[tz] User time zones
Thom at pointsix.com
Wed Dec 7 21:23:34 UTC 2011
Right. I use the long name exclusively.
From: tz-bounces at iana.org [mailto:tz-bounces at iana.org] On Behalf Of Mark Davis ?
Sent: Wednesday, December 07, 2011 2:14 PM
To: Steven Abner
Cc: tz at iana.org
Subject: Re: [tz] User time zones
I just want to make sure that people realize that the tz abbrevations are at most useful as internal identifiers.
Most of them are not recognizable by end users at all, and are not appropriate for display or choice by end users.
— Il meglio è l’inimico del bene —
On Wed, Dec 7, 2011 at 11:03, Steven Abner <pheonix at zoomtown.com> wrote:
Thank you for the input!
Maybe I should clarify the file. This is an attempt to allow users or peoples access to their times zones.
A date string, publication, scanned document, broadcast, etc. can contain the time zone. The tz database
even includes these time zones. Some functions even require them to operate.
Take the "conceptional problem" example. BRT/BRST are the abbreviations used for the Brazilia Time
zone. The ":America/Sao_Paulo" file/location is defined as using the Brazilia Time rule "Brazil". Since this
location follows Brazilia Time, it is given the abbreviation for that zone. It is not given a synonym for an
offset from UTC. An example to clarify could be the recent offset change of Moscow Time zone from an
offset of 3 to that of 4. MSK is the abbreviation for the regional time zone using the standard time definition of
that zone. The ":Europe/Moscow" file assigns the offset used for that zone. The Moscow file can now safely
be used to represent the "Moskva" rule that is the regional time zone, rather than creating a new zone. Since
it is the only location that uses that time zone, one can assign ":Europe/Moscow" file as a link.
The GMT example is an oddity case. GMT can stand both for a time, :Etc/GMT which I assume is the
observatory location, and the English Isles regional time zone. I am also guessing that that was one of
the reasons for UTC, so that an offset of 0 from the observatory would be taken as the offset rather the
the time zone the English use.
I also only compiled the times, as stated in the file, from 1970 to present. It is known that abbreviations
are not unique. However, the list of conflicting zones, see near the end of file, is really small. Especially
when Australia is assigned the local, state, country definitions and Indonesia.
I will look farther into the assignment to see if any additional zones need creation. As it is clear that a
present location might not actually be assigned to a time zone. I did not try to resolve conflicts, just link
to the base location file that defined the actual time zone for a region. I did try to make sure to avoid not
linking a file that didn't represent the regional time zone, but best to be safe.
Thanks again, was helpful!
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