I have an image from a cities districts and their boundaries and I need them as polygons in QGIS.
I tried "Raster -> Conversion -> Polygonize (Raster to vector)" as described here, but that vectorised every single pixel.
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Sign up to join this communityI have an image from a cities districts and their boundaries and I need them as polygons in QGIS.
I tried "Raster -> Conversion -> Polygonize (Raster to vector)" as described here, but that vectorised every single pixel.
Since the number of districts is quite low, you could just digitize them manually. That will probably be faster than anything else you try.
Otherwise, as Mapperz commented:
If you cannot get the data in a more appropriate format somewhere else, get the Vector SVG file and convert and georeference that. For more info on that issue see: How to Import SVG into GIS?
http://upload.wikimedia.org/wikipedia/commons/7/7e/N%C3%BCrnberg_Statistischer_Bezirke.svg