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I read about the planarize function in ArcGIS, which seem to do exactly what I want. Is there a similar feature in QGIS or another free tool?

I have a shapefile with various shapes intersecting each other and I want each intersection to become a node and between every two nodes to have a simple line.

The goal is to easily convert my .shp in .osm and use it with Graphserver. As it is, Graphserver says I don't have edges, and I deduced the above is my problem.

Thanks a lot

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In GRASS GIS which is topological you can use v.net for this operation. You can access it through the QGIS-GRASS Toolbox.

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Hi! I had a look about the v.net documentation, I'm not sure about the end result I should get to be able to import this in the graphserver… – charlax Oct 6 '11 at 1:44
    
You can then export to a OGR supported format with v.out.ogr. – markusN Oct 8 '11 at 23:59
    
Odd the documentation isn't very explicit that it handles intersections. Did you try this and does it work? – Sideshow Bob Sep 17 '12 at 13:10
    
Not sure this works - see my other answer – Sideshow Bob Dec 10 '15 at 13:28

In GRASS GIS the v.clean tool can be set to break intersections. The rmsa and rmdupl options to v.clean are useful as well.

Returning to this question for a third time: the snap option to v.clean will snap together features by altering their shape to fix apparent intersections, etc. snap followed by break should thus do a job similar to ArcGIS Planarize.

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