[mkgmap-dev] Bogus anti-island warnings for tiny natural=coastline polygons

Wed Dec 18 15:17:46 GMT 2013

On Tue, Dec 17, 2013 at 12:18:23PM -0800, GerdP wrote:
>@Marko: Please check if the "converting anti-island" messages are gone 
>now.

There are 20 of them for Finland after applying my filter. There could 
also be valid warnings, because I have been ignoring these errors and 
not adding them to my filter either.

I checked one example:

2013/12/18 16:28:01 WARNING (SeaGenerator): 63240002.osm.pbf: Converting 
anti-island starting at 
http://www.openstreetmap.org/?mlat=60.20405&mlon=25.49942&zoom=17 into 
an island as it is surrounded by water

It looks like this is referring to the 1.5m wide islet or rock

http://www.openstreetmap.org/way/242824968

which is a closed polygon, with land on the left. I think that the 
proper action would be to shrink this to a single point and then discard 
it, because it would be a polygon with zero area.

Best regards,

	Marko