digitize polygon/polyline snapping more than one node of another vector object

[flv]

It would be useful to digitize a polygon or a polyline snapping to a part of an existing line/polyline of another vector layer or in the same layer. For example: digitize a land use polygone snapping to a river border from first vertex (of the river) to the 30th (for a river border with 100 vertex i.e.).

[borysiasty]

This is implemented for polygons. You can enable 'Avoid intersections of new polygons' and then digitize, you know, 'overmuch', overlapping a part of existing polygon. Your polygon will be clipped to the existing boundary.

For lines, only way I see is Ctrl-C, Ctrl-V and then manage somehow ;)

[flv]

Replying to borysiasty:

This is implemented for polygons. You can enable 'Avoid intersections of new polygons' and then digitize, you know, 'overmuch', overlapping a part of existing polygon. Your polygon will be clipped to the existing boundary.

Yes, you're right.

For lines, only way I see is Ctrl-C, Ctrl-V and then manage somehow ;)

Yes. the problem I found is that if I try to digitize a new polygon wich has to snap to a part of a polyline I have to snap the vertex one by one. It would be useful if the user was able to select only "a part" of a polyline and then continue the digitizing away.