Felix,
Okay, so manual coastlines are probably still needed except for very large extracts or islands.
Don't know what you mean by "manual coastlines" - the whole map is "manual", isn't it?
BTW it would be better to have mkgmap=land or similar, instead of natural=land because natural=land does exist and is used. I would prefer to have a different color for real natural=land vs mkgmap land background.
Well, according to the wiki (I know, who gives a flying fuck about the wiki) it says about natural=land: "Land that exists within another area, such as a lake. (i.e an island)." Spot on, I'd say. No one in their right mind would think that natural=land wasn't appropriate for island and other land masses. So I prefer to keep the default as natural=land. I like it. But just for you Felix, I have put in an option so you can specify the tag to use. Be creative. Mark