Language selection


About the Canadian Hydrographic Service

DFO-Science CHS Strategic Directions and Quality Policy 2018/28

Who we are

Who we are

Since 1883, the Canadian Hydrographic Service has studied Canadian waters to ensure their safe, sustainable, and navigable use.

Canada has the longest coastline of any country in the world, with more than a third of our territory under water. Our lakes, rivers, and oceans are used by millions of craft every year for:

  • carriage of passengers and goods by sea;
  • national defense;
  • fishing and industry; and
  • recreation and tourism.

Using technological advancements and more than a century of expertise, the CHS has become a recognized world leader in hydrography.

The CHS is a division of the science branch of Fisheries and Oceans Canada (DFO). With access to Canadian Coast Guard ships, the CHS takes advantage of every opportunity to take hydrographic and oceanographic measurements. We conduct regular field surveys, especially for higher risk, higher priority areas.

The 4 areas of our business

The CHS is involved in a wide range of activities that continue to deepen our knowledge of Canadian waters. These activities include:

  • determining Canada's maritime zones and boundaries in support of Canada’s sovereignty;
  • monitoring tides, currents, water levels, and essential information for detecting and predicting climate change and climate variability, as well as natural hazards;
  • producing navigational charts and nautical publications to ensure the safe navigation of Canada's waterways; and
  • collecting high-resolution data on the depth, shape and structure of Canada's oceans, lakes and rivers.
What we do

What we do

We are a world leader in hydrography. This is the science of measuring and describing water features and depths for the primary purpose of navigation.

Hydrographers take surveys and produce essential charts and related publications.

Hydrographic surveys

Surveying is collecting and combining soundings (water depth measurements) and other key data.

Canada is a large country, has the longest coastline in the world and many navigable waters within its boundaries. We do not have the resources to survey and chart all waters, and by law, we have no obligation to chart them all. We make decisions on which waters to survey and chart in priority, depending on relevant considerations, such as:

  • safety of navigation
  • efficiency and density of maritime traffic
  • natural features of the area (tides, currents, winds, geography, and hazards)
  • access to ports and waters for ocean-going vessels

CHS hydrographers survey the waters of the Great Lakes, the Atlantic, Pacific, and Arctic Ocean coasts.

We follow rigorous, internationally recognized standards and guidelines when we conduct hydrographic surveys. Our surveys capture:

  • water depths
  • hazards to navigation
  • geographical features
  • sea bottom characteristics
  • tides
  • currents
  • water levels

Hydrographers use the data collected to produce charts and nautical publications which support a broad range of marine activities.

Nautical chart publication and updates

We publish and maintain thousands of products. The nautical charts that we produce are the most authoritative and complete available in Canada. They are renowned the world over for their quality.

We update charts promptly every time we learn about:

  • a new geographical feature, shoal and/or depth discovery
  • the removal or installation of an aid to navigation (buoys, beacons and lighthouses)
  • a new wharf construction
  • the laying of an undersea cable

We use Printing On Demand (POD) technology to add changes via computer. This generates fresh copies with all the latest updates included.

Chart publication and distribution

We distribute a total of nearly 300,000 nautical charts, tide tables and other nautical publications every year, including:

In 2007, we began distributing Electronic Navigational Charts (ENC) in S-57 format as well as Raster Navigational Charts (RNC) in BSB format as Canadian Hydrographic Service digital charts.

We have also switched to a print-on-demand technology for our paper charts. We no longer print in bulk and store charts in warehouses. Mariners now receive the latest chart with the most recent updates, with no more hand-drawn corrections or glued-on patches. This allows us to get charts out 6 to 8 weeks faster.

We license our intellectual property to more than 1,000 private and public sector clients. We're a partner in the development of ocean technology and applications. Our intellectual property includes a host of information on waterways and their surrounding areas.

Mariners are required to carry and use charts and other nautical publications issued by or on the authority of CHS, in accordance with the Canada Shipping Act (Navigation Safety Regulations, 2020) and the Arctic Waters Pollution Prevention Act.

Water column data

The water column is all of the water between the surface and the floor.

We collect, record and share measurements of temperatures, waves, tides, water levels and contaminants affecting marine life and their habitats.

Argo international project

Canada participates in this international project to measure ocean conditions all over the globe and shares the information in real-time via satellite technology. CHS is involved in managing the data collected by Canada.

Over 20 countries participate in the project. They all cooperate to deploy, monitor and maintain a fleet of about 3,000 sophisticated profiling floats. The floats drift, sink to pre-programmed depths for specific lengths of time and rise to the surface, taking a variety of important measurements as they rise.

Today, Argo data is used for fishery planning, weather forecasting and a whole range of other applications.

