8262f384-88e7-4dad-89f5-45687b4e2d5a eng utf8 dataset dataset NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom polardatacentre@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact 2025-08-28 ISO 19115 Geographic Information - Metadata ISO 19115:2003(E) European Petroleum Survey Group (EPSG) Geodetic Parameter Registry 2008-11-12 publication European Petroleum Survey Group EPSGadministrator@iogp.org https://www.epsg-registry.org/ EPSG Geodetic Parameter Dataset The EPSG Geodetic Parameter Dataset is a structured dataset of Coordinate Reference Systems and Coordinate Transformations, accessible through this online registry. information publisher urn:ogc:def:crs:EPSG::3031 6.18.3 Imagery and crabeater seal point locations from aerial surveys of Crystal Sound and Marguerite Bay, West Antarctic Peninsula 2015 2025-08-28 creation 2025-08-28 revision 2025-08-28 publication 2025-08-28 released 1.0 https://doi.org/10.5285/8262f384-88e7-4dad-89f5-45687b4e2d5a doi GB/NERC/BAS/PDC/02085 https://data.bas.ac.uk/ NE/W009641/1 award 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 This dataset comprises of vertical aerial imagery of sea ice in Marguerite Bay and Crystal Sound in 2015, the point locations of ice seals detected in that imagery, and polygons denoting the area of the surveys. It was done initially to test the possibility of counting ice seals in aerial and satellite imagery and will be used in future as a baseline dataset to track ice seal abundance in the region. The points were manually digitised in ArcGIS by one observer. The original imagery was taken by operators from the BAS Mapping And Geographic Information Centre. Counting and analysis was part of the NERC grant NE/W009641/1. No credit. completed Fretwell, Peter British Antarctic Survey Researcher author Ireland, Louise British Antarctic Survey Researcher author NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact asNeeded completed EARTH SCIENCE > Spectral/Engineering > Visible Wavelengths > Visible Radiance theme Global Change Master Directory (GCMD) Science Keywords 2026-01-27 publication 23 Global Change Data Center, Science and Exploration Directorate, Goddard Space Flight Center (GSFC) National Aeronautics and Space Administration (NASA) Greenbelt MD United States of America https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords Global Change Master Directory (GCMD) Keywords The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. information publisher Ice seals Lobodon carcinophagus aerial survey crabeater seals population density sea ice theme Marguerite Bay, Western Antarctic Peninsula Antarctica Crystal Sound, Western Antarctic Peninsula Antarctica place otherRestrictions no limitations to public access otherRestrictions no limitations license Open Government Licence v3.0 otherRestrictions This data is governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/ otherRestrictions This data is governed by the NERC data policy and supplied under Open Government Licence v.3 otherRestrictions None. doi doi crossReference url url crossReference textTable eng utf8 biota -66.84 -66.44 -66.54 -66.29 2015-10-31 2015-11-10 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. NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information distributor application/vnd.shp image/tiff bytes 17179869184 http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=8262f384-88e7-4dad-89f5-45687b4e2d5a WWW:LINK-1.0-http--link Get Data Download data download bytes 17179869184 http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=8262f384-88e7-4dad-89f5-45687b4e2d5a WWW:LINK-1.0-http--link Get Data Download data download dataset 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) asNeeded completed