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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

Tide and current predictions, offline, on every platform, powered by the open Slackwater prediction engine and station database.

  • iOS — iPhone, iPad & Apple Watch
  • Android — the Android app
  • Libraries — the prediction engine for TypeScript and Swift
  • API — hosted HTTP API for tides and currents
  • Database — a public database of tide and current stations
  • Signal K Plugin — tide and current 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

    Tide and current prediction engine for TypeScript and Swift

    TypeScript 36 10

  2. slackwater-database slackwater-database Public

    Station database for tide and current predictions

    TypeScript 25 7

  3. seascape seascape Public

    A map of the seafloor built from global open bathymetry.

    Python 20

  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 11

Repositories

Showing 10 of 37 repositories
  • crowd-depth Public

    Collect and share depth data from your marine vessel with crowd-sourced bathymetry programs.

    openwatersio/crowd-depth's past year of commit activity
    TypeScript 8 MIT 1 6 4 Updated Oct 11, 2026
  • slackwater-ios Public

    Slackwater for iPhone: offline tide and current predictions

    openwatersio/slackwater-ios's past year of commit activity
    Swift 3 GPL-3.0 0 44 3 Updated Oct 11, 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 11, 2026
  • almanac Public

    Offline sun & moon engine — positions, rise/set, moon phase, eclipses. Twin Swift + TypeScript ports, one fixture corpus.

    openwatersio/almanac's past year of commit activity
    HTML 3 MIT 0 3 0 Updated Oct 11, 2026
  • openwaters.io Public

    The website

    openwatersio/openwaters.io's past year of commit activity
    Astro 0 0 10 8 Updated Oct 11, 2026
  • OpenWaters Public

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

    openwatersio/OpenWaters's past year of commit activity
    TypeScript 13 GPL-3.0 1 37 4 Updated Oct 11, 2026
  • seascape Public

    A map of the seafloor built from global open bathymetry.

    openwatersio/seascape's past year of commit activity
    Python 20 0 53 15 Updated Oct 11, 2026
  • seamap Public

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

    openwatersio/seamap's past year of commit activity
    TypeScript 11 GPL-3.0 0 18 11 Updated Oct 11, 2026
  • slackwater Public

    Tide and current prediction engine for TypeScript and Swift

    openwatersio/slackwater's past year of commit activity
    TypeScript 36 MIT 10 14 13 Updated Oct 11, 2026
  • signalk-tides Public

    SignalK plugin for offline tide predictions at the vessel's position, powered by Slackwater

    openwatersio/signalk-tides's past year of commit activity
    TypeScript 5 Apache-2.0 12 5 1 Updated Oct 11, 2026