[Geocoding] Reverse geocoding functionalities

[Brian Quinion]

I'm going to assume you are talking about nominatim - if not sorry.

> As far as I know the reverse geocoding looks for the nearest place in the
> database, so it also gives result for "unmapped" territories. For example if
> I use an extract of a city, the reverse geocoding will produce an address
> inside that city for coordinates anywhere in the world.

Well, not entirely.  Beyond 1 degree of lat/lon from the imported area
it will simply return an error.

> How could I check the validity of the result?
> Is it possible to get the coordinates of the result (or even the
> geographical distance from the input coordinates)?

The output could certainly be extended to include this fairly easily.
This information is calculated internally but not exposed.

> Can the country be determined for a position outside the "mapped"
> territories? (Maybe somebody has a method for using the data of the
> import_worldboundaries.sql script)

That is a valid point.  This used to be done and has been lost recently.

--
 Brian