[tz] [PATCH 2/3] Replace some zones with links when that doesn't lose non-LMT info.
Brian Inglis
Brian.Inglis at systematicsw.ab.ca
Tue Sep 3 08:15:21 UTC 2013
On 2013-09-03 01:34, Paul Eggert wrote:
...
> Link to America/Port_of_Spain instead of having a separate zone
> that differs only in LMT. Each LMT entry is just a placeholder for
> unavailable info, and by itself does not justify a separate zone.
> Using just one zone simplifies maintenance, makes the runtime
> a bit smaller, and can help simplify user selection of zones.
> * southamerica (America/Aruba): Likewise, for America/Curacao.
> * backward (America/Virgin):
> * northamerica (America/St_Barthelemy, America/Marigot):
Folks seem to have forgotten that initial LMT entries contain the Standard Time
start date, as well as the prior GMTOFF based on longitude of that location.
While I agree that merging zones with different GMTOFF makes no significant
difference, merging zones with different Standard Time start date loses useful
historical data, unless the tzdb is seen mainly as a source of DST changes since
1970.
In the changes highlighted below, Standard Time start dates vary from 1890-1921,
with some different dates in 1911-1912.
Zones should be merged only if all linked locations have the same Standard Time
start date, if we wish to maintain the history of when Standard Time was
established in each time zone.
...
> # Anguilla
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/Anguilla -4:12:16 - LMT 1912 Mar 2
> - -4:00 - AST
> +Link America/Port_of_Spain America/Anguilla
>
> # Antigua and Barbuda
> # Zone NAME GMTOFF RULES FORMAT [UNTIL]
> @@ -2871,9 +2869,7 @@ Zone America/Havana -5:29:28 - LMT 1890
> -5:00 Cuba C%sT
>
> # Dominica
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/Dominica -4:05:36 - LMT 1911 Jul 1 0:01 # Roseau
> - -4:00 - AST
> +Link America/Port_of_Spain America/Dominica
>
> # Dominican Republic
>
> @@ -2922,18 +2918,13 @@ Zone America/El_Salvador -5:56:48 - LMT 1921 # San Salvador
> -6:00 Salv C%sT
>
> # Grenada
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/Grenada -4:07:00 - LMT 1911 Jul # St George's
> - -4:00 - AST
> -
> +Link America/Port_of_Spain America/Grenada
> # Guadeloupe
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/Guadeloupe -4:06:08 - LMT 1911 Jun 8 # Pointe a Pitre
> - -4:00 - AST
> +Link America/Port_of_Spain America/Guadeloupe
...
> # Montserrat
> -# From Paul Eggert (2006-03-22):
> -# In 1995 volcanic eruptions forced evacuation of Plymouth, the capital.
> -# world.gazetteer.com says Cork Hill is the most populous location now.
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/Montserrat -4:08:52 - LMT 1911 Jul 1 0:01 # Cork Hill
> - -4:00 - AST
> +Link America/Port_of_Spain America/Montserrat
...
> # St Kitts-Nevis
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/St_Kitts -4:10:52 - LMT 1912 Mar 2 # Basseterre
> - -4:00 - AST
> +Link America/Port_of_Spain America/St_Kitts
>
> # St Lucia
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/St_Lucia -4:04:00 - LMT 1890 # Castries
> - -4:04:00 - CMT 1912 # Castries Mean Time
> - -4:00 - AST
> +Link America/Port_of_Spain America/St_Lucia
...
> # St Vincent and the Grenadines
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/St_Vincent -4:04:56 - LMT 1890 # Kingstown
> - -4:04:56 - KMT 1912 # Kingstown Mean Time
> - -4:00 - AST
> +Link America/Port_of_Spain America/St_Vincent
...
> # British Virgin Is
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/Tortola -4:18:28 - LMT 1911 Jul # Road Town
> - -4:00 - AST
> +Link America/Port_of_Spain America/Tortola
>
> # Virgin Is
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/St_Thomas -4:19:44 - LMT 1911 Jul # Charlotte Amalie
> - -4:00 - AST
> +Link America/Port_of_Spain America/St_Thomas
...
> # Aruba
> -# Zone NAME GMTOFF RULES FORMAT [UNTIL]
> -Zone America/Aruba -4:40:24 - LMT 1912 Feb 12 # Oranjestad
> - -4:30 - ANT 1965 # Netherlands Antilles Time
> - -4:00 - AST
> +Link America/Curacao America/Aruba
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