Time Zone Names

Markus Kuhn Markus.Kuhn at cl.cam.ac.uk
Wed Sep 30 08:25:49 UTC 1998

Ken Pizzini wrote on 1998-09-30 00:22 UTC:
> Markus Kuhn wrote:
> >  As I have pointed out before, I don't like the
> > continent prefix in the Olson/style names, therefore I do not want to
> > make this particular syntax immortal in an ISO standard (I much prefer
> > just ":Paris" over "Europe/Paris").
> Interesting example.  Is ``:Paris'' "Paris, France", or "Paris, Texas",
> or perhaps one of the other half-dozen or so cities named Paris?

Remember that time zone names refer to the most populated area within a
region with common time zone history. This rule should already resolve
practically all ambiguities. If there are really two Paris that are both
candidates for TZ entries as they are both most populated areas in
different time zone regions, then they should get qualifiers added (or
at least all but the largest one should). This way, all those little
Paris clones in the US are not of concern any more, and "Paris" would be
guaranteed to refer to the real big one under the Eiffel's tower.

To remove any ambiguity, we have the coordinates of the place, and a GUI
TZ selector tools can easily indicate on a map what region we are
talking about.

> I'm not particularly thrilled with the continent name either, but it
> does serve a purpose.

But not very well. How many Paris are there in the US alone?

An ISO 3166-1 country code or where necessary ISO 3166-2 country/region
code for those hypothetical cases where there could occur an ambiguity
would serve this purpose much better. The continent names come from the
file organization of the Olson DB, and this implementation detail should
IMHO not leak through to the name space. That's why I am not particular
happy with seeing iCalendar people making these continent/city names
more permanent by quoting them in their standards.

If I had to design proper tz names from scratch, they might look more



Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK
email: mkuhn at acm.org,  home page: <http://www.cl.cam.ac.uk/~mgk25/>

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