Use of modern measurement technology as the basis for the reconstruction of a Bronze Age well
During the work of an archaeological excavation campaign at the University of Tübingen, a 3000-year-old well was discovered. It contained a wealth of intact and fallen wooden beams, which were to be documented on the basis of modern surveying and evaluation techniques. For this type of recording, laser scanning and image-based methods were used to document the complex find in the form of 3D models.
The excavations on the ruined mound of Tall Misrife, the ancient Qatna, are part of an international project launched in 1999 in which the University of Tübingen under Prof. Dr. Peter Pfälzner is playing a leading role. The ruined mound of Misrife, covering an area of 100 ha, is home to the largest known Bronze Age city complex in Western Syria. The focus of the excavations was the uncovering of a well in which dozens of intact Bronze Age logs and worked wooden beams were found, including pieces up to 5 metres long. These pieces were preserved by the moist soil in the well for thousands of years and probably belonged to a roof construction that collapsed - possibly in the course of the destruction of the palace - three and a half thousand years ago.
A comprehensive documentation of the wooden finds with regard to their absolute position and their geometric shape was realised by the i3mainz in the period from 2008 to 2012. Terrestrial laser scanning and 3D photogrammetry (Structure from Motion) were used as measuring methods.
The main focus of the laser scanning was to record the continuous recording of the find location for later reconstruction, in order to be able to draw conclusions about the type and manner of destruction. For this purpose, six exposed excavation states of the timber collapse layer were recorded in the form of 3D point clouds.
Photogrammetry was the preferred measurement method for the complete three-dimensional recording of all recovered timber parts and serves as the basis for the reconstruction of the original timber construction.
The transformation of the photogrammetrically generated 3D models to the corresponding absolute find positions in the well was done with the help of the layer-by-layer scanned areas of the well.
The result of the work is a detailed 3D model of the timber collapse situation, which serves for analyses regarding related timber fragments or individual hypotheses of the collapse process. Future objectives are to build up a knowledge-based system which, taking into account interdisciplinary expert knowledge, enables the processing of the information obtained and thus the reconstruction of the well roof.