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Sources and credits · kierie

Where kierie's cards come from

Last Updated: November 7, 2026

kierie is built on open data from Dutch government bodies, cities, researchers and volunteers. Thank you to all of them. Every card in the app names its sources under "More info", with how fresh the data is and what it can't tell you. This page lists them all, by topic, with the licence they are shared under.

A few sources are marked "reuse to confirm": we have asked their owners, and we take a source out if they say no.

Weather

  • KNMIWeather warnings, rain radar forecast, UV index, chance of dangerous weather, bird migration radar. CC BY 4.0.
  • Open-MeteoThe weekend forecast, and pollen from the Copernicus Atmosphere Monitoring Service (CAMS). CC BY 4.0, under a commercial plan.

Sky and space

  • CelesTrakOrbits of the ISS, Tiangong and Starlink satellites. Use allowed by CelesTrak, also commercially, with credit.
  • NOAA Space Weather Prediction CenterNorthern lights forecast (Kp index). Public domain (US government).
  • NASA JPL (DE421 ephemeris)Positions of the moon and planets, eclipses. Public domain (US government).
  • International Meteor OrganizationDates and rates of the meteor showers. Source: International Meteor Organization (IMO) – www.imo.net; IMO Meteor Shower Calendar 2026. The peak times and the moon are our own calculation.

On the move

  • NDW (Nationaal Dataportaal Wegverkeer)Planned bridge openings, roadworks, events that close roads, and public charging points with how many are free. CC0.
  • Rijkswaterstaat, Fairway Information ServicesNames of bridges. CC0.
  • Public transport operators, via OVapiTravel notices and stops (stops CC0). Free to use; OVapi and kierie do not speak for the operators.
  • NS (Nederlandse Spoorwegen)Train disruptions and planned works at stations, via the NS API. Reuse to confirm.
  • PDOK LocatieserverStreet names at a location. CC0.

Energy, air and water

  • ENTSO-E Transparency PlatformDay-ahead electricity prices. Free to reuse with credit.
  • LuchtmeetnetAir quality index per station, shown exactly as published. CC BY-ND 4.0, source: www.luchtmeetnet.nl.
  • RijkswaterstaatOfficial bathing spots and their EU water quality. CC0.
  • UK Hydrographic Office, via EMODnetShipwrecks off the coast. Contains public sector information licensed under the Open Government Licence v3.0.

History, art and remembrance

  • Cultural Heritage Agency (Rijksdienst voor het Cultureel Erfgoed)Mills and lost mills, historical tramways, drained lakes, burial mounds, hunebeds, dike-breach ponds. CC0 or Public Domain Mark 1.0.
  • BAG (Kadaster, via PDOK)Building years and place names. CC0.
  • WikidataMonuments, street namesakes, artworks, memorials, landmarks, the Rijksmuseum's best-known paintings. CC0.
  • WikipediaThe first sentence about a landmark or town. CC BY-SA 4.0, with a link to the article.
  • Wikimedia CommonsArchive photos of streets and national monuments, most from the Cultural Heritage Agency's image bank. Licence per photo (public domain, CC0, CC BY, CC BY-SA); each photo shows its maker and licence.
  • Kadaster (Topotijdreis)The topographic maps of around 1900 and 1950. Free to use with credit: Kadaster.
  • Open Beelden (Sound and Vision)Films from before 1960 made in your town. Public Domain Mark, CC BY or CC BY-SA per film.
  • OpenStreetMapStolpersteine, museums, libraries. ODbL, © OpenStreetMap contributors.

Nature and birds

  • City tree registersAmsterdam, Utrecht (CC BY 4.0), Arnhem, Delft, Breda, Eindhoven and Nijmegen: the cities' own lists of street trees. Licences per city; Amsterdam's still to confirm.
  • Landelijk Register Monumentale Bomen (Bomenstichting)Monumental trees. CC BY 4.0.
  • Officiële bekendmakingen (KOOP)Municipal permits to fell trees in public space. CC0.
  • Natura 2000 (RVO, via PDOK; species from the European Environment Agency)Protected nature areas and what they protect. Public Domain Mark 1.0; EEA reuse to confirm.
  • eBird (Cornell Lab of Ornithology), via GBIFWhich birds are seen here this month. CC BY 4.0; only CC0 and CC BY records.
  • NDFF Lijst Kwetsbare SoortenUsed only to leave vulnerable species out, so no rare bird's spot is ever shown.

Under your feet

  • AHN, Actueel Hoogtebestand Nederland (via PDOK)Ground height. CC0.
  • BRO (TNO, Wageningen Environmental Research, via PDOK)Landforms (CC0), soil and groundwater depth (CC BY 4.0).
  • Palaeogeographic maps (RCE, TNO, Deltares)How the land looked from the year 100 to now. CC BY 4.0.

Out and about

  • OpenStreetMapMarkets and their hours, playgrounds, petting farms. ODbL, © OpenStreetMap contributors.
  • City of AmsterdamMarkets and what they sell. Public domain.
  • City of UtrechtStreet parties and events with a permit. CC0.
  • RijksoverheidSchool holidays per region. CC0.
  • Nevobo (volleyball) and NBB (basketball)Match programmes per sports hall. Reuse to confirm.

Own one of these sources and have a question, or see something credited wrongly? hello@blauwtoffie.nl