CKAN is the Comprehensive Knowledge Archive Network, a non-profit registry of open data. CKAN prepares data and provides access to data in ways that make that data more discoverable and usable.
The government of Norway makes some datasets available through CKAN, including data on famous buildings in Oslo; National Groundwater Database; municipal boundaries; land use and planning information; traffic data; and more.
The CKAN API provides access to this data. The API is RESTful and returns responses in JSON and JSONP.