Splitting lines by polygons in QGIS

Question

I have a river network (lines) and a .shp with states (polygon). I would like to split the lines at the state boundaries i.e. split lines by polygon boundaries.

Is there a geoprocessing tool to do this in QGIS? I can't merge the lines by the way, since they are meaningfully split into tributaries/main river.

I have tried using vector geometry/ vector overlay / lines intersect tool. This gives me a point layer where lines overlap. However not all overlapping points were found, and I would still prefer if it can be done automatically. — Elena Wimmerwuchs, Dec 18 '14 at 15:03

score 12 · Answer 1 · edited May 13 '21 at 19:47

12

This is now possible by default in QGIS with the "Intersection" tool.

edited May 13 '21 at 19:47

Taras

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answered Mar 05 '17 at 12:45

joost schouppe

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The "intersection" tool clips the lines - it removes lines outside the polygon. This is different from simply splitting, which means cutting lines and including all the resulting parts in the output. – jberrio Jan 18 '24 at 06:48
They are splitting by state, so what interests them is rivers split by individual state. Usually, I would expect that rivers outside of the whole set of polygons are not interesting to them. But good word of warning for those that don't want that! – joost schouppe Jan 20 '24 at 13:00

score 2 · Answer 2 · answered Nov 14 '18 at 03:27

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Intersect didn't work for me in 2.18 or 3x.

To split road lines by zone polygons I used SAGA - Line Polygon intersection that split the line by the polygon

Then the "Attribute Transfer" plugin conflated the attributes across.

answered Nov 14 '18 at 03:27

GeorgeC

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score 2 · Answer 3 · answered May 13 '21 at 16:25

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I did not have success with the Line-Polygon tool. I converted my polygon to lines and then used the SAGA->Vector line tools->Split lines with lines. This worked for me.

answered May 13 '21 at 16:25

kyjote

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score 1 · Answer 4 · edited Mar 21 '22 at 11:22

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In the Processing Toolbox under "Vector Overlay" use the "Split with lines" tool.

edited Mar 21 '22 at 11:22

Kadir Şahbaz

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answered Mar 21 '22 at 11:21

Swapnil Maskar

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score 0 · Answer 5 · answered Jul 04 '23 at 13:52

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It can be done with GRASS. v.overlay

answered Jul 04 '23 at 13:52

Federico Framarini

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Can you add a more detailed description how it can be done with v.overlay? – MrXsquared Jul 04 '23 at 14:28

Splitting lines by polygons in QGIS

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