[tz] Fwd: TZDB Questions
eggert at cs.ucla.edu
Tue Aug 28 03:46:38 UTC 2018
[Forwarded with permission.]
-------- Forwarded Message --------
Subject: TZDB Questions
Date: Mon, 27 Aug 2018 17:52:53 -0700
From: Mikey Schott <maschott at gmail.com>
To: eggert at cs.ucla.edu
Hello, Dr. Eggert. First let me express my thanks to you for all of the
time and energy you have put into the upkeep of the time zone database. I
appreciate all of the thought and detail that goes into the decisions
regarding each zone.
I've been working extensively with the time zone database over the past
month to identify a list of currently unique time zones for use in a
front-end web application. I'd be happy to share the details of my work if
you are curious, but since its purpose is tangential to that of the time
zone database, I'll leave them out of this email.
The reason I'm writing is because after working so closely with the data, I
had a few questions I was hoping you could answer for me. I have more or
less completed the work I was doing, so these questions come more from
curiosity than necessity.
1. Has there been any consideration to move the source data into a more
structured format like csv, xml, or json? I realize I'm probably in the
minority here in terms of people who would find this useful.
2. The latest zone entry for some zones that no longer use dst still
point to dst rules, e.g. Asia/Tokyo and the Japan rule set even though dst
is no longer used in Japan . Is there a reason why some non-dst zones use
this method where they point to an outdated rule set whereas most non-dst
zones use no rule set (i.e. rule = '-')?
3. I've noticed that some zones just use a shortened version of their
offset for their format, whereas timeanddate.com gives them a more
descriptive format (e.g. Europe/Volgograd uses MSK vs. +03). Is there a
reason for the discrepancy? Does the time zone database error on the side
of caution here?
4. I believe that one of the primary purposes of the Link zones is to
ensure that there is a zone that covers every country. Is there a specific
list or source that the time zone database uses to decide the list of
countries that are covered? I noticed that Bouvet Island (BV) and Heard and
McDonald Islands (HM) are not included despite having ISO-3166-2 country
codes. (Although both have a population of 0, so it hardly qualifies as an
5. Do you have a favorite time zone? I've become quite fond of
Antarctica/Troll both for its name and its unique offset.
Thanks again for all of your work on the database. I've signed up for the
mailing list so I can keep up to date.
More information about the tz