convertlinepolygonpolygonizeqgis
I have a shapefile with city areas, but unfortunately the shapefile only contains single lines. The shapefile looks like this:
I want to convert those lines to an area-polygon shapefile in QGIS. I tried it with the "Lines to polygons" tool (Vector > Geometry Tools > Lines to polygons), but it didn't work correctly. After using this tool, the shapefile looks like this:
Is there any other way to convert the line shapefile to an area polygon shapefile in QGIS?
I am using QGIS 2.14.3 Essen.
This is an old question, but I ran into a similar problem today and found a way to do it. I have a shp of city blocks, but each "block" is actually a set of 4 street lines. This is the way to convert them into areas:
v.build.polylines will convert connected lines to a polyline.
v.type to convert the polylines to boundaries.
Finally v.centroids to add centroids to the closed boundaries and thus create areas
Try dissolving based off of OBJECTID or FID. Then use Feature To Polygon (Data Management) to convert your polylines to polygons if you wish. To illustrate, here are some sample lines:
Attribute table before dissolve by OBJECTID
Attribute table after dissolve by OBJECTID
Best Answer
The "Polygonize" tool from the Processing toolbox still works fine for me on simple lines:
It is however necessary that the lines intersect, or share common vertices. And lines should have no self-intersection.
You might need to snap the corner vertices to get it working. I usually set the snapping tolerance to 10 pixels to the vertex.