The "Magnetic Stations" product contains measurements from magnetic reference stations deployed by the French Hydrographic and Oceanographic Service (SHOM) near marine magnetic survey areas. Measurement files are available by station and by year. These magnetic reference measurements correct marine measurements for diurnal and high-frequency variations in the Earth's magnetic field.

In the absence of a maritime boundary agreement with a neighbouring State, the French Republic can unilateraly claim a delimitation. This boundary has indeed a provisional aspect pending the ratification of a boundary agreement. The theme "Maritime limits unilaterally claimed" gathers those limits unilaterally claimed by France. Some of those elkements are published by decree.

This product includes Shom 3D digital data on tidal currents in the area "Loire" in shapefile and geotiff formats. These digital files provide information on tidal current components (speed and direction) on an hourly basis (6 hours either side of high water for a reference port), and for two typical tidal coefficients (45 and 95). Saint-Nazaire is taken as the reference port. Three layers are available: Surface; mid-depth; and sea-bed.

The combined error grid of the SIO V31 gravity anomaly model (D. T. Sandwell, H. Harper, B. Tozer et al., Gravity field recovery from geodetic altimeter missions, Advances in Space Research, https://doi.org/10.1016/j.asr.2019.09.011) is computed with a method described in a paper submitted to Earth and Space Science (AGU). The model’s extension is North Atlantic.

Compilation of marine gravity surveys acquired in the Northeast Atlantic by Shom between 2001 and 2016. These surveys were compiled to perform a quantification of the error of the gravity anomaly models derived from satellite altimetry. This dataset represents more than 22,000 measurement points distributed in 9 ascii survey files sampled at 1 kilometer. The file’s format is as follows: longitude latitude Gravity_anomaly error line_label.

This product includes Shom 3D digital data on tidal currents in the area "Loire" in shapefile and geotiff formats. These digital files provide information on tidal current components (speed and direction) on an hourly basis (6 hours either side of high water for a reference port), and for two typical tidal coefficients (45 and 95). Brest is taken as the reference port. Four layers are available: Surface; mid-depth; - 10 m above the sea bed and sea-bed.

Litto3D is a unique and continuous land-sea database which can provide 3D models of the shape and location of French coastal terrain. Litto3D digital models are available in two formats: a set of 3D points and a qualified terrain mesh.

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. <br /> October 27 2025 version

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. <br /> October 27 2025 version

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. <br /> October 27 2025 version