[Proj] trying to understand results of reprojecting from epsg 4326 to epsg 31370

Clifford J Mugnier cjmce at lsu.edu
Tue Jul 7 11:36:26 EST 2009

There are two different geodetic conventions to the sense of the rotations used for 7-parameter transformations.  There is the right-handed rule used by the Americans and the Australians, and the left-handed rule used by the Europeans.  
Explanations regarding which is "correct" generally deteriorate into ethnocentric insults ...  :-)
Cliff Mugnier


From: proj-bounces at lists.maptools.org on behalf of Moritz Lennert
Sent: Tue 07-Jul-09 11:00
To: PROJ.4 and general Projections Discussions
Subject: Re: [Proj] trying to understand results of reprojecting from epsg 4326 to epsg 31370

On 07/07/09 16:56, Noel Zinn wrote:
> Consider changing the signs of the three rotations if you can do that
> manually, or the rotation sense of the 7-parameter transformation.

That was it. Thanks also to Clifford for the same hint. Could someone
explain the logic to me ? Why negate the translation, but not the
rotation compared to the WGS84->Bel72 transformation ?

And: should the information linked to EPSG code 31370 be corrected ? How
should I go about doing this ?

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