[tz] tz dependency lat & lng

Paul Eggert eggert at cs.ucla.edu
Thu Sep 5 23:18:58 UTC 2013

Guy Harris wrote:
> what particular administrative region of Kentucky would be the biggest one that should
> be tagged with timezone=America/Kentucky/Louisville?  Or *is* there no such region?

Sorry, I don't know.  That would require research.

The Shanks data could be examined
to find a set of locations whose time zone
histories equal that of Louisville since
1970, as far as Shanks is concerned.
But that would take a lot of work, I'm afraid.
Hundreds, probably thousands of locations
would have to be examined, by hand.
Or someone would have to scan the data
and try to automate the search.  Either
way, the results would not be that reliable.

More reliable would be to consult newspapers
of all the locations that plausibly have had
the same time zone history as Louisville since
1970, and check for time zone announcements
in these newspapers.

If you change the time horizon to 1950 instead
of 1970, you'll have more work to do, not only
because there are more newspapers to read and
more of them are not digitized, but also because
there is more local variance in the rules the further
you go back.

I hope it's understood I'm not volunteering to
do all this.

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