[gdal-dev] SRS-Transformation(DHDN/GK=>ETRS89/UTM) with towgs84 - Accuracy

[Jean-Claude Repetto]

Gregor Fikoczek wrote :
> 3.) using towgs-option (Transform-Parameter)
> 
> ogr2ogr -s_srs "+proj=tmerc +lat_0=0 +lon_0=6 +x_0=2500000 +y_0=0 
> +ellps=bessel +units=m 
> +towgs84=590.1181,99.6226,340.1890,1.185095,-1.334952,-2.904521,1.00001651559" -t_srs "+proj=utm 
> +ellps=GRS80 +datum=WGS84 +zone=32" -f GML points_7P_gdal.gml points.gml
> 
> -----------------------------------------------------------------------------------------------------------
> Results 					|		difference
> East[m]	     |	North[m]		|	E	    |	   N	    |  distance
> -----------------------------------------------------------------------------------------------------------
> 340408,056  |	5617072,821	|	-0,023  |	-0,334  |	0,334
> 342695,237  |	5614820,058	|	-0,007  |	-0,309  |	0,309
> 343584,897  |	5608927,933	|	0,004   |	-0,295  |	0,295
> 
> 
> Parameter:
> dX	+590.1181m
> dY	+99.6226 m 	
> dZ	+340.1890 m
> rX	+1.185095"
> rY	-1.334952"
> rZ	-2.904521"
> dm = 1.00001651559
> 
> 

Hello,

Where did you find these parameters ? The EPSG database gives these ones :

dX	598.1
dY	73.7
dZ	418.2
rX	0.202
rY	0.045
rZ	-2.455
dm	6.7

Regards,
Jean-Claude