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. This product is available with either the Lowest Astronomic Tide (LAT) or the Mean Sea Level (MSL) as a vertical reference.

The coastal topo-bathymetric DTM of the Arcachon basin and its surroundings at a resolution of 0.0002° (~ 20 m) was produced as part of the HOMONIM project. The DTM covers the coastline of a part of the Gironde department, from the Carcans and Hourtin ponds in the North, to the Cazaux and Sanguinet lakes in the South. It covers the entire Arcachon basin and extends offshore to about 40 m depth. The DTM is intended to be implemented in hydrodynamic models in order to produce accurate forecasts of water heights and sea states at the coast and to improve the French storm surge warning system. This product is available with the Lowest Astronomic Tide (LAT) or with the Mean Sea Level (MSL) as a vertical datum.

The coastal topo- bathymetric DEM for the coasts of Morbihan with a resolution of 0.0002° (~ 20 m) was prepared as part of the TANDEM project (Programme Investissements d'Avenir, ANR-11-RSNR-00023-01). It covers the French administrative department of Morbihan and part of Loire-Atlantique. This DEM runs from the Gâvres peninsula in the north west to La Baule in the south east and covers the Gulf of Morbihan, the Quiberon bay and peninsula, Houat, Hoëdic and Belle-Ile islands and the Vilaine estuary. 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 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.

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.

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 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). This product is available at different vertical references, either the lowest astronomical tide (LAT) or the mean sea level (MSL).

The bathymetric DEM for the coasts of Mayotte with a resolution of 0.001° (~ 100 m) was prepared as part of the HOMONIM project. It covers the entire island of Mayotte and extends to Anjouan island in the west. The model ranges off-shore to a depth of 3700 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. This product is available with the Lowest Astronomic Tide (LAT) or the Mean Sea Level (MSL) as a vertical datum.

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 Anguilla in the north to Saba in the south. The model ranges off-shore to a depth of 3275 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.

A bathymetric DEM for the coasts of Gulf of Lion – Côte d’Azur with a resolution of 0.001° (~ 100 m) was prepared as part of the HOMONIM project. It covers the entire Mediterranean metropolitan facade. The model ranges off-shore to a depth of 2800 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. This product is available with the Lowest Astronomic Tide (LAT) or the Mean Sea Level (MSL) as a vertical datum.