We plotted the straight sections of the larger cursuses in GIS, and then extended the lines across the mainland of Britain.
It was apparent that some cursus lines aligned on a regionally significant hill. For example, the Stanwell cursus aligns on Leith Hill (Surrey) whilst the Aston cursus could have been intended to align far to the south west on Rippon Tor or Ryders Hill (both Dartmoor, Devon).
It was also noticed that exactly at right angles to some cursus sections lies a prominent, although not necessarily high, hill. Examples include Greater Cursus and Lesser Cursus both to Old Sarum; two sections of Gussage to Winklebury Hill and Drayton North to the Sinodun Hills
Some remarkable geometry also appeared consisting of right angled triangles and isoceles triangles, The angles within the triangles were usually multiples of 10 and/or15 degrees including 15, 30, 45, 60, 75.
It seems that the cursuses were part of a vast geometric scheme that was designed to relate to the landscape. The end result was very complex. However, if one assumes that the cursuses which were fundamental to the scheme needed to be the most accurate, and therefore were the largest, we can deduce fundamental parts of the design.
Such a scheme would have to be pre-planned with knowledge of the landscape from a previous survey - we suggest from the Enclosure survey.
The maps on the next page show likely key lines for southern Britain. Note, however, that recent analysis suggests Dunkery Beacon did not play the pivotal role as indicated.
INTERPRETATION
These observations are consistent with the idea that, for a period, Neolithic surveyors chose to survey the mainland of Britain by imposing a triangular geometry across it.
The earlier Enclosures method extended the survey across the landscape by moving in a crab like manner, identifying and incorporating the next survey stations as it went. The Cursus survey was very different in that it followed a top down design which was planned in advance to cover at least the whole mainland, and probably islands such as Orkney too.
The design may have used Dunkery Beacon to Leith Hill as a baseline at some point, but the line due west from Leith Hill - which isn't quite the same - is what was settled upon given the Greater Cursus west end was built. Some other cursus lines were planned from this, including the Stanwell line at 75 degrees (5/24 of a circle) to it, and the Lesser Cursus line at 15 degrees (1/24 of a circle) to it.
Causewayed Enclosures are rare north of the River Trent. We suggest that the Enclosures method was abandoned because as the survey extended northwards, inconsistencies became apparent which meant the previously surveyed lines to the south could not be relied upon. That method, building out from previous survey triangles, was therefore deemed flawed. The new approach was to impose, top down, very large triangles which stretched across the mainland. These would give a framework into which smaller local triangles would be bound to fit.
The cursus monuments were sometimes planned to align on a prominent hill. This would assist the setting out of the cursus line in the field. Cursuses were also sometimes positioned so that a prominent hill was at 90 degrees to the cursus banks. In this case the hill would assist in the setting out of a long-distance survey line at right angles to the cursus.
The Circle and Henge survey, which succeeded the Cursus survey, sought to improve upon both of the preceding methods. A top down design was again planned, often reusing cursus sites. However, the new method also provided significant flexibility to vary techniques locally to suit the local conditions and objectives.