Ship's papers

Data & credits

Griblet is built on open data and open-source work. Here is every source it uses, what for, under which licence, and the credit its owner asks for.

Forecast models

Griblet fetches these itself after each model run and draws them as they come: nobody checks a forecast before you see it.

GFS and GFS-Wave

NOAA, National Weather Service (NCEP)

The live forecasts: wind, gusts, pressure, temperature, rain, cloud, CAPE, visibility, waves and swell, the GRIB downloads, and the North Atlantic sample.

Licence: US public domain, NOAA open data
Credit: Forecast data: NOAA Global Forecast System (GFS) and GFS-Wave, from NOMADS and the NOAA Open Data Dissemination program (registry.opendata.aws/noaa-gfs-bdp-pds).
Changes: Cropped, thinned, quantized and re-encoded by Griblet: what you see is not original, unaltered NOAA data.
Note: Griblet is not endorsed by or affiliated with NOAA or the National Weather Service.
Links: GFS at NCEP
NOMADS
NOAA on AWS

ECMWF IFS open data

European Centre for Medium-Range Weather Forecasts (ECMWF)

The ECMWF forecast (wind, gusts, pressure, temperature, rain, cloud and waves), the comparison with GFS, and its GRIB downloads.

Licence: CC BY 4.0
Credit: © 2026 European Centre for Medium-Range Weather Forecasts (ECMWF)
This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF).
Source: www.ecmwf.int. This ECMWF data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence.
Changes: Cropped, thinned and compared with GFS by Griblet.
Note: ECMWF does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use.
Links: ECMWF open data
ECMWF terms of use

Official warnings

NWS marine alerts and zone outlines

NOAA, National Weather Service

Official marine warnings for US waters, drawn on the chart and listed in a banner.

Licence: US public domain
Credit: Warnings: National Weather Service (api.weather.gov).
Changes: Zone outlines are simplified to about 1 km by Griblet.
Note: Shown as the National Weather Service issues them. Griblet is not an official source and is not endorsed by NOAA or the NWS.
Links: NWS marine
api.weather.gov

Tides and streams

TICON-3 tidal constants

Hart-Davis, Dettmering & Seitz, from GESLA-3 tide gauge records

Tide heights, times and springs/neaps at about 2,000 coastal gauges.

Licence: CC BY 4.0
Credit: Hart-Davis, M. G., Dettmering, D. & Seitz, F. (2022): TICON-3: Tidal Constants based on GESLA-3 sea-level records from globally distributed tide gauges including gauge type information (data). PANGAEA, https://doi.org/10.1594/PANGAEA.951610
Changes: Merged per gauge and predicted by Griblet. Heights are given above an approximate lowest astronomical tide that Griblet works out.
Link: TICON-3 on PANGAEA

2D tidal current atlas (English Channel)

Shom, the French hydrographic and oceanographic service

The tidal streams overlay and the wind-against-tide check in the Channel.

Licence: Licence Ouverte 2.0 (Etalab)
Credit: © Shom. Shom, 2026. 2D tidal current atlas in netcdf format, https://dx.doi.org/10.17183/ATLASCOURANTS2D_NETCDF (2026 edition).
Changes: Resampled and packed for the web by Griblet.
Note: Shom says to use the atlas only alongside official nautical charts and publications.
Links: Shom data
Open Licence 2.0 (English)

Places and coastlines

World Port Index (Pub. 150)

US National Geospatial-Intelligence Agency (NGA)

Ports and harbours in place search, port details, and route waypoints that snap to a port.

Licence: US public domain (US government work)
Credit: Ports: NGA World Port Index, Pub. 150.
Changes: Trimmed and merged with GeoNames by Griblet.
Link: World Port Index

GeoNames

GeoNames (geonames.org)

Coastal towns and their spellings in place search (cities15000 and country info).

Licence: CC BY 4.0
Credit: Places: GeoNames, geonames.org, CC BY 4.0.
Changes: Filtered to towns near the sea and merged with the World Port Index by Griblet.
Link: GeoNames

Natural Earth

Natural Earth (naturalearthdata.com)

Capes, islands, straits, bays and seas in place search (1:10m), the land check on routes (1:50m) and logbook thumbnails (1:110m).

