I am building a Nominatim server which will serve as reverse geocoding api server. Only city/state(province)/country information are required in the api result. The street/road level information are not required.

For example, the server will give result: http://localhost/nominatim/reverse?lat=43.815031&lon=-79.716834

{ city:Brampton; state:Ontario; country:Canada }

I would like to use osmosis to filter the data before I import the whole planet data. What command line should I use for this purpose? How about the one below? Thank you.

filter relations by administrative

osmosis --read-pbf planet-latest.osm.pbf --tf accept-relations boundary=administrative --used-way --used-node --lp --write-pbf import1.osm.pbf

filter ways by administrative

osmosis --read-pbf planet-latest.osm.pbf --tf accept-ways boundary=administrative --used-node --tf reject-relations --lp --write-pbf import2.osm.pbf

merge all files together

osmosis --read-pbf import1.osm.pbf --read-pbf import2.osm.pbf --merge --write-pbf import.osm.pbf