In early 2013 the archaeological aerial survey of the North Devon Coast AONB was completed by the AONB’s project team of staff from AC Archaeology and Devon County Council, as part of English Heritage’s (now Historic England) National Mapping Programme.
‘Archaeology has long benefited from the use of aerial photography, revealing sites that are often difficult or even impossible, to see on the ground.’ Historic England 2015
Archaeological sites in Britain have been photographed from the air since the early twentieth century. Historically entwined with the military, service personnel such as OGS Crawford realised the full potential for aerial reconnaissance to help identify archaeological sites not – or barely – visible at ground level, in the years following the First World War.
Many thousands of archaeological sites have first been recognised from the air by both military and civilian aerial photographers since then. Now Historic England’s National Mapping Programme (NMP) provides a methodology for the systematic examination and recording of archaeological sites and landscapes using the available aerial photographic sources.
Second World War pillbox at Chivenor in 2013. Photograph: Stephanie Knight
NMP aims ‘to enhance the understanding of past human settlement, by providing primary information and synthesis for all archaeological sites and landscapes visible on aerial photographs or other airborne remote sensed data. This … is intended to assist research, planning, and protection of the historic environment’ (Horne 2009).
Looking Down on the Past, Understanding the Present
Aerial photograph collections used in aerial survey include vertical images, taken by a fixed camera at set intervals and a fixed height, military photographs taken at an oblique angle, and specialist oblique photographs that target particular sites and landscapes. They also include forms of remote sensing such as lidar that can help to verify the existence and condition of sites that are otherwise obscured by vegetation.
Archaeological sites may be visible from the air as structures, earthworks, and cropmarks or soilmarks. The aerial perspective provides an excellent overview of former landscapes and the layout of sites that are not distinguishable on the ground, and lidar can define even very low earthworks.
Aerial survey is especially important in the identification of cropmarks and soilmarks over the levelled remains of earthwork banks, ditches and walls of archaeological sites, through changes in the colour and composition of soils and the colour and height of crops. Air photo interpreters are trained to distinguish geological, natural and contemporary agricultural features from archaeological ones.
Royal Air Force (RAF) vertical aerial photographs taken during the Second World War and just after (as part of Operation REVUE) provide very good coverage. These and later sorties have a 60% overlap between frames to enable viewing through a stereoscope. This ‘tricks’ the mind into seeing the landscape in three dimensions and has proven very useful for recognising subtle earthworks and structures.
Stereo Viewing. Photograph: Stephanie Knight
Oblique photographs can often add crucial detail to the plan view seen on vertical photographs, and give a sense of perspective. Examining sources from the 1940s or earlier up to the present day enables as comprehensive a record as possible to be made of the archaeological sites visible on aerial photographs: different parts of a site may be visible in different years. It also allows an appreciation of historic activity and changes to the historic environment to be developed.
An Aerial Lens on the Heritage of the North Devon Coast
From December 2011 to February 2013 the NMP project team worked their way through over 6000 hard copy aerial photographs loaned from the Historic England Archive, Cambridge University Collection of Aerial Photography and those held by Devon County Council, as well as multiple lidar coverages and modern digital datasets of vertical aerial photographs.
In the 278 square kilometres surveyed, over 1100 monuments visible on aerial photographs were transcribed onto base mapping and recorded in the Devon Historic Environment Record (HER), available through Heritage Gateway and the Devon Environment Viewer. Four in five of these had not previously been recorded on the HER.
The air photo interpreters were particularly excited to identify a probable southern extension of the iconic Iron Age hillfort of Clovelly Dykes (MDV169), as well as some enticing and previously unrecorded cropmark and earthwork sites such as a possible prehistoric pit alignment and an embanked enclosure very tentatively identified as of civil war date.
Looking at the bigger picture rather than individual sites (no matter how intriguing!) the project helps to achieve a greater understanding of the extent and character of the militarised landscape on the North Devon coast in the Second World War. The international dimension of this was clearly demonstrated by the aerial photographic evidence.
From an aerial survey perspective, the effect of military activity on this striking protected landscape is second only to the long-term impact of agriculture from at least the medieval period. This is particularly important considering the proximity of the AONB to the rare working open field system of Braunton Great Field.
A Multi-faceted Landscape
From hunter-gatherer landscapes of circa 8000 years ago to structures erected in the Cold War, a very wide variety of monuments and sites were observed and recorded during the project. More information on some of the sites recorded from the aerial photographs can be viewed by clicking on the links below. Although some of the sites are accessible to the public, inclusion on the Historic Environment Record does not imply a right of access, and most are on private land.
As the project progressed several themes became especially prominent, and these can be explored further by clicking on the links on the menu to the right. Military activity transformed large areas of the AONB, reflecting the importance of the North Devon coast for defence and training in the Second World War, but a string of Iron Age forts seems to have dominated the coastal edge and access to the sea two millennia previously.
Second World War anti-tank blocks on the Skern, viewed from Northam Burrows in 2013. Photograph: Stephanie Knight.
Medieval field boundaries were the most numerous single monument type recorded, and in this rural area farming settlements abandoned between the prehistoric and modern periods were observed. Agriculture is another enduring and dominant theme traceable through aerial photographs, adapting in line with changing economic and social pressures over the centuries.
The distinctive marine environment and intertidal zone of the estuaries includes submerged prehistoric land surfaces, fish weirs of possible medieval date, and hulks from the eighteenth to the twentieth century.
Horsey fish trap in 1960. NMR RAF/543/1017 PSFO-0131-2 10-AUG-1960. English Heritage (RAF Photography).
On the high ground, the Bronze Age funerary landscapes of the earliest farmers overlook the seascape. Small scale industrial activity was observed, mainly in the form of extraction pits, while the long-standing attraction of the North Devon coast for recreation bequeaths a liberal scattering of the remains of historic leisure facilities.
Historic England. 2015. Using Aerial Photographs.
Horne, P. 2009. A Strategy for the National Mapping Programme. English Heritage.
Wilson, D. (1982) Air Photo Interpretation for Archaeologists. London: Batsford.
Project highlight report
Information on other NMP projects in Devon is also available.
Would you like to share additional information on any of the sites we recorded from aerial photographs, or do you have a different interpretation? Let us know! We read all submissions but unfortunately due to the volume of responses we are unable to respond personally to every comment.