[tz] Number of active tz regions?

David Patte ₯ dpatte at relativedata.com
Wed Jul 17 16:53:35 UTC 2013

Thanks for checking this for me.

I also have a related question about the creation of new zones.

Am I correct to say, that for every lat/lng there (theoretically) exists 
a zone in that country and/or region that represents its timezone rules 
since 1970; that if no tz zone exists in that country and/or region that 
represents it clock rules since 1970 correctly, that a new zone is to be 
created in tz for it?

I am looking at this from the perspective of timezone boundaries; that 
tz boundaries (theoretically) don't change unless new tz zones are 
created, or it is discovered that a latlng's clock 'rules' since 1970 
can be more accurately be described by a different tz zone?

On 2013-07-17 10:38, Paul_Koning at Dell.com wrote:
> On Jul 16, 2013, at 10:54 PM, David Patte ₯ wrote:
>> I guess I could calculate it myself using the data that I have, but does anyone know off-hand how many tz regions are currently in use?
> Depends on how you define "in current use".  Looking at the zone output files (the ones produced from the text files), one system has 580 zone files, another 587.  In that first system, there are 436 unique files (the remainder being links, or files with the same content but a different name).  The other system has 321 unique files, because it uses a modified zic that discards any data older than 2001.
> So there are 436 distinct regions if you go back to the beginning of the zone data, and 321 if you consider only places that differed sometime in the 21st century.  That's a surprisingly high number.
> 	paul


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