The coastal topo- bathymetric DEM for the coasts of Boulogne-Sur-Mer with a resolution of 0.0001° (~ 10 m) was prepared as part of the TANDEM project (Programme Investissements d'Avenir, ANR-11-RSNR-00023-01). The DEM covers the entire Boulogne-sur-Mer port, from north of Wimereux to south of the Boulogne-sur-Mer urban sprawl. 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.

Lidar marine part is a unique and continuous land-sea database which can provide 3D models of the shape and location of French coastal terrain. A line separates sea and land data acquisition zones, and the associated survey readings obtained using bathymetric lidar technologies or multibeam echosounders for sea readings and airborne lidar topographical surveys for land readings, with 300 m overlap. Litto3D digital models are available in two formats: a set of 3D points and a qualified terrain mesh. The product Tahiti 2015 V. 20160630 corresponds to the zone: North West of Tahiti.

The bathymetric DEM for the coasts of Guadeloupe and Martinique with a resolution of 0.001° (~ 100 m) was prepared as part of the HOMONIM project. The DEM covers some of the Lesser Antilles islands, from Montserrat in the north to Sainte-Lucie in the south. The model ranges off-shore to a depth of 5800 m. 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.

The Histolitt® coastline corresponds to the high tide line with an astronomic tidal coefficient of 120 and in normal weather conditions (no sea breeze and no low pressure systems likely to raise sea level). The Histolitt® coastline models this theoretical input as a series of 2D polylines. In mainland France, it is recommended to use the land-sea limit product which replaces this Histolitt® coastline. There is no land-sea limit in the French overseas areas for the moment.

The coastal topo- bathymetric DEM for the coasts of the straight of Pas-de-Calais with a resolution of 0.0002° (~ 20 m) was prepared as part of the TANDEM project. The DEM covers the eastern Channel and southern North Sea, including the French coast of the Nord - Pas-de-Calais administrative department and part of the British coast, in the county of Kent, and the south part of the Thames estuary up to Rye. 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.

The update of the coastal topo-bathymetric DEM of the Pertuis charentais at a resolution of 0.0002° (~ 20 m) was carried out in the third phase of the HOMONIM project. The DEM extends from the terrestrial domain to about 60 meters depth over all the pertuis (pertuis Breton, pertuis d’Antioche and pertuis of Maumusson). The DEM is intended to be implemented in hydrodynamic models in order to produce forecasts as accurate as possible of water heights and sea states at the coast to improve the relevance of the Wave-Submergence Vigilance. The vertical reference for this product is the Lowest Astronomical Tide (LAT).

Bathymetric datasets, collected after 2005, are controlled and qualified. They are mainly acquired with multi-beam echosounders.

The bathymetric DEM for the coasts of New-Caledonia with a resolution of 0.001° (~ 100 m) was prepared in the framework of a Shom-IRD partnership as part of the TSUCAL project. The DEM covers the basin from New Caledonia in the west to the Vanuatu archipelago in the east. The DEM is designed to be used in hydrodynamic models in order to improve the pertinence of the Waves-Submersion monitoring programme.

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 Sèvre Niortaise to the Spanish border.

Bathymetric datasets are an extraction of surveys belonging to the Shom public database. For depth up to 50m, the vertical precision of soundings varies from 30cm to 1m and the horizontal precision varies from 1 to 20m. In deep ocean, the vertical precision is mainly around 1 or 2% of the bottom depth. It is sometimes more, it depends on the technology used. The data are referenced to ZH which is assimilated to LAT. Data are corrected for sound velocity variations.