Deleting floating lines from network using GRASS 7 in QGIS

Question

I'm trying to find a way to remove floating line segments from a road network shapefile.

Is there a relatively fast way to identify and delete these features?

I've been using GRASS 7 in QGIS to remove dangles < 100m and generalize its shape, but I haven't found an appropriate tool for removing these segments that are not part of the main network.

I'm open to finding solutions in QGIS, but I'm curious to see what GRASS tools can do for situations like this.

Answer 1

I'd use network analysis in GRASS GIS here (v.net.*) and then find the connected parts of the network. The tools might be v.net.components which computes strongly and weakly connected components in the network or v.net.spanningtree which computes minimum spanning tree for the network.

The isolated network parts ("floating line segments") will not be reached.