[Qgis-user] georeferencing

[M.E.Dodd]

I want to show a detailed map of buildings and vegetation over a background image e.g. openstreetmap or google etc. Don't think qgis can do on the fly transformation of rasters at moment so assume I have to geocode the detailed map using epsg:900913 so it can be shown with openstreetmap.  Converted a set of fixed point locations from original map into google's x and y then did the geocoding in qgis and plotted over openstreetmap.  The individual points then came out in the correct place but the map itself was shown about 19km too far north.  If I'd had made a mistake in the x,y coordinates or the coordinate system then the points should not be in the correct place so I am a bit mystified as to what has happened and how to go about fixing it.
The map I am trying to georeference is a .tiff with transparency hoping that this would allow the details to show over the background, however the 'transparent' part is showing up black at the moment so some adjustment here needed too.


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