<HTML dir=ltr><HEAD><TITLE>[Proj] Egypt Datum Transformation Parameters</TITLE>
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<DIV dir=ltr><FONT face="Times New Roman" color=#000000 size=2>Irwin,</FONT></DIV>
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<DIV dir=ltr><FONT face="Times New Roman" color=#000000 size=2>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.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>The NIMA/NGA transformation parameters are from ED50 - European Datum 1950 to WGS84 as well as Old Egyptian Datum 1930 to WGS84.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>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 ... :-)</FONT></DIV>
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<DIV dir=ltr><FONT size=2>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.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>You likely will have to "make do" with what you have unless you receive Egyptian Government authorization to do otherwise.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>Cliff Mugnier</FONT></DIV>
<DIV dir=ltr><FONT size=2>LOUISIANA STATE UNIVERSITY</FONT></DIV></DIV>
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<FONT face=Tahoma size=2><B>From:</B> proj-bounces@lists.maptools.org on behalf of Irwin Scollar<BR><B>Sent:</B> Tue 26-Aug-08 09:03<BR><B>To:</B> proj@lists.maptools.org<BR><B>Subject:</B> [Proj] Egypt Datum Transformation Parameters<BR></FONT><BR></DIV>
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<P><FONT size=2>Can anyone supply Helmert 7 parameter datum parameters between WGS84<BR>Ellipsoid and the Helmert 1906 Ellipsoid used in the "Red Belt, Blue<BR>Belt, Purple Belt, Purple Belt Extended" Old Egyptian 1907 areas or<BR>a link to where they may possibly be found?<BR><BR>I have only the 3 parameter Molodensky transform data in the NIMA<BR>1987 Madtran and the later Geotran2 programs which may not have<BR>errors as low as those of a modern dual frequency GPS receiver.<BR><BR>Irwin Scollar<BR><BR>_______________________________________________<BR>Proj mailing list<BR>Proj@lists.maptools.org<BR><A href="http://lists.maptools.org/mailman/listinfo/proj">http://lists.maptools.org/mailman/listinfo/proj</A><BR></FONT></P></DIV></BODY></HTML>