The update of the coastal topo-bathymetric DEM of the Gironde estuary - upstream with a resolution of 0.0002° (~ 20 m) was carried out in the third phase of the HOMONIM project. This DEM covers the upstream part of the Gironde estuary, from Pauillac to Bordeaux on the Garonne and to Libourne on the Dordogne. It is complementary to the DEM covering the downstream estuary (between Pauillac and the mouth of the Gironde). 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 Mean Sea Level (MSL).

The coastal topo-bathymetric DEM of Moorea with a resolution of 0.0002° (~ 20 m) was produced by the Shom for Météo-France (Inter-regional Direction in French Polynesia). This DEM covers the Moorea lagoons down to the 100 m isobath, in order to meet the need for modeling marine submersions in French Polynesia. It complements the bathymetric DEM of Tahiti and Moorea, with a resolution of 0.001° (~ 100 m). The vertical reference for this product is the Lowest Astronomical Tide (LAT).

The update of the coastal topo-bathymetric DEM of the Gironde estuary - upstream with a resolution of 0.0002° (~ 20 m) was carried out in the third phase of the HOMONIM project. This DEM covers the upstream part of the Gironde estuary, from Pauillac to Bordeaux on the Garonne and to Libourne on the Dordogne. It is complementary to the DEM covering the downstream estuary (between Pauillac and the mouth of the Gironde). 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).

The coastal topo-bathymetric DEM of Tahiti with a resolution of 0.0002° (~ 20 m) was produced by the Shom for Météo-France (Inter-regional Direction in French Polynesia). This DEM covers the Tahiti lagoons down to the 100 m isobath, in order to meet the need for modeling marine submersions in French Polynesia. It complements the bathymetric DEM of Tahiti and Moorea, with a resolution of 0.001° (~ 100 m). The vertical reference for this product is the Lowest Astronomical Tide (LAT).

Litto3D Marine Part is an intermediate product of the Litto3D product containing only marine data.Litto3D 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 coastal topo- bathymetric DEM of a part of the Norman-Breton gulf with a resolution of 0.0002° (~ 20 m) was prepared as part of the PAPI Saint-Malo. It covers the Minquiers plateau in the north-west to the bay of Mont-Saint-Michel in the south-east. 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.

Bathymetric datasets, collected between 1970 and 1990, are mainly acquired with single-beam echosounders. Quality controls and qualification, conducted by the Shom, on these datasets are not exhaustive. Datasets may present significant uncertainties and errors may remain.

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 topobathymetric DEM of Ré Island's surroundings, with a resolution of 0.00005° (~5 meters), was created by Shom as part of the HOMONIM-3 project. It covers the coast of the municipalities of Ars-en-Ré and Saint-Clément-des-Baleines, extending offshore to a depth of about 20 meters, to the west of the Phare des Baleines lighthouse. This DEM is designed for use in hydrodynamic models to enhance the modeling of coastal processes, particularly forecasting submersion risk. The product complements the coastal topobathymetric DEM of the Pertuis-Charentais, with a resolution of 0.0002° (~20 meters), and the bathymetric DEM of the Atlantic coast, with a resolution of 0.001° (~100 meters). It is available in the vertical reference of the Lowest Astronomical Tide (LAT) or the Mean Sea Level (MSL).

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.