Generally, if layers differ, there should not be an intersection. Roads going over a river, stream, lake, etc. should have bridge=yes and layer=1. Tunnels should also have layer=-1. Otherwise, every at-grade intersection should have a node where the ways cross.
JOSM’s validator lets you select the ways in the error, and then Shift+I will make an intersection node if it should be there. (It will not throw the error if layers differ, but it will if you added just bridge=yes or tunnel=yes and forgot the layer tag.)
I have fixed whole cities in Rhododactylia where the mapper just threw ways together without bothering to make intersection nodes. Thankfully with JOSM’s plugins it was about one-tenth of the pain in the donkey it could have been.
OpenGeofiction
Discussion
Comment from wangi on 4 May 2017 at 11:42
Yes, worry about it. It’s important that you have nodes where your roads cross.
Comment from GruzzlyBear on 4 May 2017 at 11:47
Ok, I’m assuming this can be fixed with just clicking and then hitting escape on every intersection?
Comment from wangi on 4 May 2017 at 12:27
Either double click on every intersection, or select all the ways and then Shift+I will add all the nodes.
osm.wiki/JOSM/Guide is worth a good read.
Comment from compdude on 4 May 2017 at 16:58
The only places where crossing ways should not have an intersection node is if one road crosses another on a bridge or tunnel.
Comment from zhenkang on 4 May 2017 at 22:32
I would advice not building roads in your country first but build some natural features which include beaches. See OGF:Making Realistic Countries.
Comment from skquinn on 5 May 2017 at 00:06
Generally, if layers differ, there should not be an intersection. Roads going over a river, stream, lake, etc. should have bridge=yes and layer=1. Tunnels should also have layer=-1. Otherwise, every at-grade intersection should have a node where the ways cross.
JOSM’s validator lets you select the ways in the error, and then Shift+I will make an intersection node if it should be there. (It will not throw the error if layers differ, but it will if you added just bridge=yes or tunnel=yes and forgot the layer tag.)
Comment from BMSOUZA on 5 May 2017 at 01:03
Oh, God! I am an “old” OGF-user and I never got atention to this error message!!
:-O
Comment from skquinn on 5 May 2017 at 01:08
I have fixed whole cities in Rhododactylia where the mapper just threw ways together without bothering to make intersection nodes. Thankfully with JOSM’s plugins it was about one-tenth of the pain in the donkey it could have been.