NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: On checking accuracy
From: Peter Fogg
Date: 2008 Aug 11, 09:05 +1000
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From: Peter Fogg
Date: 2008 Aug 11, 09:05 +1000
Bill the non-engineer writes:
My initial impression was that Bill the engineer was suggesting different
slopes and different placements. Reading carefully, he stated "There is an
infinity of possible lines OF THAT SLOPE."
You've collectively lost me there, the Bills. There is only one slope, which depends on the latitude and azimuth of the body observed. There is judgement to be exercised about how to fit that slope to the pattern of observations.
He does not, I think, argue with
the concept of fitting to the actual slope, but rather questions, as I did,
how to make the agonizing decision of where (horizontally and vertically) I
should place the slope in relationship to the plotted points.
Yes, it can be agonising. It calls for thought, the balancing of the evidence of the sights, and the exercise of judgement. If you are working from a known position, or have a GPS to hand, then the answer as to whether the exercise works or not, whether it succeeds in reducing erratic error to a useful extent, is available.
Bill the engineer writes:
"I haven't reached a conclusion and await further enlightenment"
Well Bill, you've received my suggestion as to further enlightenment:
"if you want to understand slope analysis then start using it"
Could be a whole lot more enlightening than alleged wisdom handed down from above by self appointed gurus. Especially those who don't know (certainly the case in this instance) what they are talking about.
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