How do I create a centerline (vector data) from two parallel polylines (vector data) in QGIS?

For example, if the distances between two parallel lines are 14m, then I want to create a centerline at 7m from both lines.


2 Answers 2


GRASS has an add-on called v.centerline. Grass add-ons are a bit different to QGIS plugins. To get GRASS add-ons working in QGIS see How do I get grass plugin working in QGIS for Windows? or search this site further for more info as 'how to install QGIS add-pns in QGIS' has been asked here a few times from memory.


If your data is a kind of polygon, you can use the new plugin by installing 'geosymplification'. After installing the ZIP file of geosymplification, choose the chordal axis on geosymplification.

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