A harmonised EMODnet Digital Terrain Model (DTM) is generated for European sea regions from selected bathymetric survey data sets, composite DTMs, Satellite Derive Bathymetry (SDB) data products, while gaps with no data coverage are completed by integrating the GEBCO Digital Bathymetry.
The DTM with its information layers is made freely available for browsing and downloading through the Bathymetry Viewing and Download service.
The EMODnet Bathymetry portal provides DTM coverage for the following regions:
- The Atlantic Ocean (Channel, Celtic Seas, Western Approaches)
- The North Sea and Kattegat
- The Western and Central Mediterranean sea and Ionian Sea
- The Iberian Coast and the Bay of Biscay (Atlantic Ocean)
- The Adriatic Sea (Mediterranean)
- The Aegean - Levantine Sea (Mediterranean)
- Madeira and Azores
- Baltic Sea
- Black Sea
- Norwegian - Icelandic Seas
- Canary Islands
- European arctic region + Barentz Sea
The EMODnet DTM is generated by regional teams from the EMODnet Bathymetry partnership following a common QA-QC process and DTM generation methodology.
In October 2016 a version of the EMODnet DTM has been released with a grid resolution of 1/8 * 1/8 arc minutes. In the meantime more survey data sets have been gathered from an increasing number of data providers and activities have been undertaken for correcting identified anomalies, where possible.
This has resulted mid September 2018 in the release of a new DTM, now with an increased grid resolution of 1/16 * 1/16 arc minutes (circa 115 * 115 meters).
This DTM data product is again freely available to users as GIS layers for viewing, while both DTM versions are also available for sharing as OGC web services (WMS, WFS, WMTS, WCS) and downloading as DTM tiles in several output formats. The DTM cells contain references to the data sets as used by CDI references for survey data, Sextant references for composite DTMs or alternatively a reference to GEBCO in case no data was available.
The geographical boundaries of the 2018 DTM service are set to: N90 W36 and N15 E43. The geodetic system for the grid is chosen as WGS84.
Users can activate and view the bathymetry layers (average, minimum, maximum waterdepths in meters to LAT) for the selected regions as well as contours and underwater features. All layers are OGC WMS services that can also be integrated into other WMS service portals. Users can zoom in/out and switch on/off several layers. Per DTM cell users can call up and browse the data as specified in the QA/QC documentation including retrieving metadata about the underlying data source. Users can draw transects and retrieve the bathymetric profile along that transect. Moreover users can download the DTM data in several output formats, in ASCII CSV, ESRI ASCII, NetCDF (CF), GeoTIFF and Fledermaus SD files.
The downloading of the DTM is done in large tiles that users have to select. For the 2016 version there are 16 tiles, while the 4 times larger 2018 version is downloadable in 64 tiles.
The Bathymetry Viewing and Download service also gives a source references layer which allows to identify the prevailing data sources used for each DTM grid cell. Activating the identification function in the sources layer will reveal for each DTM cell which survey data set or composite DTM was used with a link to their metadata from the CDI Data Discovery and Access service or Sextant Catalogue service. Grey areas are derived from GEBCO.
The metadata of bathymetric surveys can be viewed as a separate WMS layer providing the location of the Common Data Index (CDI) metadata that are describing the so far collated bathymetric survey data sets. Users can define a lat - lon box that will jump to the CDI Data Discovery and Access service for retrieving CDI metadata for the survey data sets within that geographical search window. This will then facilitate the users to refine their query and to request access to the high resolution survey data sets themselves.
Online 3D viewing service: 3D visualization functionality has been added to the bathymetry viewing that can be used in the browser without requirement of plugins. The 3D application is based on Cesium. However a dedicated data structure has been developed by EMODnet Bathymetry based on a triangulated irregular network (TIN). Having a TIN instead of a regular grid enables faster representation of the complexity of the map (i.e. the number and size of triangles). Software has been developed to create tiles in quantized mesh format out of a raster format such as used in EMODnet DTM. Later this software will be documented and made available at GitHub and promoted at the EMODnet Bathymetry portal.
GLOBE software: this software has been developed and is maintained by IFREMER. It has been customized for the EMODnet Bathymetry methodology and EMODnet Bathymetry partners are encouraged to make use of this software for processing their data contributions and for generating local and regional DTM's that are contributing to the EMODnet DTM. The EMODnet DTMs are provided in GLOBE NetCDF format and can be visualised by using the 3D visualisation tool of GLOBE software. More info about the GLOBE software can be found here
Offline 3D Viewer: the DTM files in NetCDF format can also be visualised by using the 3D visualisation tool (3D Viewer) that has been developed in the EU FP7 Geo-Seas project. This viewer is based on the existing open source NASA World Wind JSK application. This software is freely available after registration and allows the visualisation of Digital Terrain Models (DTM) in the existing GLOBE NetCDF format and Web Map Service (WMS) which are plugged into a virtual globe. More info about the 3D viewer and link to the registration page can be found here.
The SD files can be visualized with the free Fledermaus 3D viewer software.
High resolution bathymetry for selected coastal regions: this layer is added in September 2015 to test the concept of a multi resolution product. High resolution data is available for the German North Sea coast, the French Mediterranean coast and Dunmanus bay in Ireland. Activating the layer will highlight these areas and the user is facilitated to zoom in further than in the overall bathymetry layers.
Coastline: is derived from OpenStreetMap 2014 WMS. It is a highly detailed coastline.
Underwater features: this layer is provided by GEBCO as GEBCO Undersea Features WMS. The GEBCO Sub-Committee on Undersea Features (SCUFN) maintains and provides a gazetteer of the names, generic feature type and geographic positions of features on the seafloor. The level of detail is dependent on the viewing scale.
Wrecks: this layer is provided by partner OceanWise as proprietary WMS service and uses the UKHO Wrecks database as source. This Wrecks layer covers all European seas and the level of detail is dependent on the viewing scale.