Time zones in the Global Gazetteer
alan at allm-geodata.com
Thu Feb 1 10:44:00 UTC 2001
members of this list may be interested in the following extract from a
recent newsletter that I sent out:
I have now included canonical time zone names in the Global Gazetteer.
The canonical name (e.g. America/New_York) is then the key to time zone
offset from GMT, and also the daylight saving time rules (date and time on
and off), using the tztab format.
There are still some gaps, most notably where the rule for assigning the
name cuts across established administrative boundaries and also where I do
not yet know the province and/or lower administrative areas within which
the place falls.
I am currently carrying out research to resolve these problems, but about
90% of records (including 'trains and boats and planes') now have
canonical names assigned. Changes to zones and DST are regularly monitored
and the records updated.
There is a short paper on the web site that explains this in a bit more
detail, describes all the various fields that are available, and explains
the tztab format for DST rules.
Other formats can be output if required.
I am not attempting to hold the wealth of historical data that the tz
database holds. I am only interested in the current and future situation.
There are two major problems that I am tackling:
1. the rather generic descriptions that are sometimes used in the tz data
and trying to match these to my hierarchy of country/province/lower level
admin area/town. For example 'far western Texas' or 'eastern Lugansk'. I
am trying to clarify these where possible and will report back, if I find
any useful information.
2. Completing the data that is in the Global Gazetteer, so that I can use
the tz rules. This especially applies to countries such as Indonesia where
many places do not yet have province name assigned, or in trying to find
out which settlements fall within the county of Yancowinna in Australia
The GLOBAL GAZETTEER: the world on file
Tel: +44 (0) 1202 417 477
More information about the tz