[OSM-talk] Boundary relation with >5000 members?

[Roland Olbricht]

Dear Julio,

> Some examples of coastline boundaries that I found in Europe:
> http://osm.org/go/xVvgL5p-- http://osm.org/go/xX2ApwZz-
> http://osm.org/go/eqe20@O-
> 
> If it is not the "right" way to do it or there is a better way to do it,
> please let me know.

Most countries in Europe (e.g. UK, Belgium, the Netherlands, Germany and 
others) have the territorial waters as national boundaries. There had been a 
longer discussion some time ago
http://lists.openstreetmap.org/pipermail/dev/2008-October/012291.html
http://lists.openstreetmap.org/pipermail/dev/2008-October/012340.html

It sums up to:
- the correct boundary would be the baseline, see
http://en.wikipedia.org/wiki/Territorial_waters
but nobody uses it, because it is difficult to obtain.
- the territorial waters line is much simpler than the coastline: it has 
10-100 times fewer nodes and it is much smoother.
- the territorial waters often have the look and feel of the boundary: a ferry 
to an island near the coast doesn't have passport controls like when you cross 
a national border

For this reason I would strongly encourage you to use the territorial waters 
like most countries in Europe. If you need a tool the generate these 
territorial water lines automatically, have a look at sweep-brim.c in
http://wmaz.math.uni-wuppertal.de/olbricht/osm/osm-boundaries-source.tgz
Feel free to ask if you need any help.

Cheers,

Roland