I am not sure if this comes from updating mkgmap-trunk from r1946 to r1953 or from this patch v2, but I get these additional warnings: 2011/05/23 22:51:09 WARNING (MultiPolygonRelation): 63240002.osm.gz: Cannot join the following ways to closed polygons. Multipolygon http://www.openstreetmap.org/browse/relation/36306 2011/05/23 22:53:04 WARNING (MultiPolygonRelation): 63240004.osm.gz: Cannot join the following ways to closed polygons. Multipolygon http://www.openstreetmap.org/browse/relation/38101 2011/05/23 22:54:18 WARNING (MultiPolygonRelation): 63240006.osm.gz: Cannot join the following ways to closed polygons. Multipolygon http://www.openstreetmap.org/browse/relation/900367 2011/05/23 22:54:18 WARNING (MultiPolygonRelation): 63240006.osm.gz: - way: http://www.openstreetmap.org/browse/way/57746082 2011/05/23 22:54:18 WARNING (MultiPolygonRelation): 63240006.osm.gz: Multipolygon http://www.openstreetmap.org/browse/relation/900367 does not contain any way tagged with role=outer or empty role. I took a look at these relations in JOSM (ctrl-L, enter http://api.openstreetmap.org/api/0.6/relation/900367/full and so on). Relations 36306 and 38101 are boundary relations, which include some maritime borders in the south. They might not be completely inside the Geofabrik extract of Finland. I do not care about them. The outer line of 900367 (one of the multipolygons for Lake Saimaa) carried natural=water, which I now removed, as the multipolygon relation already carries that attribute. The roles of the relation are correct: all member ways are either role=outer or role=inner. JOSM does not complain. I guess that mkgmap is just dropping the role=outer line, because it is incomplete in the tile: 63240006: 2832510,1317344 to 2916352,1462272 # : 60.779070,28.267136 to 62.578125,31.376953 The bbox of the role=outer way is 62.69143,28.0395 to 62.516,28.46425. That is, the outer line is slightly inside the tile. To be exact, the following nodes (two bays) of the outer way are inside the tile: 244270918 244272962 244270916 244272960 244270922 244270920 244272964 244270915 244270919 244272963 244272961 244270923 359093973 244270921 One island is partly at the NW corner of the tile: way 26228126. The other bay does not contain islands in the map data. Now, let me check 62.578125,28.2671360 in the generated map. Sure enough, a section of the lake is missing SE of the island. I guess it is showing just the background there. Am I right that this is a splitter problem (possibly fixable by increasing the split-radius)? Marko