Thanks Frank.<br>I use QGis 1.5 from osgeo4w (I don't know exactly which version of Proj.4 is used).<br>I just try with your suggested definition. It's better but I always have a deviation of about 5 meters.<br><br>
Thibaut.<br><br><div class="gmail_quote">2010/10/4 Frank Warmerdam <span dir="ltr"><<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div class="im">Thibaut Gheysen wrote:<br>
> Hi,<br>
><br>
> I have a problem in QGIS with the Stereo 1970 coordinate system (EPSG<br>
> 31700).<br>
> I have a shapefile in the WGS 84 coordinate system (from a GPS device).<br>
> I projected this shapefile in Stereo 1970 using ArcMap.<br>
> In ArcMap, the source and projected points are in the same place. In<br>
> Qgis, I have a deviation of about 100 meters when displaying this 2<br>
> shapefiles and activating the "on the fly projection" (stereo.jpg). This<br>
> deviation is the same that the one I obtain in ArcMap without<br>
> "geographic coordinate system transformations".<br>
<br>
</div>Thibault,<br>
<br>
I'm not sure exactly what version of PROJ.4 you are using, but after my<br>
"datum shift identification upgrade" the EPSG dictionary for proj now<br>
has this as the suggested definition of 31700:<br>
<br>
<br>
+proj=sterea +lat_0=46 +lon_0=25 +k=0.99975 +x_0=500000 +y_0=500000<br>
+ellps=krass +towgs84=28,-121,-77,0,0,0,0 +units=m +no_defs<br>
<br>
Perhaps you could try with this?<br>
<br>
Best regards,<br>
--<br>
---------------------------------------+--------------------------------------<br>
I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a><br>
light and sound - activate the windows | <a href="http://pobox.com/%7Ewarmerdam" target="_blank">http://pobox.com/~warmerdam</a><br>
and watch the world go round - Rush | Geospatial Programmer for Rent<br>
<br>
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</blockquote></div><br>