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#1821 ✓resolved
Reuben Sivan

time_zone.rb: which Georgetown?

Reported by Reuben Sivan | January 29th, 2009 @ 05:20 PM | in 2.x

ActiveSupport::TimeZone.MAPPINGS contains an entry mapping 'Georgetown' to "America/Argentina/San_Juan". There is no city or place named 'Georgetown' in Argentina. However I am hesitant whether to propose deleting this entry or trying to guess which of the many Georgetown cities in the world might be preferred here. Any comments?

Comments and changes to this ticket

  • Geoff Buesing

    Geoff Buesing January 29th, 2009 @ 07:52 PM

    I think this is the Georgetown in Argentina -- maybe it's a district of the city of Cordoba, Argentina?,+Argentina+Cordoba,+Capital,+Argentina&sll=37.0625,-95.677068&sspn=57.292148,75.234375&ie=UTF8&cd=2&geocode=FTQwIf4dKOcs_A&split=0&ll=-31.391158,-64.160156&spn=31.082451,37.617188&z=5&iwloc=addr

    Fwiw, Windows has a "Buenos Aires, Georgetown" time zone:

    Also fwiw, this zone has been wired to "America/Argentina/San_Juan" since the first version of the tzinfo_timezone plugin (which the current Rails TimeZone mapping is based on). So, this set has been tested out in the wild for nearly three years now.

  • Reuben Sivan

    Reuben Sivan January 29th, 2009 @ 08:45 PM

    I agree it is not worth investing much into it. But FYI I was born in Argentina and my wife lived many years in both Córdoba, Argentina, and San Juan, Argentina, and neither of us can find a town by the name of Georgetown of any significant size in Argentina.

  • Reuben Sivan

    Reuben Sivan January 29th, 2009 @ 08:59 PM

    Also, I interpret the Buenos Aires/Georgetown time zone as the US Pacific/Tijuana time zone: they represent two different geographic areas sharing a time zone. Before Argentina moved (recently) to a complicated (and not widely observed by all provinces) daytime savings scheme, it is likely the Buenos Aires time zone coincided (a few years back) with the Georgetown, Guyana time zone, which might explain the confusion here. In my OS X 10.5 there is a time zone defined for Georgetown, Guyana, which coincides with San Juan, PR, which makes me believe that's the town they had in mind originally.

  • Geoff Buesing

    Geoff Buesing January 30th, 2009 @ 03:11 PM

    I appreciate your help and persistence with this issue. It does make me realize that at best, the "Georgetown" zone is ambiguous, and potentially confusing.

    Regarding Buenos Aires and Georgetown, Guyana having similar zones -- as far as I can tell, there are no similarities in the standard utc offsets & DST offsets -- up until the recent Brazilian DST change, Buenos Aires was -3 hours from utc for the entire year, and Puerto Rico was -4 hours for the entire year. With the new rules, Buenos Aires is -3 standard offset, and -2 DST. So, would be strange if Windows put these two different zones into the same selection.

    However, I do find it odd that, other than Google maps, I can't find any other evidence of a Georgetown in Argentina on the net. The fact that you and your wife have lived there and have never heard of it makes it seem even more suspect.

    I guess if this zone were wrong, there is a possibility that it could go unnoticed for three years -- maybe very few people have used it, if the labeling is unclear.

    As a next step, we could ask a current Brazilian resident if they've ever heard of a Georgetown, and if it would make sense to them in a time zone select.

  • José Valim

    José Valim January 30th, 2009 @ 10:04 PM

    I'm brazilian and I've never heard of Georgetown around here. :)

  • José Valim

    José Valim January 22nd, 2010 @ 08:34 PM

    • Assigned user set to “Geoff Buesing”

    Geoff, any news here?

  • Geoff Buesing

    Geoff Buesing January 26th, 2010 @ 04:08 AM

    Looking at the historical data, Buenos Aires and Georgetown, Guyana shared the same base UTC offset (-03:00) from 1975 to 1991, which is probably why Windows combines these two zones into one selection ("Buenos Aires, Georgetown").

    Since 1991, Guyana has had a -04:00 UTC offset. Seems odd if Windows still hasn't updated that, but maybe Windows users in that part of the world are used to selecting a different zone? Maybe they weren't aware that the "Georgetown" in "Buenos Aires, Georgetown" was supposed to refer to them, and not a city in Argentina?

    The ActiveSupport time zones look to be derived from the Windows list, with zones like "Islamabad, Karachi, Tashkent" broken out into separate zones, hence the separate zones for Buenos Aires and Georgetown.

    Given all this, and given that there's no other Georgetown of any size in South America that this could be, I think the best step forward will be to wire the ActiveSupport Georgetown zone to "America/Guyana" (we'll need to bundle this new TZInfo zone), and change the default offset to -04:00.

    I'll take care of this soon.

  • Repository

    Repository January 27th, 2010 @ 02:23 AM

    (from [1cda85d08a68888744bd230bccd75bf268587028]) Georgetown TimeZone is now mapped to "America/Guyana" instead of "America/Argentina/San_Juan" [#1821 status:resolved]

  • Geoff Buesing

    Geoff Buesing January 28th, 2010 @ 02:31 AM

    • State changed from “new” to “resolved”

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