NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Round-off
From: Peter Fogg
Date: 2009 May 15, 12:34 +1000
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From: Peter Fogg
Date: 2009 May 15, 12:34 +1000
John Karl wrote:
This question is more a matter of navigational philosophy. I
subscribe to the old adage that it's most important to know where you
are not, i.e., DEFINITELY where you are not. And that's not a matter
of statistics. I'm not satisfied to miss reefs only a percentage of
the time. So I look at the maximum round off error. Rounding every
one of 12 numbers to the nearest whole minute could lead to a maximum
error of about 0.4'x12 = 4.8'. Why introduce this possible error when
it's completely unnecessary?
I think the simple answer is that for practical reasons you have to give consideration to how probable error leading to risk is. A statistical analysis can do this. Risk can thus be usefully evaluated, leading to an informed decision as to action, if any.
If you considered that the maximum potential risk should always be applied then I don't think you would go sailing at all.
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