's city hall -# at 47 degrees 15' 51" N, 101 degrees 46' 40" W, which yields an offset -# of 6h47'07". +# at 47° 15' 51" N, 101° 46' 40" W, which yields an offset of 6h47'07". Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 12:12:53 -7:00 US M%sT 2010 Nov 7 2:00 @@ -458,7 +457,7 @@ Zone America/Denver -6:59:56 - LMT 1883 Nov 18 12:00:04 # California, northern Idaho (Benewah, Bonner, Boundary, Clearwater, # Kootenai, Latah, Lewis, Nez Perce, and Shoshone counties, Idaho county # north of the Salmon River, and the towns of Burgdorf and Warren), -# Nevada (except West Wendover), Oregon (except the northern 3/4 of +# Nevada (except West Wendover), Oregon (except the northern ¾ of # Malheur county), and Washington # From Paul Eggert (2016-08-20): diff --git a/southamerica b/southamerica index d97343e..c6c461c 100644 --- a/southamerica +++ b/southamerica @@ -1694,7 +1694,7 @@ Link America/Port_of_Spain America/Tortola # Virgin Islands (UK) # auspices of the National Institute for the Prediction of Time. It is unclear # exactly what offset was used during this period, though Ley No. 7200 of # 1920-04-23 used the Observatory of the National Meteorological Institute in -# Montevideo (S 34 deg. 54'33", W 056 deg. 12'45") as its reference meridian, +# Montevideo (34° 54' 33" S, 56° 12' 45" W) as its reference meridian, # retarding legal time by 15 minutes 9 seconds from 1920-04-30 24:00, # resulting in UT-04. Assume the corresponding LMT of UT-03:44:51 (given on # page 725 of the Proceedings of the Second Pan-American Scientific Congress, diff --git a/zone1970.tab b/zone1970.tab index a3b6b04..2d90ed7 100644 --- a/zone1970.tab +++ b/zone1970.tab @@ -12,7 +12,7 @@ # of ISO 3166 2-character country codes. See the file 'iso3166.tab'. # 2. Latitude and longitude of the zone's principal location # in ISO 6709 sign-degrees-minutes-seconds format, -# either +-DDMM+-DDDMM or +-DDMMSS+-DDDMMSS, +# either ±DDMM±DDDMM or ±DDMMSS±DDDMMSS, # first latitude (+ is north), then longitude (+ is east). # 3. Zone name used in value of TZ environment variable. # Please see the theory.html file for how zone names are chosen. -- 2.14.3

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models for timezones
by scs＠eskimo.com Feb. 14, 2018

