Aerial imagery of Ynyslas coastal sand dunes, Wales in 2020

The data contains Aerial imagery of Ynyslas Dunes, Wales saved in a GeoTiff format. The imagery covers 8000 m2 of a discrete coastal sand dune at northern distal end of a spit in Dyfi National Nature Reserve. Data was collected during a six-minute flight on 5th February 2020 made by a DJI Mavic Pro 2 uncrewed aerial vehicle (UAV). The flight was planned with Pix4DCapture based on a ground pixel resolution of 0.01 m. Lateral and longitudinal overlap was set to 80%. Prior to flying, eight (5.8 per 100 photos) Ground Control Points (GCPs) were evenly distributed throughout the dune and their location surveyed using a differential global positioning system (DGPS).

Orthorectification and mosaicking of the aerial imagery collected was performed using Pix4Dmapper utilising a fully automated workflow based on Structure-from-Motion (SFM) digital photogrammetry algorithms. The data was collected to test the accuracy and repeatability of bare sand and vegetation cover in dunes mapped from aerial imagery. Data was collected and processed by Dr Ryan Wilson (University of Huddersfield) and interpreted by Dr Thomas Smyth (University of Huddersfield).

The work was supported by the Natural Environment Research Council NE/T00410X/1.

本数据集包含存储于GeoTiff格式的威尔士因尼斯拉斯（Ynyslas）沙丘航拍影像。该影像覆盖戴菲国家自然保护区（Dyfi National Nature Reserve）沙嘴北端远端区域一处独立沿海沙丘的8000平方米范围。数据采集于2020年2月5日，由DJI Mavic Pro 2型无人驾驶航空飞行器（UAV）执飞，总飞行时长6分钟。此次飞行任务基于0.01米的地面像素分辨率，通过Pix4DCapture规划完成，旁向与航向重叠度均设置为80%。飞行前，在沙丘区域内均匀布设了8个地面控制点（Ground Control Points, GCPs，每100张照片对应5.8个控制点），其位置通过差分全球定位系统（differential global positioning system, DGPS）完成测量。

所采集的航拍影像的正射校正与影像拼接工作通过Pix4Dmapper完成，采用基于运动恢复结构（Structure-from-Motion, SFM）数字摄影测量算法的全自动化作业流程。本数据集的采集旨在验证通过航拍影像绘制的沙丘裸沙与植被覆盖情况的准确性与可重复性。数据集由哈德斯菲尔德大学（University of Huddersfield）的Ryan Wilson博士负责采集与处理，由同校的Thomas Smyth博士完成解译工作。

本研究得到自然环境研究委员会（Natural Environment Research Council）编号NE/T00410X/1的项目资助。