I suspect that in a lot of cases, the principle of the boundary lay-
out is specified in a treaty (like "the 49 deg. line"), but the
actual demarcation is left for after the conclusion of the treaty.
Then the field work starts, and errors inevitably creep in. The
border markers are put on their spots, and from that time they are
considered to be standing right on the border. So I think Brendans
guess that the lines between bdy. markers are great circles is
basically correct. That is, of course, if the boundary treaty speakes
of a line like a parallel or some other line normally perceived
as "straight". Sometimes, a boundary between two markers is defined
in a treaty as "following a river" or some other feature in the
field. In that case, other rules apply, of course.
In this respect, it is interesting to know that along the benl
border, very well marked by those nice and tall border monuments,
this also occurs. On some stretches, auxiliary border markers are
used. Eef Berns has a nice photo report of one of these stretches
(where a lot of moving sand dunes constantly made the border a lot
less visible) at http://home.wanadoo.nl/~eefberns/tussenpaaltjes%
20bij%20putte.html .
Peter S.
--- In BoundaryPoint@y..., "Brendan Whyte" <brwhyte@h...> wrote:
>
>
>
> >From: "Jesper & Nicolette Nielsen" <jesniel@i...>
> >Reply-To: BoundaryPoint@y...
> >To: <BoundaryPoint@y...>
> >Subject: [BoundaryPoint] Fiat boundaries
> >Date: Tue, 1 May 2001 07:45:41 +0200
> >
> >Which international boundaries are 100% fiat, meaning 100%
straight?
> >
> >On the map I see:
> >
> >Morocco-Western Sahara
> >Algeria-Mauretania
> >Western Sahara-Algeria
> >Nigeria-Chad
> >
> >But perhaps there are minor irregularities I cannot see on my map,
so who
> >can confirm this?
> >
>
> Define 'straight'. Especially on a sphere. The only stright line on
a sphere
> occurs on a great circle. A line following any parallel apart fomr
the
> equator (the only great circle of latitude) is not straight, it
bends left
> or right. Therefore the US Canada boundary along the 49th is NOT a
straight
> line.
> therefore the N-S segments of Mor-West sahara, the small WS-Alg and
parts of
> Niger-Chad probably are.
> Second, although defined in treaties as following given parallels
or
> latitudes, or 'stright lines' joining certian points on diagonals
(eg
> Algeria's boundaries... are they great circles, or not?), most
boundaries on
> the ground are straight lines joining pillars erected where the
paralleles
> etc are thought at the time to be.
> The US-Canada boundary was so defined, a series of line segments
joining
> pillars. Even if the pillars ARE on the 49th, the 'stright lines'
joining
> them will not be except at those pillars. So at leats once,
intermediate
> pillars were erected to make shorter line segments, and keep the
boundary as
> close as practical to the pilars.
>
> I am guessing that a straight line of sight fomr a pillar to
another IS a
> great circle segment.
>
> BW
>
>
>
>
>
> >Jesper
> >
>
>
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