The DTM is a compilation of multibeam echosounder surveys acquired in 2013. The resolution is 1/64 arc-minutes (~30m). Surveys are located on the Capbreton Submarine Canyon (France) with depths from -4.7m to -344.9m. Depths are referenced to the Lowest Astronomical Tide and the coordinates are expressed into the WGS84 reference frame. The surveys which compose the DTM are S201306500-09 and S201306500-11. Data and metadata associated to these surveys are available on the website http://diffusion.shom.fr/pro/lots-bathy.html. The DTM is not to be used for navigation.

The regional bathymetric Atlantic – Channel – North-Sea DTM has a resolution of 0.001° (~111m). Its geographic coverage includes the Bay of Biscay, the English Channel and a part of the North Sea. The DTM extends from the coast to the continental slope (about of 4800m deep). This DTM is produced in the framework of the HOMONIM project which aims at improving operational forecast capabilities for the national coastal flood warning system. This DTM is offered openly on the Shom diffusion website (http://diffusion.shom.fr/produits/bathymetrie/mnt-facade-atl-homonim.html). http://dx.doi.org/10.17183/MNT_ATL100m_HOMONIM_WGS84

The “World Seabed Sediment Map” product contains geo-referenced digital data, describing the nature of the sediment encountered in different seas and oceans of the world. The objects are all surface areas and the description of an object includes in particular the nature of the sediment including rock-type bottoms.

The Shom uses a 2D barotropic version of the HYCOM code (https://hycom.org/) to compute water level /surge forecasts (astronomical tides and meteorological surges) for the Atlantic, Mediterranean, Antilles-Guyane and Indian Ocean domains. The configurations use curvilinear grid with resolutions of several km offshore and ranging from 1.5km to around 500m on the french mainland coasts and the Antilles-Guyana coast. A downscaling by nesting allows a resolution of 800m to 200m over the Indian domain. These models have been adapted by the Shom to be operable in coastal areas by taking into account, in particular, the tide and high resolution bathymetry in these areas (from 100m for DTMs of facade to 20m for coastal DTMs) using Litto3D surveys by airborne LIDAR. The models are operated by Météo-France and the Shom in the framework of the HOMONIM project for the coastal flood/wave warning system.

The bathymetric DEM of the atlantic facade with a resolution of 0.001° (~ 100 m) was prepared as part of the HOMONIM project. It encompasses part of the North Sea, the Channel and the Bay of Biscay. Offshore, this DTM extends beyond the slope to approximately 4800 m depth. The DEM is designed to be used in hydrodynamic models in order to produce high-precision forecasts for coastal water levels and sea conditions and therefore improve the pertinence of the Waves-Submersion monitoring programme. This product is available with the Lowest Astronomic Tide (LAT) or the Mean Sea Level (MSL) as a vertical datum.

The product "BathyElli surfaces v2.1" contains the surface realisation of the ellipsoidal height at the reference date of 1 January 2000 of the characteristic tidal levels corresponding to : - Highest Astronomical Tide (HAT): "BathyElli v2.1 HAT / ell" ; - Mean Sea Levels (MSL): "BathyElli v2.1 MSL / ell"; - Lowest Astronomical Tide (LAT): "BathyElli v2.1 LAT / ell"; - Chart Datum (CD) vertical sea level reference for each tidal zone: "BathyElli v2.1 HZ / ell".

Information layer containing the SAR Zones (Search and Rescue). This layer contains a description of the French search and rescue (SAR) areas and the location of the associated Maritime Rescue Coordination Center (MRCC). it covers the areas of responsibility of France. The layer was produced by the Shom pursuant to the Circular Circular of the International Maritime Organization (IMO No. SAR.8 / Circ.4 of 1 December 2012).

The product contains a description of submarine cables and pipelines brought to the attention of Shom on French areas of responsibility. These are 2D linear objects of the seabed that divide into two categories: • The submarine cables: these are cables placed on the seabed where electricity or information (telecommunication) flows. They represent the vast majority of objects (more than 90%); • Emissaries and submarine pipes: these are pipes that allow the discharge, sampling or circulation of fluids.

The product “Maritime limits and boundaries” (French: “Délimitations maritimes”) gathers all the elements used for the definition of the maritime spaces under the French sovereignty or jurisdiction through the world. Those spaces are defined by the Ordonnance n° 2016-1687 of 8 December 2016 relating to maritime spaces under sovereignty or jurisdiction of the French Republic. This ordonnance is the transcription in the French legislation of the United Nations Convention on the Law of the Sea (UNCLOS) which was signed in Montego Bay (Jamaica) on 10 December 1982 end ratified by France on 11 April 1996. These elements of maritime limits and boundaries come from the limits computed by Shom on the basis of International Law, from the international agreements relating to maritime boundary and the technical conventions ratified between France and other States, from the decisions of international juridical bodies, from the recommendations of the Commission of the Limits of the Continental Shelf (UNO) or from unilateral claims from France in the absence of agreement. The elements are divided into seven themes: 1- Straight baselines 2- Outer limits of the territorial sea (12 nautical miles) 3- Outer limits of the contiguous zone (24 nautical miles) 4- Outer limits of the exclusive economic zone (200 nautical miles) 5- Maritime boundaries established by a bilateral agreement or decided by an international juridical body 6- Maritime boundaries unilaterally claimed by France in the absence of agreement 7- Outer limit of the continental shelf beyond 200 nautical miles December 2022 version

Litto3D provides 3D, continuous sea-land description of French coastal areas. Data is acquired by airborne topo-bathymetric LiDARs. Litto3D products come in 3D point clouds and digital terrain models formats. The product "Litto3D - Nouvelle-Aquitaine 2020-2022" covers the geographical area from the Charente-Maritime to the Spanish border. For the maritime part, the data produced by Shom extend offshore down to signal extinction, approximatively 20 depth when environmental conditions are optimal. On land, the data are truncated at a limit that ensures the product retain its coastal character.