About the Canadian Hydrographic Service (CHS)

Since 1883, the Canadian Hydrographic Service (CHS) has studied Canada's oceans, lakes and rivers to ensure their safe, sustainable and navigable use. Find out why CHS is a recognized world leader in hydrography.

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

Who We Are

Who We Are

Taking the Measurements of Canada's Waterways

Canada has the longest coastline of any country in the world. More than a third of its territory is under water. Its lakes, rivers and ocean waters are used by millions of craft every year for recreation and tourism, fishing and industry, international shipping and national defence.

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

Today CHS is a division of the Science Branch of the Department of Fisheries and Oceans Canada. With 300 dedicated employees distributed across Canada, CHS publishes and maintains nearly a thousand nautical charts as well as hundreds of publications. These products are renowned the world over for their quality.

With access to Canadian Coast Guard ships, CHS takes advantage of every opportunity to take hydrographic and oceanographic measurements. We conduct regular field surveys – especially for higher-risk, higher-priority areas – with both shore parties and marine vessels including specialized hydrographic craft.

The four pillars of our business

CHS is involved in a range of activities that continue to deepen our knowledge of Canadian waters.

Maritime Transportation

CHS’s exceptional nautical charts and navigational products help ensure the safe navigation of Canada’s waterways.

Ocean and Freshwater Mapping

CHS uses the latest technology to collect high-resolution data on the depth, shape and structure of Canada’s oceans, lakes and rivers.

Coastal Natural Hazards

CHS monitors tides and water levels – essential information for detecting and predicting climate change and variability, and natural hazards.


CHS plays a vital role in determining Canada’s maritime boundaries and sovereignty.

Today, taking advantage of technological advancements and more than a century of expertise, CHS is a recognized world leader in hydrography.

What We Do

What We Do

What is hydrography?

Hydrography is the science of measuring and describing the features and depths of seas and coastal areas for the primary purpose of navigation. Hydrographers take surveys and produce essential charts and related publications.

We take surveys…of the hydrographic sort

Surveying is the age-old art of collecting and collating soundings (measuring water depths) and other key data to make charts and navigational publications.

CHS hydrographers are actively engaged in surveying and measuring Canada’s inland navigable waterways to the edge of the continental shelf and beyond, the Great Lakes, and the Atlantic, Pacific and Arctic Ocean coasts.

Hydrographic surveys capture water depths, geographical features, hazards to navigation, man-made and natural features that aid navigation, tides, currents and water levels, and sea bottom characteristics. We follow rigorous, internationally-recognized standards and guidelines when we conduct hydrographic surveys.

The data collected by hydrographers is used to produce authoritative nautical charts and publications which support a broad range of marine activities.

942 charts and counting

CHS publishes and maintains nearly a thousand nautical charts. These charts are the most authoritative and complete available – renowned the world over for their quality. Every time we notice that a buoy has moved, a wharf has been built or an undersea cable laid, we update our charts promptly.

These corrections were once made exclusively by hand, but with the help of on-demand printing technology, we’re able to add changes via computer and generate fresh copies with all the latest updates included. In 2007 alone, CHS received more than 55,000 print-on-demand orders.

Quick facts:

  • In 2007-2008, CHS distributed more than 124,000 charts and 73,000 publications via some 800 authorized dealers around the world.
  • In 2007, CHS began distributing electronic navigational charts (ENC) in the S-57 format as well as raster navigational charts (RNC) in the BSB format.
  • CHS now licenses access to its intellectual property to more than 1,000 private- and public-sector clients, and is a partner in the development of ocean technology and applications. Our intellectual property includes a host of information on waterways and their environs, and is used to design new marine infrastructures, plot shipping routes and more.

Delivering 300,000 charts and publications every year

CHS receives orders every year from some 800 chart dealers in Canada, the United States and as far away as Japan.

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

Sailing directions
offering detailed descriptions of the best approaches to harbours, harbour facilities, anchorages, local history, regulations and more.
Digital charts on CD
with technical support and easy access to updates.
Paper charts
946 in all, covering all three of the country’s coastlines plus major inland waterways.
Chart catalogues
describing all available CHS charts.
Canadian tide and current tables
providing the predicted tides in Canadian waters for one year.
Tide current atlases
providing the hourly velocity and direction of tidal currents.
Online water level bulletins
for the Great Lakes and Montreal, continually updated at www.waterlevels.gc.ca.

Going even deeper

CHS has expanded the view of Canada’s waterways to include all of what’s known as the ‘water column’ – the entire extent of water between the surface and the floor. A whole range of important factors are measured and tracked – from climate and temperature to plankton densities (which are important both to ocean food chains and also to the seas’ ability to process carbon).

