[OSM-dev] What country is something in?

Hakan Tandogan hakan at gurkensalat.com
Fri Oct 31 13:57:34 GMT 2008

On Wed, October 29, 2008 23:32, Roland Olbricht wrote:
> Hello everybody,
> you can now download a first version of the discover-boundaries tool. In
> ...
> For example, in europe the inner-country boundary consists of about
> 100.000 nodes, but the coastline has about 7 million nodes. So just
> adding the coastline would make the polygons 70 times more complex.

You could aggresively smooth the border derived from the coastline,
especially if you use the 12nm "bubble" around the country. For most
purposes, one node every 1 km should be enough.

Maybe you could use some code from gpsbabel?

> The "United Nations Convention on the Law of the Sea" leaves it to the
> respective nations whether they exhaust the full 12-nm-zone or not. But
> unfortunately, it seems quite difficult to get the data of the official
> border. I started to try with Germany, but I was not able to find any
> official document stating the border on the web.

I think that you might get different data depending on which official site
you go to. I remember hot disagreements over the 12 miles regulation
between Turkey and Greece (which has been solved peacefully, thank god).

> * automatically compute the 12-nm-line and submit it as boundary to OSM

Try to automatically compute the water border and leave it to the OSM'ers
to fix it. It is a wikified map after all ;-)

You could add a note tag with FIXME in it to prod people into looking at
your border data.

And be prepared for some heated discussion, "correct" borders are even
more difficult than "correct" place names :-)


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