[Proj] Swiss CORINE: Bessel 1841 Hotine Oblique Mercator Azimuth Natural Origin?

Ziegler Stefan Stefan.Ziegler at bd.so.ch
Fri Jul 10 15:05:09 PDT 2009


Hi Markus

please check in the proj4 epsg-file the definition of 21781. It needs
the +towgs84 parameter:

+proj=somerc +lat_0=46.95240555555556 +lon_0=7.439583333333333
+x_0=600000 +y_0=200000 +ellps=bessel
+towgs84=674.374,15.056,405.346,0,0,0,0 +units=m +no_defs  

The 200 meters shift sounds a bit like a forgotten towgs84 parameter but
that's just a guess. 
Does the Grass ticket still needs some clarification?

regards
Stefan

> -----Ursprüngliche Nachricht-----
> Von: Markus Neteler [mailto:neteler at osgeo.org]
> Gesendet am: Freitag, 10. Juli 2009 16:18
> An: Ziegler Stefan
> Cc: proj
> Betreff: Re: Re: [Proj] Swiss CORINE: Bessel 1841 Hotine Oblique
> Mercator Azimuth Natural Origin?
> 
> Hi Stefan,
> 
> I should have asked earlier here :) Thanks a lot.
> However, the map seems to be shifted for 200-300 meters.
> If there any datum which I should specify? This reminds me
> of
> http://trac.osgeo.org/grass/ticket/35
> 
> Best regards
> Markus Neteler
> 
> On Fri, Jul 10, 2009 at 4:07 PM, Ziegler 
> Stefan<Stefan.Ziegler at bd.so.ch> wrote:
> > Hi Markus
> > try this:
> > ogr2ogr shp_dir/ -s_srs epsg:21781 -t_srs epsg:3035 clcbn85p.shp
> > epsg:21781 is forcing ogr2ogr to use the real swiss 
> prj-definition. Forget
> > the strange definition in the delivered prj-file.
> > regards
> > Stefan
> >> -----Ursprüngliche Nachricht-----
> >> Von: Markus Neteler [mailto:neteler at osgeo.org]
> >> Gesendet am: Freitag, 10. Juli 2009 14:59
> >> An: PROJ.4 and general Projections Discussions
> >> Betreff: Re: [Proj] Swiss CORINE: Bessel 1841 Hotine 
> Oblique Mercator
> >> Azimuth Natural Origin?
> >>
> >> Dear list members,
> >>
> >> I was earlier sending this message to the gdal-dev list without
> >> answer. trying here now:
> >>
> >> On Mon, Jun 8, 2009 at 5:24 PM, Markus
> >> Neteler<neteler at osgeo.org> wrote:
> >> > hi,
> >> >
> >> > I am trying to reproject the Swiss CORINE data CLC90 [1] 
> into LAEA.
> >> > The .prj file is attached. Unfortunately the 
> transformation fails:
> >> >
> >> > ogr2ogr -t_srs eu_etrs89_laea.prj /tmp/clc90_eu_laea.shp
> >> /geodata/clcbn85p.shp
> >> > ERROR 6: Failed to initialize PROJ.4 with `+proj=omerc
> >> > +lat_0=46.95240555555556 +lonc=7.439583333333333 +alpha=90 +k=1
> >> > +x_0=-9419820.590700001 +y_0=200000 +ellps=bessel +units=m
> >> +no_defs '.
> >> > lat_0 = 0 or 90 or alpha = 90
> >> > Failed to create coordinate transformation between the
> >> > following coordinate systems.  This may be because they
> >> > are not transformable, or because projection services
> >> > (PROJ.4 DLL/.so) could not be loaded.
> >> > Source:
> >> > 
> PROJCS["Bessel_1841_Hotine_Oblique_Mercator_Azimuth_Natural_Origin",
> >> >    GEOGCS["GCS_Bessel_1841",
> >> >        DATUM["Not_specified_based_on_Bessel_1841_ellipsoid",
> >> >            SPHEROID["Bessel_1841",6377397.155,299.1528128]],
> >> >        PRIMEM["Greenwich",0.0],
> >> >        UNIT["Degree",0.0174532925199433]],
> >> >    PROJECTION["Hotine_Oblique_Mercator"],
> >> >    PARAMETER["False_Easting",-9419820.5907],
> >> >    PARAMETER["False_Northing",200000.0],
> >> >    PARAMETER["Scale_Factor",1.0],
> >> >    PARAMETER["Azimuth",90.0],
> >> >    PARAMETER["Longitude_Of_Center",7.439583333333333],
> >> >    PARAMETER["Latitude_Of_Center",46.95240555555556],
> >> >    UNIT["Meter",1.0]]
> >> > Target:
> >> > PROJCS["ETRS89 / ETRS-LAEA",
> >> >    GEOGCS["ETRS89",
> >> >        DATUM["European_Terrestrial_Reference_System_1989",
> >> >            SPHEROID["GRS 1980",6378137,298.2572221010042,
> >> >                AUTHORITY["EPSG","7019"]],
> >> >            AUTHORITY["EPSG","6258"]],
> >> >        PRIMEM["Greenwich",0],
> >> >        UNIT["degree",0.0174532925199433],
> >> >        AUTHORITY["EPSG","4258"]],
> >> >    UNIT["metre",1,
> >> >        AUTHORITY["EPSG","9001"]],
> >> >    AUTHORITY["EPSG","3035"]]
> >> >
> >> > Suggestions welcome to reproject this data set...
> >> >
> >> > thanks
> >> > Markus
> >> >
> >> > [1]
> >> http://www.bfs.admin.ch/bfs/portal/de/index/dienstleistungen/g
> > eostat/datenbeschreibung/corine_land_cover.html
> >>    Data: -> GIS-Daten CORINE Land Cover Schweiz 1990 (ZIP file)
> >>
> > Is there a way to enable PROJ4 to support this projection?
> > thank in advance,
> > Markus
> > _______________________________________________
> > Proj mailing list
> > Proj at lists.maptools.org
> > http://lists.maptools.org/mailman/listinfo/proj
> 

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