Broadscale Remote Survey and Mapping of Sublittoral Habitats and Biota of Milford Haven, Pembrokeshire and South Cardigan Bay
Arolwg o bell a mapio graddfa eang cynefinoedd a biota isarforol Aberdaugleddau, Sir Benfro a de Bae Ceredigion

  • English
  • wel
  • All

The Broadscale Mapping Project has been devised and funded by a consortium consisting of the Crown Estate, the Countryside Council for Wales, English Nature, Scottish Natural Heritage and the SeaMap research group based at Newcastle University and undertaken by SeaMap. Three trial areas were selected, around Milford Haven, Pembrokeshire and South Cardigan Bay, for developing and testing the methodology, although experience from many other surveys conducted by SeaMap have also contributed to the development of the methodology. The aim of this data collection was to map the seafloor sediments and biota, for habitats and biotope mapping. This was supplemented by maps and supporting data showing the location of ground truth samples and the positions of the acoustic tracks.

Identification

Dynodydd
Identifier
NRW_DS110037
Laith Metadata
Metadata Language
English
Lineage

Image processing requires ground truth samples of the biota and habitats from the sea floor and the sampling techniques range from the traditional grab, trawl and dredge to the deployment of remote video. The video is especially useful since it provides a vista of the sea floor which is approximately of the same extent as the area of the seafloor that is covered by one pulse from an echo sounder (the 'footprint'). Image processing is a two-stage process: In the first stage the acoustic data in the immediate vicinity of the ground truth positions are selected and tagged according to the type of habitat or biotope of the ground truth sample. The acoustic data are pooled for each habitat or biotope type and the acoustic characteristic calculated from the mean and standard deviation of the depth and the hardness and roughness values. In this way an acoustic signature is created for each habitat or biotope type. In the second stage each pixel is matched to the signatures and the likelihood of the pixel belonging to each habitat or biotope calculated. An automated process then selects the most likely category for the pixel. This second stage is, therefore, called a maximum likelihood classification. The methodology relies on the relatively inexpensive acoustic ground discrimination system (AGDS) based on a single beam echo sounder. AGDS analyse the echo from the sounder and gives a measure of the hardness and roughness of the sea floor, as well as depth. These records, in the form of point data, are logged together with time and position as the vessel tracks over the survey area. The point data are used to create continuous digital images for each of the variables through interpolation. This conversion to digital images consisting of rows and columns of pixels enables powerful image processing software, designed primarily for the processing of satellite images, to be applied to the acoustic data.
Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
Dataset Reference Date (Publication)
1999-12-31

Temporal Extent

Begin date
1994-01-01
End date
1998-12-31
 
Categori pwnc
Topic category
  • Oceans
    Oceans
  • Biota
    Biota
Perchennog
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Cychwynnwr
Originator
  Newcastle University -
Newcastle upon Tyne, Tyne and Wear, Newcastle, NE1 7RU
http://www.ncl.ac.uk/
 

Extent

Extent

Hyd
Geographic Extent
Wales (WLS)
N
W
E
S
Map representing the geographic extent of the dataset


 

Vertical Extent

Medin Extent Keyword

benthic boundary layer
 
 

Distribution

Fformat - Math a Disgrifiad
Format Type and Description
  • Geographic Information System ( )

    Specification

    [A] Report (MS Word [B] GIS Data (Mapinfo native and Idrisi format files) [C] Image Data (3D topographic models .jpg) [D] Spreadsheet Data (MS Excel)

 

Quality

Ansawdd Data
Data quality

Cwmpas Ansawdd
Quality Scope
Dataset
Dataset
Cydymffurfiad
Conformity
Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services
Explanation

This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
Degree
false
Lineage

Image processing requires ground truth samples of the biota and habitats from the sea floor and the sampling techniques range from the traditional grab, trawl and dredge to the deployment of remote video. The video is especially useful since it provides a vista of the sea floor which is approximately of the same extent as the area of the seafloor that is covered by one pulse from an echo sounder (the 'footprint'). Image processing is a two-stage process: In the first stage the acoustic data in the immediate vicinity of the ground truth positions are selected and tagged according to the type of habitat or biotope of the ground truth sample. The acoustic data are pooled for each habitat or biotope type and the acoustic characteristic calculated from the mean and standard deviation of the depth and the hardness and roughness values. In this way an acoustic signature is created for each habitat or biotope type. In the second stage each pixel is matched to the signatures and the likelihood of the pixel belonging to each habitat or biotope calculated. An automated process then selects the most likely category for the pixel. This second stage is, therefore, called a maximum likelihood classification. The methodology relies on the relatively inexpensive acoustic ground discrimination system (AGDS) based on a single beam echo sounder. AGDS analyse the echo from the sounder and gives a measure of the hardness and roughness of the sea floor, as well as depth. These records, in the form of point data, are logged together with time and position as the vessel tracks over the survey area. The point data are used to create continuous digital images for each of the variables through interpolation. This conversion to digital images consisting of rows and columns of pixels enables powerful image processing software, designed primarily for the processing of satellite images, to be applied to the acoustic data.
 

Keywords

Allweddair
Keywords

GEMET - INSPIRE themes, version 1.0
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2008-06-01
Code
geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Allweddair
Keywords

NRW Thesaurus
  • acoustic remote sensing
  • South Cardigan Bay
  • Milford Haven
  • remote survey
  • satellite images
  • Pembrokeshire (county pre 1974)( county since 4/96)
  • sea floor
  • digital images
  • mapping (map drawing) (cartography)(see also digital mapping)
  • acoustic ground discrimination system
  • marine and freshwater inventory
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2026-08-27
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords

Allweddair
Keywords

SeaDataNet Parameter Discovery Vocabulary
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2024-06-19
Code
geonetwork.thesaurus.external.theme.rdf+xml
 

Spatial Reference System

Code
British National Grid (EPSG::27700)
 

Content

Gwybodaeth Cynnwys
Content Information

Proffil CNC
NRW Profile

Elfennau CNC
Custom Elements

NRW Related Title

Broad scale remote survey and mapping of sublittoral habitats and biota of the Milford Haven, Pembrokeshire and South Cardigan Bay
 

Constraints

Constraints

Limitations on Public Access and Use

Math o Gyfyngiad
Restriction type
Other restrictions
Other restrictions
 

Access Constraints Directive

Limitations
no limitations
 

Access Constraints Text

Other constraints

There are no access restrictions to this data. NRW may release, publish or disseminate it freely.
 

Use Constraints

Cyfyngiadau Defnyddio
Use constraints type
Other restrictions
Other restrictions
Other constraints

© CNC/NRW 1999. There are no use restrictions on this data. Recipients may re-use, reproduce, disseminate this data free of charge in any format or medium, provided they do so accurately, acknowledging both the source and NRW's copyright, and do not use it in a misleading context. It is the recipient's responsibility to ensure the data is fit for the intended purpose, that dissemination or publishing does not result in duplication, and that it is fairly interpreted. Advice on interpretation should be sought where required. To avoid re-using old data, users should periodically obtain the latest version from the original source.
 
 
 

Metadata

Metadata

Dynodydd Ffeil
File Identifier
4f4c4942-4343-5764-6473-313130303337 XML
Laith Metadata
Metadata Language
English
Math o adnodd
Resource type
Dataset
Dataset
Dyddiad Metadata
Metadata Date
2026-09-28T11:50:11.323Z
Enw Safonol Metadata
Metadata Standard Name
NRW
Fersiwn Metadata
Metadata Standard Version

1.0

Pwynt Cyswllt
pointOfContact
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
 
 

Publishing Body

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