为什么北达科他州在Olson数据库中有一个单独的时区名称空间

Question

在编制时区列表时，我想知道为什么北达科他州(以及阿根廷)有自己单独的名称空间。

例如

。阿姆斯特丹有Europe/Amsterdam，伦敦有Europe/London，但是北达科他州有自己的命名空间:

America/North_Dakota/Beulah
America/North_Dakota/Center
America/North_Dakota/New_Salem

北达科他州有什么特别之处，它在奥尔森数据库中有自己的命名空间?

Answer 1

有许多这样的位置，其中分区(县，省等)具有历史时差。您可以在tzdb源的注释中阅读它们的历史。

您提到的北达科他州三个地区的条目目前如下:

# Oliver County, ND switched from mountain to central time on 1992-10-25.
Zone America/North_Dakota/Center -6:45:12 - LMT 1883 Nov 18 12:14:48
            -7:00   US  M%sT    1992 Oct 25  2:00
            -6:00   US  C%sT
# Morton County, ND, switched from mountain to central time on
# 2003-10-26, except for the area around Mandan which was already central time.
# See <http://dmses.dot.gov/docimages/p63/135818.pdf>.
# Officially this switch also included part of Sioux County, and
# Jones, Mellette, and Todd Counties in South Dakota;
# but in practice these other counties were already observing central time.
# See <http://www.epa.gov/fedrgstr/EPA-IMPACT/2003/October/Day-28/i27056.htm>.
Zone America/North_Dakota/New_Salem -6:45:39 - LMT  1883 Nov 18 12:14:21
            -7:00   US  M%sT    2003 Oct 26  2:00
            -6:00   US  C%sT
# From Josh Findley (2011-01-21):
# ...it appears that Mercer County, North Dakota, changed from the
# mountain time zone to the central time zone at the last transition from
# daylight-saving to standard time (on Nov. 7, 2010):
# http://www.gpo.gov/fdsys/pkg/FR-2010-09-29/html/2010-24376.htm
# http://www.bismarcktribune.com/news/local/article_1eb1b588-c758-11df-b472-001cc4c03286.html
# From Andy Lipscomb (2011-01-24):
# ...according to the Census Bureau, the largest city is Beulah (although
# it's commonly referred to as Beulah-Hazen, with Hazen being the next
# largest city in Mercer County).  Google Maps places Beulah's city hall
# at 47 degrees 15' 51" N, 101 degrees 46' 40" W, which yields an offset
# of 6h47'07".
Zone America/North_Dakota/Beulah -6:47:07 - LMT 1883 Nov 18 12:12:53
            -7:00   US  M%sT    2010 Nov  7  2:00
            -6:00   US  C%sT

还有其他更臭名昭著的例子，比如印第安纳州，它在tzdb中有8个子区域条目，还有一篇详细的维基百科文章描述了混乱的历史。