I seem to have misconstrued the original quest as pertaining to tripoints.
If it pertained to [just] points, then I think that the two points farthest
apart diametetrically would be the two equatorial or very nearly equatorial
antipodes with the greatest combined elevation above sea level. The bulging
equatorial diameter would easily overcome any elevational advantages of
non-equatorial points. I would nominate some Ecuadorian peak and its Sumatran
antipode.
The two most circumferentially distant antipodes present an entirely different
question. The polar flattening causes the shortest circumferential routes
between any two antipodes to be along a great circle through the poles. On a
smooth oblate spheroid (an earth without relief), any pair of antipodes would be
equally interdistant one from the other. This is because any imaginable great
circle connecting them would make two crossings of the bulging equatorial region
and two of the flattened polar regions. On the real world, only the matter of
elevational relief crossed in the process would differentiate the distances
between any pair of antipodes. You would want to pick the diametrically
opposite pair of west and east longitudes that cross the maximum amount of
continental relief during their circuit of the earth, then choose any two
antipodes on that circuit--perhaps something like 70° W and 110° E.
Lowell G. McManus
Leesville, Louisiana, USA
----- Original Message -----
From: "acroorca2002" <orc@...>
To: <BoundaryPoint@yahoogroups.com>
Sent: Wednesday, March 10, 2004 12:41 PM
Subject: [BoundaryPoint] Re: How far is it?
> in bp terms
> you have improved as well as redeemed what was only a try
> pointing quest by turning it into an actual tripointing quest
>
> moreover your upgraded version is interesting in its own right
>
> & it holds forth some promise of being ultimately answerable too
>
>
> so have a leading pair of candidates suggested themselves yet
>
>
>
> & having tried a few things too
> i can report that the original quest
> namely
> which points on earth are farthest apart
> & exactly how far apart are they
> remains as hard to make any real headway with as it is hard to
> improve upon in curiosity value & elegance
>
>
> --- In BoundaryPoint@yahoogroups.com, "Lowell G. McManus"
> <mcmanus71496@m...> wrote:
> > If one wanted to determine the two tripoints that are farthest
> apart, one should
> > first determine which few pairs are the most likely candidates
> based on their
> > relative antipodality from each other. This would take some
> trial and error.
> > However, since the antipodes of most continents are oceanic,
> there shouldn't be
> > an abundance of likely candidates.
> >
> > Next, the few candidates might have to be evaluated for the
> effects of the
> > spheroidicity of the earth and for elevation. The earth is an
> oblate spheroid,
> > bulging at the Equator and flattened at the poles. However, the
> difference
> > between sea level diameters pole-to-pole and Equator to
> Equator is typically
> > stated in the range of 40 to 43 km. The supposedly most
> precise model pegs the
> > figure at 42,952 meters, which is less than 27 miles. On top of
> this distance,
> > elevation could add a few more miles if one found a pair of
> relatively antipodal
> > tripoints both in high mountains. Elevation would most affect
> diametric
> > distance and would be much less significant circumferentially.
> >
> > Considering the relative paucity of land-land antipodes and the
> relative paucity
> > of tripoints near the poles, the variations due to spheriodicity
> and elevation
> > above sea level would probably be inconsequential in
> determining the two most
> > interdistant tripoints.
> >
> > At http://williams.best.vwh.net/gccalc.htm , you will find yet
> another
> > great-circle distance calculator into which one can enter the
> coordinates of any
> > two points and get their circumferential distance apart. This
> calculator
> > differs from the others in that you can chose from various
> mathematical models
> > of the shape of the earth, from perfectly spherical through a
> number of
> > spheroidal models. Among these last, the one currently
> accepted is
> > WGS84/NAD83/GRS80.
> >
> > Lowell G. McManus
> > Leesville, Louisiana, USA
> >
> >
> >
> > ----- Original Message -----
> > From: "acroorca2002" <orc@o...>
> > To: <BoundaryPoint@yahoogroups.com>
> > Sent: Wednesday, March 10, 2004 8:31 AM
> > Subject: [BoundaryPoint] Re: How far is it?
> >
> >
> > > really
> > > i dont remember that
> > >
> > > & it is an interesting question
> > > as well as a challenging try pointing quest
> > >
> > > perhaps even 2 of each
> > > since the farthest pair of points measured circumferentially
> > > might not be the same points as the diametrically farthest
> pair
> > >
> > >
> > > yet exactly how to solve for either set
> > >
> > >
> > >
> > > alternatively
> > > someone may already have solved & posted answers for
> them
> > >
> > > so perhaps a prior question is
> > > exactly how to search for any such ready made answers
> > >
> > >
> > > &or
> > > failing that
> > > there must be some data on the geoid already developed &
> > > available somewhere that might be useful toward these
> ends
> > > if we knew what to look for
> > >
> > > like
> > > greatest circumference & diameter figures might be a good
> > > place to start
> > > since these are likely to have been worked out to some
> degree
> > > of specificity & accuracy
> > >
> > > but where & how to find them
> > >
> > > & could we in fact approach the correct answers via these
> data
> > >
> > > & if so
> > > by exactly what means could we get there from here
> > >
> > >
> > >
> > > but can anyone solve or advance this
> > >
> > > or even clearly see the right way to go
> > >
> > >
> > > --- In BoundaryPoint@yahoogroups.com, "L. A. Nadybal"
> > > <lnadybal@c...> wrote:
> > > > We discussed some time back the maximum distance that
> any
> > > two places
> > > > on earth could be from one another.
> > > >
> > > > This site claims to deliver the distances between two
> selected
> > > points:
> > > >
> > > > www.indo.com/distance/
> > > >
> > > > LN
> > >
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>