Sorry for the prolonged lack of communication while we’ve been looking at how best to address this.
Around the same time that the search issue occurred, we were also in the process of making some changes to Twitter’s apps which modified the ways in which users were encouraged to share their location information - the move to places, rather than specific geocoordinates. As part of this change, the ability to add a precise set of coordinates to a Tweet is not as visible as it was previously.
The percentage of Tweets tagged with geolocation data by users who choose to share that information has historically been low: ~2% of Tweets have been tagged. The change across to place data means that the number which have exact coordinates is very small. We’re committed to respecting our users’ privacy, so we don’t surface location information they have not chosen to share.
So, the ongoing lower volumes of Tweets seen following this change also flows into some of the UI and UX changes in the Twitter app; and ultimately, will continue to mean that geo search results on the public API remain low volume.
We do offer an enriched geolocation search via the enterprise Gnip APIs, which are fully supported and can provide some additional fallback defaults in cases where a user has tagged his or her location in their profile, but not on the Tweet. This may be an option for some developer use cases, although it is a commercial option. At our recent Flight conference, we shared some more information on how this works, and a video replay of that session will be online very soon.
Finally, we’re aware of the appetite for an enhanced search API and we are investigating whether this is something we can provide as part of the recent #HelloWorld feedback. Stay tuned for more on this.