Every once in a while a new location-aware application appears that is a little bit different than the rest. Today I came across Twisst, an interesting Twitter app that alerts you every time you can see the International Space Station (ISS) pass through the sky in your locale.
Twisst combines a variety of services to do this. First of all, it requires users to follow the @twisst Twitter account which functions as the alert system. Then, it queries Twitter as to the geographical information provided by followers in their respective Twitter profiles. If coordinates are provided, as many iPhone users tend to do, coordinates are used for location pinpointing. If a geographical name is used (like ‘Winnipeg’ in my case), Twisst uses Google Maps or Yahoo to convert the place name, or geocode it, into latitude and longitude coordinates.
Once coordinates for a user are obtained, they are passed to the website Heavens Above in order to find out what time the ISS will pass over the coordinate pair. In order to account for differing time zones, Twisst queries the geographical database, Geonames, in order to convert normalized passover times for each users’ actual time zone.
Once this is done, Twisst sends an alert to each users’ Twitter account, in localized time, regarding each ISS fly-by.