FW: Time Zone naming

Olson, Arthur David (NIH/NCI) [E] olsona at dc37a.nci.nih.gov
Thu Dec 4 16:04:11 UTC 2008

I'm forwarding this message from Martin Barnes, who is not on the time
zone mailing list.

Those of you who are on the list, please direct replies appropriately.


From: Martin Barnes [mailto:barnes at yahoo-inc.com] 
Sent: Friday, November 28, 2008 11:48
To: tz at lecserver.nci.nih.gov
Subject: Time Zone naming

I have a question related to the accepted standard for expressing the
"Olsen" name where multiple zones exhibit the same "behaviour" in terms
of belonging to the same country, having the same UTC offset and exactly
the same DST rules.

For example, it appears that all clocks within all locations within
Argentina will have the same time all year round. The 12 zones reveal
the same behaviour. The same is true of China and a number of other
I have been aware of the concept of a "consolidated" or "preferred" time
zone which is a combined zone that takes the name of the most important
location (eg. "America/Buenos_Aires" in the case of Argentina)

Do these combined "super" zones exist? If so, is there information
available that indicates how the individual zones roll up?

My enquiry relates to a need to provide information that can identify
the correct timezone for every place (city, postcode, county, state, etc
etc) on earth via a back-end mapping service that calculates the spatial
relationship between the place coordinate and the timezone boundary.
I am looking to build up an accurate timezone boundary map essentially
using existing map objects as building blocks.

Many thanks
-Martin Barnes
GeoData Manager
Yahoo! Geo Technologies
Geo Informatics team

More information about the tz mailing list