I hope y'all realize that while you're lost in all these maths, any competent
surveyor with a transit and a rod man could locate BCIDWA with sufficient
accuracy on the line-of-sight CAUS in less than a half-hour from CAUS monument
195 (which is only about 900 feet away) even if neither monuments 194 nor 195
are visible from BCIDWA.
I can explain how on request.
Lowell G. McManus
Leesville, Louisiana, USA
----- Original Message -----
From: "aletheiak" <aletheiak@...>
To: <BoundaryPoint@yahoogroups.com>
Sent: Monday, September 13, 2004 2:10 PM
Subject: [BoundaryPoint] Re: special to ron & dave
now i am getting really out of order here doc
not only because you are still catching up
but also because we have not yet established whether there is
even any hope of obtaining a real sight line from caus marker
194 to 195 with the 1909 idwa marker & environs simultaneously
in view
which
i have to agree
with i think dave who suggested it
doesnt seem terribly likely
ever
in view of all we do know about the distances & relative
elevations & roughness of the clearcut
so forgive me for racing ahead to this delicious presumption
that we do indeed already have all she ever wrote to legally
define or mark this point
& that we can proceed on the basis of the published geocoords
alone
but this already seems to me to be our leading premise & hope
& so
based only on what we do have
&
solely to advance the analysis
foreclosing on the hope of better data
i think we can proceed from merely guessing the parameters &
probabilities to actually mediating & reducing the caus centisec
ribbon down to its precise midpoint along the idwa meridian
for i think caus is presumptively a true line rather than a ribbon
& the only remaining question then in this scenario of no longer
guessing but concluding
it seems to me
is whether it would be correct to continue to rationalize the
ambiguity of the plaque coords as a vegas betting line
or to leave them as 2 distinct & unresolved probabilities
or to foreclose on one of them in favor of the other
& despite all the fun it occasioned
i would gladly shelve the vegas line til
& if ever
we get the sight line that would trump & test the computations &
settle any bets
& to the same end
i recall dave has offered some hope of communicating with the
surveyor who created & stamped these messy coords in the first
place
so pending only that loose end & to sum up
it still seems to me as it did in message 15332
except moreso now
that
measured in inches due north of the 1909 disk center
the major probability for true bcidwa stands at 18 point 85129
& its minor probability stands at 18 point 24318
& unless & until dave or someone else learns which of them is
true
their weighted probability also still stands at 18 point 82696
all significant digits too i think
but far more importantly
the target hole has been reduced from over a foot to less than 5
eighths of an inch
& most happily
& regardless of any subsequent outcome
a human fingertip could now cover all 3 of these putative
positions at once
so we both still do & dont any longer have somewhere to go in
this case depending only on personal taste for punctiliousness
for that is indeed how close it seems to me we now are to the
truest available bcidwa
or would you or someone disagree
--- In BoundaryPoint@yahoogroups.com, "aletheiak"
<aletheiak@y...> wrote:
> bravissimos maestro
> we are counting on you
>
> & of course your point500 outshoots my point508
> as your finer instruments prove
> because mine were farther out of touch with the true geoid
>
> very nice
>
> & so
> at the standard quadrisignificant conversion rate of point3048
> i now get my foot enhanced by only as much as
> point0135061242
>
> now
> if only 5 of those 9 working digits are authentic & significant
> as i believe
> & if they are also already at the limit of human perception
> as i also believe
> then my previous computations completely hold up for now as
> the limit of what can be known of true bcidwa without an
> intermonumental sight line
>
> but ironically all this hard won precision is idle for now
because
> we are still shooting at a centisec target here that is more than
a
> foot wide
>
> hopefully tho
> it will actually be useful to an aspiring punctoscopist somehow
> somewhere some day
>
> --- In BoundaryPoint@yahoogroups.com, "Ron McConnell"
> <rcmcc@e...> wrote:
> >
> > "aletheiak" says,
> > "...the length of a minute of latitude at
> > the 49th parallel as 1853meters plus 508mm
> > & borrowing directly ...
> > <http://home.online.no/~sigurdhu/Grid_1deg.htm>
> > i have it as 1853meters plus 500mm
> > so which is truer
> > & how many digits are reliable in any case?"
> >
> > Vincenty & Sodano = 1853.496 m
> > USCG POSAID2 = 1853.5016 m
> > Both round to 1853.50m
> >
> > We just returned home. I'll try to study
> > the rest of the message later after
> > taking care of chores.
> >
> > Cheers,
> >
> > Ron McC.
> > w2iol@a...
> >
> > Ronald C. McConnell, PhD
> >
> > WGS-84: N 40º 46' 57.6" +/-0.1"
> > W 74º 41' 22.1" +/-0.1"
> > FN20ps.77GU31 +/-
> > V +5058.3438 H +1504.2531
> >
> > http://home.earthlink.net/~rcmcc
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