Merci Even,<div><br></div><div>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. </div><div><br></div><div>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?</div>
<div><br></div><div>Regards</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 3:27 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;">
Selon Hilmy Hashim <<a href="mailto:hilmyh@gmail.com">hilmyh@gmail.com</a>>:<br>
<div class="im"><br>
> Sorry to bring this up again. I've been looking for why epsg_tr.py -proj4 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 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>
</div>--> You are not looking to the right repository (the one above is an import of<br>
an older GDAL version by the FDO project). The main GDAL repository is 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 +alpha=323.0<br>
257905 +k=0.99984 +x_0=804670.24 +y_0=0 +gamma=323.1301023611111 +a=6377295.664<br>
+b=6356094.667915204 +units=m +no_defs<br>
<div class="im"><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>
</div>> *Hilmy*<br>
><br>
<br>
<br>
</blockquote></div><br></div>