Digital excavation recording at Keiss Broch, Caithness

As part of the Knowledge Transfer Project, AOC Archaeology Group and The University of Nottingham have been developing laser scanning as means of creating digital terrain models. The project has focussed on producing raster and TIN digital terrain models compatible with standard desktop GIS georeferenced to ordnance survey co-ordinates. This technique has been used to record archaeological landscapes at Keiss, Caithness, resulting in a terrain model of the foreshore area containing ‘broch village’ complexes.

By integrating data collected using more traditional survey equipment, however, we have also been able to introduce ‘interpreted’ data into laser scan point clouds. During the excavation of Keiss Harbour broch in Caithness in 2006, part of the River of Stone Project, laser scanning was employed alongside traditional recording as a means of documenting the deposits and built structures encountered. Scanning was carried out at every stage where a hand-drawn plan was deemed necessary, and the resulting point-clouds registered to a common Ordnance Survey georeferenced site grid. Each stage of the excavation could thereby be overlain on the previous scan, providing phased plans that showed the depths of removed material. By digitising the resulting point-clouds in CAD, two-dimensional plans were produced and registered in to the site survey in GIS. By recording the locations of all finds and samples retrieved during the excavation in the same georeferenced coordinate system, a GIS project was compiled recording the locations of all significant archaeological material. The result is a step towards 3D recording of archaeological excavations. Further development of the technique is planned for future seasons of excavation.

KTP Associate: Dr Graeme Cavers
AOC Partner: John Barber
University of Nottingham Partner: Dr Jon Henderson