Frederik Ramm wrote: > > Interestingly I joined this list a while ago because I had got my > hands on some admin boundary data for England and wanted to know if it > was any good (the answer was no). I then forgot to unsubscribe. I'm > still planning to extend the Geofabrik excerpts to cover all English > counties individually once I have proper data. Unfortunately simply > using OSM boundaries only works for landlocked counties; the coastal > ones don't seem to include the coastline, and even if they did, a > "proper" coastline is not what you want to use for the excerpt, > instead you want to draw a line a few kilometres out to sea where the > border meets the coastline, then up/down in a straight line, and back > in - which saves computing time and also ensures that any pier etc. > that crosses the coastline is also included. > I have discovered recently that coastal counties end at the mean low water mark, with a few exceptions. I'm working on improving the boundary to be accurate, starting close to home in East Yorkshire. I need a few visits to the coast first. This will move the boundary, currently roughly along the line of the cliffs or sea wall further out to an estimate of the mean low water mark. It will allow a much needed tag for beaches, mud-flats etc. If you push the boundary further out to sea then any calculation of the area of the county will be unnecessarily large. I do agree that piers need some thought, and off-shore islands too.
BTW Frederik, does the (very useful) Geofabrik download for East Yorks use the coastline as its edge? If so when I move the boundary I'll ask you to change the edge for the download. Cheers, Chris _______________________________________________ Talk-GB mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-gb
