[Qgis-user] on the fly transformation with NTv2

[Giovanni Manghi]

Hi,

> does anyone know whether a shape-layer can be transformed on the fly
> with using the definition of  an NTv2 file


yes, you just need no create two custom CRSs. Assuming that your NTv2
grid file is for a transformation from crs A to crs B than the two
custom CRSs must be defined as

Ac = A +nadgrids=yourfile.gsb +wktext

and

Bc = B +towgs84=0,0,0 +wktext


and then set Ac as crs for your layers and Bc as crs for your project.


A plugin is under development to make (much) easier to handle NTv2 grids
and transformations under QGIS.


Cheers

-- Giovanni --