Data Sources & Licences

Open data acknowledgementsSea Chart uses marine and mapping data under the terms stated by each provider. We gratefully acknowledge the following providers and contributors.

Basemap and seamarks

Open databases used by the chart experience

OpenFreeMap basemap

OpenFreeMap weekly build / OpenStreetMap data

The application basemap is built from OpenStreetMap data.

Licence: ODbL 1.0
Acknowledgement: OpenStreetMap contributors · OpenFreeMap · OpenMapTiles

OpenSeaMap seamarks

OpenSeaMap + OSM Planet

Community-maintained nautical seamarks and OSM supplements.

Licence: ODbL 1.0
Acknowledgement: OpenSeaMap and OpenStreetMap contributors

Satellite imagery

Open aerial and satellite imagery used by the satellite map layer

OpenAerialMap / Open Imagery Network

OpenAerialMap (OAM) / Humanitarian OpenStreetMap Team

Openly licensed aerial and satellite imagery used where coverage is available.

Licence: CC BY 4.0
Acknowledgement: © Open Imagery Network contributors
Terms: OpenAerialMap Terms and License. API and imagery use beyond reasonable use should be arranged with OAM.

Copernicus Sentinel-2

European Union Copernicus Programme / European Space Agency

Sentinel-2 source imagery downloaded from the Copernicus Data Space Ecosystem and processed by Sea Chart into satellite map tiles.

Licence: Free, full and open use under the Copernicus Sentinel Data Legal Notice
Acknowledgement: Contains modified Copernicus Sentinel data [year of acquisition].
Source: Copernicus Data Space Ecosystem

LINZ Aerial Imagery Basemap

Toitū Te Whenua Land Information New Zealand (LINZ)

New Zealand aerial and satellite imagery supplied through LINZ Basemaps.

Licence: CC BY 4.0
Acknowledgement: © LINZ CC BY 4.0 © Imagery Basemap contributors
Source: LINZ Basemaps

National Agriculture Imagery Program (NAIP)

United States Department of Agriculture (USDA) Farm Service Agency

High-resolution aerial imagery of the continental United States, captured during agricultural growing seasons.

Licence: U.S. Public Domain
Acknowledgement: U.S. Department of Agriculture, Farm Service Agency — National Agriculture Imagery Program (NAIP)
Source: USDA NAIP imagery service

NSW Imagery

NSW Spatial Services, Department of Customer Service

New South Wales imagery service combining satellite and orthorectified aerial imagery from multiple sources.

Licence: CC BY 3.0 AU
Acknowledgement: NSW Spatial Services and the applicable imagery data contributors.
Terms: Imagery has mixed sources; retain applicable attribution and check the use constraints for each individual imagery series.
Source: Data.NSW — NSW Imagery

PDOK Luchtfoto RGB (Open)

PDOK / Beeldmateriaal Netherlands

Nationwide Dutch colour aerial imagery: 25 cm summer coverage and 8 cm, partly 5 cm, winter high-resolution coverage.

Licence: CC BY 4.0
Acknowledgement: PDOK Luchtfoto RGB (Open) / Beeldmateriaal Netherlands
Source: PDOK Luchtfoto RGB (Open) web services

Geospatial Ontario Imagery

Geospatial Ontario (GEO), Government of Ontario

High-resolution orthophotography of settled areas of Ontario, generally acquired on a five-year cycle. Coverage is regional, not annual coverage of all Canada.

Licence: Open Government Licence – Ontario
Acknowledgement: Contains information licensed under the Open Government Licence – Ontario.
Terms: Since 2024, GEO-funded collections are released openly when ready as mappable products. The licence applies only to collections for which Ontario owns the intellectual-property rights.
Source: Geospatial Ontario Imagery

Bathymetry and tide data

Source acknowledgements for marine data used by Sea Chart

Regional bathymetry

GEBCO 2026, LINZ, NOAA, GA/IMAS/AIMS, Kartverket/NGU and EMODnet

Global GEBCO 2026 plus regional datasets selected by coverage.

Licence: Dataset-specific terms apply
Acknowledgement: GEBCO, LINZ, NOAA, Geoscience Australia, IMAS, AIMS, Kartverket, NGU and EMODnet

NOAA / National Weather Service

United States federal data

Weather, chart and hydrographic data products.

Licence: Public Domain / CC0 where stated
Acknowledgement: Credit NOAA or the named NOAA programme.

EOT20 ocean tide model

DGFI-TUM

Global empirical ocean tide model.

Licence: CC BY 4.0
Acknowledgement: DGFI-TUM · Hart-Davis et al. (2021) · DOI 10.17882/79489

New Zealand standard ports

Toitū Te Whenua Land Information New Zealand (LINZ) / EOT20

Port levels are derived from LINZ standard-port tidal levels. Harmonic phases and minor constituents are derived from EOT20.

Licence: LINZ tide-table reuse terms / EOT20 CC BY 4.0
Acknowledgement: Contains tidal level data sourced from Toitū Te Whenua LINZ. Harmonic predictions are derived using EOT20 and are not official LINZ tide predictions.

UHSLC tide gauge stations

University of Hawaii Sea Level Center

Quality-controlled tide gauge observations used to derive harmonic constants for supported port stations.

Licence: Free use and redistribution under UHSLC dataset terms; not for legal use
Acknowledgement: University of Hawaii Sea Level Center (UHSLC) and the original tide gauge data contributors

Source names and licences are shown for attribution only. Sea Chart is not affiliated with or endorsed by these providers. Navigation information is for reference only.