[OSM-talk] administrative boundaries and is_in

[Martin Trautmann]

Robin Paulson wrote:
> can someone explain a few things about the way boundaries work, and
> their relation to the is_in key?
> 
> as far as i can tell, when a location (say the suburb of balham, in
> london) is added to the map, the is_in tag needs to be set, multiple
> times. in this case, it would be set as follows:
> 
> is_in:Westminster (...i think)
> is_in:greater london
> is_in:england
> is_in:united_kingdom
> is_in:British_Isles
> is_in:Great_Britain
> is_in:Europe
> ...etc.
> 
> which seems counter-intuitive, not to mention requiring huge amounts
> of work. do we set this for every item - roads, churches,
> supermarkets,....thousands of other items?

For central Europe there's another project, named opengeodb, which is 
structured hierarchically. Here it's enough to take the lowest matching 
level (by loc_id), while all other levels above can be heritated.

The names which are used for is_in have no need to be unique. Thus you 
can not derive info.

- Martin