In the past I did not use a background polygon on my Oregon. But since the default green color was not the best, I defined a background with a light beige color. Since this change the blue color for the see is gone. (Lakes are still shown) I’m sure there is a solution to show the see togethere with a background, but all articles I found wer not helpful. The land polygon is defined as 0x4b and it is the only polygon with draw-prio = 1. The sea polygon is defined as 0x32 and it has draw-prio = 2. The last commands in polygons file are natural=sea [0x32 resolution 14] natural=land [0x4b resolution 14] Splitter Option --keep-complete=true mkgmap Option precomp-sea=sea_20141027.zip generate-sea=multipolygon Is there anything else I could check? Walter