I am in the UK and my QGIS projects are based on UK Ordnance Survey mapping data and are set up in EPSG:27700. Whenever I have tried dropping an OpenLayers layer (Google Satellite/Bing Maps Aerial) in via the OpenLayers plugin (v0.90) it is always offset by 10 metres or so from my mapping data (rendering it useless).
I have tried turning on 'on the fly' reprojection, reprojecting in Google Mercator (EPSG:900913), starting a new QGIS project in Google Mercator projection, etc etc but the result is always the same.
I don't suppose anyone can describe a workflow that would result in a QGIS project containing an OpenLayers layer correctly aligned with (UK Ordnance Survey) mapping data?
(Apologies if this is the wrong place to post this type of query but I am inclined to think it is a case of me being stupid rather than a bug in the software.)
—-Edit—-
Update… The problem appears to be with QGIS, as an export of a correctly georeferenced vector map to KML as suggested by nhopton below also results in a misalignment with the satellite imagery.
Best Answer
If you have a shift of a few metres, you should try using a nadgrid instead of the constant +towgs84 parameters as defined by EPSG:27700. The three-parameter transformation used only has a accuracy of 21m.
You can find the official grid data here: http://www.ordnancesurvey.co.uk/oswebsite/gps/osnetfreeservices/furtherinfo/ostn02_ntv2.html
An alternative solution would be
with an accuracy of 2 metres.
See also:
Raster incorrectly reprojected to OSGB(27700)
How to reproject a raster file in QGIS with datum transformation?