The Mapping and Charting Establishment (MCE), of the Department of National Defence (DND), is responsible for the production, validation, and maintenance of Digital Nautical Charts (DNC) as part of a bi-lateral co-production agreement with the U.S. National Geospatial-Intelligence Agency (NGA). Canada, as a member nation of the North Atlantic Treaty Organization (NATO), is responsible for the production and maintenance of Additional Military Layers (AMLs) as part of NATO agreements. MCE is also responsible for Canadian waters and approaches to Canadian waters for both DNC and AML production. MCE makes extensive use of Canadian Hydrographic Services (CHS) Electronic Navigation Charts (ENC) to support these production activities. DNCs are digital vector-based nautical charts intended primarily to support marine navigation using the Electronic Chart Display and Information Systems (ECDIS). A DNC is made up of libraries (e.g. General, Coastal, Approach, and Harbour). These libraries are generally based on the scale of existing nautical charts. DNCs are produced in Vector Product Format (VPF), which is commonly used in other mapping, charting, and Geospatial Information Systems (GIS). AMLs are a range of maritime digital products for the defence user. AMLs were originally specified to the S-57 standard but DIGEST specifications are presently being developed to ensure complete compatibility among NATO nations.
S-57 is the electronic data transfer standard prepared by the International Hydrographic Organization (IHO) committee. The geo-database model allows the user to import ENC files, which in turn provides the user with a highly accurate vector data set that is ideal as foundation data. DIGEST is a comprehensive "family of standards" capable of supporting the exchange of raster, matrix, and vector data (and associated text) among producers and users. DIGEST can support the entire range of levels of topological structures. These exchange standards are used by NATO countries to augment the S-57 standards and ensure interoperability.
