[OSM-talk] 12nm territorial borders - useful or rubbish?

David Murn davey at incanberra.com.au
Mon Feb 14 06:52:26 GMT 2011

On Mon, 2011-02-14 at 03:22 +0100, Frederik Ramm wrote:
>     I've been thinking about the 12nm territorial borders on sea that we 
> have in many places, notably in Europe. Many of them seem to have been 
> auto-generated by simply placing a buffer around the coastline.
> My first question is, do they really have legal significance?

> For example, if I am inside this triangle between Scotland and Ireland, 
> will my legal status (concerning, say, fishing quotas, or whom I can 
> marry on board of my vessel, or whatever funny things influcenced by 
> international borders) be really any different from the status I had if 
> I moved my vessel 2 miles in either direction?

Try approaching by sea to within 13 miles of China, Iran or Pakistan,
then travel another 2 miles across the territorial border and see if the
locals think it makes a difference.

Im sure I remember reading a linked news story posted on this mailing
list about a soldier crossing into enemy country because of incorrect
mapping on his GPS.

> Would the UK coastguard have a good laugh when I claim to be in international 
> waters at that location?

If youre more than 12 miles from the coast (which is what is mapped)
then youre in international waters, why would they laugh at that fact?

> My second question is, assuming that indeed there is significance to the 
> 12 nm boundary - should such auto-generated data be in OSM at all? If 
> you're out on the sea, should whatever navigational aid you carry not 
> compute by itself how far you are from the coast, rather than telling 
> you whether you're to the left or to the right of a previously computed 
> 12nm line?

What happens if the international waters stretch further than 12nm in
some areas?  The generally accepted rule is that 12nm is the edge of
territorial waters, but by treaty/agreement this can be changed.

> I'm not saying we should delete them; but whenever I see them on the map 
> I tend to shrug and say "well, seems like someone was trying out his 
> PostGIS skillz"

A ships captain might look at a neatly laid out park and say 'why bother
putting each tree, thats just showing off that you can make pretty
patterns', in the same way that a non boating person might fail to see
the value in territorial water boundaries.


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