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Agreed that slope analysis can help make some sense of things.  However,
that assumes (there's that word again... ) there's a quick and easy way
to do this with some rigor and/or time to play with the numbers.  Some
days, one or the other is lacking.  Oh my!

Related to this is the notion of "navigator vertigo", induced by the
numbers saying one thing and the navigator's intuition saying another
thing.  The best cure is to see multiple data sources agree.  My
inclination, when in a state of vertigo, is to hope the "voodoo boxes"
(be they GPS receivers or calculators) agree and all are telling at
least a good approximation of the truth.  Or at least that there are
some other, confirming cues (landmarks or other boats following the same
route are good for that).

Rick Emerson
S/V One With The Wind

Peter Fogg wrote:
> Richard B. Emerson wrote:
>
>> It's the
>> slight errors that are really annoying.  Maybe the boat moved, the body
>> wasn't really on the horizon, the sextant was off the vertical, a second
>> or two was lost in recoding the time... the list of reasons for these
>> small but inescapable errors can be depressingly long.
>>
>
> Imagine 2 sights that can sit on, or very nearly on the slope and a
> third that is only off by a small extent.  A resolution of this
> dilemma that approximates averaging would be to put the line between
> the pair and the single one, favouring the pair.  And that could be
> the best solution.  With averaging its the only solution.
>
> On the other hand, maybe the 2 sights are good ones and the other
> indicates a greater extent of error.  Such is the agonising that slope
> analysis can encourage!  Its fairly evident that more sights are
> potentially helpful, although they can simply complicate things.
>
> But at least with slope analysis you are afforded the opportunity to
> do that agonising, which may entail trying to remember the
> circumstances of each sight, compared to the others.  Sometimes you
> just think "Yes!" at the time (about a sight), while are left feeling
> doubtful about another observation, for a whole variety of reasons.
>
>
>> After all, some assumptions can be made in error...
>>
>
> Yes, I agree with this.
>
> >
>
>
>

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