CHS collects, records and shares data from ocean areas adjacent to Canada – on everything from tide and water levels, wave data, to contaminants affecting marine life and their habitats.

Bobbing for data: Argo

CHS is also involved in managing the data collected through Canada’s participation in Argo, an exceptional international project that measures ocean conditions literally all over the globe and shares the information in real-time via satellite technology. Over twenty countries participate in the project – cooperating to deploy, monitor and maintain a ‘fleet’ of some 3,000 sophisticated profiling floats (i.e., buoys). These drift around the world’s oceans, sinking to pre-programmed depths of 2,000 metres for specific lengths of time, then rise to the surface, taking a variety of important measurements as they ascend.

Today, Argo data is used for weather forecasting, fishery planning and a whole range of other applications. Anyone with a computer can acess Canadian Argo information at www.meds-sdmm.dfo-mpo.gc.ca. Argo data from around the globe can be accessed at www.coriolis.eu.org/cdc/.

How We Work

How We Work

CHS has channelled its in-depth knowledge and extensive expertise into the development of new technologies and scientific procedures – today offering everything from three-dimensional views of Canada’s seabeds to real-time updates on water levels in the St. Lawrence River.

How we develop our nautical charts

We’ve come a long way from our hydrographers lowering lead lines – lead weights attached to a line – into the water to measure its depth. This slow method, which could not provide continuous, gap-free coverage of the water bottom, has given way to the echo-sounder which measures depths by bouncing sound waves off the seabed. By measuring the length of time it takes for the echo to return, hydrographers can calculate the distance to the sea bottom.

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. In the past, the main tool for determining the vessel's position was a hand-held instrument called a “sextant” which was used to measure angles. The sextant has largely been replaced with the tools of our modern age - computers, satellites, multibeam acoustics, and electronic charts.

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

Along with water depths, our hydrographers also measure tides and other changes in water level. CHS has installed permanent water-level gauges along Canada's coasts and larger inland waterways to monitor tidal- and water-level data. Two CHS gauges on the West Coast are part of an international warning system for tsunamis – dangerous ocean or tidal waves triggered by earthquakes or seabed eruptions.

CHS hydrographers also obtain the positions of all buoys, lighthouses, and other fixed or floating navigational aids as well as the position of landmarks, natural or man-made, which mariners use as reference points.

When the survey work is completed, our multidisciplinary hydrographers combine the measurements with shoreline and other topographical data, changing them to the required scale for a navigational chart. From this mass of material, the information most critical to safe navigation is selected and enhanced and 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 electronic charts to its library, CHS has tripled the size of its traditional product line. Burned to CD-ROMs, these ENCs run on onboard computers and allow for onscreen navigation. A pioneer in this area, Canada has one of the largest ENC portfolios in the world.

Electronic charts have the potential to provide more information than their paper cousins. For example, they can reveal multi-dimensional views of waterways, showing the shape and the depth of the lake or sea floor and revealing alternative points of view. They can even capture relatively small-scale attributes such as the height, length, age and ownership of a specific wharf – at the click of a computer mouse.

When combined with GPS, radar, ship course, speed and draft in an Electronic Chart Display and Information System (ECDIS), the Electronic Navigational Chart (ENC) becomes part of a powerful system that allows mariners to know their ship’s position instantly and accurately and to be warned of dangerous situations. The magnitude and demands of today's ships have made accurate and timely hydrographic information more vital than ever.

'Seeing' into the oceans (multibeam systems)

Canada is a world-renowned leader in multibeam systems modeling technologies. Oceans modeling and remote sensing provide multidimensional, real-time information about water, sea floor, coastal and bank conditions in waterways such as the St. Lawrence River.

Multibeam imagery allows fishers to view the seabed and target specific species. This is important for environmental reasons – for example, scallop fishers can reduce the area of seabed they disturb with their rakes since they know which seabeds are most likely to contain scallops.

The ability of multibeam systems to produce an aerial photograph-like image of the seabed has led to a demand for multibeam mapping to support other applications such as mapping pipeline and cable routes, proposed marine protected areas, and fishing grounds.

Why It Matters

Why It Matters

The critical importance of hydrography is summed up in the motto of CHS: “Nautical charts protect lives, property and the marine environment.”

As Canada’s hydrographic authority, CHS surveys the country’s navigable inland and marine waters – to the edge of the continental shelf and beyond. Our charts are the ‘road maps’ that guide mariners safely from port to port. They provide an incredible wealth of detail: depths, buoys, lighthouses, hazards and more.

Keeping pace with change

A further challenge for CHS is to keep up with changes to Canada’s waterscape. High-traffic areas such as the Great Lakes shipping lanes and popular recreational areas like Trent-Severn Waterway are high priorities for resurveying.

