A nautical-themed map with depths, seamarks, and hazards for the whole planet, rebuilt weekly from OpenStreetMap seamark data, with global bathymetry from Seascape.
See the Seamap documentation for tile endpoints, MapLibre integration, and attribution.
The chart shows what you'd expect from a paper chart, drawn live from open data: buoys and beacons with IALA colours and topmarks, lights with sector arcs and characteristics (Fl(3)WRG.10s), depth shading, contours and spot soundings, rocks, wrecks and obstructions, traffic separation schemes, anchorages and restricted areas, marinas, slipways and shore facilities.
Warning
Not for navigational use
This is a web map drawn in the style of a nautical chart, which makes it easy to mistake for one. It is not. Seamarks come from crowd-sourced OpenStreetMap data and may be missing, outdated, or wrong, and no hydrographic authority reviews any of it. Depths carry Seascape's caveats: they are not reduced to a chart datum, and do not account for tides or water level. Always consult official nautical charts for navigation.
The tiles, style, and sprites are served from tiles.openwaters.io and free to use with attribution (CC-BY, see License):
- TileJSON:
https://tiles.openwaters.io/seamap/tiles.json— vector tiles, zoom 0–14. - Ready-made style:
https://tiles.openwaters.io/seamap/style.json— the complete chart (base map, bathymetry, symbology) for any MapLibre GL client. - Whole-planet download: each build is a dated, immutable archive at
https://tiles.openwaters.io/seamap/<YYYY-MM-DD>.pmtilesfor offline use.
To compose the chart with your own layers, use the npm package @openwaters/seamap, the style as an MIT-licensed library.
- To improve the chart data (add a missing buoy, fix a mislabeled harbour), see improving chart data.
- To improve how data is displayed on the chart (symbology, rendering, tooling), see CONTRIBUTING.md.
| Source | Used for | License |
|---|---|---|
| OpenStreetMap | seamarks, coastline, waterways | ODbL |
| Seascape | depth shading, contours, soundings | per-source, see project |
| VersaTiles | base map | ODbL data, free tiles |
| Noto | label glyphs | SIL Open Font License |
| quantenschaum/mapping | chart symbol artwork | used with permission |
The generated tiles, styles, and sprites served from tiles.openwaters.io are CC-BY 4.0. Attribute "© Open Waters: Seamap https://openwaters.io/charts/seamap". They derive from OpenStreetMap data, © OpenStreetMap contributors (ODbL). Each source above carries its own license and attribution requirements.
Code is GPL-3.0, except the style/ npm package, which is MIT apart from its sprite sheet and the chart symbol sources it is built from. This project is a fork of prozessor13/seamap, whose profile and style it grew from; the code inherited from it remains MIT. The chart symbols are used with permission.