[Qgis-user] OTF reprojection and +towgs84 parameters

[Standaert Arnout]

-----Original Message-----
>From: Giovanni Manghi [mailto:giovanni.manghi at gmail.com] 
>
> I can set correctly the +towgs84 parameters for other projections but as
> a fact it doesn't seems to work with the one you describe.
>
> Did you find any solution to your problem?

Well, it's an odd problem. I have figured out the PROJ string that gives me correctly aligning results after transformation using ogr2ogr. It's actually the exact same string that the people on the PROJ mailing list have identified as the correct one, so I'm pretty sure that it is the right one.

So, this works perfectly: Lambert 72 SHP file --> ogr2ogr conversion --> load into QGis, match with Google Streets layer: good alignment

However, when using this same PROJ string for the layer in QuantumGIS, the OTF reprojection does *not* align. So there must be something that QGis does differently than the PROJ tools, right?
For clarity: Lambert 72 SHP file --> load in QGis, set CRS to the PROJ string --> match with Google Streets layer, project CRS = Google Mercator: alignment off by ~100m.

I'm going to set up an example and send it to the qgis-dev mailing list separately. I hope it will get some attention, it feels like an important issue for us Belgians :-)

> when I add the google layers with the openlayers plugin the maps are
> pretty transparent, how do you made to see the google layers in full
> color?

Actually, the transparency varies here too. After a zooming operation, I usually see almost only white, only after panning around at that zoom level, colors come up. Sometimes very transparent, sometimes full color, I haven't really detected a pattern yet...
Is the OpenLayers developer on this mailing list? Might be good to contact him?

Greets,
Arnout


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