[Qgis-user] Isolate area of water supply network using existing valves

[欧阳乐岩]

Hi all,

I have a water distribution network with valves. For any given 
selection, I would like to find the valves that can be used to isolate 
it from the rest of the network and extract the selected area. This is a 
very standard feature for GIS aimed at water supply.

It is not a very complicated problem and after failing to find a tool 
doing it, I started a plugin that can do it. However, before spending 
too much time trying to do it cleanly and efficiently, is there a way to 
do it already that I have overlooked, e.g. via a plugin, a Sextante 
algorithm, etc. ?

This seems like in could be a quite general tool in network 
manipulation, does this problem have a more general name that could help 
me find resources ?

Regards,

Leyan