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I am doing some topology testing using Grass in QGIS. I am hoping to snap nodes to eliminate gaps between polygons. When I use the v.clean.snap function in Grass it does not work on polygons. When I test it on lines it completes the tasks as I was hoping. Does anyone know of a way to run v.clean.snap or a similar function in Grass on Polygons? Attached are two screen grabs showing the errors as polygons, and the fix as a line.Grass v.clean.snap with polygons

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up vote 1 down vote accepted

mhm, not sure. from the grass manual for v.clean ... snap: snap lines to vertex in threshold It says lines, not boundaries. Don't know how semantically over-correct those manuals are, but a boundary of a polygon isn't a line i think.

Did you try using the snapping while importing the layer to grass? Thats what i tend to do (advanced options of

an the manual there says:

Snapping threshold for boundaries
'-1' for no snap
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