98 lines
4.3 KiB
HTML
98 lines
4.3 KiB
HTML
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<TITLE>Sources for Time Zone and Daylight Saving Time Data</TITLE>
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<H1>Sources for Time Zone and Daylight Saving Time Data</H1>
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<P>
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<H6>
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@(#)WWW.htm 7.16
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</H6>
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<H2>Paul Eggert writes:</H2><P>
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The public-domain tz database contains code and data
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that represent the history of local time
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for many representative locations around the globe.
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It is updated periodically to reflect changes made by political bodies
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to UTC offsets and daylight-saving rules.
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This database (often called <samp>zoneinfo</samp>)
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is used by several implementations,
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including BSD, DJGPP, GNU/Linux, HP-UX, IRIX, Solaris, and UnixWare.
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In the tz database's
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<A HREF="ftp://elsie.nci.nih.gov/pub/">FTP distribution</A>,
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the code is in the file <samp>tzcode<var>C</var>.tar.gz</samp>,
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where <samp><var>C</var></samp> is the code's version;
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similarly, the data are in <samp>tzdata<var>D</var>.tar.gz</samp>,
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where <samp><var>D</var></samp> is the data's version.
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<P>
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The <A HREF="ftp://ftp.gnu.org/pub/gnu/GETTING.GNU.SOFTWARE">GNU C Library</A>
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has an independent, thread-safe implementation of
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a time zone file reader.
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This library is freely available under the GNU Library General Public License,
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and is widely used in GNU/Linux systems.
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<P>
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The Web has several other sources for time zone and daylight saving time data.
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Here are some recent links that may be of interest.
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<UL>
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<LI><A HREF="http://www.bsdi.com/date">Date and Time Gateway</A>
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is a text-based source for tables of current time throughout the world.
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Its point-and-click interface accesses a recent version of the tz data.
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<LI><A HREF="http://www.worldtime.com/">WORLDTIME: interactive atlas,
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time info, public holidays</A>
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contains information on local time, sunrise and sunset,
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and public holidays in several hundred cities around the world.
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<LI><A HREF="http://www.hilink.com.au/times/">Local Times Around the World</A>
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is a text-based system containing links to local time servers
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throughout the world; though the coverage is limited,
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the live data provide a nice way to check one's tables.
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<LI><A HREF="http://tycho.usno.navy.mil/tzones.html">World Time Zones</A>
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contains US Naval Observatory data, used as the source
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for the <samp>usno*</samp> files.
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<LI>The United States Central Intelligence agency publishes time zone maps;
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the
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<A HREF="http://www.lib.utexas.edu/Libs/PCL/Map_collection/world_maps.html">
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Perry-Castañeda Library Map Collection</A>
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of the University of Texas at Austin has on-line copies of
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the 1995 and 1997 editions.
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The pictorial quality is good,
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but the maps do not indicate summer time,
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and parts of the data are a few years out of date.
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<LI><A HREF="http://pisolo.cstv.to.cnr.it/toi/uk/toi.html">The
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Time of Internet</A>
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contains good descriptions of Time Zones and daylight saving time,
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with diagrams.
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The time zone map is out of date, however.
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<LI><A HREF="http://ecco.bsee.swin.edu.au/chronos/GMT-explained.html">A
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Few Facts Concerning GMT, UT, and the RGO</A>
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answers questions like ``What is the difference between GMT and UTC?''
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<LI><A HREF="http://www.energy.ca.gov/daylightsaving.html">Daylight
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Saving Time -- Saving Time, Saving Energy</A>
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is a history of DST in the US.
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<LI><A HREF="http://dir.yahoo.com/Science/Measurements_and_Units/Time/Time_Zones/">Yahoo! - Science:Measurements and Units:Time:Time Zones</A>
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is where the famous Internet indexing service Yahoo! collects its time zone
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info.
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<LI>The <A HREF="http://www.iata.org/">International Air Transport Association</A>
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publishes the IATA Standard Schedules Information Manual (SSIM),
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which gives current time zone rules for
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all the airports served by commercial aviation.
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<LI><A HREF="http://hpiers.obspm.fr/webiers/results/bul/README.html">Bulletins
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of IERS</A> contains official publications of the
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International Earth Rotation Service, the committee that decides
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when leap seconds occur.
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</UL>
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<P>
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-- <A HREF="mailto:eggert@twinsun.com">eggert@twinsun.com</A>
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(1998-09-22)
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</P>
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<H2>Arthur David Olson writes:</H2><P>
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A good source of information about ISO 8601 seems to be
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<A HREF="http://www.cl.cam.ac.uk/~mgk25/iso-time.html">International
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Standard Date and Time Notation</A>
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maintained by Markus Kuhn.
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<P>
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-- <A HREF="mailto:arthur_david_olson@nih.gov">arthur_david_olson@nih.gov</A>
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(1996-01-04)
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</P>
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</BODY>
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</HTML>
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