From Roman settlements near Rotherham in South Yorkshire to Second World War defences in Southampton in Hampshire, to secret Cold War military installations across England, for the first time, Historic England has made the results of over 30 years of aerial photograph mapping projects freely available online.

 Like a huge archaeological jigsaw puzzle, the map pieces together archaeological landscapes recorded during analysis of over 500,000 aerial photographs. More than half of England is covered by the map.

The map contains thousands of archaeological sites that have been identified on aerial photographs and from imagery derived from airborne laser scanning, also known as lidar data. Lidar uses laser light to create a 3D representation of the Earth’s surface and is a newer technology that can be applied to the work of an aerial archaeologist.

The earliest sites in England that have been mapped date to around 6000 years ago and include long barrows, flint mines and causewayed enclosures of the Early Neolithic period while the most recent sites belong to the second half of the 20th century – for example, those associated with the Cold War. There are also Bronze Age round barrows, Iron Age hillforts, Roman camps, settlements, trackways and field systems which represent several millennia of activity.

The mapping allows the archaeological features to be seen not just as individual sites, but as part of complex, multi-period landscapes. Visualising the evidence in this way can help transform understanding of those landscapes, especially when studied alongside other forms of evidence – the site-based data available from local Historic Environment Records or the Heritage Gateway and historic maps.

Every site mapped has a simple description with links to the full Historic Environment records held online and for most of the areas mapped there is also a free report detailing the highlights and new discoveries encountered in each project.

The mapping work continues – not only are there areas which Historic England hasn’t analysed in detail yet, but new discoveries are still being made in places previously studied.

8 examples of hidden history revealed through aerial photos and archaeological maps

Hadrian’s Wall, White Moss, near Carlisle, Cumbria

Roman temporary camps discovered and Second World War Sites.

Hadrian’s Wall was part of a broader system of Roman infrastructure which included roads, forts, and temporary camps which form the Hadrian’s Wall World Heritage Site. Some of these sites, such as Housesteads Fort, have been excavated and can be seen on the ground but others remain hidden from view until seen from the air. At White Moss near Carlisle are the remains of two Roman temporary camps first spotted from the air in 1949. During dry summers, the ditches of the camp can be viewed as cropmarks, as its growth is affected by the buried archaeological remains.

When construction of the wall began in AD 122 the landscape had already been settled and farmed for generations. Aerial photography reveals traces of settlements along the course of the wall. On the Solway Plain in the west many have been discovered from the air along with traces of field boundaries and trackways that would once have linked them.

After the Roman military forces withdrew from Britain around AD 410, Hadrian’s Wall continued to shape the landscape. From aerial mapping, it is possible to see how medieval and post medieval fields were laid out to either side of the wall. Around 1,800 years after the construction of Hadrian’s Wall, this area was once again host to military forces, only this time defending against invasion. During the Second World War, sites ranging from airfields to military camps, gun batteries and anti-invasion defences were constructed.

An aerial photograph of the excavated remains of a fort on Hadrian's wall

The partially excavated remains of Housesteads Roman Fort on Hadrian’s Wall. 20534_033 31-MAR-2006. © Historic England Archive. Photographer: Dave MacLeod.

Yorkshire Dales National Park

One of the first areas of England to be extensively mapped with features drawn by hand on transparent  film – discoveries of prehistoric earthworks and mining for lead in the Post-Medieval period.

The Yorkshire Dales National Park is home to some of the most spectacular archaeological landscapes in the country. The pattern of stone walled fields and barns is just one layer in a landscape with a history stretching back thousands of years. It was one of the first areas of the country to be extensively mapped from aerial photographs. Before the use of digital technology, in the 2000s, features were drawn by hand on transparent film – requiring considerable skill. These maps have since been scanned and turned into digital images. Even though the mapping is 30 years old, it still an amazing record of the landscape.

In field after field, aerial photographs reveal lumps and bumps or features representing the remains of settlements dating back to the prehistoric period. Some of the most spectacular remains can be seen at Grassington where the long shadows in winter months pick out the earthworks of fields and enclosures.

In the post medieval period, the Yorkshire Dales were extensively mined for lead. Traces of the shafts and spoil heaps litter the uplands. Just a few kilometres away from Grassingon’s prehistoric field system is an extensive area of lead mines which are protected as a scheduled monument.

An aerial photograph showing traces of field systems in a Dales landscape.

Low sun reveals remains of prehistoric settlements and field systems near Grassington in the Yorkshire Dales. 20845_050 25-NOV-2008. © Historic England Archive.

Cannock Chase, Staffordshire : a prehistoric Hillfort

Evidence of medieval farming, 18th and 19th century coal mining and vast First World War training camps.

The Cannock Chase landscape reveals archaeology spanning many centuries. Lidar commissioned by Staffordshire County Council with aid from the National Lottery Heritage Fund in 2015-17 allowed a unique insight into the surviving archaeology of the Chase, which was hidden by vegetation. The aerial survey revealed a complex history ranging from a prehistoric hillfort to extensive medieval and later land management, 18th and 19th century coal mining, with the most recent activity being vast training camps established there during the First World War. The camps were designed to house up to 20,000 people. Although the buildings and roads were removed after the war, the foundations for the camps survive today.

A composite lidar image showing terrain with and without vegetation, the latter revealing a military camp.

In this lidar image of Cannock Chase in Staffordshire, the vegetation has been digitally removed to reveal some of the earthworks that show where First World War huts for a military camp housing 20,000 army personnel once stood. © Historic England: Source Fugro Geospatial BV.

