[postgis-users] Transform not transforming longitude

[Nathaniel]

Hello all,

I've recently installed PostGIS/Proj4/GEOS.

Calls to Transform() between two datums (Eg
WGS84->NAD27, WGS84->ED50) are not altering the
longitude. Also, the latitude change is not exactly
right (compared to other reliable transformers).

Is this something that other users have experienced?
Installation on Mac OS X was completely trouble-free
and by-the-book, so my hunch is that the error is my
ignorance.

My guess is that the Transform call is not doing a
datum shift, but rather is just reprojecting onto the
new ellipsoid. If this is the case, what do I have to
do to shift datums?

Thanks in advance for any help.



Here's an example:


select srid(geom) AsText(geom) from gtest;

 srid |          astext
------+--------------------------
 4326 | POINT(-3.51885 56.50298) 


select AsText(Transform(geom,4320)) from gtest;

              astext
--------------------------------
POINT(-3.51885 56.503736259005) 




		
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