I have committed an improved version of the flood blocker to the coast branch. It is configurable in some parts (please refer to the help file to the exact config options). What are the improvements now ? 1. I observed that in many good sea polygons there are some highways which are located very close to the edge of the polygon (e.g. a street that ends in the sea). It is now possible to set a gap to ignore these points during the flood blocking algorithm. (Parameter fbgap=NUM (meter)) 2. Now I count the number of land points and sea points in the sea polygon. Given n(bad) = (n(land)-n(sea)) the flood blocker ignores all sea polygons where n(bad) < fbthres (Parameter fbthres=NUM) 3. At least the number of n(bad)/size of polygon gives a ratio. The polygon is removed if the ratio is higher than fbratio. (Default fbratio=0.5) Current rules which coords are used for flood blocking evaluation: Land: highway=* or and not highway=construction not layer!=0 not man_made=pier not man_made=dam not bridge=yes/true/1 not tunnel=yes/true/1 Sea: route=ferry or boundary=administrative and maritime=yes Next I want to add a configuration file for the flood blocking rules. Please try the current version and play a little bit with the options and tell me what you think and if it fits your needs. WanMil