For further information on Argo, visit:

How We Work

How We Work

The Canadian Hydrographic Service (CHS) has channeled its in-depth knowledge and extensive expertise into the development of new technologies and scientific procedures. Today we offer everything from 3D views of Canada's seabed to real-time updates on water levels in the St. Lawrence River.

How we develop our nautical charts

Hydrographers use echo-sounders to calculate the distance to the sea floor. These tools measure depths by bouncing sound waves off the seabed and measuring the length of time that it takes for the echo to return.

Surveys done this way follow pre-planned lines along which the surveying vessel steers. How closely the lines are spaced depends on the complexity of the seabed. In hazardous waters, complete coverage of the bottom is required.

Hydrographers must know exactly where the vessel is when each sounding is made in order to indicate depths at the correct locations on charts. To do this, they use tools such as satellites, electronic charts, and multibeam acoustics.

A significant advance in determining a ship's position is the Global Positioning System (GPS). This allows us to achieve an accuracy of plus or minus 20 metres 95% of the time. The differential GPS (DPS) has since allowed us to achieve an even greater accuracy of plus or minus 3 metres.

Along with water depths, our hydrographers also measure tides and other changes in water levels. The CHS has installed permanent water level gauges along Canada's coasts and larger inland waterways to monitor tidal- and water level data. The CHS has 2 gauges on the West Coast that are part of an international warning system for tsunamis.

CHS hydrographers also obtain the positions and map all aids to navigation such as buoys, lighthouses, beacons, and natural or man-made landmarks used by mariners as reference points.

After the survey work is completed, our multidisciplinary hydrographers (MDH) combine the collected measurements with shoreline and other topographical data, and then convert the data to the required scale for a navigational chart. The information most critical to safe navigation is selected from all of the data gathered. CHS charts are created in both digital and paper formats.

Navigation in the digital era

With the addition of Electronic Navigational Charts (ENCs) and Raster Navigational Charts (RNCs) to its library, the CHS has tripled the size of their traditional product line. Digital charts run on onboard computers and allow for onscreen navigation. Canada is a pioneer in this area and has one of the largest ENC portfolios in the world.

ENCs are "smart charts", which means the user can click on different features, such as a light or buoy, to retrieve additional information not available in paper or raster charts. For example, a wharf appears only as an image on an RNC, but an ENC can identify it as a wharf and attach attributes to it such as height, length, age, ownership, number of berths, etc. This additional data, which is contained directly within the ENC, might otherwise only be available by consulting the relevant Sailing Directions publication. Click here to learn more.

The magnitude and demands of today's maritime navigation have made accurate and timely hydrographic information more vital than ever. The ENC is part of a powerful system that allows mariners to achieve their goals safely.

Multibeam systems used to see into the oceans

Canada is a world-renowned leader in multibeam modelling technologies. Ocean modelling and remote sensing provide multi-dimensional and real-time information about the sea floor and waterways, as well as their coastal and bank conditions. Multibeam systems can produce an aerial photograph-like image of the seabed. This has led to a demand for multibeam mapping to support other uses such as mapping fishing grounds, pipeline and cable routes, and marine protected areas (MPA). For example, scallop fishers can reduce the area of seabed that they disturb with their rakes since they know which areas are most likely to contain scallops.

Active around the world

Since 1951, Canada has been an active member of the International Hydrographic Organization (IHO). The CHS represents Canada at the IHO and works with the Hydrographic Offices of several foreign States to promote safety and efficiency of navigation through the development of international standards and new technologies for surveying, navigational charting, and mapping of the sea floor.

Marine transportation is a global activity and consistency among products and services is essential. Uniform standards allow for integration of hydrographic information across scientific and international boundaries. This contributes to better overall understanding of the coastal and offshore environment.

The CHS participates in several working groups of the IHO, allowing Canada to contribute to the development of standards.

The CHS ensures that Canadian navigational products, data, and hydrographic services meet the international standards.

Why hydrography matters

Why hydrography matters

The motto of CHS sums up why hydrography matters: 'Nautical charts protect lives, property and the marine environment.'

Our charts are the roadmaps used by mariners to navigate their vessels safely from port to port. They provide a wealth of detail, such as the depiction of the shoreline, depths, hazards to navigation such as shoals, and aids to navigation such as buoys, lights, and lighthouses.

Keeping up with changing waterscapes

An important challenge for CHS is keeping up with changes to Canada's waterscape. High priorities for resurveying include high-traffic areas, such as the Great Lakes shipping lanes and popular recreational areas, like the Trent-Severn Waterway.

Also on the priority list are artificial islands located in the western Arctic that are no longer used for oil and gas development. These islands change shape due to ice scouring and currents, and present navigational hazards.

People sometimes assume we know all there is to know about our waterways. I like to remind them that we have more accurate maps of the moon than we do of our own ocean floors.

