nice stuff thanx
& please look for quite a few inserts ahead

--- Hugh Wallis <hugh@...> wrote:

> >>thus as likely wgs84 as any<<
>
> definitely won't be WGS84 since that was not in use
> until 1984 (hence the
> "84" in its name).

hahaha you certainly may disallow me & i knew dat
about 84
but i dont infer wgs84 should be ruled out for that
reason

on the contrary i think the relative newness &
universality of wgs84 may especially recommend &
automatically promote it in this special case

for diametrically unlike the maritime borders of
indonesia
where technical & legal complications create a
particular urgency to get all these datums clarified
the situation at eglysd smacks of complete
indifference & utter neglect over many decades

& so i reason in the apparent absence of any evidence
of a specified datum for this point since its creation
in 1925 til the present
that it either remains unspecified until today & thus
highly subject to the wgs84 default principle
or else that any specificity it may have acquired
would most likely have occurred post 1984 & would thus
very likely be in the form of wgs84 for that reason as
well

also where so many as 3 parties are involved universal
norms tend to be preferred to local ones

your indonesia text says flat out
for its own special case but with universal
applicability in this case
wgs84 seems to be most sensible to adopt
&
all decisions should be legally agreed by all
countries involved

> I suspect that the Egypt 1907 Datum might have been
> used

but what in particular leads you to guess egypt 1907

i can imagine egypt & sudan adopting it but not so
readily libya

> - but see
>

<http://www.fig.net/pub/cairo/papers/ts_45/ts45_01_abidin_etal.pdf>

>

http://www.fig.net/pub/cairo/papers/ts_45/ts45_01_abidin_etal.pdf

> where it
> notes, using Indonesian maritime boundaries as its
> focus, that often the
> datum is NOT specifically denoted in a relevant
> treaty

exactly my point as well as my guess here at eglysd
since day 1 in 1925 & even up to the present

> and discusses the
> issues that arise as a result.

yes naturally many in the worlds busiest seas but none
in the worlds most desolate wasteland

> If you don't have
> time to read the whole
> paper

who me
i have all the time in the world for such
deliciousness

> the following section from the summary can
> help to understand the
> thesis:
>
> "The uncertainty in geodetic datum of boundary
> points introduces
> complications and problems
> in spatial management of Indonesia's maritime
> boundaries, since it can
> displace the boundary
> lines from their assumed true location. The
> displacements of boundaries in
> WGS84 datum are
> generally in the order of a few hundred meters, i.e.
> about 200 to 400 m,

indeed did you notice 420m was the max they cited
later in the article

sounds like your datum shift demo wants to take place
in the indonesian jungles

> depending on the
> assumed original geodetic datum of the boundaries
> stated in the treaties.
> These boundary
> displacements are spatially advantageous for
> Indonesia in some cases and
> also
> disadvantageous in others."

i also appreciated & hope you did too the specific
reference in this article to the attainment of
submeter level accuracy in pilotage by ecdis dgps in
2004
which nicely fills in a blank space in our earlier
discussion here
http://groups.yahoo.com/group/BoundaryPoint/message/18568

end inserts
& sweet dreams

> The following paper might be relevant to EGLYSD -
>

http://www.asprs.org/resources/grids/06-2003-kenya.pdf

> - although it
> primarily refers to Kenya it also mentions the use
> of various datums in
> Egypt and the Sudan.
>
> Googling "latitude longitude datum egypt" will
> provide a host of other links
> too numerous to reproduce here that will provide a
> wealth of additional
> information.
>
>
>
>
> _____
>
> From: BoundaryPoint@yahoogroups.com
> [mailto:BoundaryPoint@yahoogroups.com]
> On Behalf Of aletheiak
> Sent: Wednesday, January 04, 2006 8:33 PM
> To: BoundaryPoint@yahoogroups.com
> Subject: [BoundaryPoint] Re: EGLYSD class b
>
>
> there is no mention in any of the relevant ibs
> numbers that the 1925 italian
> egyptian
> agreement establishing this tripoint or the 1934
> italo british egyptian
> agreement
> reaffirming it included any official maps or even
> specified any official
> datum or datums
>
> various british french american & north african maps
> of the 1930s thru 1960s
> tho are said
> there to reliably depict the various borders
> convergent here at eglysd
>
> & one cant conclude the datum is elusive for it
> might well just be the
> common &
> nonelusive default datum of
> none specified
> & thus as likely wgs84 as any
> in which case the try or rather the result would
> indeed be a very loose
> class b
> as represented by the little man in the gully in the
> first pic
> or more likely a tight class c at probably 14 meter
> range
> but if this is not correct
> then there remains some possibility of a class d or
> even class e
>
> for there also remains an outside chance that the
> tripoint is in fact marked
> whether by an official durable marker
> since some other parts of these remote borders are
> so marked
> or even by just some little cairn or something these
> folks could have missed
> since there is also no evidence that they were
> really studying the border
> alignments or
> trying for the tripoint in any other way than just
> for the lat long
> intersection
>
> --- In BoundaryPoint@yahoogroups.com, "aletheiak"
> <aletheiak@y...> wrote:
> >
> > wow
> > nicely done
> > & a pleasure to see the shots back on goal & the
> discussion back on target
> again
> >
> > & since all 3 ibs numbers
> > 10 & 18 & 61
> > join brownlie in indicating this tripoint is
> unmarked
> > or at least was unmarked as recently as 1979
> > it is hard to argue with the bona fides of their
> perfect gps readings
> > no matter what datum they may have been using
> >
> > but since even they are only claiming 14 meter
> range at best
> > & were having difficulty getting it
> > i think i would credit them only with a class c
> > as in seeing the objective for certain with their
> eyes
> > somehow
> > at some point
> > in their overall visitation process
> > rather than a class b
> > as in necessarily having been at the exact spot
> with their bodies
> > for i think that honor would remain to be won
> > in this unusual circumstance
> > by someone with a better quality gps receiver
> >
> > --- In BoundaryPoint@yahoogroups.com, "Jesper
> Nielsen" <jesniel@i...>
> wrote:
> > >
> > > Thanks to the unknown visitor to Borderbase, who
> submitted the entry
> > >
> > >
> > >
> > > http://www.confluence.org/confluence.php?lat=22
> > > <http://www.confluence.org/confluence.php?lat=22
>

<http://www.confluence.org/confluence.php?lat=22&lon=25>

> &lon=25> &lon=25
> > >
> > >
> > >
> > > Jesper
> > >
> > >
> > >
> > > --
> > >
> > > Borderbase - your online guide to international
> borders and tripoints
> > >
> > > http://www.nicolette.dk/borderbase
> > >
> >
>
>
>
>
>
>
> _____
>
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