On Wed, Sep 08, 2010 at 10:27:46AM +0800, maning sambale wrote:
But this is a very interesting case because, previous builds have sea polygons even when there are coastline errors. I'm using mkgmap svn 1649
Educated guess: previous errors canceled out each other (the errors must have been visible in a smaller area). Unless your map extract is a perfect island, you may have to move the coastline endpoints to make mkgmap happy. When I successfully enabled coastline generation for Finland, I both adjusted the Geofabrik cutting polygon (it took a few iterations with Frederik Ramm) and moved the endpoints of the mainland coastline to the tile boundaries (so that the last bit of coastline is a straight N-S or W-E line). I played with the idea of merging real coastline of neighbour countries to the map, but that did not work out, and it would have been less obvious to see where the mapped territory ends. Moving the coastline endpoints can be done with a trivial Perl or sed script. See my osm2img.sh at http://www.polkupyoraily.net/osm/ for an example. To find the endpoints of your map extract, you can extract the natural=coastline ways from your map extract and load that to JOSM. Marko