I'm using OSGeo4W on Windows 7. I just checked using the OSGeo4W shell and setting gdaldev environment epsg_tr does give me +gamma. On my Ubuntu 10.04 box with GDAL 1.7.3, the gamma is not there.
I've just updated QGis 1.7.0-114 and I don't get the gamma in the CRS listing. Thanks *Hilmy* On Thu, Apr 14, 2011 at 3:51 PM, Even Rouault <even.roua...@mines-paris.org>wrote: > Selon Hilmy Hashim <hil...@gmail.com>: > > > Merci Even, > > > > Didn't know which one is the effective code, there are so many versions > > around. It's good to know that changes have been made. > > > > I'm using QGis 1.7 dev and the About say it's using GDAL/OGR 1.8.0. How > come > > the +gamma is not included there? > > I know they have updated very recently their srs.db to sync it with GDAL > 1.8.0. > Perhaps you should also update to the latest svn version of qgis ? > > A comment in the GDAL code also shows that the +gamma parameter is only > understood by PROJ 4.8.0 (so the svn version as 4.8.0 is unreleased yet). > > But one thing is definitely weird and should be investigated first : > epsg_tr.py > -proj4 3168 *should* show the +gamma parameter (whatever your proj version > is). > If you don't see it, it's a clear sign you don't use GDAL 1.8.0. > > What does epsg_tr.py --version return ? > > > > > Regards > > > > *Hilmy* > > > > > > On Thu, Apr 14, 2011 at 3:27 PM, Even Rouault > > <even.roua...@mines-paris.org>wrote: > > > > > Selon Hilmy Hashim <hil...@gmail.com>: > > > > > > > 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* > > > > > > > > > > > > > > > > > >
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