Multispectral Orthomosaic Image for the Glacier Creek Road Beaver Dams and Ponds, Seward Peninsula, Alaska, 09 August 2021

Emergence of beavers as ecosystem engineers in the New Arctic project focuses on establishing field sites at tundra beaver ponds to study the implications of beaver engineering on hydrology and permafrost. Drones are being used to collect baseline data and track beaver dam building and pond evolution over time. This dataset consists of a multispectral orthomosaic derived from drone surveys on 09 August 2021 at the Glacier Creek Road site on the Seward Peninsula, Alaska. 3,648 digital images from five spectral bands were acquired from a DJI Phantom 4 Real-Time Kinematic (DJI P4RTK) quadcopter with a DJI D-RTK 2 Mobile Base Station. The mapped area was around 45 hectares (ha). The drone system was flown at 120 meters (m) above ground level (agl) and images were captured using the hover and capture at point mode. The orientation of the camera was set to 90 degrees (i.e. looking straight down). The along-track overlap and across-track overlap of the mission were set at 80% and 70%, respectively. All images were processed in the software Pix4D Mapper (v. 4.8.4) using the standard 3D Maps workflow and the accurate geolocation and orientation calibration method to produce the multispectral orthophoto mosaic at a spatial resolution of 10 centimeters (cm). Images of a MicaSense calibrated reflectance panel were used for radiometric processing and calibration of each spectral band in the Index Calculator in Pix4D. A Leica Viva differential global positioning system (GPS) provided ground control for the mission and the data were post-processed to WGS84 UTM Zone 3 North.

“新北极区域海狸作为生态系统工程师”研究项目聚焦于在苔原海狸池塘设立野外样地，以探究海狸工程活动对水文与永久冻土的影响。本项目借助无人机采集基线数据，并长期追踪海狸水坝修建与池塘演化过程。本数据集源自2021年8月9日在阿拉斯加州苏厄德半岛冰川溪路（Glacier Creek Road）样地开展的无人机航拍所生成的多光谱正射镶嵌图（multispectral orthomosaic）。本次航拍采用DJI Phantom 4 实时动态差分（DJI Phantom 4 Real-Time Kinematic，简称DJI P4RTK）四旋翼无人机搭配DJI D-RTK 2移动基准站，共获取5个光谱波段的3648张数字影像。航拍覆盖区域约45公顷（ha）。无人机飞行高度设定为距地面120米（agl），影像采集采用悬停定点拍摄模式，相机朝向设置为90度垂直向下。本次任务的航向重叠度与旁向重叠度分别设置为80%与70%。所有影像均通过Pix4D Mapper软件（版本4.8.4），采用标准三维地图作业流程结合精准地理定位与姿态校准方法进行处理，最终生成空间分辨率为10厘米（cm）的多光谱正射影像镶嵌图。研究采用MicaSense校准反射板的影像，在Pix4D的指数计算器（Index Calculator）中完成各光谱波段的辐射定标与辐射处理。本次任务采用徕卡Viva差分全球定位系统（GPS）作为地面控制点，并将数据后处理至WGS84 UTM Zone 3 North坐标系。