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Dates Before 1754?

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  • Brian Mulloy
    Hi Steve, It seems like dates before 1754 cannot be plotted, but instead start plotting at 1970. Is there a workaround for that? Dmitry think it might be to
    Message 1 of 3 , Jan 19, 2007
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      Hi Steve,

      It seems like dates before 1754 cannot be plotted, but instead start
      plotting at 1970. Is there a workaround for that?

      Dmitry think it might be to do with this:
      http://www.litencyc.com/php/stopics.php?rec=true&UID=141

      And the code seems to confirm that, from dates.c:
      #define BASEYR 1970 /* 1970 = start of unix epoch */
      #define BASEOLDYR 1754 /* old, but not so old as to run into Sep
      1752 anomoly */
      ...
      if( y < BASEYR ) refyear = BASEOLDYR; /* switch to BASEOLDYR as year
      basis for calculations */
    • Stephen C. Grubb
      Brian, perhaps you could simply plot years as integers, and use plain numeric scale? On Sept 14, 1752 the British empire adopted the Gregorian calendar and
      Message 2 of 3 , Jan 22, 2007
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        Brian, perhaps you could simply plot years as integers, and use plain
        numeric scale? On Sept 14, 1752 the British empire adopted the Gregorian
        calendar and skipped 11 days (Sept 2 was immediately followed by Sept 14).

        -Steve

        On Sat, 20 Jan 2007, Brian Mulloy wrote:

        > Hi Steve,
        >
        > It seems like dates before 1754 cannot be plotted, but instead start
        > plotting at 1970. Is there a workaround for that?
        >
        > Dmitry think it might be to do with this:
        > http://www.litencyc.com/php/stopics.php?rec=true&UID=141
        >
        > And the code seems to confirm that, from dates.c:
        > #define BASEYR 1970 /* 1970 = start of unix epoch */
        > #define BASEOLDYR 1754 /* old, but not so old as to run into Sep
        > 1752 anomoly */
        > ...
        > if( y < BASEYR ) refyear = BASEOLDYR; /* switch to BASEOLDYR as year
        > basis for calculations */
        >
        >
        >


        Stephen C. Grubb scg@... x-6633
        Scientific Software Engineer, The Jackson Laboratory
        600 Main Street Bar Harbor, Maine 04609 USA
      • Brian Mulloy
        that just might work for our use case. Thanks, Stephen. -b
        Message 3 of 3 , Jan 23, 2007
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          that just might work for our use case.  Thanks, Stephen.

          -b

          On 1/22/07, Stephen C. Grubb <scg@...> wrote:


          Brian, perhaps you could simply plot years as integers, and use plain
          numeric scale? On Sept 14, 1752 the British empire adopted the Gregorian
          calendar and skipped 11 days (Sept 2 was immediately followed by Sept 14).

          -Steve

          On Sat, 20 Jan 2007, Brian Mulloy wrote:

          > Hi Steve,
          >
          > It seems like dates before 1754 cannot be plotted, but instead start
          > plotting at 1970. Is there a workaround for that?
          >
          > Dmitry think it might be to do with this:
          > http://www.litencyc.com/php/stopics.php?rec=true&UID=141
          >
          > And the code seems to confirm that, from dates.c:
          > #define BASEYR 1970 /* 1970 = start of unix epoch */
          > #define BASEOLDYR 1754 /* old, but not so old as to run into Sep
          > 1752 anomoly */
          > ...
          > if( y < BASEYR ) refyear = BASEOLDYR; /* switch to BASEOLDYR as year
          > basis for calculations */
          >
          >
          >

          Stephen C. Grubb scg@... x-6633
          Scientific Software Engineer, The Jackson Laboratory
          600 Main Street Bar Harbor, Maine 04609 USA


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