thanxx
i appreciate the question no less than the critical
review behind it
but first
with regard to the egsd signs
all indications thus far are that they date from the
militarily tense early to mid 1990s period
so their accuracy was very likely limited by selective
availability in any case
& regarding egly
yes indeed i could & probably should ask this just to
rule it out with greater certainty
tho i have already given my reasons for doubting there
is a bilaterally official datum even there
in my previous post
to which i should now add that the elusiveness or
formlessness of all those so hopefully lovely egly
border arcs
which arent at all discernible as arcs on any maps i
have yet seen
is just one more indication of the crudeness & hence
datumlessness of the 1927 egly demarcation survey
& yikes reason even to doubt that the commissioners
would have been proud enough of their handiwork in the
wilderness to even plat it out
or worry about it in any other way much beyond
degmindec or degmindodec
let alone degminsec etc
but in the meantime i also realized that tho my
proposed 487 mile extrapolation from the nearest egly
rock would nail the longitude of eglysd with as much
precision as that rock itself had already been nailed
with
it still wouldnt at all necessarily nail the latitude
of eglysd any better than we already have it
22nd parallel
hahahahaha
ahhh
nevertheless i believe this will prove to be a smaller
shortcoming than one might initially think
because the far greater component of any datum shift
displacement
both potentially & typically i believe
is in the longitude rather than the latitude
since latitude is first a sidereal fact while
longitude is only a terrestrial & far more subjective
one
meaning all possible versions of the 22nd or any other
parallel will bunch up much closer together generally
than will all possible versions of the 25th or any
other meridian
for example the example i think we may have begun with
azconmut shifting between nad27 & nad83
has 59 meter longitudinal displacement & only 2 meter
latitudinal
which btw per pythagoras means more than 99point94
percent of the distance of any shift there is
contributed by the longitudal portion of the shift
alone
so our range of possible latitude values here at
eglysd should be a correspondingly small fraction of
the distance from the 25th meridian of the
southernmost egly rock
in whatever datum it is bagged & or expressed
which means
using say pilotage gps on the southernmost egly rock
we would get the correct submeter wide ribbon of
longitude for eglysd in any datum
& but only the correct say meter or at most several
meter broad ribbon of latitude for it
& thus using commercial gps any datum shift in the
latitude would most likely be imperceptible
& tho i thought of this saving grace shortly before
falling asleep last night
the confirmation of it came to me in a dream
from which i awoke laughing out loud
in the dream i had just reached eglysd by car & found
a border guard there with his young son who was
operating a walkie talkie
of course the guard asked me to open my trunk
which i did
& inside it
much to my surprise
was his other son
an identical twin for all i could tell
talking back to them on another walkie talkie
hahahahaha
& smiling & shaking my head in amazement ever since
can you dig it
but anyway
where do i think we are now
i think
we are beginning to think mohamed wont answer perhaps
because he doesnt know
& we are looking for brownlie just to check as much as
we can of our guesswork to date
as well as to get a better fix on any potential source
docs
but actually
it just occurs to me too
since this southernmost egly rock
which we are trying to hang our hat on
is so beguilingly close to the 29x25 project
intersection point
why dont we just sponsor a fellowship for some
deserving confluencer to bag it for us
--- "Lowell G. McManus" <
lgm@...> wrote:
> While you're corresponding with them, couldn't you
> just ask if there is an
> official datum for the delimited but undemarcated
> portions of the EGLY boundary
> and what datum they used when erecting the
> (presumably) unilateral signs on
> EGSD? Wouldn't that beat trying to extrapolate from
> afar?
>
> Lowell G. McManus
> Leesville, Louisiana, USA
>
>
> ----- Original Message -----
> From: "aletheiak" <aletheiak@...>
> To: <BoundaryPoint@yahoogroups.com>
> Sent: Tuesday, January 10, 2006 9:36 PM
> Subject: [BoundaryPoint] Re: but why suppose an
> eglysd datum has ever been
> stated or even can be synthesized
>
>
> > aha & far better
> > we just ask the egypt border force if it happens
> to have gps era survey data
> > on this
> > southernmost egly marker at any level of
> exactitude
> > & extrapolate eglysd from it
> > aha
> > of course
>
>
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