get_tidal_stream
Read-onlyIdempotent
The tidal stream and the tide at one point, from the tidal atlases alone.
For the questions about a pass or a harbour entrance: when to be at
the Raz de Sein to carry the stream, when the Fromveur turns, how
hard it runs at Port-Navalo tomorrow, when high water is at Chausey.
Costs no weather request: harmonic predictions from the atlases this
server ships (SHOM, MARC and others), the same ones ``plan_passage``
applies leg by leg.
Args:
lat: latitude in degrees, at sea, in the pass itself.
lon: longitude in degrees.
start: ISO-8601 datetime with the user's UTC offset; every time
in the answer comes back in that offset.
end: ISO-8601 datetime, timezone-aware. At most 400 steps.
heading_deg: optional course through the point (true degrees,
the direction you head to). With it, each step gets
``along_kn`` (positive: the stream carries you, negative: it
stems you) and the answer lists the ``favourable`` and
``adverse`` windows.
step_minutes: 5 to 180, default 30.
Returns ``covered``, ``source``, ``confidence``, ``points`` (a table:
``columns`` time, ``speed_kn``, ``direction_to_deg`` it flows to,
``along_kn``, ``height_m`` around mean sea level; one row per step),
``slack`` (the moments the stream nearly
stops), ``high_waters`` / ``low_waters``, ``favourable`` /
``adverse`` when a heading is given, ``tide_coefficient`` (French
national coefficient, Brest, on French atlases), a ``warning`` when
the atlas does not resolve the pass, and ``openwind_url``.
Outside every atlas (most of the Mediterranean, the open sea)
``covered`` is false: say so, and use ``get_marine_forecast``, which
returns the global model's current where it matters.
Astronomical tide only: no surge, no wind-driven current. The windows
are facts about the stream, not a recommendation: weigh them against
the wind (``get_marine_forecast``) and the whole passage
(``plan_passage``). Present the answer yourself, the time to be at the
pass in one sentence and the few times that back it: no widget comes
with this tool.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| end | Yes | ||
| lat | Yes | ||
| lon | Yes | ||
| start | Yes | ||
| heading_deg | No | ||
| step_minutes | No |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||