Selon Hilmy Hashim <[email protected]>: > Sorry to bring this up again. I've been looking for why epsg_tr.py -proj4 is > not including the +gamma (RectifiedToSkew angle) parameter for the > +proj=omerc projection as used in EPSG:3168, EPSG:3375, etc. It seems that > it is not set in > https://svn.osgeo.org/fdo/trunk/Thirdparty/gdal/ogr/ogr_srs_proj4.cpp:
--> You are not looking to the right repository (the one above is an import of an older GDAL version by the FDO project). The main GDAL repository is located at http://svn.osgeo.org/gdal/trunk. I can see that a fix for the gamma parameter in http://trac.osgeo.org/gdal/changeset/18950. This is in GDAL 1.8.0 and the testepsg utility gives : PROJ.4 rendering of [EPSG:3168] = +proj=omerc +lat_0=4 +lonc=102.25 +alpha=323.0 257905 +k=0.99984 +x_0=804670.24 +y_0=0 +gamma=323.1301023611111 +a=6377295.664 +b=6356094.667915204 +units=m +no_defs > > else if( EQUAL(pszProj,"omerc") ) > > { > SetHOM( OSR_GDV( papszNV, "lat_0", 0.0 ), > OSR_GDV( papszNV, "lonc", 0.0 ), > OSR_GDV( papszNV, "alpha", 0.0 ), > 0.0, /* ??? */ > OSR_GDV( papszNV, "k", 1.0 ), > OSR_GDV( papszNV, "x_0", 0.0 ), > OSR_GDV( papszNV, "y_0", 0.0 ) ); > } > > ... > > > else > { > sprintf( szProj4+strlen(szProj4), > "+proj=omerc +lat_0=%.16g +lonc=%.16g +alpha=%.16g" > " +k=%.16g +x_0=%.16g +y_0=%.16g ", > GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0), > GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0), > GetNormProjParm(SRS_PP_AZIMUTH,0.0), > GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0), > GetNormProjParm(SRS_PP_FALSE_EASTING,0.0), > GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) ); > } > > There seems to be some uncertainty about this parameter. How can this be > resolved and how can I help? > > Thanks. > > *Hilmy* > _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
