I want to manually trace over an existing map image to replicate the boundaries using QGIS. If this was an existing polygon and I need to split this into 3 separate polygons, I would take the existing outer boundary, and then I would have to manually trace the boundaries of the inner areas - as a polyline or region? How would I join the inner boundaries to the outer boundary, and then create the 3 separate polygons within the base map table? I hope I have explained this clearly?
You are after the
This algorithm takes a lines layer and creates a polygon layer, with polygons generated from the lines in the input layer.
You first need to convert you polygon to lines: