Coast line problem in Guernsey

Over recent years I’ve gradually been adding roads and footpaths to Guernsey. I’m off there again shortly on holiday so will add some more detail. However, the coast line seems to have gone wrong recently and I’m not sure why. Any ideas?

I did notice someone had added a marina which overlapped the coastline, so I tried to sort out the overlaps, but it hasn’t cured the problem.

You can see what I mean by clicking here:

It doesn’t affect Mapnik though.

Best wishes,


The JOSM validator found a short length of reversed coastline. I’ve now reversed that, and requested a rerender on Information Freeway, so I’ll see if that fixes it.
Note coastline ways should be in the direction that land is on the left side and water on the right side of the way. Otherwise, it may cause rendering problems.

Also, there’s nothing wrong with other ways overlapping the coastline, and I think its correct for things like marinas etc. Just so long as the coastline is a series of unbroken ways, in the correct direction.

Many thanks! I had a quick look on potlatch and found one segment of coast that didn’t fit the rule so reversed that earlier today - it may be there was another section I missed. I think the person that added some detail around St Sampson’s harbour must have changed the direction without realising it.