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.

Bathymetric datasets, collected between 1990 and 2005, are digital data controlled and qualified. They are acquired with single-beam echosounders and the first generations of multi-beam echosounders.

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 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.

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).

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.

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.

This data layer contains the current status of hydrographic knowledge expressed in terms of CATZOC (category of zone of confidence, cf. https://iho.int/uploads/user/pubs/standards/S-67/S-67%20Ed%201.0.0%20Mariners%20Guide%20to%20Accuracy%20of%20Depth%20Information%20in%20an%20ENC_EN.pdf), as well as the target defined by the national hydrography program.

The coastal topo-bathymetric DEM was produced using the bathymetric and topographic data acquired between 2012 and 2015 by Shom and the PASSION programme team. The 20 m coastal grid covers the Passion atoll – Clipperton and the local flanks of the atoll to a depth of 1500 m. Passion island - Clipperton, in the eastern Pacific Ocean, is a remote uninhabited atoll over 5,000 km from Tahiti in French Polynesia and over 1,000 km from the Mexican coasts. Passion island is the highest point on the Clipperton ridge, and the only location above water level. This is the only coral atoll in the eastern Pacific in the northern hemisphere, at a longitude of W 109° and a latitude of N 10°.