Provides a reference to the Yahoo GeoPlanet WOEID.
This key is used to reference the Yahoo GeoPlanet database for a given feature (eg a place) using that features WOEID (Where On Earth ID). The aim of GeoPlanet database is to provide a permanent ID for each place on earth, as well as provide a hierarchy between all the known places.
From the GeoPlanet documentation:
Yahoo! GeoPlanet helps bridge the gap between the real and virtual worlds by providing an open, permanent, and intelligent infrastructure for geo-referencing data on the Internet.
In practical terms, Yahoo! GeoPlanet is a resource for managing all geo-permanent named places on Earth. It provides the geographic developer community with the vocabulary and grammar to describe the world's geography in an unequivocal, permanent, and language-neutral manner. Developers can geo-enable their applications by using GeoPlanet to traverse the global spatial hierarchy, identify the geography relevant to their users and their businesses, and in turn, unambiguously geotag, geotarget, and geolocate data across the Web.
The WOEID for a place can be found through the GeoPlanet API (key required) or by parsing the data file available (under CC-by-3.0 licence) to download from their site.
Example usage ():