[tz] [PATCH] tzdata: Asia/Ha_Noi: Add new timezone

Tim Parenti tim at timtimeonline.com
Sat Oct 4 23:33:32 UTC 2014


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...timparenti:2014-10-vietnam-wip-1

--
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.

-------------- next part --------------
From 2c371e8c25f29eeee1e45612d1b0f38d8d6fb705 Mon Sep 17 00:00:00 2001
From: Tim Parenti <tim at timtimeonline.com>
Date: Sat, 4 Oct 2014 16:22:06 -0400
Subject: Adjust Asia/Ho_Chi_Minh and Asia/Phnom_Penh between 1906 and 1911.

* asia (Asia/Ho_Chi_Minh, Asia/Phnom_Penh): Standard time of UT+7:06:30
was introduced on 1906-07-01 and observed until the introduction of
UT+7:00 on 1911-05-01.
* NEWS: Document this.
---
 NEWS | 11 +++++++++++
 asia | 23 +++++++++++++++++++----
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/NEWS b/NEWS
index 5e33102..6640268 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,16 @@
 News for the tz database
 
+Unreleased, experimental changes
+
+  Changes affecting past time stamps
+
+    The date of the introduction of standard time in Asia/Ho_Chi_Minh and
+    Asia/Phnom_Penh was 1906-07-01, not 06-09; additionally, UT+7:00 was
+    adopted in these locations on 1911-05-01, not 03-11.  The time has been
+    adjusted by a few seconds during this time.
+    (Thanks to Trần Ng�c Quân for reporting the problem.)
+
+
 Release 2014h - 2014-09-25 18:59:03 -0700
 
   Changes affecting past time stamps
diff --git a/asia b/asia
index 0be896b..7ca109f 100644
--- a/asia
+++ b/asia
@@ -272,8 +272,8 @@ Zone	Asia/Rangoon	6:24:40 -	LMT	1880        # or Yangon
 
 # Cambodia
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
-Zone	Asia/Phnom_Penh	6:59:40 -	LMT	1906 Jun  9
-			7:06:20	-	SMT	1911 Mar 11  0:01 # Saigon MT?
+Zone	Asia/Phnom_Penh	6:59:40 -	LMT	1906 Jul  1  0:00
+			7:06:30	-	PLMT	1911 May  1  0:00 # Phù Liễn MT
 			7:00	-	ICT	1912 May
 			8:00	-	ICT	1931 May
 			7:00	-	ICT
@@ -2775,14 +2775,29 @@ Zone	Asia/Tashkent	4:37:11 -	LMT	1924 May  2
 # from Saigon's location.  For now, ignore this and stick with Shanks
 # and Pottenger.
 
+# From Trần Ng�c Quân (2014-10-03):
+# http://www.thoigian.com.vn/?mPage=P80D01
+# is a good Vietnamese-language source for several 20th-century decrees
+# related to time in Vietnam.
+#
+# Translation from Brian Inglis (2014-10-04):
+# "When completed construction Observatory Phu Lien, Indochina government
+# decree dated 1906-06-09 (Official Gazette dated 1906-06-18 Indochina)
+# fixed now legal for all countries of Indochina under the meridian passing
+# through Phù Liễn (104°17'17" east of Paris) from 0 hours on 1906-07-01."
+#
+# From Tim Parenti (2014-10-04):
+# The Paris meridian is at 2°20'14"; adding 104°17'17" gives 106°37'31", or
+# UT+7:06:30.
+
 # From Arthur David Olson (2008-03-18):
 # The English-language name of Vietnam's most populous city is "Ho Chi Minh
 # City"; use Ho_Chi_Minh below to avoid a name of more than 14 characters.
 
 # From Shanks & Pottenger:
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
-Zone	Asia/Ho_Chi_Minh	7:06:40 -	LMT	1906 Jun  9
-			7:06:20	-	SMT	1911 Mar 11  0:01 # Saigon MT?
+Zone	Asia/Ho_Chi_Minh	7:06:40 -	LMT	1906 Jul  1  0:00
+			7:06:30	-	PLMT	1911 May  1  0:00 # Phù Liễn MT
 			7:00	-	ICT	1912 May
 			8:00	-	ICT	1931 May
 			7:00	-	ICT
-- 
2.1.1

-------------- next part --------------
From 3abaa481ae9709135ae0a494bd5a417672a6cdc3 Mon Sep 17 00:00:00 2001
From: Tim Parenti <tim at timtimeonline.com>
Date: Sat, 4 Oct 2014 19:19:51 -0400
Subject: Update Asia/Ho_Chi_Minh and create Asia/Hanoi.

