Data sources and licences

SeaLagom shows lights, buoys, ships, depths and land from open data published by national authorities and open projects. Here is every source, what we use it for, its licence and the credit it asks for.

Each credit is shown exactly as its licence asks, in the words of the source.

Not for navigation. Everything SeaLagom shows from these sources is for awareness. Navigate only with official nautical charts and publications.

Lights, buoys and other sea marks

NOAA Office of Coast Survey

NOAA ENC Direct to GIS

What we use: Lights, buoys, beacons, racons and fog signals in US waters, the US territories and the Great Lakes.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC0 1.0 Terms of the source
Credit: Source: NOAA Office of Coast Survey
What we change: Changed by SeaLagom: one record per aid across the chart scale bands, light characters written in chart notation and merged with other sources. Not NOAA ENC data and not an official product
How often: We load it every week. 10714 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. NOAA says ENC Direct to GIS does not meet USCG chart carriage requirements for commercial vessels. Use official charts and lists of lights.

U.S. Coast Guard Navigation Center (NAVCEN)

USCG Light List (MSI GeoJSON)

What we use: Every aid in the U.S. Coast Guard Light List: lights, buoys, daybeacons, racons and fog signals, with the faults the Coast Guard reports.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: Public domain Terms of the source
Credit: Source: U.S. Coast Guard Light List (NAVCEN)
What we change: Changed by SeaLagom: selected, reformatted into one list of aids to navigation, light characters written in chart notation and merged with other sources
How often: We load it every week. 57119 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Shom (Service hydrographique et océanographique de la Marine)

Balisage maritime (BDML_BALISAGE)

What we use: Lights, buoys, beacons, racons and AIS aids to navigation in French waters, mainland and overseas.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: Licence Ouverte 2.0 Terms of the source
Credit: Shom, 2026. https://dx.doi.org/10.17183/DOI_BALISAGE_MARITIME. Data of 2026-06-17
What we change: Changed by SeaLagom: selected, reformatted into one list of aids to navigation, light characters written in chart notation and merged with other sources
How often: We load it every week. 12195 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Shom says: do not use for navigation (ne pas utiliser pour la navigation).

Kystverket (Norwegian Coastal Administration)

Navigasjonsinstallasjoner

What we use: Lights with their sectors, fixed and floating marks and racons in Norway and Svalbard.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: NLOD 2.0
Credit: Contains data under the Norwegian licence for Open Government data (NLOD) distributed by Kystverket
What we change: Changed by SeaLagom: Norwegian values translated, sector lines turned into light sectors, staff fields left out and merged with other sources
How often: We load it every day. 22914 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Kystverket says: ikke til navigasjon (not for navigation).

Väylävirasto (Finnish Transport Infrastructure Agency)

Vesiväylätiedot (turvalaitteet, loistot, valosektorit)

What we use: Every Finnish aid to navigation at sea and on the lakes, with light sectors and racons.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC BY 4.0 Terms of the source
Credit: Source: Finnish Transport Infrastructure Agency / Open API, license CC 4.0 BY
What we change: Modified by SeaLagom: light colours joined from the sector layer, characters written in chart notation and merged with other sources
How often: We load it every night. 35176 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Väylävirasto says the data is not suitable for navigation (aineisto ei sovellu navigointikäyttöön).

Rijkswaterstaat

Vaarwegmarkeringen Nederland

What we use: Floating and fixed fairway marks in the Netherlands, the North Sea included.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC0 1.0
Credit: Source: Rijkswaterstaat, Vaarwegmarkeringen Nederland
What we change: Changed by SeaLagom: selected, reformatted into one list of aids to navigation, light characters written in chart notation and merged with other sources
How often: We load it every week. 18438 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Instituto Hidrográfico (Marinha Portuguesa)

Ajudas à Navegação

What we use: Aids to navigation of Portugal, Madeira and the Azores.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC BY 4.0 Terms of the source
Credit: Source: Instituto Hidrográfico, Ajudas à Navegação, CC BY 4.0
What we change: Changed by SeaLagom: selected, reformatted into one list of aids to navigation, light characters written in chart notation and merged with other sources
How often: We load it every week. 1998 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Plovput d.o.o. Split

