[Proj] Egypt Datum Transformation Parameters
Clifford J Mugnier
cjmce at lsu.edu
Tue Aug 26 12:31:29 EDT 2008
There are numerous academics and government agencies in Egypt that can supply what you want, but nobody is likely going to do so. I have tried to get such information for years, and have never even received the courtesy of a reply. Note that such information is considered a military secret in some countries, and I suspect that Egypt is one of those countries.
The NIMA/NGA transformation parameters are from ED50 - European Datum 1950 to WGS84 as well as Old Egyptian Datum 1930 to WGS84.
If you need better accuracy, I recommend you perform the observations yourself and publish your derived transformation parameters on this list for everyone else. I would like to point out that 7-parameter transformations are really applicable only to small provincial areas that are significantly smaller in areal extend than a single Egyptian Transverse Mercator Belt. Working with a crew of a dozen men all with dual-frequency receivers, you should get the job done within a decade or so ... :-)
The point to this is that what you desire is likely a government secret, and you are asking for geodetic-quality transformations for an entire country. That sort of thing is implemented with algorithms such as NTv2 or NADCON - not with a Molodensky or Bursa-Wolfe model. I have used such models in the past, but for tiny regions such as a single international boundary line or for a city.
You likely will have to "make do" with what you have unless you receive Egyptian Government authorization to do otherwise.
LOUISIANA STATE UNIVERSITY
From: proj-bounces at lists.maptools.org on behalf of Irwin Scollar
Sent: Tue 26-Aug-08 09:03
To: proj at lists.maptools.org
Subject: [Proj] Egypt Datum Transformation Parameters
Can anyone supply Helmert 7 parameter datum parameters between WGS84
Ellipsoid and the Helmert 1906 Ellipsoid used in the "Red Belt, Blue
Belt, Purple Belt, Purple Belt Extended" Old Egyptian 1907 areas or
a link to where they may possibly be found?
I have only the 3 parameter Molodensky transform data in the NIMA
1987 Madtran and the later Geotran2 programs which may not have
errors as low as those of a modern dual frequency GPS receiver.
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