[Proj] from EPSG:28992 to EPSG:25832

[Bart van den Eijnden (OSGIS)]

An update on this issue after I had some contact with Jan Hartmann.

There is something strange going on in our opinion, the same command 
yields different results in PROJ 4.5 and 4.6. PROJ 4.5 is very close to 
the expected result.

PROJ 4.6:
cs2cs -f %.9f +proj=sterea +lat_0=52.15616055555555 
+lon_0=5.38763888888889 +k=0.999908 +x_0=155000 +y_0=463000 
+ellps=bessel +units=m 
+towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812 
+no_defs +to +proj=utm +zone=32 +ellps=GRS80 +units=m +no_defs
96197.31 390964.35
290505.483235725        5710539.888875010 0.000000000

PROJ 4.5:
290464.957702205        5710439.900326397 44.377755052

If Jan changes the ellipsoid of the UTM zone from GRS80 to WGS84 things 
are okay in PROJ 4.6.

Can somebody shed some light on this? Did something changes with the 
ellipsoids? How can different PROJ versions yield different results on 
the same command?

Best regards,
Bart

Bart van den Eijnden (OSGIS) wrote:
> Hi list,
>
> why is the conversion from EPSG:28992 to EPSG:25832 not very accurate?
>
> The official calculator from agrs.nl gives the following:
>
> Original system RD and NAP
> X 196197,31
> Y 390964,35
>
> Target system UTM(ETRS89)
> Zone 32
> Northing 5710439,825
> Easting 290464,836
>
> This is what I get with PROJ 4.6:
>
> cs2cs -f %.9f +proj=sterea +lat_0=52.15616055555555 +lon_0=5.38763888888889
> +k=0.999908 +x_0=155000 +y_0=463000 +ellps=bessel +units=m
> +towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812
> +no_defs +to +proj=utm +zone=32 +ellps=GRS80 +units=m +no_defs
> 196197.31 390964.35
> 290505.483235725        5710539.888875010 0.000000000
>
> Any ideas what could be causing this? Is there a correction grid involved (I
> am no projections expert unfortunately ... ).
>
> TIA.
>
> Best regards,
> Bart
>
> --
> Bart van den Eijnden
> OSGIS, Open Source GIS
> http://www.osgis.nl
>
>
>
>
>
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>   


-- 
Bart van den Eijnden
OSGIS, Open Source GIS
bartvde at osgis.nl
http://www.osgis.nl