Abstract:
Aerial survey of the Hound Bay elephant seal colony during the 2022/23 season conducted using a RPAS (remotely piloted aerial system).
The aerial survey was conducted as part of the Darwin Plus (DPLUS) 109 project: Initiating Monitoring Support for the SGSSI-MPA Research and Monitoring Plan for the purpose of establishing a baseline population estimate of key indicator species around South Georgia.
Dataset includes the original images and log files, the original RINEX GNSS (global navigation satellite system) base station files, the post-processed GNSS and imagery data, along with the resulting georeferenced DSM (digital surface model) and an orthorectified mosaic of the imagery.
This dataset is from flight number DPLUS_109_35 and was carried out on 26/10/2022.
This work was supported by the Overseas Territories Environment and Climate Fund under Grant Darwin Plus ref: DPLUS109: Initiating monitoring support for the SGSSI-MPA Research and Monitoring Plan. Funding for this work was also received from the UK Blue Belt fund through GSGSSI.
Keywords:
Aerial Survey, Digital Surface Model, Drone, Elephant Seal, Orthorectified Mosaic, South Georgia
Fenney, N., Hollyman, P., Coleman, J., Fox, A., Trathan, P., & Collins, M. (2024). Aerial survey of the Hound Bay, South Georgia, elephant seal colony during the 2022/23 season, flight number DPLUS_109_35 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/eb210711-85e1-4671-97a8-8c2791979a19
| Access Constraints: | Data under embargo until 31/12/2025. |
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| Use Constraints: | Data supplied under Open Government Licence v3.0 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2024-10-01 |
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| Dataset Progress: | Planned |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | PDC BAS |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Philip R Hollyman |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Nathan Fenney |
| Role(s) | Investigator, Technical Contact |
| Organisation | British Antarctic Survey |
| Name | Jamie Coleman |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Dr Adrian J Fox |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Dr Philip N Trathan |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Dr Martin A Collins |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
| Reference: | Fenney, N., Coleman, J., Fox, A., Trathan, P., N., Collins, M., A. and Hollyman, P., R., The application of autonomous fixed-wing drones operating beyond visual line of sight in the sub-Antarctic to enable large area population monitoring of key species in a changing environment, manuscript submitted for publication (copy on file with author). | |
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| Quality: | Please refer to Fenney et al. for further information on the data collection and post processing methodologies. PPP processing accuracy is reported in the CSRS PPP processing report (.pdf). PPK processing accuracy (by image) is reported in the eMotion camera centre geoinfo file (.txt). Data resolution Target GSD of aerial survey (1.9 cm). Resolution of final outputs: DSM (1.9 cm) Orthorectified mosaic (1.9 cm) |
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| Lineage: | Data collection: Aerial survey conducted using a RPAS (AgEagle eBee X). The survey consisted of collecting overlapping imagery of the target area, with a minimum forward overlap of 80% and a side overlap of 60%. The altitude during acquisition was species specific, determined by the required ground sampling distance (GSD), but was generally between 80 m and 120 m AGL (above ground level). During the aerial surveys a geodetic Trimble GNSS base station receiver collected data. Post flight processing: Precise point positioning (PPP) was undertaken using the online Canadian Spatial Reference System PPP tool to generate the position of the base station during the survey. The PPP solution generated was then used to process the eBee X's onboard GNSS receiver using post-processed kinematic (PPK) processing within eMotion to improve the accuracy of the camera centres captured during flight. Once complete, the coordinates for each image was then updated in the EXIF data and reexported from eMotion as .jpg's. Photogrammetry / final outputs: Structure from motion photogrammetry was used to determine the exterior orientation (x, y, z, omega, phi and kappa (or roll, pitch, yaw)) of the camera during image acquisition using a combination of the PPK solutions and common points within the images. Once the camera centre and orientation for each image was determined, a dense point cloud was extracted of the surface within the target area. The dense point cloud was then transformed into a DSM, which in turn was used to resample the images onto a map projection, removing camera perspective and terrain distortions, in a process called ortho-rectification and resulted in a single complete mosaic of the imagery. Please refer to Fenney et al. for further information on the data collection and post processing methodologies. |
