Evaluating rangeland condition using fine-scale remote sensing from unoccupied aerial vehicles

This repository contains drone data from vegetation surveys conducted in 2024 in the Kalahari savanna ecosystem of Botswana. Surveys were carried out at three 50 × 50 m areas of interest (AOI) representing high, medium, and low grazing intensity. To acquire RGB images for SfM canopy height modelling, we used a DJI Phantom 4 Pro drone. To capture spectral reflectance data, we used the DJI Phantom 4 Multispectral drone. There are four main outputs for each survey: SfM point cloud—Generated in Agisoft Metashape from RGB imagery, provided in .laz format, representing the full 3D structure of the surveyed area. RGB orthomosaic—stitched from the same SfM process, using multiple overlapping RGB UAV images captured at a spatial grain of ca. 5 mm with 80 % front and side overlap. Canopy height model (CHM)—generated in R from the SfM point cloud, showing vegetation height above ground level. Multispectral orthomosaic—produced from multispectral imagery in Agisoft Metashape, including derived vegetation index layers. A CSV file contains ground-measured above-ground biomass (g/m²) from 30 circular plots per site (33 cm radius). These measurements are labelled with the corresponding plot ID codes, plot coordinates, AOI, and dominant herbaceous species. Please see the README file for further details on the data contents. For any queries on this dataset, please contact Alan Nare ([e-mail]) and Andrew Cunliffe ([e-mail]).本数据集仓库包含2024年于博茨瓦纳喀拉哈里稀树草原生态系统开展植被调查所获取的无人机采集数据。本次调查共设置3块50×50米的关注区域（Area of Interest, AOI），分别对应高、中、低三级放牧强度。为获取用于运动恢复结构（Structure from Motion, SfM）冠层高度建模的RGB影像，研究采用了大疆精灵4 Pro（DJI Phantom 4 Pro）无人机；为采集光谱反射率数据，则使用了大疆精灵4多光谱（DJI Phantom 4 Multispectral）无人机。 每项调查共生成四类核心成果： 1. SfM点云：通过Agisoft Metashape基于RGB影像生成，格式为.laz，可完整呈现调查区域的三维结构。 2. RGB正射影像：由同一SfM流程拼接得到，所用的重叠RGB无人机航拍影像空间分辨率约为5毫米，航向与旁向重叠度均为80%。 3. 冠层高度模型（Canopy Height Model, CHM）：基于SfM点云通过R语言计算生成，用于展示植被相对于地面的高度信息。 4. 多光谱正射影像：由Agisoft Metashape基于多光谱影像生成，包含衍生的植被指数图层。 另有一份CSV文件，包含各调查点位30个半径33厘米的圆形样地的地面实测地上生物量数据（单位：克/平方米）。该数据集标注有对应的样地ID编码、样地坐标、所属关注区域以及优势草本物种信息。 有关数据集的详细内容，请参阅项目README文件。若对本数据集有任何疑问，请联系Alan Nare（邮箱：[e-mail]）与Andrew Cunliffe（邮箱：[e-mail]）。