By default, Carmen attempts to resolve tweet locations by three methods,
in the following order:
Using the place resolver, which matches Twitter Places to known
locations by name.
This resolver takes two options:
allow_unknown_locations determines whether unknown Places are
converted to locations that may be returned from resolution.
By default, this option is False.
resolve_to_known_ancestor determines whether tweets with
unknown Places are resolved to the nearest known ancestor
location containing that Place.
For example, an unknown city may be resolved to a known state-
or provincial-level location.
Such a backed-off location, unlike others returned from this
resolver, may be superseded by more confident estimates from
other resolvers.
This option is only effective if allow_unknown_locations is
False, and itself defaults to False.
Using the geocode resolver, which finds the known location
nearest the tweet’s geographic coordinates.
This resolver takes a single option, max_distance,
which specifies the maximum distance away from the coordinates,
in miles, that the resolver will look for matching locations.
Using the profile resolver, which matches the “location” fields
of tweet authors’ user profiles to known locations by name.
This resolver takes no options.
The resolution_method attribute of each Location
object, and the corresponding resolution_method key in the resulting
JSON output, contain a string specifying the name of the resolver used
to determine a tweet’s location.