The CitySDK Linked Data API offers unified and direct access to open transport, mobility and general data from government, commercial and crowd sources alike. It is designed to work closely with other open source projects as OpenTripPlanner, OpenTripPlanner Analyst, Open311, GTFS, and OpenStreetMap.

In the CitySDK Linked Data API, data sets are called layers. Each layer can contain objects, and each object contains, per layer, key/value data. In the API, real-world objects like buildings, bus stops and municipalities are represented by objects, which can contain data on one or more layers. This way, multiple data sets can tell something about one single object.

The master branch of this repository contains the API — written using Ruby, Grape and PostGIS — the gh-pages branch contains the project's website.

For more information about the CitySDK LD API, see the project's website or wiki.

• A Ruby gem for easy programmatic access to the CitySDK LD API is available in the citysdk-rubygem repository,
• And in the citysdk-amsterdam repository, you can find importers for Amsterdam-specific data sets.