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    Re: International Date Line --invented by Schedler
    From: Frank Reed
    Date: 2011 Jul 9, 23:48 -0700

    John H., you wrote:
    "I think we discussed the issue recently of a country in the Pacific (Kiribata?) that shifted the dateline on their own. Is there any modern body that 'polices' the dateline by convention these days, or is it still kind of willy-nilly?"

    It's entirely up to local governments. So there's no ambiguity when you're standing on land. Of course, local governments are only able to claim control out to some limit beyond their coastlines, so a "genuine" international date line would probably have to consist of a bunch of circles around the various islands of the Pacific. Hundreds of miles out to sea, it's just a map-drawing convention (so, yes, "willy-nilly"!). The 180 degree meridian of course is the preferred "date line" for ships at sea and back in the first few decades after Schedler introduced the so-called "international date line", the maritime dateline was frequently called the "commercial date line".

    As for the shift of the date line around Kiribati, many mapmakers have not bothered to make that shift, probably just because they find it aesthetically unappealing. It just doesn't seem "right". There's another change coming up at the end of this year. Samoa will be shifted back to the eastern hemisphere date after a 119-year interlude on the western hemisphere side. They've pointed out that they can even use this to generate some tourist revenue since a visitor to American Samoa could celebrate a birthday or anniversary and then pop over to Samoa and get another 24 hours worth. There was a news article a few months back where some Samoan official was rather forlornly asking who else they should contact since so far they had only had seemingly official interest in this shift from a map publisher. Little did he know...

    Finally, let's imagine an alternative history where, thanks to some backroom wheeling and dealing and infighting among the Europeans, they decide to make the meridian of Washington, DC the Prime Meridian for international use. Where would you draw the "date line" then? You can see rather quickly that 180 degrees from the meridian of Washington would never work. The seemingly obvious fact that the date line should be directly opposite the Prime Meridian as nearly as possible is probably just an accident of history. The best place for the date line, however defined, is where it will inconvenience the fewest people. And that's probably the mid-Pacific no matter where the Prime Meridian is located.


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