The team at ORCA are well versed in tackling any archaeology job in almost any weather! When a client asks for a project to be completed on time and in budget then the team provide solutions and get the job done - even when the Scottish climate does it's best to make things a little difficult.
The picture shows ORCA Project Officer Rick Barton preparing to complete a survey of eroding archaeology on one of the northern islands in Orkney. Rick and Paul Sharman, ORCA Senior Project Officer, first assessed the situation in terms of Health and Safety and ,judging the situation to be safe, worked in torrential rain and very difficult conditions to identify features from an excavation completed in 1982.
For Paul, this was a back to the future experience as he originally worked on this particular site as a young graduate. Rick added to the occasion by reminding Paul that he wouldn't have been allowed to work on that dig because he was only one year old at the time. Paul's reaction is not noted in the documentation!
Archaeology is increasingly using technology to both shed new light on research questions and speed up processes in a drive to become more efficient. ORCA is investing in new technologies and the skills that people such as Jim Bright are now bringing to commercial archaeology.
Jim is a recent MSc graduate of the UHI Archaeology Institute who has developed photogrammetry and 3D modelling through his research at the world-renowned Neolithic excavation at the Ness of Brodgar and the equally important Iron Age dig at The Cairns, South Ronaldsay, Orkney.
Photogrammetry is a method by which a vast number of photographs can be converted into 3D computer models, which can then be viewed by anyone who possesses a computer and readily accessible social media platforms such as Sketchfab.
Following discussions with Pete Higgins, Senior Project Manager Orkney Research Centre for Archaeology, the ORCA team realised that Jim’s skills could be used in a commercial archaeology setting to offer clients a new resource and service. 3D modelling is a powerful resource, which can be used to aid client’s own public relations activity, but also, due to the accuracy inherent in the data collection methods, the technique is also used to record archaeologically important sites; replacing time consuming hand drawing– saving precious time on clients sites.
The main tools used are a camera, a Nikon D60 SLR and the software AgiSoft PhotoScan. The process of creating a good 3D model of a structure or item is a multi-phased one. Firstly Jim photographs the area around the object or area for modelling, making sure that the photographs overlap at every angle. Once all the photos had been taken they are uploaded into the software where each photo is checked, removing any blurry or unwanted areas using the masking tool. The alignment process can then begin, this is where the software takes millions of points in each photograph, compares them to the other photographs to identify the position and angle in which they were taken, and from this generate a base point cloud.
Once this is done, any potential errors or bad data can be removed by selecting certain parameters in the software before beginning the dense point cloud generation, where millions of points in a model are created as you can see in the two pictures below, the top image is of the whole model and the bottom one is zoomed right in so you can see all the points which make up the model.
When the dense point cloud has been made, the model is trimmed and tidied before creating the wireframe mesh, where the points are essentially joined up, and millions of triangles or faces are created ready for textures to be painted onto them. The texture file is made up of all the photographs taken to create the model which will then be wrapped around the mesh. The texture generation is the final process in the workflow of creating a 3D model.
That data’s geolocation coordinates are recorded using a total station theodolite (an electronic/optical instrument used for surveying and building construction). Once input, the ruler tool becomes available in the software, which allows the user to measure the 3D model down to the nearest millimetre.
The 3D models can be used as embedded images in presentations, press releases or social media have been used as an addition to the archaeological record of certain trenches, where models are created at different phases of excavation.
The archaeological work on the hospital site was successful in identifying where the archaeology was located and informing the strategy to avoid it.
An archaeological watching brief was undertaken on behalf of NHS Orkney, during the topsoil strip by machine, across the site of the new hospital and healthcare facilities in Kirkwall from the 24/04/2017 - 1/05/2017.
During the watching brief a number of linear features, interpreted as post-medieval land drains and boundary ditches were identified. Also identified was the edge of a former quarry pit that was shown on the First Edition 6-inch Ordnance Survey map.
The watching brief confirmed that the surviving significant (prehistoric) archaeology was focused in the area investigated during the evaluation in Trenches 1 and 9
This area had been avoided by the design for the current scheme of works. No features or material of archaeological significance were identified during the programme of archaeological works.
This blog has been created by Orkney Research Centre for Archaeology in beautiful Orkney. We aim to add features and news about our work on the islands and further afield on a regular basis.