
The plan to more closely examine the stone structure began in November 2011 when English Heritage, the U.K. government's statutory adviser on the historic environment, commissioned the most detailed laser scan survey of Stonehenge ever undertaken. During the project, each stone was recorded with point spacing of 0.5 millimeters by the Greenhatch Group survey company. The resulting resource, comprising more than 850 GB of survey data, would lead to new discoveries about the monument.
In April 2012, the enormous task of examining the data was awarded to ArcHeritage, part of the York Archaeological Trust, whose Geomatics and Visualisation team examined the laser scan survey. One challenge was to visualise a large amount of information and identify and isolate very subtle features. Preliminary examination of meshed models showed promising signs of useful information in the data set. For example, individual tool marks more than 5,000 years old could be seen and identified, but there were also tantalizing hints that the data contained prehistoric artwork carved onto the surfaces of the stones.