Hi, I have a serious problem with making maps for Garmin´s marine devices: Marine devices do not support type files. So it is not possible to control the priority of polygons. I have the following lines in my polygons style file: waterway=riverbank [0x10303 resolution 18] seamark:type=fairway [0x10304 resolution 22] The fairway polygons should be drawn always on top of the riverbank polygons. But sometimes the fairway is drawn below the riverbank and covered by this. We found out that this behavior is depending on the order in which the polygons occur in the osm file. This problem occurs not only with those water depth areas. Buildings are also covered by landuse polygons. It will be necessary to sort those critical polygons out an render them later on top of the rest. If one could specify layers like waterway=riverbank [0x10303 resolution 18 layer 0] seamark:type=fairway [0x10304 resolution 22 layer 1] and that mkgmap scanned the input once for each layer value in ascending order (with default as layer 0), then one could control which polygon is drawn last and on top. Jürgen