Possible error with timezone for Saint Pierre/Miquelon?

Hancock, David (dhancock) dhancock at arinc.com
Mon Mar 17 16:03:18 UTC 2008


We have fixed this by hand-entering the timezone name as "America/Miquelon."

The web server we used to obtain the timezone (given lat/lon coordinates)
gave "Etc/GMT-3" and that was the primary source of our confusion.

Thanks for enduring my new-to-timezones questions, and
Cheers!
-- 
David Hancock | dhancock at arinc.com


> From: "Hancock, David (DHANCOCK)" <DHANCOCK at arinc.com>
> Date: Thu, 13 Mar 2008 11:43:10 -0400
> To: <tz at elsie.nci.nih.gov>, <tz at lecserver.nci.nih.gov>, "Raymond, Bill
> (BRAYMOND)" <BRAYMOND at arinc.com>
> Conversation: Possible error with timezone for Saint Pierre/Miquelon?
> Subject: RE: Possible error with timezone for Saint Pierre/Miquelon?
> 
> Chris: Thanks for the note. We are using a Python wrapper around the TZ
> database. I will have a look at the chain starting from our side to see where
> the "no dst" is being introduced. The library we use gets distributed with a
> copy of the Olson DB, but if we see an update that's newer than the pytz
> distribution, we obtain the newer distribution and put it where pytz looks for
> it.
> 
> I'll let you know what I discover from our end. Apologies for blaming the
> database first! We're in the midst of encoding real timezone names for all of
> our airports, and this was the first error that wasn't simply having the name
> incorrect.
> 
> I should note, though, that worldtimeengine.com (which uses Olson data and a
> GIS approach for mapping locations to the timezone name) also shows no DST in
> 2008, but administrative region is Canada. The following URL ends with an
> underscore:
> 
> http://worldtimeengine.com/doTime/miquelon_st_pierre_and_miquelon_saint_pierre
> _miquelon_ 
> 
> Thanks, and
> Cheers!
> --
> David Hancock | dhancock at arinc.com
> 
> 
> -----Original Message-----
> From: Chris Walton [mailto:Chris.Walton at telus.com]
> Sent: Thursday, March 13, 2008 11:26 AM
> To: tz at lecserver.nci.nih.gov; Hancock, David (DHANCOCK); Raymond, Bill
> (BRAYMOND)
> Subject: RE: Possible error with timezone for Saint Pierre/Miquelon?
> 
> I am unable to replicate the "Saint Pierre/Miquelon" problem reported by David
> Hancock and Bill Raymond.
> 
> America/Miquelon is configured to follow the "Canada" ruleset. Daylight saving
> in Canada started on March 9 this year.
> Zone America/Miquelon   -3:44:40 -      LMT     1911 May 15     # St Pierre
>                         -4:00   -       AST     1980 May
>                         -3:00   -       PMST    1987 # Pierre & Miquelon Time
>                         -3:00   Canada  PM%sT
> 
> # TZ=America/Miquelon date '+%Z %z'
> PMDT -0200
> 
> # zdump -v America/Miquelon | grep 2008
> America/Miquelon  Thu Mar 13 15:04:41 2008 UTC = Thu Mar 13 13:04:41 2008 PMDT
> isdst=1
> America/Miquelon  Sun Mar  9 04:59:59 2008 UTC = Sun Mar  9 01:59:59 2008 PMST
> isdst=0
> America/Miquelon  Sun Mar  9 05:00:00 2008 UTC = Sun Mar  9 03:00:00 2008 PMDT
> isdst=1
> America/Miquelon  Sun Nov  2 03:59:59 2008 UTC = Sun Nov  2 01:59:59 2008 PMDT
> isdst=1
> America/Miquelon  Sun Nov  2 04:00:00 2008 UTC = Sun Nov  2 01:00:00 2008 PMST
> isdst=0
> 
> David and/or Bill,
> Are you using standard compiled zone files with a standard C library?
> Or are you doing something more complex that might have introduced an error?
> 
> -chris
> -----Original Message-----
> From: Olson, Arthur David (NIH/NCI) [E] [mailto:olsona at dc37a.nci.nih.gov]
> Sent: March 13, 2008 9:19 AM
> To: tz at lecserver.nci.nih.gov
> Subject: FW: Possible error with timezone for Saint Pierre/Miquelon?
> 
> I'm forwarding this message from David Hancock; since sending it, he has asked
> to be added to the time zone mailing list and has been added.
> 
> --ado
> 
> From: Hancock, David (dhancock) [mailto:dhancock at arinc.com]
> Sent: Thursday, March 13, 2008 8:05
> To: tz at lecserver.nci.nih.gov
> Cc: Raymond, Bill (BRAYMOND)
> Subject: Possible error with timezone for Saint Pierre/Miquelon?
> 
> Please see the note below from one of my colleagues, Bill Raymond. He was
> following up on a discrepancy in our airport local-time lookup for one of the
> airports our customers use. He verified that the island follows DST by calling
> the airport authority there. Neither of us knows the start and end
> dates for DST, though.
> One of our destination airports is LFVP - Saint Pierre/Miquelon.  There is a
> timezone America/Miquelon but the current setting is GMT -3 with no DST.  LFVP
> is currently is DST and is GMT -2.  It looks like the Olson data has DST info
> for 2007 but not for 2008.  I did check several sources to
> confirm, including making a call to Air St. Pierre at the airport to check
> local time.
>  
> For now I set LFVP to Etc/GMT -2.  Please let me know if there will be an
> update.
> 
> We recently integrated the timezone DB into our flight-planning site and it's
> working out very well. We've also been using worldtimeengine.com, which is
> great for obtaining timezone information using latitude and longitude.
> 
> Cheers!
> --
> David Hancock | dhancock at arinc.com
> 
> 





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