I was wondering if there is a way to create centre lines from polygons in QGIS? I have a polygon layer, but ideally need the centrelines as a separate file.
I've been working on implementing the model depicted in @RajGovind's answer to Creating Centrelines from Road Polygons/Casings? which is quite close to what @geogeek described in his answer here in this thread.
You can download the model from Github https://raw.githubusercontent.com/anitagraser/QGIS-Processing-tools/master/2.12/models/polygon_to_centerline.model
you can try This algorithme:
get vertices from the polygons(poly_vertex). -make voronoi using (poly_vertex) as input the result could be called(poly_voronoi). -get lines from (poly_voronoi) => (poly_voronoi_lines). -get the originale polygon contour (polygon_lines). -remove (poly_voronoi_lines) touching (polygon_lines) the result is supposed to be the center lines , but you may need further clean up.
i don't know how it could be implemented on Qgis
i wish it could help
there is a good tool with the name of ET GeoWizards 10.2 for Esri products, but i dont know whether it is a good solution or not...
you can get some info from here
beside this in grass you can check out r.thin function for basic use..
r.thin - Thins non-zero cells that denote linear features in a raster map layer.
i hope it helps you...
just find the length of the whole thing
How exactly should be the result? An approximation is perimeter divided by 2.
To get a better result: You can manually measure some polygons.Then determine the difference between the measurement and perimeter divided by 2. Apply this correctionfactor to the whole datset.