I imported a .shp file to QGIS with polygons from a non-topological database. Polygons were adjacent and shared borders, but most nodes didn't coincide. I then proceeded to fix all nodes and intersections manually (more than 3000) enabling snapping (with a 10 pixel tolerance) and topological editing. Sometimes topology worked and moving the node moved both borders, most of the time it did not. I finished correcting and checking all the nodes, topology checker indicates that there are no invalid geometries but a whole lot of gaps and intersections... except they DO NOT exist (I zoomed all the way to 50:1 and still can't see them). And all nodes seem to be corectly snapped to one another. Tried using v.clean in all possible ways but nothing happens because I suppose there is no cleaning needed. My guess is that since the shapefile is from a non-topological origin QGIS is not able to create topology for all the nodes even if they have been snapped together.
Does anyone have any idea how to fix this?
Or are there still elements missing from QGIS to achieve this?