I have a road network (black line) and I want to identify all segments that are completely cut off by my flood polygon (blue polygon).
I have clipped the road network to get all roads within the road network and I have been able to identify some road segments that are cut off by the flood zone polygon (green lines and pink lines), but not all of them. I did this through a combination of the 'intersection' tool and the 'Spatial Query' plugin.
I'm using QGIS for this.
I used the 'Topology Checker' tool to identify all 'dangles' but it highlights road segments that are, for example, just dead ends but are connected to the wider road network. I guess I'm looking for 'double dangles'?
I'm basically looking for road segments that are completely disconnected from the larger road network but they can be connected to one another. 'Dangle islands'?
If an agent is placed on a 'dangle island' and is not able to access the full network, then that road network is a 'dangle island'!