[OSRS-PROJ] PROJ and ellipsoid shifts

[Jean-Paul Berroir]

> Jean-Paul,
>
> I get the same problem, and I have found it is a botched change I made

> to the Convert_Geodetic_To_Geocentric() routine in September.  As far
as
> I can tell this will always screw up any conversion from geodetic to
> geocentric.   I have correct the geocent.c file and now I get values
close
> to your reference position, but still off by 12 meters.  I am assuming
this
> is due to the +towgs84 transform being only an approximation of the
correct
> transformation.
>
> I have committed the fixed geocent.c, and also place it at:
>
>  ftp://gdal.velocet.ca/pub/outgoing/geocent.c
>
> I would appreciate your trying the fix and verifying things are OK for
you.
> I think I had better issue a PROJ.4.4.5 soon since this is a very
serious
> flaw in the datum shifting support.

Thank you Mark
I've tried your fix and as you say, the results agree with reference
points by less than 12 meters -even less with other points-, which is
more than enough for me.  And more, the +towgs84 specification now has a
normal behavior

many thanks again -  and happy new year (with version 4.4.5?)

Regards

Jean-Paul




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----------------------
AIR project - INRIA - BP 105 - F78153 Le Chesnay Cedex
Tel: +33 1 3963 5703 Fax: +33 1 3963 5880
jean-paul.berroir at inria.fr


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