FW: Theory - zone name, zone creation, zone lifetime

Paul Eggert eggert at cs.ucla.edu
Sun Sep 11 13:52:16 UTC 2011

On 09/11/11 04:18, Olson, Arthur David (NIH/NCI) [E] wrote:

> From: Mr tobias conradi [tobias_conradi at yahoo.de]
> Sent: Sunday, September 11, 2011 12:19 AM
> 1) Where are these regions listed?
> The only lists of geographical areas I could find are:
> - the zones in zone.tab
> - (current) countries in iso3166.tab

Yes, that's where the regions are listed in the database.
There are efforts to list the boundaries of the regions,
but these are outside the scope of the current database.

> Theory reads:
> Use ISO 3166 (see the file iso3166.tab) to help
> decide whether something is a country.
> [...]
> or when locations change countries
> (e.g. Hong Kong from UK colony to China)
> Issue:
> 1) "help to decide" - decision process is undefined.

It is not a deterministic algorithm; there are border cases
that require human judgment.

> 2) Hong Kong is listed in iso3166.tab as HK.
> For the purpose of zone creation is it
> 2a) a country,

Yes, that's right.

> Theory reads:
> Within a file name component, use only ASCII letters
> Issue:
> 1) It is not defined what the term
> "file name component" refers to in the
> context of zone naming.

A maximal name component that does not contain '/'.

> Theory reads:
> E.g. prefer `Paris' to `France', since
> France has had multiple time zones.
> Issue:
> 1) It does not matter what zones France "had" in the past.
> 2) It may matter that Europe/Paris might be split in the future.

Yes, (2) is the point.

> 3) There is no proof in zone.tab that France had
> multiple time zones at all

It did, during both World War I and World War II.  Shanks & Pottenger
partition France into 28 distinct regions.  But this sort of detail
isn't needed in the table.

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