This paper tests the applicability of an unmanned aerial system (UAS) in obtaining spatial data from archaeological sites in forested areas. Our case study discusses the remains of the anti-Turkish fortifications called ‘Turške Šance’—the defensive ditches that are preserved in the area of the Preški vrh (Ravne na Koroškem, Slovenia). Up to 10 fortifications of various shapes and sizes were built in the last quarter of the 15th century. Today, they represent a unique archaeological site. A detailed geodetic survey of the site was performed and compared with results of photogrammetry using the DJI Phantom 4 PRO UAS drone and DJI Phantom camera. Furthermore, official Slovenian LiDAR data of the area were obtained, and archaeologic field surveys, in situ inspections and metal detector scanning were made. The points obtained from the total station were used for 3D modelling and taken as a reference. Drone photogrammetry was performed once per week to compare each point cloud with another using CloudCompare and to the reference one depending on the volume of the tree leaves which was estimated with green leaf index (GLI) and leaf area index (LAI). The increase of the tree leaves volume deteriorates the point cloud obtained with a UAS. The paper analyses how significant this influence is. As expected, the impact grows more severe with the increase in leaf mass from week to week.

中文翻译：

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半专业无人机系统在林区快速考古记录中的适用性

本文测试了无人机系统 (UAS) 在从森林地区的考古遗址获取空间数据的适用性。我们的案例研究讨论了被称为“Turške Šance”的反土耳其防御工事的遗迹——Preški vrh（斯洛文尼亚的 Ravne na Koroškem）地区保留的防御性沟渠。15 世纪最后 25 年建造了多达 10 座不同形状和大小的防御工事。今天，它们代表了一个独特的考古遗址。对该场地进行了详细的大地测量，并与使用 DJI Phantom 4 PRO UAS 无人机和 DJI Phantom 相机的摄影测量结果进行了比较。此外，还获得了该地区的斯洛文尼亚官方激光雷达数据，并进行了考古实地调查、原位检查和金属探测器扫描。从全站仪获得的点用于3D建模并作为参考。每周进行一次无人机摄影测量，以使用 CloudCompare 将每个点云与另一个点云进行比较，并根据使用绿叶指数 (GLI) 和叶面积指数 (LAI) 估计的树叶体积将每个点云与参考点云进行比较。树叶体积的增加会恶化使用 UAS 获得的点云。本文分析了这种影响的重要性。正如预期的那样，随着叶质量逐周增加，影响变得更加严重。每周进行一次无人机摄影测量，以使用 CloudCompare 将每个点云与另一个点云进行比较，并根据使用绿叶指数 (GLI) 和叶面积指数 (LAI) 估计的树叶体积将每个点云与参考点云进行比较。树叶体积的增加会恶化使用 UAS 获得的点云。本文分析了这种影响的重要性。正如预期的那样，随着叶质量逐周增加，影响变得更加严重。每周进行一次无人机摄影测量，以使用 CloudCompare 将每个点云与另一个点云进行比较，并根据使用绿叶指数 (GLI) 和叶面积指数 (LAI) 估计的树叶体积将每个点云与参考点云进行比较。树叶体积的增加会恶化使用 UAS 获得的点云。本文分析了这种影响的重要性。正如预期的那样，随着叶质量逐周增加，影响变得更加严重。