The regional bathymetric Atlantic – Channel – North-Sea DTM has a resolution of 0.001° (~111m). Its geographic coverage includes the Bay of Biscay, the English Channel and a part of the North Sea. The DTM extends from the coast to the continental slope (about of 4800m deep). This DTM is produced in the framework of the HOMONIM project which aims at improving operational forecast capabilities for the national coastal flood warning system. This DTM is offered openly on the Shom diffusion website (http://diffusion.shom.fr/produits/bathymetrie/mnt-facade-atl-homonim.html). http://dx.doi.org/10.17183/MNT_ATL100m_HOMONIM_WGS84

The DTM is a compilation of multibeam echosounder surveys acquired in 2013. The resolution is 1/64 arc-minutes (~30m). Surveys are located on the Capbreton Submarine Canyon (France) with depths from -4.7m to -344.9m. Depths are referenced to the Lowest Astronomical Tide and the coordinates are expressed into the WGS84 reference frame. The surveys which compose the DTM are S201306500-09 and S201306500-11. Data and metadata associated to these surveys are available on the website http://diffusion.shom.fr/pro/lots-bathy.html. The DTM is not to be used for navigation.

Shom manages a network of permanent digital coastal tide-gauges on French coasts: the RONIM Sea Level Observation Network. Most tide-gauge observatories are partnered with one or more local partners.<br /><br /> Four main types of data are available for download:<br /> - “Raw high frequency" data: raw observations neither validated nor evaluated, obtained directly from the sensor. 1-minute measurement; integration time 15 seconds (on the minute); sampling period: 1 second.<br /><br /> - "Raw non-real time" data: raw observations neither validated nor evaluated, obtained directly from the sensor. 10-minute measurement; integration time 121 seconds (around every 10 minutes); sampling period: 1 second.<br /><br /> - "Validated non-real time" data: observations checked and validated by Shom from the "Raw non-real time" data. 10-minute measurement; integration time 121 seconds (around every 10 minutes); sampling period: 1 second.<br /><br /> - "Validated hourly" data: observations checked and validated by Shom, generated from "Validated non-real time" data. Hourly measurement obtained from the Vondrak filter with triangular weighting. The hourly height cannot be calculated in the event of an observation gap greater than 1.5 hours.

The Shom uses a 2D barotropic version of the HYCOM code (https://hycom.org/) to compute water level /surge forecasts (astronomical tides and meteorological surges) for the Atlantic, Mediterranean, Antilles-Guyane and Indian Ocean domains. The configurations use curvilinear grid with resolutions of several km offshore and ranging from 1.5km to around 500m on the french mainland coasts and the Antilles-Guyana coast. A downscaling by nesting allows a resolution of 800m to 200m over the Indian domain. These models have been adapted by the Shom to be operable in coastal areas by taking into account, in particular, the tide and high resolution bathymetry in these areas (from 100m for DTMs of facade to 20m for coastal DTMs) using Litto3D surveys by airborne LIDAR. The models are operated by Météo-France and the Shom in the framework of the HOMONIM project for the coastal flood/wave warning system.

RasterMarine is a series of digital images taken from nautical charts, with no additions, legends or georeferencing information. The RasterMarine range is available at six sets of scales: - RasterMarine10 1:10,000 - RasterMarine25 1:25,000 - RasterMarine50 1:50,000 - RasterMarine100 1:100,000 - RasterMarine350 1:350,000 - RasterMarine1M 1:1,000,000. Unless exceptional circumstances apply, the RasterMarine range is updated on a weekly basis and the modified grid squares are re-published, replacing the previous versions. All corrections, publications, editions and suppressions with an effect on the reference nautical charts are taken into consideration. <br /> 01/10/2026 version <br />

Shom is the national referent for the level of the sea in situ on all areas under French jurisdiction. In this capacity, he assures under the acronym REFMAR different coordination functions in the collection and dissemination of public data related to water level observations, in order to promote their use in multiple applications within the framework of international recommendations.

"Aids ton navigation" product contains a description of landmarks, beaconage or buoyage, in the French Exclusive Economic Zone (EEZ). <br /> June 17 2026 version

The “Maximum tidal current speeds for mean spring tides” product provides information on the maximum speeds reached by tidal currents on mainland French coasts (English Channel and the Atlantic). These data can be used to identify areas subject to the strongest surface tidal currents and to characterize the maximum current intensity reached during a tidal cycle under mean spring tide conditions. The data are provided in shapefile format, with polygons associated with maximum current speed values, without any temporal or directional information. The values are expressed in knots.

"Traffic Separation Schemes" product contains a description of TSS in French maritime spaces. A TSS is a routeing measure aimed at the separation of opposing streams of traffic by appropriate means and notably by the establishment of traffic lanes. The measures taken aim at improving navigation safety in areas where navigation is threatened by the density of traffic associated with various natural difficulties. Several classes of objects constitute this product, the acronyms used are those of IHO standard S-57: - Traffic separation scheme lane part (TSSLPT): area of a traffic lane in which the direction of flow of traffic is uniform; - Traffic separation scheme boundary (TSSBND): outer limit of a traffic lane part or a traffic separation scheme roundabout; - Traffic separation line (TSELNE): common boundary between two traffic lanes, or between one traffic lane and one inshore traffic zone; - Traffic separation zone (TSEZNE): separation areas between two traffic lanes, or between one traffic lane and one inshore traffic zone, or to the central area of a roundabout; - Inshore traffic zone (ISTZNE): area between the landward boundary of a traffic separation scheme and the adjacent coast; - Precautionary area (PRCARE): area, within defined limits, where ships must navigate with particular caution, and within which the direction of traffic flow may be recommended; - Deep water route part (DWRTPT): sections within which the flow of traffic either follows one defined direction for one-way traffic, or follows one defined direction and its reciprocal for two-way traffic. A deep-water route is a route in a designated area within defined limits which has been accurately surveyed for clearance of sea bottom and submerged obstacles to a minimum indicated depth of water; - Two-way route part (TWRTPT): sections within which traffic flows in two directions along one bearing and its reciprocal. These route parts are generally two-way, but some may be restricted to one-way traffic flow; - Radio calling-in line (RDOCAL_lne) : positions at which vessels are required to report to a traffic control centre.

Tidal ranges on the French coasts of the Channel and the Atlantic for a coefficient of 95 : tidal range for mean spring tides for average atmospheric conditions..