I am having issue with georeferencing a scanned map. Warping has occurred in the West in Morocco (near Marrakesh) as well as a sort of "black holes" in Libya and Northern Chad. As far as I can tell, the GCP coordinates are correct, and I have checked to see if the reference/scanned map is accurate, and as far as I can tell, it is. Furthermore according to documentation for QGIS (which is what I am using) the dX and dY fall within acceptable variation/range (not being greater than 10), which presumably rules out the GCPs being misplaced.

Any idea as to what may be the issue? The transformation setting for target SRS maybe? Other portions of the map are referenced fine.

Picture showing the warping and "black holes"

Picture showing the plotting GCPs on the raster reference/scanned map

  • 1
    looks like you swapped some coordinates on accident... I would just delete the points in that area and try going without them as usually you just need 4 GCPs to produce an okay result. and you have plenty...
    – Leo
    Commented Feb 7, 2020 at 13:13

1 Answer 1


It is really a weird image. Maybe you have a GCP point with a high mistake, try to eliminate this point. Anyway, here you have a help in this post: https://www.cursosgis.com/sencilla-explicacion-para-georreferenciar-imagenes-en-qgis/ sorry because it is in Spanish but you can translate it and follow the tutorial easily. Regards

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