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.
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 v.in.ogr).
an the manual there says:
snap=float Snapping threshold for boundaries '-1' for no snap