Canadian Open Data
National Hydro
Network (NHN)
Download National Hydro Network (NHN) open data
The National Hydro Network (NHN) is a seamless geospatial vector data set with attributes that represents Canada’s framework of inland surface waters. It was created from different databases as part of the GeoBase Surface Water Program, to help with flow analysis, watershed management, environmental and hydrographical applications, as well as a multitude of other cartographic applications.
The NHN uses the best base data available from regions all across Canada and essentially provide:
- a linear drainage network composed of linear flow vectors linking in a continuous network of all the hydrographic features present;
- the flow direction onto each segment of the linear network;
- the toponyms associated with features providing additional info to query and analyze
- other water related features such as water falls, rapids, dams, wharves;
- the grouping of data by drainage area rather than by cartographic topographic quadrangles
The National Hydro Network (NHN) includes:
- geospatial data features representing lakes, reservoirs, rivers, streams, canals and islands
- a linear network, showing the directional flow of surface water and structured by watershed
- place names (geographical names) associated with NHN features
The spatial resolution of the data is approximately 1:50 000 (… some of it was created at larger scales such as 1:10,000 and 1:20,000) and should suffice for most projects that requires hydrographic information. If you are creating large scale maps then you may want to check the regional or municipal data portals.
NHN data is separated into units that generally corresponds to sub-drainage areas, and is distributed in a variety of formats including GML (Geography Markup Language), KML (Keyhole Markup Language), SHAPE (ESRI) and GPKG (Geopackage). There are also maps of drainage areas that you download in PDF format
For more details on the data set refer to the Data Product Specifications documents that accompanies the NHN data sets
This data was originally distributed and housed within the GeoBase portal, but is under the responsibility of Natural Resources Canada and can now be found on the Federal Government’s Open data portal => https://open.canada.ca/data/en/dataset/a4b190fe-e090-4e6d-881e-b87956c07977
To find out what drainage units you need to download, you can use one of the index files that will provide you with the NHN unit number http://ftp.maps.canada.ca/pub/nrcan_rncan/vector/geobase_nhn_rhn/index/
There is also an interactive map viewer that you can use to determine what NHN unit number you need http://ftp.geogratis.gc.ca/pub/nrcan_rncan/vector/index/html/geospatial_product_index_en.html#link
Or you can use the Google Earth KMZ index file, that will both help you find the NHN unit number you need and provide the links you to download the data http://ftp.maps.canada.ca/pub/nrcan_rncan/vector/geobase_nrn_rrn/doc/
[Page originally published March 2019]
