Hi all,
I've looked a bit deeper at this issue and found this: The SeaGenerator in mkgmap creates polygons with the tag natural=sea (what else) If you use a style for polygons that contains a line like this natural = sea [0x32 resolution 17]
(as Klaus does for his norway map) mkgmap adds a lot of data to the output file to save the sea polygons. I assume a better solution would be to remove this line and use the colour for sea as the background colour. Does that make sense?
Gerd
How do you avoid that land area is filled with the sea/background color? What you describe is the --generate-sea=polygon variant which can be used in combination with --precomp-sea. But this has the disadvantage that you have a background sea polygon covering the whole tile and land polygons on top of it. So if you click on land you always have sea under the land... WanMil