Registar objekata sigurnosti plovidbe (ROSP)

What we use: Lights and other aids to navigation in Croatia.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: Otvorena dozvola Terms of the source
Credit: Sadrži informacije tijela javne vlasti u skladu s Otvorenom dozvolom. Source: Plovput d.o.o. Split, Registar objekata sigurnosti plovidbe. Data of 2026-08-20
What we change: Changed by SeaLagom: Croatian abbreviations written in the international form, object types translated and merged with other sources
How often: We load it every week. 1255 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Vegagerðin (Icelandic Road and Coastal Administration)

Vitar (lighthouses)

What we use: The lighthouses of Iceland.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC BY 4.0 Terms of the source
Credit: Source: the Icelandic Road and Coastal Administration (IRCA), lighthouses (vitar_2024_1), CC BY 4.0. Data of 2026-11-15
What we change: Changed by SeaLagom: positions converted from ISN93, characters written in chart notation
How often: We load it every week. 101 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Maritime and Port Bureau, MOTC (交通部航港局)

燈塔燈質表 (lighthouse light characteristics table)

What we use: The lighthouses of Taiwan, Penghu, Kinmen, Matsu and Taiping.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: Open Government Data License, version 1.0 (Taiwan)
Credit: Maritime and Port Bureau, MOTC 2026, 燈塔燈質表 (lighthouse light characteristics table), version of 2026-07-23. The open data is made available to the public under the Open Government Data License, version 1.0
What we change: Changed by SeaLagom: Chinese light characters written in chart notation, sectors taken from the remarks
How often: We load it every week. 83 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Wikidata contributors

Wikidata lighthouses (community data)

What we use: Major lighthouses worldwide, used only where no official source has the light.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC0 1.0 Terms of the source
Credit: Wikidata (community data), CC0 1.0
What we change: Changed by SeaLagom: light characters written in chart notation, used only where no official source has the light
How often: We load it every week. 4905 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Community data, positions to about a tenth of a minute. Use official charts and lists of lights.

Bundesamt für Seeschifffahrt und Hydrographie (BSH)

Seezeichen nach S-57

What we use: Lights, buoys and beacons in the German North Sea and Baltic.
Where it shows: Map Sky and sea view (Alpha)Shown on our map and sky view only, not passed on through the data API.
Licence: GeoNutzV (Nutzungsbestimmungen für die Bereitstellung von Geodaten des Bundes)
Credit: Quelle: © BSH 2019, verändert
What we change: Changed by SeaLagom: one record per aid across the chart scale bands, characters written in chart notation
How often: We load it every week. 9061 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. BSH says: die Verwendung der Daten zu Navigationszwecken ist nicht gestattet (use for navigation is not allowed).

Department of Transport, Western Australia

Navigation Aids DoT (DOT-004)

What we use: Positions and types of the navigation aids of Western Australia.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC BY 3.0 AU
Credit: Source: Department of Transport (WA), Navigation Aids (DOT-004), CC BY 3.0 AU
What we change: Changed by SeaLagom: positions and types only, reformatted for the map
How often: We load it every week. 2816 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Commissioners of Irish Lights

Aids to Navigation

What we use: Positions and types of the aids to navigation around Ireland.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC BY 4.0
Credit: Source: Commissioners of Irish Lights, Aids to Navigation, CC BY 4.0. Data of 2024-09-05
What we change: Changed by SeaLagom: positions and types only, reformatted for the map
How often: We load it every week. 202 records on our map now.
Licence last checked: 2026-11-15

Not for navigation. Use official nautical charts and lists of lights.

Ships (AIS)

Fintraffic Digitraffic (Finland)

What we use: Ship positions from the Finnish shore stations.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: CC BY 4.0 Terms of the source
Credit: Source: Fintraffic / digitraffic.fi, license CC 4.0 BY
What we change: Changed by SeaLagom: merged with other AIS sources and checked
Licence last checked: 2026-11-05

Not for navigation. AIS positions come from shore receivers and can be late, incomplete or wrong.

