v0.1.0

First release.

NOAA CO-OPS tidal-current station data — the extractor, the schema, the validation
method, and a write-up of how the API actually behaves.

currents.json (attached) is the prebuilt US bundle: 856 harmonic + 1,705
subordinate stations, 0 unresolved references. Vendor it, or extract your own subset
with the CLI.

npm install @sailingnaturali/current-stations
npx current-stations extract mine.json --stations PUG1717,PUG1701

What's in here

• Extractor for NOAA's station list, harmonic constituents, and subordinate offsets
• Live predictions client (currents_predictions)
• current-stations check — one request, fails when NOAA's station list drifts from
  the pinned lock (runs weekly here)
• current-stations golden — captures constituents plus NOAA's own predictions into
  one fixture, so a prediction engine can be validated offline
• JSON Schema for the bundle, and TypeScript types

The parts that cost us days

Documented in docs/noaa-api.md:

• harcon.json returns an empty list at any bin except the station's currbin —
  which reads as "NOAA doesn't publish current constituents." It does, for 856 stations.
• Z₀ (majorMeanSpeed) is a DC offset on the velocity curve, and slack is where that
  curve crosses zero. Omitting it measured 15.6 min mean error; including it, 7.4.
• A reference is a (station, bin) pair, not a station — 14 subordinates in US waters
  reduce against a non-primary bin.
• A type: S station is not necessarily offset-reduced; 1 of 1,706 carries its own
  harcon, and predicting it the other way is 89 minutes wrong.

Zero dependencies. Code MIT; NOAA data is public domain. Derived predictions are
unofficial — not for navigation.