[tz] Comments and mapping of tz zones to the real world

Tobias Conradi tobias.conradi at gmail.com
Wed May 9 11:51:52 UTC 2012

Guy Harris,

thanks a lot for this analysis and the detailed descriptions of the
selection processes.

I forgot a /not/ in my message:
"I would /not/ use one software to
determine the extend of the database."

>> tzselect, which according to tzcode2012b/tzselect.8.txt seems to use
>> the comments column from the zone.tab.
> Yes, it does use that.  Perhaps that column should be called "description" rather than "comments", so that it's not confused with "comments" in the sense of
>        # Lines beginning with `#' are comments.
> in zone.tab.
I strongly support your proposal to better distinguish between
comments in the source code sense and the text in the comment field of
zone.tab. Renaming the field to "Description" sounds good to me. It
allows for geographic description as well as for current real world
time zone information as "Moscow+00" or "Eastern Standard Time".

>> But for Russia (map at http://efele.net/maps/tz/russia/ ) the zone.tab
>> data is not sufficient for the zones:
>> Europe/Moscow Moscow+00 - west Russia
>> Europe/Volgograd      Moscow+00 - Caspian Sea
>> Europe/Samara Moscow+00 - Samara, Udmurtia
>> The comments in the europe file give for Europe/Volgograd
>> # Astrakhanskaya oblast', Kirovskaya oblast', Saratovskaya oblast',
>> # Volgogradskaya oblast'.
>> Without that information mapping may fail. This information is needed.
> So perhaps either
>        1) zone.tab needs to have something better than "Moscow+00 - {xxx}" in it
> or
>        2) zone.tab needs more fields
> or perhaps whatever *localized* databases are used by
> various OS's/desktop environments' time zone
> selection UIs needs to have more information.

The proposal at
would follow 1) and improve {xxx}. to have a mapping to the real world.

>CN .... Asia/Urumqi most of Tibet & Xinjiang
>... probably not sufficient for a "general users" user interface.

It might be good to change this to the more common "most locations", i.e.

Asia/Urumqi Tibet & Xinjiang - most locations

Same for
America/Halifax	Atlantic Time - Nova Scotia (most places),...
America/Halifax	Atlantic Time - Nova Scotia (most locations),...

/and/ to specify this in the Theory file.

Maybe if there is
"XXX - most locations"
it should be required to have at least one line
"XXX - <some locations not included in most locations>"

Tobias Conradi
Rheinsberger Str. 18
10115 Berlin


More information about the tz mailing list