Hi, I'm building my own OSM map for Garmins since quite some time, but now I wanted to fix the issue, that the sea isn't drawn correctly. For this I played with the generate-sea option. But independent to which value I set this option, I always get this java error after quite some time: java.lang.ClassCastException: java.util.TreeMap$1 incompatible with java.util.NavigableSet at uk.me.parabola.mkgmap.reader.osm.SeaGenerator.createInnerWays(SeaGenerator.java:518) at uk.me.parabola.mkgmap.reader.osm.SeaGenerator.end(SeaGenerator.java:337) at uk.me.parabola.mkgmap.reader.osm.OsmReadingHooksChain.end(OsmReadingHooksChain.java:78) at uk.me.parabola.mkgmap.reader.osm.xml.Osm5MapDataSource.load(Osm5MapDataSource.java:73) at uk.me.parabola.mkgmap.main.MapMaker.loadFromFile(MapMaker.java:145) at uk.me.parabola.mkgmap.main.MapMaker.makeMap(MapMaker.java:56) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:220) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:217) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:314) at java.util.concurrent.FutureTask.run(FutureTask.java:149) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:897) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:919) at java.lang.Thread.run(Thread.java:736) Exiting - if you want to carry on regardless, use the --keep-going option I tested snapshot 1812 and 1829. Any idea what causes this and how to fix/workaround this? Thanks, Thorsten