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.<div><br></div><div>I've just updated QGis 1.7.0-114 and I don't get the gamma in the CRS listing.</div>
<div><br></div><div>Thanks</div><div><br clear="all"><span style="font-size:large"><i><font face="garamond, serif"><b><font color="#FF6600">Hilmy</font></b></font></i></span><br>
<br><br><div class="gmail_quote">On Thu, Apr 14, 2011 at 3:51 PM, Even Rouault <span dir="ltr"><<a href="mailto:even.rouault@mines-paris.org">even.rouault@mines-paris.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">Selon Hilmy Hashim <<a href="mailto:hilmyh@gmail.com">hilmyh@gmail.com</a>>:<br>
<br>
</div><div class="im">> Merci Even,<br>
><br>
> Didn't know which one is the effective code, there are so many versions<br>
> around. It's good to know that changes have been made.<br>
><br>
> I'm using QGis 1.7 dev and the About say it's using GDAL/OGR 1.8.0. How come<br>
> the +gamma is not included there?<br>
<br>
</div>I know they have updated very recently their srs.db to sync it with GDAL 1.8.0.<br>
Perhaps you should also update to the latest svn version of qgis ?<br>
<br>
A comment in the GDAL code also shows that the +gamma parameter is only<br>
understood by PROJ 4.8.0 (so the svn version as 4.8.0 is unreleased yet).<br>
<br>
But one thing is definitely weird and should be investigated first : epsg_tr.py<br>
-proj4 3168 *should* show the +gamma parameter (whatever your proj version is).<br>
If you don't see it, it's a clear sign you don't use GDAL 1.8.0.<br>
<br>
What does epsg_tr.py --version return ?<br>
<div><div></div><div class="h5"><br>
><br>
> Regards<br>
><br>
> *Hilmy*<br>
><br>
><br>
> On Thu, Apr 14, 2011 at 3:27 PM, Even Rouault<br>
> <<a href="mailto:even.rouault@mines-paris.org">even.rouault@mines-paris.org</a>>wrote:<br>
><br>
> > Selon Hilmy Hashim <<a href="mailto:hilmyh@gmail.com">hilmyh@gmail.com</a>>:<br>
> ><br>
> > > Sorry to bring this up again. I've been looking for why epsg_tr.py -proj4<br>
> > is<br>
> > > not including the +gamma (RectifiedToSkew angle) parameter for the<br>
> > > +proj=omerc projection as used in EPSG:3168, EPSG:3375, etc. It seems<br>
> > that<br>
> > > it is not set in<br>
> > > <a href="https://svn.osgeo.org/fdo/trunk/Thirdparty/gdal/ogr/ogr_srs_proj4.cpp" target="_blank">https://svn.osgeo.org/fdo/trunk/Thirdparty/gdal/ogr/ogr_srs_proj4.cpp</a>:<br>
> ><br>
> > --> You are not looking to the right repository (the one above is an import<br>
> > of<br>
> > an older GDAL version by the FDO project). The main GDAL repository is<br>
> > located<br>
> > at <a href="http://svn.osgeo.org/gdal/trunk" target="_blank">http://svn.osgeo.org/gdal/trunk</a>.<br>
> ><br>
> > I can see that a fix for the gamma parameter in<br>
> > <a href="http://trac.osgeo.org/gdal/changeset/18950" target="_blank">http://trac.osgeo.org/gdal/changeset/18950</a>. This is in GDAL 1.8.0 and the<br>
> > testepsg utility gives :<br>
> ><br>
> > PROJ.4 rendering of [EPSG:3168] = +proj=omerc +lat_0=4 +lonc=102.25<br>
> > +alpha=323.0<br>
> > 257905 +k=0.99984 +x_0=804670.24 +y_0=0 +gamma=323.1301023611111<br>
> > +a=6377295.664<br>
> > +b=6356094.667915204 +units=m +no_defs<br>
> ><br>
> > ><br>
> > > else if( EQUAL(pszProj,"omerc") )<br>
> > ><br>
> > > {<br>
> > > SetHOM( OSR_GDV( papszNV, "lat_0", 0.0 ),<br>
> > > OSR_GDV( papszNV, "lonc", 0.0 ),<br>
> > > OSR_GDV( papszNV, "alpha", 0.0 ),<br>
> > > 0.0, /* ??? */<br>
> > > OSR_GDV( papszNV, "k", 1.0 ),<br>
> > > OSR_GDV( papszNV, "x_0", 0.0 ),<br>
> > > OSR_GDV( papszNV, "y_0", 0.0 ) );<br>
> > > }<br>
> > ><br>
> > > ...<br>
> > ><br>
> > ><br>
> > > else<br>
> > > {<br>
> > > sprintf( szProj4+strlen(szProj4),<br>
> > > "+proj=omerc +lat_0=%.16g +lonc=%.16g +alpha=%.16g"<br>
> > > " +k=%.16g +x_0=%.16g +y_0=%.16g ",<br>
> > > GetNormProjParm(SRS_PP_LATITUDE_OF_ORIGIN,0.0),<br>
> > > GetNormProjParm(SRS_PP_CENTRAL_MERIDIAN,0.0),<br>
> > > GetNormProjParm(SRS_PP_AZIMUTH,0.0),<br>
> > > GetNormProjParm(SRS_PP_SCALE_FACTOR,1.0),<br>
> > > GetNormProjParm(SRS_PP_FALSE_EASTING,0.0),<br>
> > > GetNormProjParm(SRS_PP_FALSE_NORTHING,0.0) );<br>
> > > }<br>
> > ><br>
> > > There seems to be some uncertainty about this parameter. How can this be<br>
> > > resolved and how can I help?<br>
> > ><br>
> > > Thanks.<br>
> > ><br>
> > > *Hilmy*<br>
> > ><br>
> ><br>
> ><br>
> ><br>
><br>
<br>
<br>
</div></div></blockquote></div><br></div>