[Using QGIS 2.12 Lyon on Mac with OS X 10.10.5]
I am struggling to georeference some old hydrographic survey maps that are in the form of TIFF files (.tif). If I open the georeferencer tool and set ground control points (GCPs) from the map canvas, then run the georeferencer, it offers to save the GCPs in a file. I have done so every time.
Now, if I change the project CRS, is the file of GCPs not going to work? That is, does the saved file of GCPs only work in the original project CRS? I ask because I have changed the project CRS and then loaded the old GCP file into the georeferencer tool, and in the image it appears that everything is fine. But georeferencing still doesn't work.