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Gentlemen

I originally proposed this "Prove It" method, so that I could discover the 
truth and cut through the hyperbole.

We proposed a test, in which George would give several altitudes around noon, 
and each contributor would then calculate the noon fix (lat lon) from the 
given altitudes.

At this juncture, we seem to be waiting for a data set to be present to Jim 
Wilson.  George, I urge you to complete that task so that we can see how a 
manually graphed method compares to the mathematically rigorous Excel least 
squares fit.

We can see that the least squares fit certainly provides a fix much like Frank 
said it would.  That is, Frank indicated longitude to within 5 miles, and 
Dave got 5.68 miles.  Let us hope that there is no quibbling over 0.68 miles. 
 I think for a least squares fit, we can convince ourselves as to the 
validity of the experiment.

What remains then is the manual graphing or paper folding methods.  While we 
can expect some degradation in performance, I do not believe we are 
discussing wholesale failure.  Rather, there will be some variance from a 
rigorous curve fit to a mark-1 eyeball fit.  This can be debated endlessly, 
as to the performance of one individual or another.  However, it is my 
estimation that the fix will be within the ballpark, and the method "proven".

I still want to see how Jim's method performs....



Best Regards
Brad


-----Original Message-----
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of George Huxtable
Sent: Friday, April 17, 2009 6:11 PM
To: NavList@fer3.com
Subject: [NavList 7987] Re: Lat/Lon by "Noon Sun" & The Noon Fix PROVE IT


Dave Walden, having generated 1000 simulations of longitude-around noon, and
arrived at a scatter of 5.68 miles rms, as reported earlier, then turned his
attention to the 20 simulations I had invented. He sent me the results for
deduced lat and long. In return, I then sent him the full table showing the
presumed lat and long that I had taken as a starting point in each case.
Dave has then analysed the difference between my 20 initial longitudes, and
his deduced results, arriving at a scatter in longitude of 5.81 miles rms.
This is only marginally different from his previous finding, and completely
compatibe with it. I see no reason to question his result.

I'm having a bit of difficulty in cobbling together an amended data set to
meet Jim Wilson's method of working, but it will come.

George.

contact George Huxtable, at  george@hux.me.uk
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.




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