Canadian Hydrographic Service (CHS) Tides

This python package provides for accessing official data on navigating modelled surface currents and water levels by the Canadian Hydrographic Service.

Rest-API Documentation

chstides uses the REST-API programming interface for the Integrated Water Level System to access the water level database (observations, forecasts, predictions) for stations across Canada.

The public API documentation is available in English only on the following website: (https://api-iwls.dfo-mpo.gc.ca/swagger-ui.html).

Station Information and Current Tide Conditions

chstides provides station information and current tide conditions. It automatically determines which station to use based on latitude/longitude provided. It is also possible to specify a specific station code of the form 00490 based on those displayed and listed on stations page. For example:

import asyncio

from chstides import TideData

tides_en = TideData(coordinates=(44.67,-63.60))
tides_fr = TideData(station_code='03251', language='french')
tides_ft = TideData(station_code='00490', measurements=ft)

# set must be called before any other function
# only needs to be run once for each station
asyncio.run(tides_en.set())

# station information
print(tide_en.station_data)

# current conditions
asyncio.run(tides_en.update())
print(tides_en.conditions)

Example Station Data

{
    "id": "5cebf1df3d0f4a073c4bbcbb",
    "code": "00490",
    "officialName": "Halifax",
    "latitude": 44.666667,
    "longitude": -63.583333,
    "type": "DISCONTINUED",
    "operating": False,
    "owner": "CHS-SHC",
    "chsRegionCode": "ATL",
    "provinceCode": "NS",
    "classCode": "B",
    "isTidal": True,
    "timeZoneCode": "Canada/Atlantic",
    "isTideTableReferencePort": True,
    "tideTypeCode": "SD",
    "timeSeries": [
        {"code": "wlp", "name": "Water levels"},
        {"code": "wlp-hilo", "name": "Water levels"},
        {"code": "wlo", "name": "Water levels"},
    ],
    "datums": [
        {"code": "CGVD28", "offset": -0.778},
        {"code": "NAD83_CSRS", "offset": -21.664},
    ],
    "heights": [
        {"value": 6.88, "code": "HAT", "name": "Highest Astronomical Tide"},
        {"value": 6.79, "code": "HHWLT", "name": "Higher High Water Large Tide"},
        {"value": 5.77, "code": "HHWMT", "name": "Higher High Water Mean Tide"},
        {"value": 5.57, "code": "HWL", "name": "High Water Level"},
        {"value": 3.39, "code": "MWL", "name": "Mean Water Level"},
        {"value": 1.32, "code": "LWL", "name": "Low Water Level"},
        {"value": 0.98, "code": "LLWMT", "name": "Lower Low Water Mean Tide"},
        {"value": -0.24, "code": "LLWLT", "name": "Lower Low Water Large Tide"},
        {"value": -0.31, "code": "LAT", "name": "Lowest Astronomical Tide"},
    ],
    "measurement": "ft",
    "tideTable": "Atlantic Coast and Bay of Fundy",
}

Example Conditions

{
    "conditions": {
        "value": 5.21,
        "eventDate": "2022-10-10T23:00:00Z",
        "status": "rising",
    },
    "hilo": [
        {"eventDate": "2022-10-10T18:41:00Z", "value": 0.66, "event": "low tide"},
        {"eventDate": "2022-10-11T00:23:00Z", "value": 5.91, "event": "high tide"},
    ],
}

Rest-API Wrapping

All API methods are wrapped and can be called. This can happen after the CHSTides object is created and the station is set. The api call uses the same format and parameters as the REST API. For example:

To get the a specific height type the api call is /api/v1/height-types/{heightTypeId} which requires a parameter called heightTypeId. So to call this in a CHSTide object, you would call it like this:

data = await tides.height_type(heightTypeId="5cec2eba3d0f4a04cc64d5d7")