[GRASSLIST:6804] Re: cs2cs and grass

[Tom Russo]

On Tue, May 17, 2005 at 07:20:19PM +0100, we recorded a bogon-computron collision of the <paul-grass at stjohnspoint.co.uk> flavor, containing:
> Francesco Mirabella wrote:
> [...]
> >
> >Just to check,
> >I tried to project the point from WGS84 to Gauss Boaga using cs2cs:
> >------------------------
> > cs2cs -E +proj=latlong  +datum=WGS84 +to +proj=tmerc +lon_0=15
> >  +k=0.9996 +x_0=2520000 +ellps=intl  -v -f %.6f
> >------------------------
> >
> >
> >After importing the point of check into the Gauss Boaga location, it
> >results to be shifted about 167 m (mainly to the North) with respect to
> >the point project (v.proj).
> >
> >where am I wrong? can anyone help??
> 
> Looks like you left +towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68 
> out of the PROJ.4 description of the rome40 location, so the datum shift 
> will not have happened there. Probably the GRASS result is the correct one?

Try using "g.proj -j" (print location projection in PROJ.4 format) in the 
Gauss Boaga location and using the output of that for your cs2cs ... +to 
options.  Bet it'll agree better, because then you can be sure you have all 
the arguments that Grass is using.

-- 
Tom Russo    KM5VY     SAR502  DM64ux         http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236 AHTB#1 
 "The only thing you can do easily is be wrong, and that's hardly
  worth the effort." -- Norton Juster