This red-green-blue (RGB) orthomosaic is composite created from 8994 photographs collected withunmanned aerial vehicles (UAVs) over the eastern part of Qikiqtaruk, Herschel Island, in the Canadian Yukon (69.5N, 138.8W). The images were collected on the 10th and 11th of August 2017. Further details on the image processing are provided in the Lineage section. This dataset was created by Andrew Cunliffe, with support from Isla Myers-Smith, William Palmer, Jeffrey Kerby and other members of Team Shrub (https://teamshrub.com/), in order to inform ongoing ecological monitoring studies in this area. Part of this orthomosaic was used for a study into permafrost coastline retreat, published in The Cryosphere (Cunliffe, A. M., Tanski, G., Radosavljevic, B., Palmer, W. F., Sachs, T., Lantuit, H., Kerby, J. T., and Myers-Smith, I. H.: Rapid retreat of permafrost coastline observed with aerial drone photogrammetry, The Cryosphere, 13, 1513-1528, https://doi.org/10.5194/tc-13-1513-2019, 2019).
Arctic, Coastline, Landscape, Permafrost
|ISO Topic Categories:||
|Name||Dr Andrew M Cunliffe|
|Organisation||School of GeoSciences, University of Edinburgh|
|Reference:||This dataset was used in the publication: Cunliffe, A. M., Tanski, G., Radosavljevic, B., Palmer, W. F., Sachs, T., Lantuit, H., Kerby, J. T., and Myers-Smith, I. H.: Rapid retreat of permafrost coastline observed with aerial drone photogrammetry, The Cryosphere, 13, 1513-1528, https://doi.org/10.5194/tc-13-1513-2019, 2019|
|Quality:||There are some small missing areas within the orthomosaic, due to insufficient image overlap of these areas (nodata is indicated by value of 255 in the Red, Green and Blue bands). Some artefacts (distortion) in the orthomosaic are expected around the periphery of the survey area, particularly where (reflective or moving) water is present.|
|Lineage:||Drone surveys were conducted using two platforms: (i) a lightweight flyingwing Zeta Phantom FX-61 with a PixHawk flight controller equipped with a Sony RX-100ii camera (100 CMOS sensor with 20.2 megapixels) and (ii) a multi-rotor DJI Phantom 4 Pro (100 CMOS sensor with 20 megapixels). Typical flying altitude was between 100 and 120 m above ground level, yielding ground sampling distances of ca. 20 to 40mm, with image overlap of more than nine photographs across most (90%) of the scene.
Spatial constraint of the orthomosaic was achieved through geotagging of individual camera positions with the UAV location, combined with n=132 black and white ground control markers deployed across the scene and precisely geolocated to an absolute accuracy of approximately 0.02m using real-time kinematic global navigation satellite system (GNSS) equipment (Leica Geosystems).
These photographs were processed using Agisoft PhotoScan (version 1.3.3) (https://www.agisoft.com/), to a spatial reference system of NAD83 UTM 7N (EPSG: 26907). The following quality settings were used:
Image quality assessment
Minimum quality score ≥0.7
Generic preselection: Yes
Reference preselection: Yes
Key point limit: 40,000
Tie point limit: 0
Adaptive camera model fitting: No
Tie point filtering
Reprojection error threshold: 0.45
Enabled parameters: F, Cz, Cy, B1, B2, K1, K2, K3, P1, P2
Fit rolling shutter: No
Depth filtering: Mild
Mapping mode: Orthophoto
Blending mode: Mosaic
Enable colour correction: Yes
Enable hole filling: Yes
For additional information on the production and use of this dataset, please refer to: Rapid retreat of permafrost coastline observed with aerial drone photogrammetry, Cunliffe, A. M., Tanski, G., Radosavljevic, B., Palmer, W. F., Sachs, T., Lantuit, H., Kerby, J. T., and Myers-Smith, I. H.: Rapid retreat of permafrost coastline observed with aerial drone photogrammetry, The Cryosphere, 13, 1513-1528, https://doi.org/10.5194/tc-13-1513-2019, 2019 and also the supplementary information accompanying the article.
|Data Set Creator||Cunliffe, A., Myers-Smith, I., Kerby, J., Palmer, W.|
|Data Set Title||Orthomosaic of permafrost landscape on Qikiqtaruk - Hershel Island, Yukon, Canada (August 2017)|
|Data Set Release Date||2019|
|Data Set Publisher||Polar Data Centre, British Antarctic Survey, NERC, Cambridge, UK.|
|Other Citation Details||shortdoi:10/c6v8|
|Horizontal Resolution Range||< 1 meter|
|Vertical Resolution Range||N/A|
|Temporal Resolution Range||Daily - < Weekly|
|Detailed Location||Qikiqtaruk, Herschel Island|
|Distribution Media||Online Internet (HTTP)|
|Distribution Size||27 GB|
|Data Storage:||The tiled orthomosaic consists of 51 geotiff files, each of which is 547,623 KB in size.|
|Use Constraints:||This data is covered by a UK Open Government Licence (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/). Further by downloading this data the user acknowledges that they agree with the NERC data policy (http://www.nerc.ac.uk/research/sites/data/policy.asp), and the following conditions:
1. To cite both the data and literature references in any publications that use this data.
Andrew M. Cunliffe, Isla H. Myers-Smith, Jeffrey T. Kerby and William F. Palmer.(2019):Orthomosaic of permafrost landscape on Qikiqtaruk - Hershel Island, Yukon, Canada (August 2017). UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation.
A. Cunliffe*, G. Tanski*, B. Radosavljevic, W. Palmer, T. Sachs, H. Lantuit, J. Kerby, and I. Myers-Smith (2019) Accelerating retreat of permafrost coastline observed by combining long-term observations with aerial drone surveys. The Cryosphere. 13(5):1513-1528. doi:10.5194/tc-13-1513-2019
2. The user recognizes the limitations of data and will not use this data for navigation purposes. Use of the data is at the users' own risk, and there is no warranty as to the quality or accuracy of any data, or the fitness of the data for your intended use. The data are not necessarily fully quality assured and cannot be expected to be free from measurement uncertainty, systematic biases, or errors of interpretation or analysis, and may include inaccuracies in error margins quoted with the data.