Lasers and Light

Wessex Archaeology were asked to contribute an animation to the new touring version of last year's successful Making History exhibition, organised by the Society of Antiquaries of London. Over the next year, Making History will visit Salisbury, Stoke on Trent, Sunderland, and Lincoln. The exhibition will change at each venue to incorporate aspects of each region's own unique heritage.

Our animation, on show in Salisbury and South Wiltshire Museum until 3rd January 2009 (and at the end of this post!), gave us the opportunity to show some more of our work with the wonderful Stonehenge LiDAR dataset, as well as 3D laser scans of the Amesbury Archer's bones, and some new data captured with the University of Southampton's Archaeology department of WWI and WWII graffiti carved into trees on Salisbury Plain.

Lasers and Light from Wessex Archaeology on Vimeo.

LiDAR uses laser survey equipment mounted in an aeroplane to record the surface of the land below in three dimensions. The animation focuses on a field system in the Stonehenge World Heritage Site. Barely visible on the ground and in aerial photography, the features of the field system are revealed when a low level light is applied to the virtual landscape, throwing the virtual landscape into relief. The light source circles the earthworks, so their extent can be seen from all angles

Lasers can also be used on a smaller scale to study objects in greater detail. Here the skull and some of the long bones from the Amesbury Archer have been scanned. The 3D model has sub-millimetre accuracy, and can be used to study and measure their physical aspects without the need to touch the original.

3D laser scanning has also been used to record graffiti on a tree trunk on Salisbury plain on which the names of soldiers stationed there during training for both World Wars. Since they were carved the tree has grown, the bark expanded and the names have become harder to read. This visualisation shows how 3D data may be able to enhance the carvings and read the names more clearly, preserving them for the future. It may be possible to correlate the information on some of the trees with military records including dates of deployment on Salisbury Plain and the fate of the soldiers who carved their names.

We are very grateful to the Environment Agency for permission to use the LiDAR dataset from Stonehenge, and to Gareth Beale and Graeme Earl from the Archaeological Computing Research Group at the University of Southampton for processing the tree graffiti data during a hectic run-up to a season of excavations in Italy.