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| Temporal Coverage: | |
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| Start Date | 2022-10-26 |
| End Date | 2022-10-26 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -54.39495 |
| Northernmost | -54.38725 |
| Longitude | |
| Westernmost | -36.26799 |
| Easternmost | -36.25627 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Location: | |
| Location | South Georgia Island |
| Detailed Location | Hound Bay |
| Data Collection: | Data collection equipment: UAV: Manufacturer: AgEagle Model: eBee X Sensor: AgEagle Aeria X (RBG camera) Flight management software: eMotion (version 3.20.0 and version 3.22.0) GNSS base station: Manufacturer: Trimble Receiver model: R9s Antenna model: Zyphr Model 2 Post-flight processing software: Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP, Version 3) eMotion (version 3.20.0 and version 3.22.0) Photogrammetry software: Agisoft Metashape (version 1.8.4 build 14671) or Pix4D (version 4.7.5.). |
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| Data Storage: | Data is archived using the following structure. Total size: 9.90 GB. 01_flight data: gnss. RINEX files (.YYg, .YYh, .YYn, .YYo,). Each file follows the same naming convention. For example, observation file 10023560.21o refers to the serial number of receiver (1002), day of year (356), session number (0) and file extension (.21o). 01_flight data: imagery. Image files (.jpg, .dng). Each file follows the same naming convention. For example, image file IX-12-29034_0069_0001.jpg refers to the platform ID (IX-12-29034 ), the sortie number (0069), the image number (0001) and the file extension (.jpg). 01_flight data: logs. UAV log files (.bb3). Please note, due to the nature of these files they are not available in open format. Each file follows the same naming convention. For example, log file IX-12-29034_0069_part001.bb3 refers to the platform ID (IX-12-29034 ), the sortie number (0069), the part number (part001) and the file extension (.bb3). 02_post_flight_output: csrs_ppp_output. CSRS PPP processing output files (.clk, .csv, .pdf, .pos, .sum, .tro). Each file follows the same naming convention. For example, file 10023560.pdf refers to the serial number of receiver (1002), day of year (356), session number (0) and file extension (.21o). 02_post_flight_output: emotion_output. PPK processed image files (.jpg). Each file follows the same naming convention. For example, image file IX-12-29034_0069_0001.jpg refers to the platform ID (IX-12-29034 ), the sortie number (0069), the image number (0001) and the file extension (.jpg). PPK processed camera centres (.txt). Each file follows the same naming convention. For example, file IX-12-29034_0069_emotion_geoinfo.txt refers to the platform ID (IX-12-29034 ), the sortie number (0069), program name (emotion), information type (geoinfo) and the file extension (.txt). 03_final_outouts: dsm. Final digital surface model files (.tif). Each file follows the same naming convention. For example, file stromness_fur_seal_dsm_eBee_X_DPlus109_21_22_UTM_24S_WGS84_HAE_IX-12-29034_0069.tif refers to the location (stromness), the species (fur_seal), data type (dsm), platform type (eBee_X), project (DPlus109), season (21_22), horizontal coordinate system (UTM_24S), ellipsoid (WGS84), vertical datum (HAE), platform ID, (IX-12-29034) and the file extension (.tiff). 03_final_outouts: ortho. Final orthorectified moasic files (.tif). Each file follows the same naming convention. For example, file stromness_harbour_fur_seal_ortho_eBee_X_DPlus109_21_22_UTM_24S_WGS84_HAE_IX-12-29034_0069.tif refers to the location (stromness), the species (fur_seal), data type (ortho), platform type (eBee_X), project (DPlus109), season (21_22), horizontal coordinate system (UTM_24S), ellipsoid (WGS84), vertical datum (HAE), platform ID, (IX-12-29034) and the file extension (.tiff). |
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