--- In BoundaryPoint@y..., "Meridien24" <meridien24@y...> wrote:
> Agggh! my head hurts! Interesting indeed that the USGS has
the
> VTNW/NYNE point NORTH of the markers! As long as all
agree that the
> international boundary draws a straight line between 644 and
645a, we
> can dismiss that data...
you & i at least do agree so far
the usigs defines line of sight as the straight line between 2
points
& then says
this line is in the direction of a great circle
but doesnt follow the curvature of the earth
of course we still havent confirmed the intervisibility of the
monuments
which will remain a grand perhaps indeed
until your forthcoming visit
as they are at a distance of nearly a mile from each other
but intervisibility may not be essential for computing the tripoint
coords from the monument coords
nor for reaching these computed coords by gps
whether the most punctilious possible result requires only the
simple averaging method i proposed yesterday
or demands the use of a spherical trig instead
isnt yet clear to me
but it seems clear that the difference is practically infinitesimal
& i dont know how exacting you or anyone would care to get
but since this is primarily your try jay
that is your decision to make
myself i might at least want to find out if spherical trig isnt truer
or what the resulting coords would be in that case
but i havent a clue how to get to those answers
yet since there is a certain degree of approximation already built
into either computation
by the positions of the monuments relative to the river
if not also by the disparity of their coords
there may actually be no advantage in using the spherical trig
even if it is technically the truer method
since our 10 foot circle target area wouldnt displace very far
in any case
& of course
the presumably lost monument 645 could always arise from the
deep to further complicate things
yikes
albeit again ever so slightly
>
> I don't have my software here, but I could just find the exact
> coordinates of the point (using topo data) and track it GPS.
you must have great software
but even using the paper topo to get the coords
would still saddle you with usgs interpretation
& perhaps the same exact strange position you say you would
like to dismiss
I just
> hope I don't fall in -- I can swim, but I don't wanna lose the
GPS!
> My wife will be along to take a picture & call authorities if I fall
> in (but, WHICH authorities?)
>
> I'll share my computer's finding of the point for all to argue
when I
> get to it... which won't be till later today - I'm leaving for
> Montreal right after work. Any help/arguments are appreciated
- I
> never thought that FINDING the point would be a problem!
>
> Locals will argue with you, but it IS the Richelieu river at that
> point. The topo map agrees. Concretely - it means that it
would
> take a darn good freeze for it to be safe near the point, but it
DOES
> happen. I have childhood memories of people skating up and
down the
> river...
>
> Otherwise, marker 644 would likely be the best vantage point?
yes i think so too
(and
> yes, I'll bring back a picture of the actual marker, too)
>
> ...Still have about 3 months to figure this out, anyway
>
>
> --Jay Di Battista
> Plattsburgh, NY
> WPTZ-TV
>
>
>
> --- In BoundaryPoint@y..., "acroorca2002" <orc@o...> wrote:
> > yes a beer for me too
> > but because 645a is more than a second south of 644
> > i find it hard to visualize so much northering as you see
> > & certainly not in the middle of the lake
> >
> > --- In BoundaryPoint@y..., "bjbutlerus" <bjbutler@b...> wrote:
> > > The great circle through both monuments would intersect
the
> > middle of
> > > the lake north of both monuments, perhaps reconciling the
> > USGS given
> > > position with your average, Mike. My spherical trigonometry
is
> > too
> > > rusty to yield a quick answer. Anybody else?
> > >
> > > By the way, I'm rooting for some beer to go with all that ice.
> > >
> > > BJB
> > >
> > > > such an averaging will produce a tripoint position of
> > > > nad27 45d00m38s3775 x 73d20m40s036
> > > > which tho probably unreliable beyond tenths of a second
> > > > still seems far more credible than the usgs positioning
> > > > which incidentally has the additional defect
> > > > of placing the tripoint north of both monuments
> > > > yikes
> > > > for how could that be true
> > > >
> > > > while neither position is terribly punctilious
> > > > they both still afford target areas of about 10 foot circles
> > > > whose centers are more than 100 feet apart