On 22/10/2007, Sanjay Vakil <[EMAIL PROTECTED]> wrote: > It appears, in looking at the zone data, that there are multiple > "city" entries in what much of the world considers a single timezone. > > I'm assuming this is for historical reasons -- Detroit and New York > were not always in the same timezone.
Yes, your assumption is correct. Detroit and New York have been different in the past, but since 27 April 1975 have used identical rules. The source tz database (http://www.twinsun.com/tz/tz-link.htm) lists all the timezones available for each country rather than just those with different current and future rules. > Is there a way to get a list of just those timezones which are > actually different going forward? There isn't a simple way to do this with TZInfo - you'd have to compare each future TimezonePeriod for each pair of Timezones to determine if they were the same. If they were the same, you'd need a rule of some sort to determine which zone you will use, so this might require some manual intervention. > I guess this relates back to my earlier question about showing > PST/EST/MST/CST. For the US, there are a set of linked timezones defining the distinct set of rules that are in force. These are: US\Alaska US\Aleutian US\Arizona US\Central US\East - Indiana US\Eastern US\Hawaii US\Indiana - Starke US\Michigan US\Mountain US\Pacific US\Samoa Phil -- Phil Ross http://tzinfo.rubyforge.org/ -- DST-aware timezone library for Ruby _______________________________________________ TZInfo-users mailing list [email protected] http://rubyforge.org/mailman/listinfo/tzinfo-users
