[gdal-dev] PROJ.4 EPSG:28992

[Frank Warmerdam]

Bart van den Eijnden (OSGIS) wrote:
> Hi list,
> 
> in PROJ version 4.6 the definition for the Dutch national grid (EPSG:28992)
> is missing the towgs84 parameters.
> 
> Is this intentional, or an oversight?
> 
> 4.5:
> <28992> +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889
> +k=0.999908 +x_0=155000 +y_0=463000 +ellps=bessel
> +towgs84=565.237,50.0087,465.658,-0.406857,0.350733,-1.87035,4.0812 +units=m
> +no_defs  <>
> 
> 4.6:
> <28992> +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889
> +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +units=m +no_defs  <>

Bart,

In gdal/data/gcs.override.csv I see:

#
# Bart van den Eijnden and Jan Hartmann suggest this datum shift value:
#
#4289,Amersfoort,6289,Amersfoort,6289,9122,7004,8901,1,0,9606,565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812

This was introduced as the way of handling overrides for GDAL 1.5.0 (from
which the PROJ definitions are derived).  I'm really not clear on why this
was left commented out.  Possibly I was uncertain if it was authoritative?

If you will file a GDAL ticket on the issue, along with some sort of
pointer to information on how the values were derived I will re-enable
it in GDAL 1.5.1 and the next batch regeneration of PROJ.4 definitions
should include it. In the meantime, you can of course update your local
definitions.

It would be ideal if you could reference an EPSG towgs84 definition that
matches this one.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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