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@openwatersio

Open Waters

Open source marine software and data

Hi!

Open Waters is a community for mariners, developers, and ocean enthusiasts. My hope is that this community can create better tools to understand and navigate the sea through open collaboration.

The ocean is a commons. We all depend on it, and we've all benefited from centuries of mariners, hydrographers, and scientists sharing what they learned. Open source works the same way: freely sharing what we build makes the tools better for everyone. Everything here is open, and contributions are welcome from anyone.

Learn more at openwaters.io, or get in touch. If you'd like to support the work, you can sponsor me on GitHub.

Cheers!
– @bkeepers

🌙 Tides & Currents

  • slackwater-ios — Slackwater, offline tide & current predictions for iPhone, Apple Watch, and widgets
  • slackwater-android — Slackwater for Android
  • slackwater — the tide and current prediction engine behind Slackwater, for TypeScript and Swift
  • slackwater-database — a public database of tide and current stations
  • station-metadata — provider-neutral tide and current station identity, aliases, and corrected positions
  • noaa-current-stations — NOAA CO-OPS tidal-current station data and the API's undocumented behaviour
  • signalk-tides — a SignalK plugin serving tidal predictions for your vessel's position

☀️ Sun & Moon

  • almanac — an offline sun & moon engine: positions, rise/set, twilight, moon phase, eclipses. Twin Swift and TypeScript ports.

📡 AIS

  • Open Waters AIS — live vessel traffic from open government feeds and volunteer receivers: a live map, aisstream.io-compatible streams, a REST API, and an MCP server. Contribute your receiver's data, or build on the aiscast source and SignalK plugin

🗺️ Bathymetry

  • seascape — a map of the seafloor built from global open bathymetry
  • seamap — a nautical-themed map with depths, seamarks, and hazards
  • crowd-depth — collect and share depth soundings from your vessel with crowd-sourced bathymetry programs

🧭 Charts & Navigation

  • OpenWaters — an experiment in modern marine charts (alpha — not for navigation)
  • enc-tiles — tools to produce vector tiles from Electronic Navigational Charts
  • chart-catalog — a catalog of freely redistributable electronic navigational charts, pre-baked as vector tiles
  • tile-fonts — SDF glyph stacks for the Open Waters map styles
  • maritime-zones — offline where-am-I and distance-to-territory lookups over the Marine Regions maritime boundaries, as FlatGeobuf tiles
  • coordinate-format — a TypeScript library to format coordinates as DMS and other formats

🛰️ Services

🤝 Get involved

Whether you're a developer, a mariner with domain knowledge, or someone who just loves the ocean, there's a place for you here. Browse the repos, open an issue, join the Discord, or say hello.

Popular repositories Loading

  1. slackwater slackwater Public

    A tide prediction engine

    TypeScript 36 10

  2. slackwater-database slackwater-database Public

    A public database of tide and current stations

    TypeScript 25 6

  3. seascape seascape Public

    A map of the seafloor built from global open bathymetry.

    Python 14

  4. OpenWaters OpenWaters Public

    An experiment in building modern marine charts. Currently alpha and not to be use for navigation.

    TypeScript 13 1

  5. enc-tiles enc-tiles Public

    Tools to produce vector tiles from Electronic Navigational Charts

    TypeScript 13 6

  6. seamap seamap Public

    A nautical-themed map with depths, seamarks, and hazards

    TypeScript 8

Repositories

Showing 10 of 37 repositories
  • slackwater-ios Public

    offline tide & current predictions for iOS

    openwatersio/slackwater-ios's past year of commit activity
    Swift 2 GPL-3.0 0 29 3 Updated Oct 4, 2026
  • status Public

    Status page and uptime history for Open Waters services

    openwatersio/status's past year of commit activity
    Markdown 0 MIT 0 0 0 Updated Oct 4, 2026
  • slackwater.xyz Public

    Landing page for Slackwater — offline tide and current predictions

    openwatersio/slackwater.xyz's past year of commit activity
    TypeScript 0 0 19 1 Updated Oct 4, 2026
  • aiscast Public

    aiscast, the Open Waters AIS network: aisstream.io-compatible streams from open feeds and volunteer receivers

    openwatersio/aiscast's past year of commit activity
    Go 7 MIT 1 16 7 Updated Oct 4, 2026
  • slackwater Public

    A tide prediction engine

    openwatersio/slackwater's past year of commit activity
    TypeScript 36 MIT 10 9 12 Updated Oct 3, 2026
  • .github Public

    Open Waters org profile & community health files

    openwatersio/.github's past year of commit activity
    0 0 1 0 Updated Oct 3, 2026
  • slackwater-database Public

    A public database of tide and current stations

    openwatersio/slackwater-database's past year of commit activity
    TypeScript 25 6 22 5 Updated Oct 3, 2026
  • openwaters.io Public

    The website

    openwatersio/openwaters.io's past year of commit activity
    Astro 0 0 4 5 Updated Oct 3, 2026
  • maritime-zones Public

    Offline where-am-I and distance-to-territory lookups over the Marine Regions maritime boundaries, as FlatGeobuf tiles

    openwatersio/maritime-zones's past year of commit activity
    TypeScript 0 0 3 0 Updated Oct 3, 2026
  • signalk-tides Public

    A SignalK plugin that provides tidal predictions for the vessel's position from various online sources.

    openwatersio/signalk-tides's past year of commit activity
    TypeScript 5 Apache-2.0 12 5 2 Updated Oct 2, 2026