Three web services providing access to official water level data

Technical specifications for accessing these services

This document provides the technical specifications for accessing three web-based water level services: predictions, observations and forecasting.

Description

The Canadian Hydrographic Service (CHS) has developed three web-based water level services, and they are available free of charge under licence. Specifically, these three web services provide access to water level predictions, water level observations, and SPINE (Service de Prévision et d’Interpolation des Niveaux d’Eau), a water level forecasting and interpolation system.

  1. The predictions web service gives access to coastal water-level predictions for all of Canada. These predictions are published annually and are similar to what is published in the Canadian Tide and Current Tables.
  2. The observations web service gives access to real-time water level observations made by the network of permanent water level recorders on the St. Lawrence between Montreal and the Magdalen Islands. Other network stations across the country will be added over time. When available, recorded observation data for the past 12 months can be accessed.
  3. The forecasting and interpolation web service (commonly called SPINE) is a system used to forecast water levels at a specific time and position up to 30 days in advance for the St. Lawrence ship channel between the Port of Montreal and Saint-Joseph-de-la-Rive. This system is based, in part, on water level forecasts derived from a hydrodynamic model that takes various weather conditions into account and, in part, on real-time observations made by the network of permanent water level recorders. To increase their accuracy, digital model forecasts are adjusted according to water level observations for the entire area. A precision matrix is also provided for forecast data.

To access these web services, simply follow the steps described in these technical specifications.

Access and restrictions

Please take a moment to read through the licence.

Data

All three web services use SOAP and XML as their communication protocol and the English language for method calling and data exchange. Each service has an XML description readable in WSDL (i.e. https://ws-shc.qc.dfo-mpo.gc.ca/predictions?wsdl). This description is useful for automatically generating code (with tools such as WSDL2Java from Apache Axis) to communicate with the services.