In the western Arctic, artificial islands no longer used for oil and gas development are changing shape due to ice scouring and currents – presenting a navigational hazard and earning a place on the priority list as well.

CHS continues to use the latest technologies such as multibeam sounders and the satellite-based Global Positioning Systems (GPS) to make the work done today more comprehensive and accurate than ever before.

CHS now offers Electronic Navigational Charts (ENCs), a remarkable contribution to safer navigation. When combined with GPS, radar, ship course, speed and draft in an Electronic Chart Display and Information System (ECDIS), the Electronic Navigational Chart (ENC) becomes part of a powerful system that allows mariners to know their ship’s position instantly and accurately and to be warned of dangerous situations.

CHS has also switched to a print-on-demand technology for our paper charts. We no longer print in bulk and store charts in warehouses. Instead, mariners now receive the latest chart with the latest updates, with no more hand-drawn corrections or glued-on patches – all six to eight weeks faster.

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

Producing trusted and authoritative information of unparalleled accuracy, CHS answers the needs of individual boaters and international shippers, fishers, industry, government and non-governmental organizations.

Commercial Shippers

Over 22,000 commercial vessels ply Canadian waters. Commercial shippers rely on our charts and publications to ensure the safe and smooth navigation of their goods. In fact, the Canada Shipping Act requires that all vessels carry up-to-date CHS charts and related publications.

Recreational Boaters

There are over two million small boats and personal watercraft registered in Canada. This means that about one in six households owns at least one boat, whether it's a sailing boat, fishing boat, inboard motor, outboard motor, rowboat, or canoe. Recreational boaters rely on our charts to navigate safely and avoid the possibility of grounding or damaging their boats or injuring themselves or their passengers.


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

Canada’s Defence

CHS provides hydrographic services to Canada’s Department of National Defence and to NATO (North Atlantic Treaty Organization) countries through various agreements. In addition to navigational information, CHS provides special surveys and charts for defence purposes, such as mine countermeasure warfare, anti-submarine warfare, and submarine navigation.

Oil, Gas and Mineral Exploration

This type of exploration requires precise measurements and accurate forecasts of sea and lake levels, currents, tides, bottom contours, and bottom types. Precisely the type of information CHS provides.

Climate Change

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

Marine Environmental Protection

Groups responsible for environmental protection in the event of a marine oil spill or similar disaster need a detailed knowledge of the surface water movements in order to respond effectively. CHS provides this expertise. CHS’s promotion of safe navigation also provides further protection for our marine beds and sea life.

Search and Rescue

The Canadian Coast Guard and other organizations involved in search and rescue operations rely on CHS’s updated charts, tide and current tables, sailing directions, and more.

Active Around the World

Since 1951, Canada has been an active member of the International Hydrographic Organization (IHO), working with countries around the world to develop international charting standards as well as new technologies for surveying and mapping 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 which contribute to better overall understanding of the coastal and offshore environment. CHS's close association with IHO ensures that Canadian navigational products and hydrographic data adhere well to international standards.

Our Levels of Service

Our Levels of Service

The Canadian Hydrographic Service has a strong service commitment. We publish and maintain nearly a thousand nautical charts.

We have clearly defined Levels of Service and each year we review how well we are meeting our commitments. Some of these goals are medium to long term. Results given are national annual averages.

We strive to balance providing our clients with up-to-date and accurate navigational information with the resources CHS has to meet these needs. We have classified the areas our charts cover by risk – high, medium and low – with the high-risk areas receiving more of our resources and more frequent updates. Many factors are considered in our risk assessments such as the number of accidents in a given area, tanker routes, traffic, infrastructure, navigational complexity, and more.

Measuring Our Results

Each year we review our work and measure how well we met our Levels of Service. Where we didn't fully meet our commitments, we analysed why and instituted changes to improve our service.

