Something I'm not doing right

Kia ora

I looked that th turoial for doing roads and rivers. I got the patten I requited and set the height/depth
as low as I could which was only 50m. for a roman style path/cobble road 10m would have been more than
enough I think but it won’t go that low. so 50m by 4 m wide (its a darkage wildeness path come track of
ruined cobble stones). My problem is when I do a render I get a row of spickes along the vector, my node setup
is just like the tutorial, the height and width are the only things different that I can see.

Shame we don’t have a path/road device that we could drop in select the options:

Cut a path
follow the terrian
width
height/depth from the terrain
colour/colours

them plot the vectors when required. Don’t know if this could be done with a macro
I have trouble making a terrain nevr mind macros at this point

Thanks in advance for any thoughts

You don’t need a specific tool you can “paint” your road on your terrain you just don’t have to merge the heightmaps, just the textures.

The point is I’m trying to follow the example asa learning process.
If I follow a tutorial andget it right I must have learned somthing, if it doesn’t
work then I need find outwhy and what I got wrong