[Proj] Egypt Datum Transformation Parameters

support.mn at elisanet.fi support.mn at elisanet.fi
Wed Aug 27 15:05:50 EDT 2008


Hello,

there seems to be some entries in EPSG database
which have also a datum defined. Here are them:

# epsg.pin:4706
# Egypt Gulf of Suez S-650 TL
proj=longlat
ellps=helmert
towgs84=-146.21,112.63,4.05,0,0,0,0
no_defs

# epsg.pin:3355
# Egypt Gulf of Suez S-650 TL / Red Belt
proj=tmerc
lat_0=30
lon_0=31
k=1
x_0=615000
y_0=810000
ellps=helmert
towgs84=-146.21,112.63,4.05,0,0,0,0
units=m
no_defs

There are also some other entries, but those are without
any datum shift. Those given seem to use only 3 parameters.

Spatialreference.org gives exactly the same data:

http://spatialreference.org/ref/epsg/?search=egypt&srtext=Search+EPSG+References

If nothing else helps you could always calculate your self
some datum parameters?? if you have some known
points available.

Regards: Janne.

-------------------

Irwin Scollar <al001 at uni-koeln.de> kirjoitti: 
> 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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