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.
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.

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:
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:
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.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 http://www.meds-sdmm.dfo-mpo.gc.ca. Argo data from around the globe can be accessed at www.coriolis.eu.org/cdc/.