Weather forecasting models are used to show atmospheric conditions by computing changes in meteorological parameters on a 3D atmospheric grid model. Physical laws are used to determine behaviour: fluid mechanics, variation in water phase, turbulence, radiation, and atmospheric interaction with space, the continents and the oceans. The initial conditions are determined by assimilating variational data including a large volume and wide variety of in situ observations obtained from remote detection systems. The weather forecasts available on data.shom.fr only contain "wind at 10m" and "atmospheric pressure at sea level" parameters. A land/sea mask is then applied to exclude non-maritime forecasts. These forecasts are taken from 2 different types of models: ARPEGE for world and European scale input (0.5° to 0.1° resolution) and AROME for mainland France (1.3 km resolution). ARPEGE is a global hydrostatic spectral model, with variable horizontal resolution (centred on France), vertical finite element modelling and hybrid vertical coordinates. ARPEGE is an integral part of the Arpège-IFS software package, designed, developed and maintained by Météo-France in cooperation with ECMWF (European Centre for Medium-Range Weather Forecasts - http://www.ecmwf.int/). AROME is a non-hydrostatic spectral model for weather forecasts in mainland France, with finite difference modelling for vertical input and hybrid coordinates. AROME was developed by Météo-France thanks to close national (CNRS) and international (CEPMMT, Aladin, Hirlam) cooperation programmes on the basis of the Méso-NH research model and the dynamic core of the Aladin model.

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 georeferenced digital image solution for the nautical chart is a digital conversion of the corresponding printed nautical chart produced by Shom or its legends, with georeferencing indications and including miscellaneous text.

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 "Sovereignty and jurisdiction maritime spaces of France" product contains the areas of sovereignty and jurisdiction maritime spaces of France all around the world.<br /><br /> It is constituted of 2D areas objects split into four categories :<br /> - the territorial sea (from baselines to a distance of 12 nautical miles or to maritime boundaries with neighbouring countries);<br /> - the contiguous zone (from 12 nautical miles to 24 nautical miles from the baselines or to maritime boundaries with neighbouring countries);<br /> - the exclusive economic zone (EEZ) (from 12 nautical miles to 200 nautical miles from the baselines or to maritime boundaries with neighbouring countries);<br /> - the continental shelf over the 200 nautical miles limit (from 200 nautical miles from the baselines to the limits recommended by the Commission on the Limits of the Continental Shelf (CLCS) or to the maritime boundaries with neighbouring countries).<br /> Internal waters, which constitute a space of sovereignty beyond the baselines, are not included in the "Sovereignty and jurisdiction maritime spaces of France" product.<br /> The "Sovereignty and jurisdiction maritime spaces of France" product may not be considered as an enforceable right. Only the “Maritime limits and boundaries” product, that can be displayed and interrogated on the website data.shom.fr (maritime boundaries category) and also downloaded on the French national portal of maritime limits (https://maritimelimits.gouv.fr), may be considered so.<br /><br /> December 2022 version.

RasterMarine is a series of digital images taken from nautical charts, with no additions, legends or georeferencing information. The RasterMarine range is available at five sets of scales: - RasterMarine 20 1: 20,000 - RasterMarine 50 1: 50,000 - RasterMarine 150 1: 150,000 - RasterMarine 400 1: 400,000 - RasterMarine 1M 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 and editions with an effect on the reference nautical charts are taken into consideration. <br /> 17/04/2025 version <br />

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.

Non-georeferenced digital images in JPEG2000 format from former hydrographical survey fair sheets obtained from Shom's historical archives.

"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.

These maps are prepared on the basis of vector-based mapping data (IHO S-57 format) including the detailed description of each object (beacons, wrecks, submarine cables, regulated zones, survey systems, etc.). These maps are the digital equivalent of printed nautical charts.