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Seabed Sediment Classification Irish Waters WGS84

Category: Environment
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Research ships working at sea map the seafloor. The ships collect bathymetry data. Bathymetry is the measurement of how deep the sea is. Bathymetry is the study of the shape and features of the seabed. The name comes from Greek words meaning "deep" and “measure". Backscatter is the measurement of how hard the seabed is.

Bathymetry and backscatter data are collected on board boats working at sea. The boats use special equipment called a multibeam echosounder. A multibeam echosounder is a type of sonar that is used to map the seabed. Sound waves are emitted in a fan shape beneath the boat. The amount of time it takes for the sound waves to bounce off the bottom of the sea and return to a receiver is used to find out the water depth. The strength of the sound wave is used to find out how hard the bottom of the sea is. A strong sound wave indicates a hard surface (rocks, gravel), and a weak signal indicates a soft surface (silt, mud). The word backscatter comes from the fact that different bottom types “scatter” sound waves differently.

Using the equipment also allows predictions as to the type of material present on the seabed e.g. rocks, pebbles, sand, mud. To confirm this, sediment samples are taken from the seabed. This process is called ground-truthing or sampling.

The seabed classification map is created by grouping seabed areas that are alike. Areas where there is no multibeam data have either been filled by EUSeaMap (predictive broadscale habitat map) or have been left as unclassified.

Sediments have been classified to the European Nature Information System (EUNIS), Marine Strategy Framework Directive (MSFD) Benthic Broad Habitat Types (BBHT), Folk (5 Themes) and European Marine Observation and Data Network (EMODnet) classification systems.

It is a vector dataset. Vector data portrays the world using points, lines and polygons (areas).

The sediment data is shown as polygons. Each polygon holds information on the classification for EUNIS, MSFD BBHT, Folk, substrate (EMODnet), biozone (EMODnet), data source and resolution.

The dataset was mapped as part of the Irish National Seabed Survey (INSS) and INFOMAR (Integrated Mapping for the Sustainable Development of Ireland’s Marine Resource).

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Theme Environment
Date released 2013-06-20
Date updated 2018-09-13
Dataset conforms to these standards The INSPIRE Directive or INSPIRE lays down a general framework for a Spatial Data Infrastructure (SDI) for the purposes of European Community environmental policies and policies or activities which may have an impact on the environment.
Rights notes ['Creative Commons Attribution 4.0 International (CC BY 4.0) licence', 'Data that is produced directly by the Geological Survey Ireland (GSI) is free for use under the conditions of Creative Commons Attribution 4.0 International license. https://creativecommons.org/licenses/by/4.0/legalcode\n\nUnder the CC-BY Licence, users must acknowledge the source of the Information in their product or application. \nPlease use this specific attribution statement: "Contains Irish Public Sector Data (Geological Survey) licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence".', 'license', 'Data that is produced directly by the Geological Survey Ireland (GSI) is free for use under the conditions of Creative Commons Attribution 4.0 International license. https://creativecommons.org/licenses/by/4.0/legalcode\n\nUnder the CC-BY Licence, users must acknowledge the source of the Information in their product or application. \nPlease use this specific attribution statement: "Contains Irish Public Sector Data (Geological Survey) licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence".', 'license']
Update frequency Continuously updated
Language English
Landing page https://gsi.geodata.gov.ie/portal/apps/webappviewer/index.html?id=85b8ecf8832e40cca6d923aa0688f08e
Geographic coverage in GeoJSON format {"type":"Polygon","coordinates":[[[-18.1, 51.5],[-18.1, 57.1], [-5.5, 57.1], [-5.5, 51.5], [-18.1, 51.5]]]}
Spatial Reference Systems (SRS) WGS 84 (EPSG:4326)
Vertical Extent {"maxVerticalExtent": "-1", "verticalDomainName": "sea level", "minVerticalExtent": "-200"}
Provenance information 1. Backscatter mosaic was generated at 5 m. 2. Acoustic classes were derived from multibeam backscatter data using an unsupervised image classification method. 3. Groundtruthing data, where available, were used to assign sediment types to the acoustic classes. 4. Rock outcrops were derived from manual interpretation of bathymetric data, LiDAR data and satellite images*. 5. Sediment classes were allocated to areas without MBES coverage by extrapolation of the sediment information obtained from neighbouring samples. 6. Unclassified substrate: areas that cannot be interpreted due to a lack of data (multibeam, sediment samples). The EUNIS habitat classification is a comprehensive pan-European system to facilitate the harmonised description and collection of data across Europe through the use of criteria for habitat identification. It is hierarchical and covers all types of habitat types from natural to artificial, from terrestrial to freshwater and marine. Lower resolution interpretations of INFOMAR data that were provided to the EMODnet Geology and EMODnet Seabed Habitats projects have been integrated into this layer. Areas where there is no multibeam data have either been filled by EUSeaMap (predictive broadscale habitat map) Version 20190426 or have been left as unclassified. The existing sediment classifications have been translated to a scheme that is supported by EUNIS and MSFD Broad Benthic Habitat Type classification systems. This reclassification scheme includes five seabed substrate classes. Four substrate classes are defined on the basis of the modified Folk triangle (mud to sandy mud; sand; coarse sediment; and mixed sediment) and one additional substrate class (rock) was included. The data is stored in an ArcGIS Enterprise geodatabase and was processed using ArcGIS Pro 3.2.1. Pairwise Dissolve was carried out on the data using all attribute fields except the OBJECTID,AREA and LEN fields. GSI standard metadata is based on INSPIRE and ISO 19115-3 standards. Plain English is used for the Abstract and Description.
Period of time covered (begin) 2000-01-01