QGIS Polygon – Splitting a Polygon Layer with a Line Layer

qgis

I am drawing administrative regions that have boundaries follow streets in another layer. As these streets are pretty long with many vertices, I don't want to re-trace them. I am looking for a way to "split" the polygon like "split features" tool (the one with the scissors icon).

Before: one whole polygon with a line running through it

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After: the line works as a pair of scissors and split the polygon into 2 parts (in the picture below, the polygons were moved apart for illustrating purpose only)

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Best Answer

First you have to union both shapes

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Then activate the Polygonizerplugin to reshape the lines to polygones:

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