But that's changing. And that's what makes this work so exciting. You can spend 28 days on a ship with your eyes on a computer monitor and one day: there it is, something new. A good example is when we discover uncharted ship wrecks or find new areas of glass sponge reef off the BC coast.

It's amazing what today's technology enables. An electronic navigational chart on a ship's bridge, for instance, can be integrated with other systems and indicate approaching dangers and hazards to the vessel. All of a sudden, we have so much knowledge at our disposal, and all of it can help improve navigational safety.

Brian Port

Multidisciplinary Hydrographer

Fisheries and Oceans Canada

Who we serve

Who we serve

Canadian vessels anywhere, and foreign vessels in Canadian waters, have an obligation by law to carry CHS charts and nautical publications. For the details of the requirements and application, see Division 6 of the Navigation Safety Regulations, 2020, made under the authority of the Canada Shipping Act, 2001.

The CHS ensures that the required charts and nautical publications are available, accurate, and authoritative.

Commercial shippers

Thousands of commercial vessels navigate Canadian waters every year. Commercial shippers rely on CHS charts and publications to ensure the safe and efficient navigation of their vessels.

Recreational boaters

Recreational boaters rely on our charts to navigate safely and avoid injuring themselves or their guests, or grounding and damaging their vessels.


Fishers rely on our charts and publications not only for safe navigation, but also as tools to help locate fish. Classification of the sea floor and contours can help locate fish populations and track migrations. Special nautical charts have also been developed exclusively for recreational fishers and boaters.

Canada's defence

Through various agreements, CHS provides hydrographic services and special surveys and charts to the Department of National Defence (DND) and to North Atlantic Treaty Organization (NATO) member-States.

Maritime Search and Rescue (SAR)

Nautical charts, detailed information on tides, currents, and other features are crucial to SAR operations at sea. The Canadian Coast Guard (CCG) and other organizations involved in SAR operations rely on CHS's products.

Oil, gas and mineral exploration

The CHS provides information that is important to the exploration for oil, gas, and minerals. These activities require precise measurements and accurate forecasts of tides, currents, water levels, bottom types, and contours.

Climate change

Information collected by the Permanent Water Level Gauging network of the CHS is essential in measuring sea level rise, an important aspect of climate change.

Protection of the marine environment

The CHS provides crucial and detailed information to departments, agencies, organizations, and groups impacted by or taking measures in response to marine pollution. The CHS's role in safety of navigation also provides further protection to our marine beds and sea life, by reducing the risks of accidents that could be the cause of a pollutant spill.

Our history

Our history

The process that led to the creation of the CHS was set in motion after a tragedy in 1883. The steamship Asia went down in Georgian Bay in Ontario, and 150 people lost their lives. Almost immediately afterwards, calls went out for a hydrographic survey of the Great Lakes to make navigation safer.

The Georgian Bay Survey

On August 13, 1883, the Georgian Bay Survey was established, 6 years after the Georgian Bay steamship tragedy.

Their primary focus in 1883 was to survey and chart the navigable waters of Georgian Bay and Lake Huron. This was eventually extended to include all of Canada's inland waterways and coastal regions.

Hydrographic charting was extended to the Pacific Coast as early as 1891 and in the waters of the St. Lawrence River below Quebec by 1905.

The tidal and current metering program began in 1893 and the precise water level gauging of the Great Lakes in 1912.

Name change and expansion

In 1904, the Georgian Bay Survey became the Hydrographic Survey of Canada. Soon after it was unofficially called the Canadian Hydrographic Service, but this name was not officially adopted until 1928.

When Newfoundland and Labrador joined the Confederation in 1949, CHS took on the responsibility of charting their coastlines.

When the distant early warning (DEW line) system was built across Canada, many stations were in the Canadian Arctic. This led to a demand for Arctic surveys, which reached a peak in 1954 to 1957.

Modernizing techniques and technologies

In the past, the main tool for determining a vessel's position was a hand-held instrument called a sextant which was used to measure angles. Early hydrographers positioned their survey vessels by shore markings while close to the land and by quadrant or sextant when surveying offshore.

Traditional approaches to hydrography included:

  • lead lines, which:
    • were a long and laborious process
    • used weighted lines lowered into the water to measure depth
  • triangulation, which uses mathematics based on the points of a triangle to establish coordinates and the distances between points

Today's hydrographer uses:

  • multibeam echo sounders, which:
    • survey the entire sea floor
    • uses highly advanced SONAR technology to provide high-resolution digital views of the ocean environment
  • a precise differential Global Positioning System (DGPS) to position the survey vessel

While paper charts are still in use, the increasing trend for modern shipping is moving away from them. Most now use Electronic Navigational Charts (ENCs) that form part of Electronic Chart Display and Information Systems (ECDIS).

Date modified: