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    Re: Bowditch [was Re: Hi (WAS: Re: ping)]
    From: Roger M. Derby
    Date: 2001 Jan 26, 14:45 EST

    Just a word of caution that I'm sure is unnecessary.  When I was programming
    a VAX to do great-circle calculations (path length and departure) using the
    equations from Bowditch, I got some very strange results.  These turned out
    to be caused by the machine's math library making different assumptions
    about quadrant than was used by Bowditch.  I finally made up a table of
    entries for two points a few nm apart using paths that hit all four
    quadrents and the four cardinal points and then checking against
    "reasonable" answers.  Had to add several IF-THENs before Singapore was a
    long way from the Lizard and in the correct direction.
    Roger
    ----- Original Message -----
    From: "Hal Mueller" <hal{at}XXX.XXX>
    To: <NAVIGATION-L{at}XXX.XXX>
    Sent: Friday, January 26, 2001 2:25 PM
    Subject: [NAV-L] Bowditch [was Re: Hi (WAS: RE: ping)]
    > >I don't have Bowditch yet, but I do have the French
    > >admiralty manuals and I don't see why the formulas would not yield the
    same
    > >results?
    >
    > I would hope they would!  :P
    >
    > I note, also, that the 1995 edition of Bowditch is online in PDF
    > format at http://www.i-DEADLINK-com/bowditch/.  At first glance the
    > sections containing formulas look better organized and more tightly
    > written than in my hardcopy 1977 edition.
    >
    > Oh yeah, regarding forms:  is there something on the Handspring site
    > to preview your forms?  Their dev tools (free) are at
    > http://www.handspring.com/developers/sw_dev.jhtml.  I use
    > Codewarrior, so haven't explored the Handspring stuff.
    >
    > H
    >
    > ----
    > Hal Mueller                hal{at}XXX.XXX
    > Mobile Geographics LLC     http://www.mobilegeographics.com/
    > Seattle, Washington        (206) 297-9575
    >
    >
    

       
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