Qesem Cave, 3D model and orthophoto, DFG-Project UT41/4-1

A 3D documentation of the cave as a whole and its surroundings (by drone) was carried out in cooperation with D. Hoffmeister and produced a 3D-model of the cave and the current excavation areas available Open Access under Zenodo. Surveys included terrestrial laser scanning of the cave site, drone flights on the slope including the cave site, and tachymetric measurements to establish a combined result of the previously mentioned measurements and an incorporation of the excavation grid and plans. Terrestrial laser scanning was conducted with a FARO Focus 3D LS120 laser scanner set up on 22 single locations. Single laser scans were combined by using the tachymetric measurements of reflecting spheres and a following fine-tuning of this initial registration with an iterative closest point algorithm. The final point cloud consists of 46 million single points. Likewise, 8 ground control points for the drone flights and 10 connection points with the excavation grid were measured by the same method and within the same local surveying system. The drone flight was conducted with a DJI Phantom 4, and the processing of the single images was conducted with Agisoft Metashape. By a mean flight altitude of about 35 m above the terrain, the final digital elevation model resulted in a resolution of 2.6 cm per pixel and the orthophoto in a resolution of 1.3 cm per pixel with an accuracy of about 2 cm. The final 3D point cloud from both surveys was manually cleaned from shrubs, trees etc. and consists of 24 million points used to establish a 3D model by meshing the single 3D points (software: Geomagic Wrap), presented in Figure X. The 3D model was used by the team for a better understanding of the setting and are the basis for ongoing research using Geographic Information Systems (GIS).