ive got to condense a sewer layer from junctions (small sections of pipe between manholes)to one section of pipe between the manholes and sum the lengths of all the sub sections.

Does anyone know of a way to do this in QGIS?

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    – underdark
    Commented Apr 20, 2017 at 17:46

1 Answer 1


You can simply dissolve by either connectivity or sewer id (whatever is most appropriate in your use-case).

Length is a 'natural' attribute of line geometry and is accessible by using the field calculator to extract this value to an attribute (open the field calculator and you'll see it if you expand 'Geometry' in the middle pane).

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