3D model of a cairn grave near the Bear Trap in Northwest Greenland

• Main Authors: Carlson, Daniel, Walsh, Matthew J., Tesjner, Pelle, Thomsen, Steffen
• Format: Dataset
• Language: English
• Published: 2020
• Subjects: Greenland; Archaeology; Structure from Motion Photogrammetry; 3D model; Cairn; Nuussuaq; Vaigat; greenlandic; kalaallisut
• Online Access: https://zenodo.org/record/3984864; https://doi.org/10.5281/zenodo.3984864

This dataset consists of four files (in addition to the README file) that can be used to view a high-resolution 3D model of a cairn grave that is positioned near ‘The Bear Trap’, a unique Norse ruin at the western end of the Nuussuaq Peninsula in NW Greenland (also called ‘Bjørnefælden’ in Danish, and ‘Putdlagssuaq’ or ‘The Great Trap’ Greenlandic Kalaallisut). The 3D model was created from 641 digital photographs that were processed using Structure from Motion Multiview Stereo photogrammetry software (in this case Agisoft PhotoScan Pro v1.4; Linux Ubuntu). A 24 megapixel Sony a6000 APS-C mirrorless camera fitted with a 17 mm lens was used to acquire ground-level imagery of the structure. Pictures were visually assessed prior to processing in PhotoScan to exclude any that were blurry and/or overexposed. The image alignment or bundle adjustment was performed using ‘High’ accuracy, a key point limit of 60000, no tie point limit, and generic preselection. After the sparse point cloud was created, the bounding box was adjusted to enclose the area of interest and the camera parameters were optimized. Gradual selection was used to remove tie points with relatively high uncertainties. The sparse point cloud was scaled using markers with known dimensions that were placed in the area of interest, and which remained stationary throughout the entire photo survey. The dense point cloud was computed using the ‘Medium’ setting, as attempts to use the ‘High’ setting were unsuccessful due to insufficient memory. The dense point cloud was then used to compute the mesh model using the ‘High’ setting. The model was then exported to the .obj and .mtl files and .pdf file that are provided here. The .obj model can be viewed using Meshlab and the .pdf can be viewed using Adobe Acrobat Reader, both of which are cross-platform and freely available. Instructions are provided in the readme file that accompanies this dataset. The image survey was conducted as part of the Vaigat Iceberg-Microbial Oil Degradation and Archaeological Heritage ...