Hi Thanks for accepting my request to join. Please see below text of a message I recently posted to talk-gb@openstreetmap.org. Hi, I hope someone can help with this. I'm a big fan of OpenMapChest and am amazed by Ben Konrath's lovely maps. There's a slight problem (of the first world type) in that in his map of Western Europe (specifically the Calais tile) the sea appears to have breached the sea wall and the land is inundated with blue! Ben says he can't help because it's due to a bad change someone has made to OSM. There's also something funny further west, around Le Havre. He says the problem will be solved by whoever made the change, but it's persisted now for quite a few iterations of his map. There does appear to be a conflict between his British Isles map and the one for Europe. However, the problem isn't replicated in OsmAnd, or in any of the other Garmin-related maps I use, which would suggest that OSM itself is OK. Any wisdom greatly appreciated! One of the replies I received was as follows: Those maps are generated with mkgmap, and this sort of problem happens occasionally when coastlines get broken in OSM. You might look at the archives for mkgmap-dev@lists.mkgmap.org.uk or perhaps post there directly. Any help with this would be much appreciated. I have MapSource screenshots available, but didn't attach them in case I messed anything up! Cheers!