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 countries.

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

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GeoData Manager

Yahoo! Geo Technologies

Geo Informatics team

London