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 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 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 “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.

Geographic information layer including the Transverse limit of the sea - mainland France, French Guiana, Martinique and Guadeloupe. This layer must be considered as an initial version to be validated locally by the competent services. Shom actively seeks out any information which could complete and improve the precision of this layer. The streams and rivers listed correspond to those mentioned in the applicable regulations and/or by a competent Government service. An inventory of existing legal and geographic information was drawn up prior to production in the form of an enquiry targeting services during the second half of 2014. The source legal text and a summary of digital conversion processes is available for each boundary proposed.Updated july 2018

Wave forecasting models allow the representation of sea states based on a spectral resolution at the global scale or at the scale of ocean basins. This code calculates the evolution of the sea state by decomposing it into a wave spectrum that propagates in different directions and with different periods. During the propagation, the wave energy is increased or decreased by the effects of wind, breaking waves and energy exchanges between the different components. The wave forecasts available on data.shom.fr are calculated with 2 different types of models: MFWAM for the offshore domain (resolution from 0.5° to 0.1°) and Wavewatch III ® (WW3) for the coastal domain (resolution from 2' to 200m). MFWAM is a sea state forecasting model (wind wave and swell) derived from the third generation WAM code (WAMDI Group, 1988). Wavewatch III ® (WW3) is developed in a collaboration between the United States Weather Service (NOAA/NCEP), Shom, the University of Darmstadt in Germany, and other partners. The forecasts published on data.shom.fr are issued from the parameterization carried out and optimized by the Shom and Météo-France within the framework of the Homonim project (national coastal flood/wave/storm 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 coastal topo- bathymetric DEM for the coasts of the Saint-Jean-de-Luz bay with a resolution of 0.0002° (~ 20 m) was prepared as part of the TANDEM project. It covers Saint-Jean-de-Luz bay and the surrounding area. The DEM is designed to be implemented in the hydrodynamic models of the TANDEM project in order to estimate the coastal effects of tsunamis for the Atlantic and English Channel, where French nuclear power plants have been installed for about 30 years. This product is available with the Lowest Astronomic Tide (LAT) or the Mean Sea Level (MSL) as a vertical datum.

"Regulation - Navigation" product contains 18 object classes, the acronyms used are those of IHO standard S-57 - International Hydrographic Organization – (https://iho.int/): - Anchorage area (ACHARE): an area in which vessels anchor or may anchor. - Anchor berth (ACHBRT): a designated area of water where a single vessel, sea plane, etc. may anchor. - Administration Area (Named) (ADMARE) - Cable area (CBLARE) - Coastguard station (CGUSTA) - Cargo transhipment area (CTSARE) - Distance mark (DISMAR): mark indicating the distance on canals or rivers. - Dumping ground (DMPGRD): sea area where dredged material or other potentially more harmful material e.g. explosives, chemical waste, is deliberately deposited. - Fairway (FAIRWY): part of a river, harbour etc. where the main navigable channel for vessels of larger size lies. It is also the usual course followed by vessels entering or leaving harbours and sometimes called "ship channel". - Ice area (over land or water) (ICEARE) - Local magnetic anomaly (LOCMAG): anomaly of the magnetic field of the earth, extending over a relatively small area, due to local magnetic influences. - Marine farm/culture (MARCUL) - Navigation line (NAVLNE): a line generally passing through two clearly defined charted landmarks, and along part of which a vessel can approach safely. - Pipeline area (PIPARE) - Recommended track (RECTRC): track of undefined width, recommended to all or only certain vessels. - Restricted area (RESARE): specified area designated by an appropriate authority within which navigation is restricted in accordance with certain specified conditions. - Sea-plane landing area (SPLARE) Detailed definitions of each of these object classes can be found in the S-57 standard (https://iho.int/en/standards-and-specifications). An online catalog is available at http://www.s-57.com/. Some of the symbols used for display on data.shom.fr portal have been adapted from icons from the OpenSeaMap open library (https://github.com/OpenNauticalChart/). For reasons of readability, not all the characteristics of the objects are systematically displayed. All available information can be consulted by querying this layer.

The georeferenced digital image solution for the nautical chart is a digital conversion of the corresponding printed nautical chart produced by Shom or its legends, with georeferencing indications and including miscellaneous text.