[mkgmap-dev] Configurable flood blocker

Wed Dec 1 19:39:23 GMT 2010

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