[Proj] Question about Italian conversion
neteler at osgeo.org
Sat Dec 29 15:09:14 EST 2007
On Dec 29, 2007 8:54 PM, Frank Warmerdam <warmerdam at pobox.com> wrote:
> massimo at studiodemarchi.net wrote:
> >>> What am I doing wrong?
> >> Trying to follow the procedure with independent software, I get the
> >> impression that you didn't transform the datum from Hayford to WGS84.
> >> You simply inverse projected from x,y to lon,lat with the proper transverse
> >> mercator projection.
> >> With the Roma40 transform parameters found at <http://crs.bkg.bund.de>
> >> I arrive at lat,lon:
> >> 45d 06m 55.252s, 10d 47m 39.415s
> >> assuming a position vector rotation model (ISO) and an initial height of 0.
> >> The proj/epsg definitions you mention don't contain any datum transform
> >> instructions.
> > Thanks for your answer. I tried to do a coordinate transform using the -s_srs
> > EPSG:3003 (or 26591) and -t_srs EPSG:4326 parameters. How can I add the
> > necessary datum transform? I checked the documentation amd the forum, but
> > didn't find a clue.
> I followed Oscar's link to http://crs.bkg.bund.de but did not see any easily
> identifiable datum transformation parameters for the Monte Mario datum.
Here they are (extracted from GRASS GIS source code):
international dx=-225 dy=-65 dz=9
(Peninsular Part)" "Accuracy 3-4m"
(Sardinia)" "Accuracy 3-4m"
"towgs84=-50.2,-50.4,84.8,-0.690,-2.012,0.459,-28.08" "Italy (Sicily)"
They were taken from http://crs.bkg.bund.de.
Hope this helps,
More information about the Proj