The contact goniometer is a commonly used tool in archaeological analysis, despite suffering from a number of shortcomings due to the physical interaction between the measuring implement, the object being measured, and the individual taking the measurements. However, lacking a simple and efficient alternative, researchers in a variety of fields continue to use the contact goniometer to this day. In this paper, we present a new goniometric method that we call the virtual goniometer, which takes angle measurements on a 3D model of an object. The virtual goniometer allows for rapid data collection, and for the measurement of many angles that cannot be physically accessed by a manual goniometer. Using fracture angle measurements on bone fragments, we compare the intra-observer variability of the manual and virtual goniometers, and find that the virtual goniometer is far more consistent and reliable. Furthermore, the virtual goniometer allows for precise replication of angle measurements, even among multiple users, which is important for reproducibility of goniometric-based research. The virtual goniometer is available as a plug-in in the open source mesh processing packages Meshlab and Blender, making it easily accessible to researchers exploring the potential for goniometry to improve archaeological methods and address anthropological questions.
Bibliographical noteFunding Information:
We would like to thank the National Science Foundation NSF Grant DMS-1816917 and the University of Minnesota’s Department of Anthropology for funding this research.
Thank you to Scott Salonek with the Elk Marketing Council and Christine Kvapil with Crescent Quality Meats for the bones used in this research. We thank the hyenas and their caretakers at the Milwaukee County Zoo and Irvine Park Zoo in Chippewa Falls, Wisconsin and the various math and anthropology student volunteers who broke bones using stone tools. Thank you to Sevin Antley, Chloe Siewart, Mckenzie Sweno, Alexa Krahn, Monica Msechu, Fiona Statz, Emily Sponsel, Kameron Kopps, and Kyra Johnson for helping to break, clean, curate and prepare fragments for scanning. Thank you to Cassandra Koldenhoven and Todd Kes in the Department of Radiology at the Center for Magnetic Resonance Research (CMRR) for CT scanning the fragments. Thank you to Samantha Porter with the University of Minnesota?s Advanced Imaging Service for Objects and Spaces (AISOS) who scanned the crystal. Bo Hessburg and Pedro Angulo-Uma?a worked on the virtual goniometer. Pedro and Carter Chain worked on surfacing the CT scans. Thank you Matt Edling and the University of Minnesota?s Evolutionary Anthropology Labs for support in coordinating sessions for bone breakage and guidance for curation. Thank you Abby Brown and the Anatomy Laboratory in the University of Minnesota?s College of Veterinary Medicine for providing protocols and a facility to clean bones. Thank you Henry Wyneken and the Liberal Arts Technologies and Innovation Services (LATIS) for statistical consulting. We would also like to thank the two anonymous referees whose feedback helped improve this paper.
© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
- Bone fragments
- Fracture angle