Orthomosaic Image and Digital Surface Model for the Kotzebue B West Beaver Dams and Ponds site, Baldwin Peninsula, Alaska, 07 August 2023

The Arctic Beaver Observation Network (A-BON): Tracking a new disturbance regime project observes beaver engineering across circumarctic treeline and tundra environments during the last half-century by mapping and tracking beaver ponds using remote sensing imagery. Drones are being used to collect baseline data and track beaver dam building and pond evolution over time. This dataset consists of an orthomosaic and digital surface model (DSM) derived from drone surveys on 07 August 2023 at the Kotzebue B West site on the Baldwin Peninsula, Alaska. 1,069 digital images 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 165 hectares (ha). The drone system was flown at 120 meters (m) above ground level (agl) and flight speeds varied from 8-9 meters/second (m/s). 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. 4.9.0) using the standard 3D Maps workflow and the accurate geolocation and orientation calibration method to produce the orthophoto mosaic and digital surface model at spatial resolutions of 5 and 10 centimeters (cm), respectively. Elevation information derived over waterbodies is noisy and does not represent the surface elevation of the feature. 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 in Ellipsoid Heights (meters).

北极海狸观测网络（Arctic Beaver Observation Network, A-BON）：本项目为新型干扰制度追踪项目，通过遥感影像绘制并追踪海狸池塘，以此监测过去半个世纪环北极林线与苔原环境中的海狸工程活动。当前正依托无人机采集基础数据，追踪海狸坝建造过程与池塘随时间的演化动态。
本数据集包含2023年8月7日于美国阿拉斯加州鲍德温半岛科策布B西点位开展的无人机测绘所生成的正射影像镶嵌图（orthomosaic）与数字表面模型（digital surface model, DSM）。本次测绘采用DJI Phantom 4实时动态定位（DJI P4RTK）四旋翼无人机搭配DJI D-RTK 2移动基站，共采集1069张数码影像。测绘区域面积约165公顷（ha），无人机飞行高度为距地面120米（agl），飞行速度介于8至9米/秒（m/s）之间。相机朝向设置为90度（即垂直向下拍摄），本次任务的航向重叠度与旁向重叠度分别设定为80%与70%。
所有影像均在Pix4D Mapper（v.4.9.0）软件中采用标准三维地图工作流，并通过精准地理定位与姿态校准方法进行处理，分别生成空间分辨率为5厘米（cm）与10厘米（cm）的正射影像镶嵌图与数字表面模型。水体区域提取的高程信息存在噪声，无法代表该地表特征的实际高程。本次任务采用Leica Viva差分全球定位系统（GPS）提供地面控制点，数据经后处理转换至WGS84 UTM 3N坐标系（椭球高，单位：米）。