[tz] Ulyanovsk, Altai Krai and Altai republic on their way to change time zones
eggert at cs.ucla.edu
Mon Feb 22 19:06:07 UTC 2016
On 02/22/2016 09:07 AM, Matt Johnson wrote:
> it looks like both of the new zones also have differing history (other
> than LMT) from the zones they were split from. Was this intentional?
Yes, the pre-1991 data come from Shanks & Pottenger, which is cited
earlier in the 'europe' file as being the default source for old data.
Shanks is not a good source but is the best we have for old data, and it
says the new zones differ before 1970. My guess is that Shanks tried to
find the dates for when these locations changed hands during the Russian
Civil War, and used them to guess time transitions. Quite a bit of
guesswork there, but it's the best we've got.
> Asia/Barnaul should be the same as Asia/Omsk before 2016, but looks
> like they also deviate considerably before that. Looks like rule
> Russia is on the wrong lines, Omsk has an extra 2011 entry that
> Barnaul doesn't, and the offsets differ as well.
Thanks for checking that. I attempted to glue together the Shanks data
with our post-1991 information. We have gaps in our information about
the 1990s, so I guessed the gaps. Now that you mention it, my guess was
probably not the best, as it should have prioritized our post-2000 data
(which is more reliable) over our pre-2000 data. Also, I should
definitely document that it's a guess, just like our guess about Tomsk
in 1993. Further proposed patch attached (I've installed this in the
experimental github version).
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 2289 bytes
Desc: not available
More information about the tz