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

Frederik Ramm frederik at remote.org
Mon Feb 14 02:22:31 GMT 2011


    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? They 
certainly give the impression of high precision, hugging every 
protruding bit of coastline in a safe distance.

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?


Or are we, by using these auto-generated (and perhaps not 
human-reviewed?) borders, suggesting a precision that isn't there? Would 
the UK coastguard have a good laugh when I claim to be in international 
waters at that location?

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?

And my third question is, assuming that there are really good reasons 
for having these lines in OSM - who takes care of updating them once the 
coastline is modified by a mapper? I think it is a rather unique 
situation to have that kind of data-derived-from-other-OSM-data in OSM 
itself, and thus this has many of the same problems that an import would 
have (i.e. the source data has changed, what now).

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", and somehow I have the suspicion that the 12nm line as 
depicted on our maps may be little more than "that's what computer geeks 
do if you tell them the border is 12 miles out...".

I'd like to hear from people who tell me that yes, these borders are 
really useful to have ;)


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

More information about the talk mailing list