Tree height and crown diameter during fieldwork expeditions that took place in 2018 in Central Yakutia and Chukotka, Siberia

This Individual-labelled trees dataset is a part of the SiDroForest data collection (https://www.pangaea.de/?q=keyword%3A%22SiDroForest%22) and contains spatial data in the form of points and polygons of 872 trees and shrubs that were recorded in Siberia during a 2-month fieldwork expedition in 2018 by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in Germany (Kruse et al., 2019). During the fieldwork, 15 m radius vegetation surveys were performed during which information such as height, species, crown diameter were recorded for individual trees. In addition, the vegetation plots were covered by 50*50-meter Unmanned Aerial Vehicle (UAV) flights and Red Green Blue (RGB) photographs were taken with a consumer grade DJI Phantom 4 quadcopter (Brieger et al. 2019). From these UAV images, orthoimages were constructed with Agisoft PhotoScan Professional (Agisoft, 2018) using using Structure-from- Motion/Multi-view Stereo (SfM-MVS) techniques. (Agisoft manual 2019). Orthophotos are geometrically corrected images that are georeferenced. When the individual is located in the orthoimage we also know the location of said individual in real life. The construction techniques are explained in detail in Brieger et al (2019). In these orthoimages, individual trees and shrubs recorded during the expeditions were mapped (Fig 1 in README). The trees recorded during fieldwork that could be located in the orthoimages were marked in a point shapefile and polygon shapefile that outlines the tree crown of the individual tree, each element contains the individual number of the tree, the species and the type (Tree or Shrub). In addition, to clarify between Tree and Shrub, the type attribute was added because in the Chukotka sites there are Pinus species that are shrubs which can be misleading. The Point shapefiles also include the x and y coordinates of the point. The individual number can be used to link the tree or shrub to the rest of the information collected during the expedition such as tree height, crown diameter and vitality.

本个体标注型树木数据集隶属于SiDroForest数据集组（https://www.pangaea.de/?q=keyword%3A%22SiDroForest%22），收录了德国阿尔弗雷德·魏格纳研究所亥姆霍兹极地与海洋研究中心（Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research）于2018年开展的为期2个月的野外考察期间，在西伯利亚地区记录的872株乔木与灌木的空间数据，数据以点与多边形形式存储（Kruse et al., 2019）。野外考察期间，研究人员开展了半径15米的植被样地调查，记录了单株树木的树高、物种、冠幅等信息。此外，研究团队使用消费级DJI Phantom 4四旋翼无人机（Unmanned Aerial Vehicle, UAV）对50米×50米的植被样地开展覆盖式航拍作业，并采集了红绿蓝（Red Green Blue, RGB）影像（Brieger et al., 2019）。研究人员借助运动恢复结构/多视图立体（Structure-from-Motion/Multi-view Stereo, SfM-MVS）技术，通过Agisoft PhotoScan Professional（Agisoft, 2018）处理上述无人机航拍影像，生成正射影像（Agisoft官方手册2019）。正射影像是经过几何校正并带有地理参考信息的影像，因此单株个体在正射影像中的位置，即可对应其真实地理坐标。正射影像的构建方法详见Brieger等（2019）。在上述正射影像中，研究人员对野外考察期间记录的单株乔木与灌木进行了矢量化标注（详见README文档中的图1）。野外考察期间记录且可在正射影像中定位的树木，被分别存储于点形状文件（point shapefile）与勾勒单株树木冠幅的多边形形状文件（polygon shapefile）中，每个要素均包含树木个体编号、物种及类型（乔木或灌木）。此外，为明确区分乔木与灌木，研究人员增设了类型属性字段——楚科奇地区存在可被误判的松树属（Pinus）物种。点形状文件还包含该点位的x、y坐标。树木个体编号可用于将单株乔木或灌木与野外考察期间采集的其他数据，如树高、冠幅与活力状况等信息进行关联。