Orthomosaic of permafrost landscape on Qikiqtaruk - Hershel Island, Yukon, Canada (August 2017)

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 Image alignment Accuracy: Highest 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 Parameter optimisation: Enabled parameters: F, Cz, Cy, B1, B2, K1, K2, K3, P1, P2 Fit rolling shutter: No Dense cloud Quality: High Depth filtering: Mild Orthomosaic 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.