How do quality nodes work?

[Shask]

How do quality nodes work? For example, high quality clay in a mudflat. Is there a single tile where it is the highest quality, e.g. Ql50, and then it decreases in a circle around that? How large is the radius of the circle? Does the size of the circle depend on the quality of the highest Ql tile, so larger qualities are easier to be found?

Edit: In my search for clay, the following situation keeps happening to me, and I don't know why:

I dig in a mudflat. My character digs up about 5 pieces of Q10 clay without stopping. I move north 5 tiles, and he digs more Q10 clay without stopping. I dig in a radius around the original spot, and my character keeps digging Q10 clay without stopping. All of a sudden, it stops. Even if I did in places where I previously dug Q10 clay without stopping, there is no more clay, nothing happens after digging.

The exact same also happens with river clay.

Why is this? Is it because I'm constantly encountering Q10 nodes, and after digging up around 15 clay in a small circle in the area, it is exhausted of clay?

[sabinati]

the first question is pretty much answered by all your other questions, which the answer is yes to

[Garath]

q nodes arnt alway centred in relevant soil, like clay being near mudflat or shallow water. there is much more land without clay then there are clay nodes, probably

[Lahrmid]

Harvesting a node will gradually deplete it. When it should normally go below 10, it'll just stop giving anything. Then it's time to wait for it to "regrow".

[Shask]

Ok, thanks. Are higher quality nodes more "spread out" than lower quality?

For example, imagine the whole world had only 2 nodes in it. One was 100 QL clay, one was 15 QL clay. Would the "detection" radius of the 100 QL clay be much bigger? Would it be about 7x bigger?

[sabinati]

Does the size of the circle depend on the quality of the highest Ql tile, so larger qualities are easier to be found?

yes