[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.
Cliff Mugnier


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.

Irwin Scollar

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