When I open the world editor on the ITALY map, the coordinates appear diagonal relative to the road. When I place a model on the map, its angle is also diagonal. How can I fix this?
The coordinates system *is* the reference, in a way it can't be wrong. It's the road you show which is not aligned along one of the coordinates axis (x, y… maybe z). I'm not sure I understand the issue but there is nothing to "fix" for the system. The only "issue" can be the placement and angles of your objects. Change the angle of your object so that it matches the direction of your road. Or change the road, but that's probably more involved. For some objects, if they need to have consistency in their related position/angle, maybe the local coordinates could help you instead of world coordinates.
Everything @rutilo says is correct. Also, this is the runway in Italy, right? If so, you should be able to find out the exact angle you'll need to match, since runways all have their heading written on them in big letters.
