It's interesting what you've said about cave systems and energy lines, here in Cornwall we have a tradition of mining.
Pretty much every metal and mineral known to man has been mined here at some point, shafts were dug way out underneath the seabed too.
I guess we may have more Geopathic stress than most places in Britain, interestingly some of the Cornish miners supposedly used dowsing to locate tin and copper lodes. One of the ways to practice was to go to the beach and follow the visible loads with dowsing rods along the rocks and shore until you got the hang of it.
Anyway, what I know about node points is minimal really, Hamish Miller and Paul Broadhurst wrote about them when they traced the Michael and Mary lines.
These lines are meandering serpentine energy lines, I have found quite a few in Cornwall, they often pass through ancient sites and churches too.
Where they pass through these sites often there are two or more of them, sometimes they cross each other inside a church or a stone circle, Quoit, or at a standing stone.
The lines tend to feel either masculine or feminine, yang or yin, positive or negative and they are made up of smaller lines or bands with a direction of flow along each individual band.
The direction of flow can run in different directions along individual bands within the same serpentine line. Some serpentine lines I have dowsed had as little as three bands, others I have found have had as many as forty bands.
Sometimes they just cross each other, but other times they can focus down in width to a small point very quickly where they cross. That small point is called a node point and it can be made up of more more than two lines as well.
The node point seems like an intense energy spot, taking energy into the earth or flowing up and out of the earth, the node points give off an energy field as well. One I dowsed gave of something like the radiating spokes of a wheel with the central core of the node as the hub of energy? Other dowsers have found different energy patterns such as pentagrams at node points too.
At the Hurlers Stone Circles a node point is marked with a standing stone inside one of the circles just slightly off centre.
At Lostwithiel Church a node point is marked with an ancient stone font with a gargoyle carved on it with a protruding spiral making up its third eye, and two serpents writhing across its head.
The serpentine lines I dowse register mostly in the mhz range whereas the node points register in ghz.
Where the node points form feels like an interaction between the lines, if the energy lines just cross without a node point then it doesn't tend to feel like an interaction or exchange of energy?
The energy of the serpentine network and nodes can feel both healthy and unhealthy too.
For a few years I lived in a house with a serpntine line running through it, the line passed through many graveyards and some places where people made offerings and said goodbye to the dead. It didn't feel healthy living there.
stay on the path, beware of the moon