The ring ditch is in a circular clearing in the woods. The group firstly walked the site, and could feel the level changes underfoot. The plane table was set up in the middle with a spirit level and plumb line, with a tape measure held in position to the outer rim. The exact GPS location of the centre and height above sea level (77m) were recorded Taking lines away from the centre members of the group called out measurements of the high and low points of the ground away from the table. The process was repeated working round in a circle in small segments. The points were plotted on tracing paper and then connected to make the circles at a scale of 1 : 200 giving an average diameter for the ditch of 40 metres.
Here is a picture of the complete ditch taken in February 2017 (thanks to David Allen of the History Society for this image)
Recently (2016) we have obtained LIDAR images of the Wood and Ring Ditch. LIDAR is a laser satellite system which ‘looks through trees’ to see the ground topography. (Public Sector information licensed under the Open Government Licence v3.0)
The ditch is possibly bronze age and may have a religious function – more work/research to do here!
Jemima Woolverton from JIGSAW Cambridge was there to train the group in the techniques and act as team leader. Our thanks to her for past and hopefully future assistance.