Correct Transformation of MGI Austria Lambert to WGS 84 needed

[gmirzi]

Hello,

I want to export a layer with MGI Austria Lambert (EPSG 31287) to WGS 84 (EPSG 4326) with fTools. The problem ist that the result has an x- and y-axis error of 100 meters or so because the transformation doesn't use the right parameters. For MGI to WGS 84 there are some different transformation methods but only MGI_To_WGS_1984_3 (EPSG 1618) is the one that is right and that is recommended by the official Austrian Institute BEV.

see also: ​http://img293.imageshack.us/img293/7675/transformation.png

and the correct parameters below:

Is it possible to change the parameters in QGIS transformation manually (user defined projection) or can you implement this function as a new transformation? Thank you!

regards, Philipp

using QGIS 1.5 under XP

1618 MGI_To_WGS_1984_3

GEOGTRAN["MGI_To_WGS_1984_3",GEOGCS["GCS_MGI",DATUM["D_MGI",SPHEROID["Bessel_1841",6377397.155,299.1528128]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],METHODPosition_Vector,PARAMETER["X_Axis_Translation",577.326],PARAMETER["Y_Axis_Translation",90.129],PARAMETER["Z_Axis_Translation",463.919],PARAMETER["X_Axis_Rotation",5.137],PARAMETER["Y_Axis_Rotation",1.474],PARAMETER["Z_Axis_Rotation",5.297],PARAMETER["Scale_Difference",2.4232]]

Source: ​http://gullhver.os.is/website/ArcXML_Guide/Support_files/elements/dattrans.htm

[lutra]

Just add a custom reference system in your QGIS installation

[pcav]

If very widely used, this can be added to the projection internal DB