Kystverket (Norway)

What we use: Ship positions from the Norwegian shore stations.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: NLOD 2.0
Credit: Contains data under the Norwegian licence for Open Government data (NLOD) distributed by Kystverket
What we change: Changed by SeaLagom: merged with other AIS sources and checked
Licence last checked: 2026-11-05

Not for navigation. AIS positions come from shore receivers and can be late, incomplete or wrong.

aisstream.io

What we use: Ship positions worldwide from AIS receivers.
Where it shows: Map Sky and sea view (Alpha)Data API
Credit: aisstream.io publishes no terms and asks for no credit.
What we change: Changed by SeaLagom: merged with other AIS sources and checked
Licence last checked: 2026-11-05

Not for navigation. AIS positions come from shore receivers and can be late, incomplete or wrong.

Finland: light faults and winter navigation

Fintraffic

Digitraffic marine (aids to navigation faults, winter navigation)

What we use: Faults of Finnish lights and buoys, and the Baltic winter navigation: icebreakers, port restrictions and dirways.
Where it shows: Map Data API
Licence: CC BY 4.0 Terms of the source
Credit: Source: Fintraffic / digitraffic.fi, license CC 4.0 BY
What we change: Changed by SeaLagom: selected for the map and reformatted
How often: We load it every 10 minutes.
Licence last checked: 2026-11-05

Not for navigation. The official notices of the Finnish and Swedish winter navigation services and the Notices to Mariners are the authority.

Depth

GEBCO Compilation Group

GEBCO 2026 Grid

What we use: Water depth on the sky and sea view and in the ship card's clearance estimate.
Where it shows: Sky and sea view (Alpha)
Licence: Public domain
Credit: GEBCO Compilation Group (2026) GEBCO 2026 Grid (doi:10.5285/4f68d5c7-45eb-f999-e063-7086abc036fa)
What we change: Changed by SeaLagom: a coarse copy that keeps the shallowest depth of each 2 arc-minute block

Not for navigation. GEBCO says its grid is not to be used for navigation or safety at sea.

Land and coastline

Natural Earth

Natural Earth 1:10m land, minor islands and lakes

What we use: The coastline and land: where the sea is on the sky and sea view, and the outlines of the NAVAREAs.
Where it shows: Map Sky and sea view (Alpha)Data API
Licence: Public domain
Credit: Natural Earth
What we change: Changed by SeaLagom: lakes of 100 square kilometres and more cut out as water

Not for navigation. Drawn for the view only, not a nautical chart.

Registry of Open Data on AWS (Mapzen and its sources)

Terrain Tiles

What we use

Land heights for the coasts and mountains drawn on the sky and sea view.

Where it shows

Sky and sea view (Alpha)

Licence

Several open licences, one for each source in the credit

Credit

Terrain Tiles, Registry of Open Data on AWS (Mapzen and its sources)

ArcticDEM terrain data DEM(s) were created from DigitalGlobe, Inc., imagery and funded under National Science Foundation awards 1043681, 1559691, and 1542736;
Canada terrain data contains information licensed under the Open Government Licence - Canada;
Europe terrain data produced using Copernicus data and information funded by the European Union - EU-DEM layers;
Global ETOPO1 terrain data U.S. National Oceanic and Atmospheric Administration;
Mexico terrain data source: INEGI, Continental relief, 2016;
United States 3DEP (formerly NED) and global GMTED2010 and SRTM terrain data courtesy of the U.S. Geological Survey.

What we change

Changed by SeaLagom: heights resampled to grids of about 200 m near the viewer and 670 m further out

Not for navigation. Drawn for the view only, not a nautical chart.

Port models

OpenStreetMap contributors

OpenStreetMap (port models)

What we use: The 3D models of the 20 biggest container ports on the sky and sea view.
Where it shows: Sky and sea view (Alpha)
Licence: ODbL 1.0
Note: The model files are a derived database, offered under the same licence.
What we change: Changed by SeaLagom: quays, breakwaters, buildings, tanks and cranes drawn as simple 3D shapes

Not for navigation. Drawn for the view only, not a nautical chart.

Programs can read this list as JSON: /api/public/data-sources/