Licence: Public domain
Credit: Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com.
Changes: Simplified by Griblet.
Link: Natural Earth

The chart

NASA GIBS: Blue Marble relief and bathymetry, land mask

NASA Earth Science Data and Information System (ESDIS)

The night chart and satellite basemaps, and the land and coastline drawn over the forecast.

Licence: NASA open data, no restrictions
Credit: We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).
The land mask is made from OpenStreetMap land polygons: © OpenStreetMap contributors, ODbL.
Link: NASA GIBS

OpenStreetMap

OpenStreetMap contributors, tiles served by the OpenStreetMap Foundation

The day chart, and harbour-scale detail on the night chart.

Licence: Open Database License (ODbL)
Credit: © OpenStreetMap contributors. Data available under the Open Database License.
Note: Tiles come from the OSMF tile servers under their tile usage policy: Griblet keeps only tiles you have looked at and never downloads them ahead.
Links: OpenStreetMap
Tile usage policy

OpenSeaMap seamarks

OpenSeaMap contributors

Buoys, lights and other seamarks over the chart, close in.

Licence: CC BY-SA 2.0
Credit: Seamarks © OpenSeaMap contributors, CC BY-SA 2.0. Base data © OpenStreetMap contributors.
Links: OpenSeaMap
Licence

Type

Young Serif

The Young Serif Project Authors

Headings.

Licence: SIL Open Font License 1.1
Notice: Copyright 2023 The Young Serif Project Authors (https://github.com/noirblancrouge/YoungSerif).
Link: Young Serif

Atkinson Hyperlegible Next

The Atkinson Hyperlegible Next Project Authors (Braille Institute)

Body text and numbers.

Licence: SIL Open Font License 1.1
Notice: Copyright 2020-2024 The Atkinson Hyperlegible Next Project Authors (https://github.com/googlefonts/atkinson-hyperlegible-next).
Link: Atkinson Hyperlegible Next

Open-source software

The main pieces Griblet is built on, with thanks.

ecCodes

ECMWF

Reading and cropping GRIB files on the server.

Licence: Apache License 2.0
Link: ecCodes

Leaflet

Volodymyr Agafonkin and contributors

The chart.

Licence: BSD 2-Clause
Notice: Copyright (c) 2010-2023, Volodymyr Agafonkin. Copyright (c) 2010-2011, CloudMade.
Link: Leaflet

leaflet-velocity

CSIRO, with code by Cameron Beccario and Stanislav Sumbera

The moving wind particles.

Licence: CSIRO Open Source Software Licence (BSD/MIT variant), with MIT parts
Notice: Copyright (c) 2021, Commonwealth Scientific and Industrial Research Organisation (CSIRO).
Includes code Copyright (c) 2013 Cameron Beccario (MIT) and L.CanvasLayer.js Copyright (c) 2016 Stanislav Sumbera (MIT).
Link: leaflet-velocity

React Leaflet

Paul Le Cam and contributors

Leaflet inside React.

Licence: Hippocratic License 2.1
Link: React Leaflet

React and React Router

Meta Platforms; Remix Software and Shopify

The pages and the server.

Licence: MIT
Notice: React: Copyright (c) Meta Platforms, Inc. and affiliates.
React Router: Copyright (c) React Training LLC 2015-2019, Remix Software Inc. 2020-2021, Shopify Inc. 2022-2023.
Links: React
React Router

Lucide icons

Lucide Contributors, with Feather by Cole Bemis

Most of the small icons.

Licence: ISC (Feather parts MIT)
Notice: Copyright (c) for portions of Lucide are held by Cole Bemis 2013-2026 as part of Feather (MIT). All other copyright (c) for Lucide are held by Lucide Contributors 2026.
Link: Lucide

Tailwind CSS

Tailwind Labs

Styles.

Licence: MIT
Notice: Copyright (c) Tailwind Labs, Inc.
Link: Tailwind CSS

Rights holders

If you own any of this data and want it credited differently or removed, email hello@griblet.app and we'll sort it promptly.

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