Drone aerial imagery of macroalgae growing around a small island in Kobbefjord (SW Greenland) acquired during Mission Arctic 2017

Aerial images of a small island in Kobbefjord (SW Greenland) were acquired on 5 July 2017 using a DJI Phantom 3 Standard quadcopter drone. The imagery was acquired during the Mission Arctic citizen science expedition (http://www.missionarctic.com/). Overlapping images were acquired during two consecutive flights using the 'interval' setting with a period of 5 seconds in the DJI Go app. The drone was flown manually around the island. This drone survey was carried out with two primary objectives in mind: 1) Identify and quantify the macroalgae growing along the island's periphery; 2) Identify any archaeological and cultural heritage sites that may be present on the island. The images were processed using Agisoft PhotoScan Pro (v1.4.4; Linux Ubuntu). Images were aligned using the script CARMA_PhotoScan_Align.py (see this script for settings). After image alignment, the bounding box was visually inspected and the sparse point cloud was thinned using thresholds for the reconstruction uncertainty, projection accuracy, and reprojection error (gradual selection). The remaining tie points in the sparse cloud were then used to build the dense cloud. The settings used for this step can be found in the script CARMA_PhotoScan_GS_DC_v2.py. Next, the dense point cloud was used to generate a digital elevation model (DEM) and, subsequently, an orthomosaic. The Agisoft PhotoScan processing report is also included