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Energy, Climate change, Environment
European Marine Observation and Data Network (EMODnet)

Bathymetry is the information that describes the topography of the seabed. It is an essential component in understanding the dynamics of the marine environment, both in terms of sediment transport but also in the prediction of tides, currents and waves. Safe ocean navigation relies on accurate bathymetry data, which are also essential for planning marine installations and infrastructure such as wind turbines, coastal defences, oil platforms and pipelines. Bathymetry plays also a key role in the distribution of marine species. Overall bathymetry forms the foundation of any comprehensive marine dataset; without it, the picture is incomplete.

Objectives of EMODnet Bathymetry

EMODnet Bathymetry aims to provide a single access point to bathymetric products, Digital Terrain Models (DTM) and data (survey data sets and composite DTM) collected and managed by an increasing number of organisation from government and research scattered over Europe.

See Specific Objectives of EMODnet Bathymetry
  • Assemble an, as complete as possible, inventory of bathymetric survey data sets held by public, research and private bodies;
  • Provide service for discovery and access to the identified bathymetry survey data sets;
  • Use these data sets for generating a harmonised multi-resolution DTM for all European sea regions.

 

Key services provided by EMODnet Bathymetry

The EMODnet Bathyemtry portal provides a range of services and functionalities to users for viewing and downloading bathymetry data products and for identifying and requesting access to the survey data sets that are used as basis input for the DTM. Currently the following key services and functionality are provided for users:

  1. Data Discovery and Access service: provides functionality to search and obtain survey data sets;
  2. Composite Products Discovery and Access service: provides functionality to search and view metadata of composite DTM;
  3. Bathymetry Viewing and Download service: provides functionality to view, browse and download digital bathymetry as DTM and obtain information about the underlying data sets used to compile the DTM.
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The Data Discovery and Access service is based on the SeaDataNet CDI system which provides an overview and a unified user interface for requesting access and downloading of survey data sets from an increasing number of distributed data providers. The majority of these survey data sets require negotiation with their owners for downloading by users.

The Composite Products Discovery and Access service is based on the Sextant Catalogue service which provides an overview of composite DTM  that have been contributed by a number of data providers as contributions to the EMODnet DTM instead of contributing their higher resolution survey data sets.

The Bathymetry Viewing and Download service is a map viewer which allows users to view, browse and download digital bathymetry as DTM and to obtain information about the underlying data sets used to compile the DTM. This  service provides users with a range of functions for browsing and downloading the EMODnet DTM such as:

  • Multiple map layers that can be switched on / off and each interrogated for their specific information;
  • Zoom in - zoom out and panning;
  • Retrieval of the DTM cell parameters such as minimum cell depth, maximum cell depth, average cell depth, standard deviation of the cell depth, number of depths used for interpolation of cell depth, number of subcells used for the computation of the average cell depth, source reference by CDI reference, composite DTM reference or GEBCO in case of missing data;
  • Retrieval of depth profiles along a track;
  • Addition of external WMS map layers as an overlay such as the CDI WMS layer;
  • Activation of a source layer indicating for each cell its underlying prevailing data source;
  • Downloading of DTM tiles in different formats: ESRI ASCII, XYZ, CSV, NetCDF, GeoTiff and SD for Fledermaus 3 D viewer software.

Approach

The following approach has been adopted for the implementation of the EMODnet Bathymetry portal:
  • Include in the portal a metadata data discovery and access service, by adopting the SeaDataNet CDI metadata standard, for providing clear information about the survey data used for the DTM, their access restrictions and distributors, and featuring online shopping request and delivery; this ensures that the bathymetry data sets can also be queried at the SeaDataNet portal;
  • Include in the portal an additional catalogue service, by adopting the SeaDataNet Sextant Catalogue service, for providing metadata on composite DTMs that are contributed by a number of data providers next to or instead of bathymetric survey data;
  • Involve research institutes, monitoring authorities, and Hydrographic offices, in providing bathymetric data sets, only for internal use by project partners for producing the Digital Terrain Models (DTM). DTM tiles are loaded and integrated into the portals' spatial database, and made available for free downloading;
  • Develop a Bathymetry Viewing and Download service on top of a powerful spatial database including various ways for browsing and interacting with the EMODnet Bathymetry digital terrain model and associated metadata by means of information layers and specific functions. It includes WMS, WCS and WFS services (OGC) to share layers also with other portals such as other EMODnet portals, the European Atlas of the Seas, and external portals.
 

Data sources

The partners of EMODnet Bathymetry combine expertise and experiences of collecting, processing, and managing bathymetric data. They have also gathered expertise in the building and management of distributed data infrastructure which routinely provides discovery, access and viewing services to users according to INSPIRE implementation rules and international standards (ISO, OGC).

Both hydrographic and scientific/academic organization are deeply involved in continuously  increasing the coverage of European seas, through the acquisition of new information using essentially modern multibeam sounders.

Show Overview of types of data providers
  • Hydrographic Offices (HO), responsible for surveying the navigation routes, fairways and harbour approach channels and producing nautical charts (paper and electronic) for navigation. The HOs are members of the International Hydrographic Organisation (IHO) and have their own data policy, which has restrictions. These restrictions are partly due to the fact that many HOs are part of the navy and high resolution data sets are treated as confidential for security purposes. Further, HOs have more or less a monopoly on the production of nautical charts and create income from this. These charts have a legal status. Every captain must use certified nautical charts and the production and publication of these is an activity which must follow stringent international procedures, consequently HOs are cautious regarding the delivery and distribution of bathymetric survey data sets.
  • Authorities responsible for management and maintenance of harbours, coastal defences, shipping channels and waterways. These authorities operate or contract regular bathymetric monitoring surveys to ensure that an agreed nautical depth is maintained or to secure the state of the coastal defences. Part of these data is already included in SeaDataNet because its data centres belong to the same institutes that perform the surveys.
  • Research institutes, that collect multibeam surveys as part of their scientific cruises. Some of these data are already included in SeaDataNet, because its data centres belong to the same research institutes.
  • Industry, especially the energy industry that contracts multibeam surveys for pipeline and cable routes (in case of windfarms) and the telecommunication industry for phone and internet cable routes.

EMODnet Bathymetry product development

Digital Terrain Model are based on 3 types of bathymetric data sources:

  • Bathymetric surveys, such as single and multibeam surveys, echosoundings and even historic leadline soundings. These data sets are most preferred as data sources because of their high resolution;
  • Composite data sets, which includes a set of surveys merged and gridded altogether;
  • Gaps with no data coverage which are completed by integrating the worldwide GEBCO Digital Bathymetric grid (in which the lack of coverage is filled by coarse resolution (up to several kilometers) information extrapolated from altimetry measurements for satellites.

Improvements in the current development Phase III (2017-2020)

  • Multi-resolution DTM (¼ of an arc minute);
  • Satellite-derived Bathymetry (SDB) data used to cover gaps in the coastal area;
  • Extended coverage  to include European coastal zones as well as the European Arctic region and Barents sea;
  • Quality index provided at the grid node level in order to inform the user about the quality of the product.