I have a series of polylines representing sewer mains, with an attribute indicating the network it is in.

Is there a way to create a polygon that wraps around all of the polylines with the same attribute in QGIS 3.4. My intention is then to use the Wrapper polylines to transfer attributes to a number of other features in the sewer network which are stored as separate SHP files (eg valves, pumps, etc).

Periodically I will need to regenerate the wrapper polygons as the network expands.

2 Answers 2


A wrapping boundary can be created with the command "Minimum Bounding Geometry" from the QGIS processing Toolbox using "Geometry Type = Convex Hull" and setting field to the appropriate setting.

I note that the polygons may overlap, so you still need to check them if this is an issue.


I would think a simple buffer would work nicely. Processing Toolbox > Vector Geometry > Buffer

A buffer would create a polygon around your polyline feature at a distance you set, the end cap style and mitre, and all your attributes will be carried over to the buffer file.

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