LiDAR Mapping the Medway Gap
Digital Surface Model of the A2, with Shorne Woods above and Cobham Hall grounds below.
Early in April this year the sky above the Medway gap saw a helicopter weaving its way to and fro, scanning the land below with a laser beam. This was not for some top secret military purpose, but for an archaeological survey. This exciting new technique, now available to archaeologists, is known as LiDAR.
The lasers reflect back from the ground surface below and by using extremely accurate GPS and measuring equipment the distance is measured. Millions of laser beams are projected and read giving a highly detailed map of the ground topography. LiDAR can even map the ground in woodland, stripping back the vegetation to reveal hidden earthworks that would just not be appreciated from the ground. A more detailed explanation of the technology and its applications can be found at http://www.english-heritage.org.uk/publications/light-fantastic/light-fantastic.pdf.
The Medway survey was commissioned and funded mainly by the Heritage Lottery Fund through the Valley of Visions Landscape Partnership Scheme and the Shorne Woods Heritage Project. Additional funds were also provided by Kent County Council and the Forestry Commission. The area surveyed extended from Shorne Woods in the north to the M20 in the south and from Meopham in the west to Bluebell Hill in the east. That adds up to over 100 square kilometers, which was surveyed in a couple of days!
The results have now come in and they are as exciting as we had hoped. LiDAR data comes back in several forms. A ‘surface model’ shows the surface as it would on an aerial photograph, with trees still visible. A ‘terrain model’ strips away the vegetation and shows the ground surface with earthworks, trackways, and in the case of Shorne Woods, the outline of the former quarry and the working strips within it, the former route of Watling Street and the traces of medieval fields and enclosures around Randall Manor.
Overall the LiDAR has provided a stunning new tool to help us to investigate the historic landscape of this archaeologically rich area. Over the coming winter Valley of Visions volunteers and the Shorne Woods Archaeology Group will be taking the survey and going out into the area to examine the features it shows. If you would like to get involved then please contact either Valley of Visions at mail@vov.kentdowns.org.uk or Andrew Mayfield at Shorne Woods - andrew.mayfield@kent.gov.uk. The results of our work will also be posted on the facebook pages www.facebook.com/archaeologyinkent and www.facebook.com/VOVLPS and the Valley of Visions website www.valleyofvisions.org.uk.