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Krieged BroadScale Substrate Map of South-west Deeps (West) rMCZ

JNCC requested that BGS carry out geostatistical analysis of sediment sample data from the CEND 8/12 survey of Swallow Sand MCZ and CEND 6/13 survey of South-west Deeps (West) MCZ in order to produce maps of sediment distribution in the sites.



For each of the MCZ a geostatistical analysis of the data is reported leading to the selection of a robust linear model of corregionalization for the composition of the sediment, based on the additive log-ratio transformation of data on mud, sand and gravel content. This model is then used for spatial prediction on a 250-m grid. At each grid node a prediction distribution is obtained, conditional on neighbouring data and the selected model. By sampling from this distribution, and back-transforming onto the original compositional simplex of the data, we obtain a conditional expectation for the proportions of sand, gravel and mud at each location, a 95% confidence interval for the value at each node, and the probability that each of the four sediment texture classes that underly the EUNIS habitat classification is found at the node.

Simple

Alternate title

GB400006

Date (Creation)
2014-03-25
Date (Publication)
2018-04-26
Citation identifier
EMODnetSeabedHabitats / GB400006
Point of contact
Organisation name Individual name Electronic mail address Role

Defra

open@defra.gsi.gov.uk

Owner

JNCC

habitatmapping@jncc.gov.uk

Custodian

GEMET - INSPIRE themes, version 1.0

  • Habitats and biotopes

http://inspire.ec.europa.eu/codelist/ReferenceHabitatTypeSchemeValue

  • Eunis

Use limitation

┬® Defra. Data may be re-used under the terms of the Open Government Licence.

Use limitation

geossAttribution

Access constraints
Other restrictions
Other constraints

no limitation

Spatial representation type
Vector
Denominator
100000
Language
English
Topic category
  • Biota
  • Oceans
N
S
E
W
thumbnail




Begin date
2013-01-01
End date
2013-12-31
Supplemental Information

LARK, R.M. 2014. .Mapping seabed sediments of the Swallow Sand and South-west Deeps (West) MCZs. British Geological Survey Internal Report, OR/14/015. 18pp.

Reference system identifier
EPSG / WGS 84 (EPSG:4326) / 7.9

Topology level
Geometry only
Distribution format
Name Version

ESRI Shapefile

1.0

OnLine resource
Protocol Linkage Name

OGC:WMS

https://ows.emodnet-seabedhabitats.eu/geoserver/emodnet_view_maplibrary/wms?

gb400006

OGC:WFS

https://ows.emodnet-seabedhabitats.eu/geoserver/emodnet_open_maplibrary/wfs?

gb400006

WWW:LINK-1.0-http--link

https://files.emodnet-seabedhabitats.eu/data/EMODnetSBHsurvey_GB400006.zip

EMODnet Seabed Habitats download

Hierarchy level
Dataset

Conformance result

Title

Corrigendum to INSPIRE Metadata Regulation published in the Official Journal of the European Union, L 328, page 83

Date (Publication)
2009-12-15
Explanation

See the referenced specification

Pass
Yes

Conformance result

Title

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

Date (Publication)
2010-12-08
Explanation

See the referenced specification

Pass
Yes
Statement

The data used for the South-west Deeps (West) MCZ (SWDW) are particle size analyses from the verification survey carried out by Cefas in 2013 (McIlwaine, 2013). The data were collected by 0.1 m2 Hamon grab from 208 locations on a pre-planned survey grid. Exploratory analysis found no duplicate locations in this data set. This is a sizeable data set to support a spatial analysis, so as described for Swallow Sand in section 2.1 above, no attempt was made to supplement these data with others from the BGS archive.



Lark et al. (2012) describe the cokriging procedure used to obtain conditional expectations of the transformed variables and covariance matrices for these at target points. This procedure was undertaken to form predictions at nodes of a 250-m grid. The simulation method used by Lark et al. (2012) was then used to generate 5000 independent realizations from the joint prediction distribution at each node. For each realization a back-transformation was undertaken to give values of gravel, mud and sand. Over all realizations the mean value of gravel, mud and sand were computed as the conditional expectation of these variables, and the 0.025 and 0.975 quantiles of the realizations were computed as confidence intervals for the predictions. It should be noted that these predictions and confidence intervals should be considered for each variable in turn. Further work is required on how conditional expectations and their uncertainty for compositional variables are most effectively expressed and communicated.



For each realization, the EUNIS level 3 sediment texture classes (Long, 2006) were identified. At each grid node the proportion of realizations that occurred in each class is an estimate of the conditional probability of finding that class at the location. One may report the probability for each class, one may also report the class of maximum probability. The uncertainty attached to treating a site as if the class of maximum probability were the true class there can be evaluated by examining that maximum probability value which may range from just over 1/k (where k is the number of classes) to 1.0.

Metadata

File identifier
f40af0d6-4ca6-41a8-b0cc-1021974f8b17 XML
Metadata language
English
Character set
MD_CharacterSetCode_utf8
Hierarchy level
Dataset
Date stamp
2020-01-15T12:14:03
Metadata standard name

ISO19115

Metadata standard version

2003/Cor.1:2006

Metadata author
Organisation name Individual name Electronic mail address Role

JNCC

HabitatMapping@jncc.gov.uk

Point of contact
 
 

Overviews

Spatial extent

thumbnail

Keywords

GEMET - INSPIRE themes, version 1.0

Habitats and biotopes


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