CHS Levels of Service Results 2016-2017

Critical Information 12-13 13-14 14-15 15-16 16-17
Notices to Mariners updates are issued within four months of CHS receiving source information. 1.9 months 3.8 months 3.4 months 3.7 months 3.5 months
Patches are available on the NOTMAR web site within five months once production commences. 4.3 months 7.9 months 11.8 months 6.5 months 8.0 months
8 patches 21 patches 28 patches 38 patches 22 patches
ENC update messages and Notices to Mariners are synchronized within one month. 0.5 months 0.7 months 0.7 months 0.5 months 0.56 months
BSB updates (file replacement) are issued monthly. 92%
11/12 months
2/9 months
5/11 months
9/12 months
12/12 months
Charting 12-13 13-14 14-15 15-16 16-17
Charts (paper, ENC, raster) in the high risk category are reviewed a minimum once every five years and new editions issued when necessary. 63.0%
3rd year
4th year
Suspended pending review
Charts (paper, ENC, raster) in the medium risk category are reviewed a minimum once everyten years and new editions issued when necessary. 64.8%
8th year
9th year
Suspended pending review
Release of New Editions (ENCs and paper charts) is synchronized within three months of each other. 0.8 months 1.0 months 0.9 months 2.9 months 2.2 months
Release of New Editions (raster BSBs and paper charts) is synchronized within one month of each other. 40.0% 52.0% 20.0% 19.2% 33.3%
Charts and Publications are always available. 99%
4 out of stock
4 out of stock
4 out of stock
1 out of stock
1 out of stock
The four Catalogues of Nautical Charts and Publications are updated and published every four years or greater than 5 changes. 50% 100% 100% 50% 50%
Tides & Water Levels 12-13 13-14 14-15 15-16 16-17
Canadian Tides and Currents Tables (paper version) are released on or before November 30. On Time On Time On Time Late 1 day Late 19 days
Requests for general tidal information are addressed within 30 days 95% of the time. 96.9% 96.4% 94.3% 97.9% 97.0%
The National Tides, Currents and Water Levels web site is accessible 95% of the time. 99.7% 99.4% 99.5% 99.1% 99.8%
The phone service for Water Levels (SINECO) Observations for the St. Lawrence and Canadian tidal information is accessible 95% of the time. 96.9% 99.1% 98.1% 97.4% 98.0%
Tele-announcing service for the Great Lakes real-time water level information will be re-instated within 2 business days of reporting a problem 95% of the time. 68%
30 of 44 reinstated within 2 days
98% 99% 99% 99%
Nautical Publications 12-13 13-14 14-15 15-16 16-17
New editions (NE) of Sailing Directions will be issued before number of corrections reach 200 per booklet  (target 100%). 75% 75% 72% 67% 69%
NE of Sailing Directions will be issued before they reach 10 years old (target 100%). 58% 58% 56% 53% 56%
Distribution 12-13 13-14 14-15 15-16 16-17
Orders are shipped to Authorized CHS Chart Dealers within 5 business days of receipt of the order 95% of the time. 98% 100% 100% 99% 100%
Service client requests for technical support resolved within 4 working days, 90% of the time. 97% not available 96% 98% 98%
Our History

Our History

It was a tragedy on Georgian Bay that set in motion the process that led to the creation of the Canadian Hydrographic Service. One hundred and fifty people lost their lives when the steamship Asia went down in those dark Ontario waters in 1883, and calls went out almost immediately for a hydrographic survey of the Great Lakes to make navigation safer.

Six years later, the surveying organization that would eventually become the CHS was born. Its mission soon expanded beyond the Great Lakes to include all Canadian waterways.

Hydrography has changed, of course, over the past 120 years. Traditional leadlines and triangulation methods are used only infrequently, having given way to innovations such as multibeam sounds and the satellite-based Global Positioning System (GPS).

Some important dates in our history

  • The Canadian Hydrographic Service, under the name of the Georgian Bay Survey, was established on August 13, 1883 after the Georgian Bay steamship tragedy.
  • The 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.
  • In 1904 the Georgian Bay Survey became the Hydrographic Survey of Canada (although it soon after was unofficially called the Canadian Hydrographic Service).
  • In 1928 the name Canadian Hydrographic Service was officially adopted.
  • Charting the long rugged coastlines of Newfoundland and Labrador only became the responsibility of CHS following the Second World War when Newfoundland and Labrador joined the Confederation in 1949.
  • The demand for Arctic surveys reached a peak during 1954-57 when the Distant Early Warning (DEW line) system was built across Canada with many stations in the Canadian Arctic.

How Far We've Come

  • Early hydrographers positioned their survey vessels by shore markings while close to the land and by quadrant or sextant when surveying offshore.
  • These hydrographers measured water depths by leadline, a long labourious process.
  • Today's hydrographer employs a precise DGPS (Differential Global Positioning System) to position the survey vessel and multibeam echo sounders to survey the entire sea floor.
  • While paper charts are still in use, the increasing trend for modern shipping is to employ ENCs (Electronic Navigational Charts) that form part of ECDIS (Electronic Chart Display and Information Systems).

Techniques and technologies: from then to now


Traditional approaches to hydrography include:

  • the use of lead lines, which are weighted lines lowered into the water to measure depth; and
  • triangulation, which uses mathematics based on the points of a triangle to establish coordinates and the distances between points.


These have been displaced by:

  • multibeam sounding, which uses highly advanced SONAR technology to provide high-resolution digital views of the ocean environment.

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