Broadscale Remote Survey and Mapping of Sublittoral Habitats and Biota of Milford Haven, Pembrokeshire and South Cardigan Bay
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.
- Dull adnabod
- Rhychwant
- Dosbarthiad
- Ansawdd
- Allweddeiriau
- System Cyfeirio Gofodol
- Cynnwys
- Cyfyngiadau
- Cynnal a chadw
- Metadata
Dull adnabod
- Dynodydd
- NRW_DS110037
- Teitl Amgen
-
- Arolwg o bell a mapio graddfa eang cynefinoedd a biota isarforol Aberdaugleddau, Sir Benfro a de Bae Ceredigion
- Laith Metadata
- English
- Datganiad
-
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)
- 1999-12-31
Ystod amser
- Dyddiad cychwyn
- 1994-01-01
- Dyddiad gorffen
- 1998-12-31
- Categori pwnc
-
- Oceans
- Biota
Rhychwant
Rhychwant
- Hyd
- Wales (WLS)
))
Maint Fertigol
- Maint allweddair MEDIN
- benthic boundary layer
Dosbarthiad
- Fformat - Math a Disgrifiad
-
-
Geographic Information System
()
- Math
-
[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)
-
Geographic Information System
()
Ansawdd
Ansawdd Data
- Cwmpas Ansawdd
- Dataset
- Datganiad
-
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.
Allweddeiriau
Allweddair
Allweddair
- NRW Thesaurus
-
- mapping (map drawing) (cartography)(see also digital mapping)
- Milford Haven
- Pembrokeshire (county pre 1974)( county since 4/96)
- marine and freshwater inventory
- remote survey
- South Cardigan Bay
- sea floor
- acoustic remote sensing
- acoustic ground discrimination system
- digital images
- satellite images
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2023-12-31
Allweddair
- SeaDataNet Parameter Discovery Vocabulary
-
- Habitat characterisation
- Math
- Theme
Dyfyniad
- Dyddiad (Adolygu)
- 2021-01-06
System Cyfeirio Gofodol
Cynnwys
Gwybodaeth Cynnwys
Proffil CNC
Elfennau CNC
- Teitlau cysylltiedig CNC
-
Broad scale remote survey and mapping of sublittoral habitats and biota of the Milford Haven, Pembrokeshire and South Cardigan Bay
Cyfyngiadau
Cyfyngiadau
Cyfyngiadau ar Fynediad a Defnydd Cyhoeddus
- Math o Gyfyngiad
- Other restrictions
Cyfarwyddeb Cyfyngiadau Mynediad
- Cyfyngiadau
- no limitations
Testun cyfyngiadau mynediad
- Cyfyngiadau eraill
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There are no access restrictions to this data. NRW may release, publish or disseminate it freely.
Defnyddiwch gyfyngiadau
- Cyfyngiadau Defnyddio
- Other restrictions
- Cyfyngiadau eraill
-
© 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
- 4f4c4942-4343-5764-6473-313130303337 XML
- Laith Metadata
- English
- Math o adnodd
- Dataset
- Dyddiad Metadata
- 2024-12-09T13:16:44.635Z
- Enw Safonol Metadata
- NRW
- Fersiwn Metadata
-
1.0