A location representing a "first-level administrative division"; ie, a state, province, or similar division.
A location representing a city
A location representing a "country" (or other geographic unit that has an ISO-3166 country code)
A location that is detached from the database, for example because it was loaded from external storage and could not be fully recovered. The parent of this location is the nearest weather station.
A location representing a named or special timezone in the world, such as UTC
A location representing a continent or other top-level region.
A location representing a weather station.
A location representing the entire world.
The size/scope of a particular #GWeatherLocation.
Locations form a hierarchy, with a %GWEATHER_LOCATION_WORLD location at the top, divided into regions or countries, and so on. Countries may or may not be divided into "adm1"s, and "adm1"s may or may not be divided into "adm2"s. A city will have at least one, and possibly several, weather stations inside it. Weather stations will never appear outside of cities.
Building a database with gweather_location_get_world() will never create detached instances, but deserializing might.