This is an GPS API server for skånetrafiken made in 24 hours by parts of popdevelop for the codemocracy event at Modul 1 in Stockholm between 4/9 - 5/9 - 2010. Participating members: Johan Brissmyr Johan Gyllenspetz Joel Larsson Sebastian Wallin

The skånetrafiken API

Skånetrafiken is offering and API on the website labs.skanetrafiken.se however the API lacks the feature of getting a specfic route and it timetable. The API only gives information about every station and the expected arrivles by vehicles at that station.

The provided API

The server provides the following API with interpolated GPS coordinates.

/lines Example return:

/lines/nbr Example: /lines/8 returns: [{"lat": 55.60821646474038, "line": 7, "lon": 13.004210592934344, "id": 3276}, {"lat": 55.608022843695949, "line": 7, "lon": 13.002227450906988, "id": 3277}, {"lat": 55.608548041991341, "line": 7, "lon": 13.002010571617223, "id": 3278}, {"lat": 55.608645327317596, "line": 7, "lon": 13.001863930711846, "id": 3279}, {"lat": 55.608664827179368, "line": 7, "lon": 13.001773641967942, "id": 3280}, {"lat": 55.60866192591768, "line": 7, "lon": 13.001646854543134, "id": 3281}, {"lat": 55.608497274442463, "line": 7, "lon": 13.000577576050782, "id": 3282}], "forward": "Centralen", "duration": 1560, "id": 7, "name": 8}] cg /lines/nbr/vehicles Example: /lines/8/vehicles returns: [{"lat": 55.566827053985662, "line": 8, "lon": 13.021741923647619, "id": 1283758015.0}, {"lat": 55.561085361699128, "line": 8, "lon": 13.021171763112262, "id": 1283757458.0}, {"lat": 55.607342947991675, "line": 8, "lon": 13.004393727340467, "id": 1283758778.0}]

The technology

Since the precision is on the minutes the server only polls skånetrafiken every minute. In between the GPS coordinates are interpolated internally by the server.

polling 1 time / minute
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+--------------------------------+ +---------+ | nginx | +---------+ serves clients with the API +---------+ | clients | +---------+