[OSM-newbies] Administrative boundaries

[James Ewen]

On Fri, Nov 7, 2008 at 6:56 PM, Simone Cortesi <simone at cortesi.com> wrote:

> there is a good consensus on the fact that using a relation is a good
> thing for borders:
> http://wiki.openstreetmap.org/index.php/Relations/Proposed/Boundaries

That leaves a lot to be desired for a description... After many hours
of contemplation, and looking at the way surrounding the Vatican, I
think I understand what it is that is being described.

Rather than create yet another way to describe a border, one would
rather simply include all the existing ways in a relation. The
relation defining a border may include other ways that define roads,
edges of woodland, rivers, or ways that only define the actual border.

> or take a look at what I used when importing italian borders few weeks
> ago: http://wiki.openstreetmap.org/index.php/Italian_Borders
>
> you need for the way:
> <tag k="boundary" v="administrative" />
> <tag k="admin_level" v="a_number_2,4,6 or 8" />
>
> for the relation:
> <tag k="type" v="boundary" />
> <tag k="boundary" v="administrative" />

The boundary page describes this format:

boundary=administrative
+ admin_level=2

But how do you apply either of these in the real world? My tool of
choice is Potlatch.

So, if I took 4 ways (roads for example) that defined a quadrilateral,
and added them to a relation, and then defined that relation as a
boundary, with an appropriate admin_level, I should get a border drawn
on the map.

James