Hi, I ran into a problem with flooded areas around the river Rhine. A europe.osm.pbf from geofabrik.de dated 2011-07-31 was used. I extracted a contiguous area containing roughly Germany and France using osmosis. This extract was spit up into 369 parts using tile splitter r179. After they have been converted using mkgmap I recognized at least 3 flooded areas at the river Rhine on my Oregon 550. The riverbank areas extended wide into the land. The riverbank in that europe.osm was defined by a really large multipolygon. (in the meantime someone else split up the gigantic multipolygon into a number of smaller multipolygons). This large multipolygon consists of 320 ways (counted inner and outer) and extends over over at least 4 of 5 tiles that were created by tile splitter. I had a look at one of the tile-files an noticed, that tile splitter removed all the ways that were completely outside the bounding box of the respective tile. However the multipolygon contained all 320 ways as members, but most of them (and the corresponding nodes) were not included in the tile-file. Im not sure wether tile splitter did some processing in order to close the multipolygon along the bounding box, but probably this ist not the case. This incomplete information in the tile file probably makes it impossible for mkgmap to correctly clip the multipolygon along the bounding box and possibly leads to the flooded areas. As I already mentioned, this large multipolygon is no more present in the actual osm database. But I probably will be able to provide some test data if required as I still have the original data and can reproduce this behavior. Regards Wolfgang