* asia (Asia/Ho_Chi_Minh): South Vietnam remained on UT+08:00 until
1955-07, not 1931-05.  It also observed UT+08:00 from 1960-01 until
1975-06-13.
(Asia/Hanoi): New zone to represent timekeeping in North Vietnam,
especially prior to reunification.
* zone.tab, zone1970.tab (VN): Add Asia/Hanoi.
* NEWS: Document this.
---
 NEWS         |  8 +++++++-
 asia         | 14 +++++++++++++-
 zone.tab     |  1 +
 zone1970.tab |  1 +
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 6640268..c17787d 100644
--- a/NEWS
+++ b/NEWS
@@ -7,7 +7,13 @@ Unreleased, experimental changes
     The date of the introduction of standard time in Asia/Ho_Chi_Minh and
     Asia/Phnom_Penh was 1906-07-01, not 06-09; additionally, UT+7:00 was
     adopted in these locations on 1911-05-01, not 03-11.  The time has been
-    adjusted by a few seconds during this time.
+    adjusted by a few seconds during this time.  Also, Asia/Ho_Chi_Minh has
+    been updated to better reflect the time in South Vietnam between 1931 and
+    1975.
+    (Thanks to Trần Ng�c Quân for reporting the problems.)
+    
+    A new zone, Asia/Hanoi, has been created to reflect the time in North
+    Vietnam prior to reunification.
     (Thanks to Trần Ng�c Quân for reporting the problem.)
 
 
diff --git a/asia b/asia
index 7ca109f..5b54b6b 100644
--- a/asia
+++ b/asia
@@ -2790,6 +2790,16 @@ Zone	Asia/Tashkent	4:37:11 -	LMT	1924 May  2
 # The Paris meridian is at 2°20'14"; adding 104°17'17" gives 106°37'31", or
 # UT+7:06:30.
 
+# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+Zone	Asia/Hanoi	7:03:24 -	LMT	1906 Jul  1  0:00
+			7:06:30	-	PLMT	1911 May  1  0:00 # Phù Liễn MT
+			7:00	-	ICT	1942 Dec 31 23:00
+			8:00	-	ICT	1945 Mar 14 23:00
+			9:00	-	JST	1945 Sep  2
+			7:00	-	ICT	1947 Mar 31 23:00
+			8:00	-	ICT	1954 Oct  9 23:00
+			7:00	-	ICT
+
 # From Arthur David Olson (2008-03-18):
 # The English-language name of Vietnam's most populous city is "Ho Chi Minh
 # City"; use Ho_Chi_Minh below to avoid a name of more than 14 characters.
@@ -2799,7 +2809,9 @@ Zone	Asia/Tashkent	4:37:11 -	LMT	1924 May  2
 Zone	Asia/Ho_Chi_Minh	7:06:40 -	LMT	1906 Jul  1  0:00
 			7:06:30	-	PLMT	1911 May  1  0:00 # Phù Liễn MT
 			7:00	-	ICT	1912 May
-			8:00	-	ICT	1931 May
+			8:00	-	ICT	1955 Jul
+			7:00	-	ICT	1960 Jan
+			8:00	-	ICT	1975 Jun 13 # Reunification
 			7:00	-	ICT
 
 # Yemen
diff --git a/zone.tab b/zone.tab
index 084bb2f..8fd436b 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	+2102+10551	Asia/Hanoi
 VN	+1045+10640	Asia/Ho_Chi_Minh
 VU	-1740+16825	Pacific/Efate
 WF	-1318-17610	Pacific/Wallis
diff --git a/zone1970.tab b/zone1970.tab
index f0e38f1..62258eb 100644
--- a/zone1970.tab
+++ b/zone1970.tab
@@ -363,6 +363,7 @@ UY	-3453-05611	America/Montevideo
 UZ	+3940+06648	Asia/Samarkand	west Uzbekistan
 UZ	+4120+06918	Asia/Tashkent	east Uzbekistan
 VE	+1030-06656	America/Caracas
+VN	+2102+10551	Asia/Hanoi
 VU	-1740+16825	Pacific/Efate
 WF	-1318-17610	Pacific/Wallis
 WS	-1350-17144	Pacific/Apia
-- 
2.1.1



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