I have a vector layer containing the potential drainage lines that have been computed from a DEM. I want to be able to click on any point and identify all the lines that are connected to my point of interest. In effect, this means identifying all the streams that contribute water to the point.
I am sure this is not a novel problem. It would be similar to identifying all electric lines/houses that get power from a particular sub-station and other real life problems. I just can't seem to phrase my problem just right to get the correct response from Google.
I understand that a simple identification of all connected lines would not take care of upstream and downstream drainages. I guess that will have to figured out later.