Using the census road network for Los Angeles, I am trying to clean the network to have nodes at all intersections. The GRASS v.clean algorithm seems to do this, but is missing some intersections - actually, many intersections. I cannot fathom why this is - the short line segments appear to be very close (if not on) to the main street segments, but they are not splitting the lines as I expect.
I read the documentation and Threshold is not used by break, so that's not an issue. I have zoomed into the intersections as closely as i can and they appear to abut. Any thoughts on how best to address this?
To demonstrate this, the red lines are the original road segments and the short stubs are connectors from block centroids (for a routing analysis i am doing). You'll see one broke the segment and the other did not. Also, it broke where clearly the lines cross, just not always when they abut.
One thought is to add a vertex to the street segment at the nearest point to the end of each short stubs - i wrote the short stubs, so i know they are all directionally towards the street. With that, then i could use v.clean snap. Would have to find a recipe for doing that.