[GRASSLIST:2336] Re: m.proj2

[Ivan Marchesini]

thanks to all for the answers...
ivan



Alle 14:55, giovedì 22 gennaio 2004, Paul Kelly ha scritto:
> On Thu, 22 Jan 2004, Markus Neteler wrote:
> > > > On Wed, Jan 21, 2004 at 02:10:38PM +0100, Ivan Marchesini wrote:
> > > > > Dear Users,
> > > > > I'm trying to use m.proj2 to translate a point from latlong ed50
> > > > > coord sistem to the italian sistem (gaus-boaga, rome40)
> > > > > I have some difficulties to write the sintax of the command....
> > > > > thank you...
> > > >
> > > > With 'cs2cs' (provided by PROJ4) it should be:
> > > > LATLONG/ED50 -> Gauss-boaga Ovest/Roma40
> > > >
> > > > cat coordsED50.txt | cs2cs +init=epsg:4230 +to +init=epsg:26591 \
> > > >       +towgs84=-85.88,-28.85,+49.67,-1.003,-2.383,-1.808,-27.82 >
> > > > coordsGB1.txt
> > > >
> > > > Fuso Est:
> > > >  Gauss-boaga Est is +to +init=epsg:26592
> > > >
> > > > Be sure to pick the right (local) towgs84 parameters.
>
> Just realised Rome40 also uses the international ellipsoid. So you may not
> need any datum transformation parameters at all in this simple example.
>
> cs2cs +init=epsg:4230 +to +init=epsg:26591
>
> should do the trick.
> It would be good if there was a test point to check.
> But anyway my other point was if neither datum is WGS84 then you need to
> provided a set of towgs84 parameters for each side of the transformation
> and then the calculation will go through WGS84 as an intermediate stage.
>
> Paul

-- 
Ivan Marchesini
University of Perugia 
Italy