[tz] Timezone history for some Pacific Islands.

Tim Parenti tim at timtimeonline.com
Thu Nov 29 00:27:08 UTC 2018

> +# From Paul Eggert (2018-11-18):
> +# "Seize the High Ground" says

I assume it was supposed to say something?

Tim Parenti

On Mon, 19 Nov 2018 at 02:24, Paul Eggert <eggert at cs.ucla.edu> wrote:

> Thanks for all that work on Pacific island time zone history. Proposed
> patch
> attached and installed in the development version; comments welcome. Some
> comments on your remarks:
> > * Then Pacific theater of WWII started and Japan slowly lose control on
> the
> > island. The webpage I linked above contain no information during this
> > period of time.
> It was chaotic. The attached patch tries to fill in some of the blanks.
>  > * Also, the NYT article linked in that website say the jump from GMT-12
> to
>  > GMT+12 in year 1993 skipped Saturday that day, however the comment in tz
>  > database from that year say it skipped Friday. That seems to be an
>  > inconsistency that should be investigated, and the comment should
> probably
>  > be annotated accordingly if the comment was not accurate
> Thanks, that is indeed an error in tzdata. I copied a datum from Shanks
> incorrectly: Shanks said "24:00" but I treated it as 00:00. Fixed in the
> attached patch.
> > * The site also pointed out that currently tzdata say Pacific/Kwajalein
> > switched from GMT+11 to GMT-12 in 1969 October without explanation,
> however
> > an 1993 article from NYT say it synchorized its day with US mainland
> about
> > 40 years ago and thus the switch should occur at around 1950s instead.
> The NYT (actually, AP) article is vague and possibly wrong about this. The
> article says the earlier switch was "40 years ago when the United States
> Army
> established a missile test range here". However, the Kwajalein Test Center
> was
> established on 1960-10-01 and was run by the US Navy. It was transferred
> to the
> US Army on 1964-07-01. See
> <https://history.army.mil/html/books/070/70-88-1/cmhPub_70-88-1.pdf>.
> Given that Shanks was right on the money about the 1993 change, I'm
> inclined to
> take Shanks's word for the 1969 change unless we find better evidence
> otherwise.
> > ANd then additional note for Bonin Islands:
> > While not part of the Southern Islands, in the period of time during
> > 1952-1968, Bonin Islands were placed under American administration. It
> > would probably be worth investigating whether they're following the
> > Japanese time or the Mariana time or some other time standard at the
> time.
> My guess is that they stayed on Japanese time; why switch?
> > * Currently tz database say Guam stopped using local mean time at 1901
> but
> > a 1902 earthquake report on Guam seems to be using LMT in the report when
> > compares to the time the earthquake recorded on the Philippines (the site
> > note that it take times for earthquake wave to transmit and thus the time
> > different between records in different place would not be identical to
> the
> > time different)
> > ** The site say Shanks used 1901 end date for LMT time for a number of
> > places around the world, probably using them as placeholder. Maybe those
> > 1901 end date should be nuked from tz database?
> We can't simply erase instances of "1901", as we need to have a transition
> date.
> If we can come up with better dates we should use them. It's not entirely
> implausible that Germany introduced time zones to the Pacific in 1901, as
> the
> imperial government of Germany didn't obtain control of much of this area
> until
> 1899 (at least, that's what Wikipedia says...).
> > * Then in year 1959 there's a daylight saving time act passed for Guam.
> > There is a table on the site that include list an link to time and order
> > for implementation and cancellation of DST at Guam but the implementation
> > time seems to be all over the place according to the list.
> It is indeed all over the place, but the cited sources look quite
> official. I
> added these transitions to the proposed patch.
> > The last time
> > the DST was implemented in Guam according to the table seems to be 1977
> > although I am not sure about the completeness of the table. If so then
> > maybe a new zone for CNI would need to be created as it's after 1970 and
> > the DST should be applicable to Guam only?
> It's not clear whether Saipan etc. followed Guam's lead here. It would be
> good
> to get more data. In the meantime I'm inclined to keep the entries unsplit.
> While we're on this topic I noticed that some of the former Spanish East
> Indies
> should have American-to-Asian transitions at the end of 1844.
> Oh, and the British occupied Manila from 1762-10-06 through 1764-04. I
> wonder
> whether Manila switched temporarily from American to Asian time during
> that
> occupation? I added a comment about this.
> Thanks again for all this work.
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