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I am new at using QGIS. How can I simply split features in QGIS? The manual tells to simply draw a line through the polygon you want to split. But it doesn't work. The line disappears when finishing it. When I select the polygon and then split it, it sometimes works and sometimes doesn't (an info appears after which it does not split the feature). Does anybody have an idea why the tool does not work properly?

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    Have you enabled editing for that layer? – DavidF Jan 11 '13 at 15:15
  • yes. sometimes it does split aometimes not. when it does not work, it gives me the info "if one feature is selelected, only this one will be split - what I exactly want to do - to split all polygons of the layer, cancel the selection - which I do not want-" – Hendrik Jan 11 '13 at 15:41
  • @Hendrik, Have you tried the same workflow method on a different polygon layer to see if you get the same error? – artwork21 Jan 11 '13 at 16:26
  • not yet, but i have changed one thing. when i do split the polygon from node to node it works without errors so far. so if nesaccary i creat a node on the point where to split the polygon. i think that works. no idea why it does not work properly when splitting between nodes. will try with another plygon layer to see what happens. Thanks – Hendrik Jan 11 '13 at 16:44
  • I have the same problem, i tried everything above, but it doesn't work! It's an object that has more polygones that are not 'touching' eachother. If I split it over one of the polygones, it does work. But I want to split it between the different polygones, and it doesn't work. Anyone an idea what I do wrong? Thanks! Linde – user17559 Feb 21 '14 at 7:50
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If you want to split your features per hand: Select your vector layer and click editing (red). Then select the scissors(green) and click two-times from one side of the polygon to the other. You will see a small dotted line. After spliting simply unable the editing and choose "save changes". Look into the attribute table to see the changes.

enter image description here

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    NB: This answer is now out of data (at least in as much as it does not apply to recent versions of QGIS). – Rostranimin Mar 20 '15 at 17:57
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    Ähh, no? You can do it with the advanced Digitalizing toolbar. Same function, just the icon looks different. – Curlew Mar 21 '15 at 11:19
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    Yes - quite correct. Sorry... that was kind of what I meant. – Rostranimin Mar 21 '15 at 21:09
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    is there any way avaialbe through programming or plugin that we can split all polygon at once instead of manual selecting – Muhammad Faizan Khan Aug 29 '16 at 11:23
  • Split by what? Geometry? Attribute? You can access and generate subsets using the vector menu bar. – Curlew Aug 29 '16 at 11:44
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To update Curlew above, as of QGIS 2.18, you would use the built-in Advanced Digitizing Toolbar, which can be accessed via View > Toolbars > Advanced Digitizing Toolbar. The toolbar will look like this and the "Split Features" button is the fifth from the right:

With that loaded, and the respective later selected and in Edit mode, select the "Split Features" tool and use it to draw through the place(s) where you want to create segments. You can then use the "Node Tool" to select vertices and move them wherever the new segments should be positioned. A quick summary looks like this:

enter image description here

In the end, each segment will then become an independent feature in your vector layer. Be sure to save your edits!

For more information, see the QGIS user manual section on advanced digitizing.

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In addition to Curlew's answer it's important to start and end your splitting line outside of the target layer. I carefully aimed for the nodes until I found that useful tip here:

http://www.cartographersguild.com/tutorials-how/17469-%5Baward-winner%5D-some-pointers-using-gis.html

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    Link 404'd (i.e. not available anymore) – AER Dec 8 '14 at 0:33
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The most important thing is to have a clear difference between right and left part of the polygon to be split across a splitting line. Otherwise it would not work. So be sure there is a "clear" border between right and left or upper and lower part even if this mean that you make unwanted cuts. These you can merge afterwards to the main parts.

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