AOC’s survey and geomatics team have been working for several years on the development of techniques for the digitisation, analysis and presentation of carved stones. As highly 3-dimensional objects, the reduction of carved stones to simple 2-dimensional drawings for presentation inevitably simplifies their complexity, while at the same time limiting the viewer to a single perspective.

3D digitisation allows a much more dynamic representation of carved stones to be created. Using 3D laser scanning and other techniques, it is possible to create a highly detailed virtual model of a carved stone- this can then be displayed in a range of ways, for example using raking light to accentuate fine features. By uploading models to websites or embedding in other digital resources, these models can also be manipulated by users, allowing ‘virtual’ interaction with the stones.

A good example of this technique are the stone sarcophagus lids discovered in the Old Steeple in Dundee in the 19th century. Impractical to put on permanent display in the McManus, the stones were 3D laser scanned and a digital resource placed online for use by the public. The project website can be found at aocarchaeology.com/Dundee-medieval-stones

Scotland’s Pictish symbol stones are among the most iconic objects of the early medieval period in Britain, and new examples come to light on a regular basis. The carvings on some are difficult to see, however, and even under dedicated lighting conditions they can be hard to present. High resolution 3D models without colour texture, when displayed under virtual lighting conditions, however, can accentuate faint carvings and illustrate features that are hard to display another way. The recently-discovered symbol stone from Dandaleith (now in Elgin Museum) shows how the technique can emphasise symbols carved on uneven surfaces of coarse boulders.

Digital data has more value than simply as static images, however. In a recent survey of the spectacular cup and ring-marked rocks at Ballochmyle on behalf of Forestry Commission Scotland, the data were used analytically, in order to colourise the digital representation of the rock surface by slope or deviation from local trends, a technique that produced innovative depictions of the rock faces, and new information that could be inspected in the field.

Research into these techniques continues, moving with the new possibilities offered by the latest technological developments. As a company, AOC is committed to developing innovative ways forward that maximise our ability to document, understand and share our heritage.