Feb. 14, 2018

It gets mentioned here often enough, but there's another significant aspect of the tz database which I'm not sure is always sufficiently appreciated, and that's how significantly it extends on the old V7/SysV/Posix model of time zones. In that old model, a time zone has one offset from Greenwich/UTC, and maybe a second offset on top of that to realize "daylight saving time", and one set of rules for deciding when to transition to and from DST. (Once upon a time, that set of rules might have been limited to the pre-1987 rules for the United States, and it might have been hard-compiled into C code. With the advent of the Posix TZ environment variable definition it's at least a little bit more flexible.) But of course (and since the beginning) the tz database has expanded on that model in at least two different ways: 1. It's not limited to one "standard" and perhaps one "daylight" time per year; there can be almost arbitrarily many offsets and arbitrarily many transition dates between them. 2. Everything -- the "base" offset (not that this is even a meaningful concept any more), the alternate offsets, and the transition dates between them can vary over time. And of course the reasons for doing this were that both changes were necessary in order to accommodate the real world; the old SysV/Posix model simply couldn't cope. But this means that there's a significantly imperfect match between the tz database and any programming language or time-handling library that has any of these notions: * A timezone is primarily defined by its base offset from UTC. * It's an additional property of a timezone whether it observes DST or not. * If DST applies to a timezone, it's defined by an additional offset and a single set of rules defining when it applies. * DST always involves a positive offset from the base offset. You *might* be able to get away with a tricky and/or imperfect mapping between the tz database and a scheme that has some of those notions -- for example, the tz reference code successfully implements the C/Posix API, isdst flag and all -- but it's bound to have warts or imperfections. Everything I've said here is, I imagine, familiar and unsurprising to any regular reader of this list, but it probably bears a bit more discussion in the Theory file. I was going to suggest adding these two new bullets under "Extensions to POSIX": * The TZ database allows for considerably more variation in time per year beyond the familiar "standard" and "daylight savings" times. A time zone can have any number of variations per year, and they may have arbitrary designations, not limited to "standard" and "daylight". * The parameters defining a time zone can vary over time, reflecting the fact that this happens in the real world all the time, as legislatures continually redefine them. Whether and when a zone observes DST (or other variants), and even the zone's notional "base offset" from UTC, are variable. (Therefore it doesn't even really make sense to talk about a zone's "base offset", since it's not necessarily a single number.) But that's in the "Time and date functions" section, and easy to overlook. So maybe these words belong as a paragraph higher up, perhaps even in the initial "Scope of the tz database" section: Because the database's scope encompasses real-world timezones which have wide-ranging complexity and are always evolving, the model for describing time zones allows for considerably more variation in time per year beyond the familiar "standard" and "daylight savings" times. A time zone can have any number of variations per year, and they may have arbitrary designations, not limited to "standard" and "daylight". Furthermore, the parameters defining a time zone can vary over time. Whether and when a zone observes DST (or other variants), and even the zone's notional "base offset" from UTC, are variable. (Therefore it doesn't even really make sense to talk about a zone's "base offset", since it is not necessarily a single number.)

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Recommendations for stable list of timezone ids
by Tobias Lindaaker Feb. 14, 2018

Feb. 14, 2018

I am trying to compile a flat list of all tzids in the Time Zone Database in a way such that the position of a tzid remains the same in the list even in the face of future changes to the Time Zone Database. I would like to know if anyone could provide me with some insight into how (a prefix of) such a list could be generated from any version of the Time Zone Database. Or would this be something I would have to maintain myself from release to release of the Time Zone Database? The requirements I would have for generating this list would be that given two releases of the Time Zone Database, X and Y. If X is released before Y, then the list generated from X must be a prefix of the list generated from Y (and vice versa: if Y is released before X, the list generated from Y must be a prefix of the list generated from X). A simple alphabetical ordering is obviously not going to work, since for example the addition of America/Punta_Arenas in 2017a would end up before many of the tzids that existed in versions prior. Since I don't require this to work for all historical releases, my first thought was to start from a fairly recent release (tzdata2013h) and verify that I got the same order when sorting the timezones based on their earliest rule. However the removal of tzids (such as Canada/East-Saskatchewan in tzdata2017c) made this impossible, since any removal makes it impossible to ensure that prior versions are strict prefixes. It now seems as if I would have to maintain this list myself, tracking each release of the Time Zone Database and ensure that any tzids added to the Time Zone Database are appended to my list in release order. If possible I would very much prefer to avoid this, since it requires me to release updates of my software to track the releases of the Time Zone Database, I would much rather like it if my software could rely on the Time Zone Database available from the system where it was running. Finally some background on why (I think) I need to generate this type of list of tzids: I am improving the support for storing timestamp values in a database management system (Neo4j), and would like to avoid having to store the timezone component of zoned timestamps as a (variable length) text component, but rather store it as a fixed size integer offset into a table of tzids. Thus I need such a stable list of tzids. I have tried searching the archives of this mailing list for similar questions before posting, but have not been able to find such an entry. The closest I found were a few questions on how to translate the tzids to localized names. Since I did not read through the entire archives, but only did a search, I apologise in advance if this has been asked and solved before, and hope that you will be able to direct my attention to that thread. Thank you, Tobias

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