Date (Creation)

2025-08-28

Date (Revision)

2025-08-28

Date (Publication)

2025-08-28

Date (released)

2025-08-28

Edition

1.0

Unique resource identifier

https://doi.org/10.5285/8262f384-88e7-4dad-89f5-45687b4e2d5a

Codespace

doi

Unique resource identifier

GB/NERC/BAS/PDC/02085

Codespace

https://data.bas.ac.uk/

Unique resource identifier

NE/W009641/1

Codespace

award

Other citation details

Please cite this item as: Fretwell, P.T., & Ireland, L. (2025). Imagery and crabeater seal point locations from aerial surveys of Crystal Sound and Marguerite Bay, West Antarctic Peninsula 2015 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/8262f384-88e7-4dad-89f5-45687b4e2d5a

Credit

No credit.

Status

Completed

Point of contact

Organisation name	Individual name	Electronic mail address	Role
British Antarctic Survey	Fretwell, Peter		Author
British Antarctic Survey	Ireland, Louise		Author
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Point of contact

Maintenance and update frequency

As needed

Maintenance note

Completed

Global Change Master Directory (GCMD) Science Keywords

• EARTH SCIENCE > Spectral/Engineering > Visible Wavelengths > Visible Radiance

Theme

• Ice seals

• Lobodon carcinophagus

• aerial survey

• crabeater seals

• population density

• sea ice

Place

• Marguerite Bay, Western Antarctic Peninsula Antarctica

• Crystal Sound, Western Antarctic Peninsula Antarctica

Access constraints

Other restrictions

Other constraints

no limitations to public access

Access constraints

Other restrictions

Other constraints

no limitations

Use constraints

License

Other constraints

Open Government Licence v3.0

Use constraints

Other restrictions

Other constraints

This data is governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/

Use constraints

Other restrictions

Other constraints

This data is governed by the NERC data policy and supplied under Open Government Licence v.3

Use constraints

Other restrictions

Other constraints

None.

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

url

Codespace

url

Association Type

Cross reference

Spatial representation type

Text, table

Language

English

Character set

UTF8

Topic category

• Biota

Begin date

2015-10-31

End date

2015-11-10

Supplemental Information

It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk.

Title

European Petroleum Survey Group (EPSG) Geodetic Parameter Registry

Date (Publication)

2008-11-12

Cited responsible party

Organisation name	Individual name	Electronic mail address	Role
European Petroleum Survey Group		EPSGadministrator@iogp.org	Publisher

Unique resource identifier

urn:ogc:def:crs:EPSG::3031

Version

6.18.3

Hierarchy level

Dataset

Statement

Methodology:

Between 31 October and 10 November 2015, British Antarctic Survey flew three lines of aerial survey over sea ice adjacent to the Antarctic Peninsula to survey pack ice seals. Image coverage of Maguerite Bay was taken twice; once on 31 October, and once on 10 November, to assess the variability of seal presence. A separate line was flown over Crystal Sound on 8 November. A Twin Otter aircraft was mounted with a vertical facing high resolution Z/I Imaging Digital Mapping Camera (DMC) and, flying at a height of 1200m, around 1600km of imagery was acquired of the pack ice with an on-the-ground resolution of 12cm per pixel. Images were taken approximately every 700m and had a 40% overlap. Each image was post processed using the IMU (inertial measurement unit) data from the aircraft that gives position and orientation to enable georectification of each photograph.

In the resulting imagery seals can be clearly seen, often with pups and recent tracks. These seals were manually digitised with a single point placed on each seal in ArcGIS (version 10.4 ESRI 2025). Searching was done systematically at 1:800 scale, where images overlapped, only the seals from the first image viewed was recorded. The resulting point shapefiles record all seals in the three flightlines.

Data collection:

Imagery was acquired using Intergraph's Z/I Imaging Digital Mapping Camera (DMC).

Points were digitised in ArcGIS version 10.4

Trimble Applanix software was used to create the camera centre points from the onboard IMU data.

SOCET GXP was used to undertake the areo-triangularization and georectification of the images.

Data quality:

Spatial resolution of the imagery is 12cm per pixel Ground Sample Distance (GSD).

Seal locations have been marked, but species cannot be differentiated.

No accuracy metrics are included.

Horizontal datum: EPSG:3031 - WGS84 Antarctic Polar Stereographic

Vertical datum: MSL (mean sea level)

Metadata

File identifier

8262f384-88e7-4dad-89f5-45687b4e2d5a XML

Metadata language

English

Character set

UTF8

Hierarchy level

Dataset

Hierarchy level name

dataset

Date stamp

2025-08-28

Metadata standard name

ISO 19115 Geographic Information - Metadata

Metadata standard version

ISO 19115:2003(E)

Metadata author

Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		polardatacentre@bas.ac.uk	Point of contact