Geolocation for Trends/Available


Since Trends/Available returns topics (keywords) that have been identified as a trending topic within a specific WOEID (other than ‘1’), does that mean that there are is a significant amount of Geotagged tweets in that WOEID that reference that specific trending keyword?

If there is no correlation between the trending topic IN a specific WOEID, then how is Twitter able to identify the location of the tweets that are being used to justify the “trendiness” of a particular topic?

Basically, what information is Twitter using to determine the location of the Tweets referencing the trending topic which that then makes said topic trending IN a specific WOEID? And how do I access that granular level of detail?

Is it the users profile location? Only looking at the geotagged tweets? Or is Twitter examing the Tweeter’s IP address (which I realize is not available, though I didn’t think that would comply with Twitter’s own policies)?