A meta object created by meta() or as_meta(), or returned
by a meta_*() object.
icbm
Latitude and longitude of geographic positions specified as
"lat, long". Can optionally be a length-two vector, i.e. c(lat, long).
geo_position
Latitude and longitude of geographic positions specified
as "lat;long". Can optionally be a length-two vector, i.e. c(lat, long).
geo_region
Name of the geographic region related to the page content,
specified using ISO-3166
2-character country code and 2-character national subdivision. Example:
"US-NY".
geo_placename
Name of the geographic place related to the page
content. Example: "Atlanta, Georgia".
...
Additional geotagging metadata keyword and value pairs, such as
geo.country, geo.a1, ..., geo.a3, etc. Underscores in the keyword
will be converted to periods, so you can also specify geo_country in
place of geo.country.