Whitley Castle Roman Fort, Alston, Cumbria

Whitley Castle is a Roman fort and is protected as a scheduled monument. It survives as a series of impressive earthworks and is unusual because instead of the typical playing card shape of Roman forts, this is lozenge shaped, adjusted to fit into an area of high ground. Archaeological mapping using aerial photographs and lidar has revealed traces of a Roman road to the east of the fort. There is also evidence of pre-Roman settlers in the Alston area of Cumbria too.

Aerial mapping of a Roman fort, roads and settlements.

Mapping of Alston Moor in Cumbria, the area around Whitley Castle Roman Fort, which shows the area has been occupied for much of its history. The image shows the Roman Fort, roads and earlier settlements. © Historic England

Unusual Discovery in clay soil of an Iron-Age/Roman settlement near Combertom, south-west Cambridgeshire

Cropmarks form more easily on free draining soils. This means that areas that are rich in clay are known as ‘heavy soils’ such as the soil in South West Cambridgeshire. This type of soil has historically been less well studied and understood from the air and the assumption has been made that the area was less occupied in history.

However, in the right weather conditions, cropmarks can form and reveal new information about the history of these areas. One example is an amazing Iron Age/Roman settlement near Comberton. Although a few of the enclosures had been previously captured on aerial photographs, the full extent of the enclosures and slighter features including up to six round-houses dating to the Iron Age and Roman period, was not appreciated.

They demonstrate the value of continued aerial survey, particularly on the heavier soils – not only for identifying new sites but also when revisiting previously recorded sites where significant new information may be revealed.

Aerial mapping of an Iron Age and Roman settlement.

The mapping at Comberton, Cambridgeshire has used multiple aerial sources to build up the current map of the site. The cropmark site was previously overlain by medieval ridge and furrow and field boundaries that has since been removed and were only revealed due to very dry conditions. Future reconnaissance in hot weather may reveal additional Iron Age or Roman settlements. © Historic England

Magnesian Limestone air photo interpretation and mapping project, west and south Yorkshire

Discovery of iron Age and Roman fields seen as a ‘brickwork’ pattern.

This project, carried out in 2005 and 2006, revealed that in the Iron Age and Roman periods these parts of South and West Yorkshire (around Doncaster and Rotherham) were extensively settled and farmed. The landscape today looks like featureless arable fields, however photographed from the air in hot, dry summers, patterns begin to emerge. Known as cropmarks, these patterns are formed when the colour and height of a crop is affected by buried archaeological features.

Archaeologists have been photographing cropmarks in Yorkshire from the air for over 50 years and thousands of sites have been recorded. When analysed together, vast lost landscapes begin to emerge.  Some of the most distinctive features are the ditches of Iron Age and Roman field systems. These are arranged in a pattern of long parallel field boundaries divided by shorter cross boundaries. They are often referred to as ‘brickwork’ field systems because of their resemblance to the pattern of a brick wall.

Small ditched enclosures can often be found in the fields. While some are likely to have been for livestock, others may have been settlements where Iron Age farming communities lived. Occasionally traces of circular Iron Age huts, can be spotted.

Aerial mapping of field systems that resemble a 'brickwork' pattern.

Frame Edenthorpe field systems (Magnesian Limestone project). Extensive Iron Age/Roman field systems mapped from aerial photographs near Edenthorpe, West Yorkshire. Some of these features now lie under modern housing development. © Historic England

Military and coastal beach defences, Newhaven, East Sussex and Portsmouth, Hampshire

During the early years of the Second World War, anti-invasion defences were built along Britain’s coastline. These defences included barbed wire, concrete anti-tank blocks, beach scaffolding, gun emplacements, pillboxes and coastal gun batteries. These defences were positioned along those parts of the coast that were suitable for an invading force to land troops and equipment and most were built along the southern and eastern coastline.

A 1940 aerial photograph of Newhaven, East Sussex, shows a variety of wartime features including lines of barbed wire extending eastwards along the beach into the distance. Several projects have mapped distinct parts of the coastal defence and they and can be followed on the map with only short gaps where natural obstacles such as cliffs or marshy ground made them unnecessary.

The map shows a long line of defences along the south coast, the South East, East Anglia and Yorkshire. The beach defences were only one part of the wartime landscape seen in aerial photographs and the map also shows some of the military camps, airfields, inland anti-tank lines and the network of anti-aircraft batteries built across the country.

A wartime Royal Air Force aerial photograph showing coastal defences.

Wartime defences at Newhaven, East Sussex. In the foreground is a coastal battery alongside the Victorian fort. In front of these are gun emplacements, anti-tank blocks and barbed wire. At the top of the photograph there are long lines of beach scaffolding extending along the beach into the distance. Several moored barrage balloons are also visible. RAF MSO_31111_O-3018 5-SEP-1943. © Historic England Archive (RAF Photography).

Medieval farming, Gloucestershire

Across parts of lowland England, the remains of medieval ploughing can still be seen in the form of ridge and furrow and these earthworks give fields a corrugated appearance. Farmland has undergone many changes since then and some of these earthworks are now covered in grass and used as pasture. Others have been ploughed flat and are no longer visible from the ground. Historic and modern aerial photographs show these remains of medieval farming either as earthworks or cropmarks. Sometimes the removal of medieval ridge and furrow reveals earlier archaeology, which show as cropmarks on aerial photographs.

An aerial photograph showing the present settlement of  Toddenham surrounded by ridge and furrow field systems.

The long shadows cast by the low winter sun highlight the earthwork remains of medieval arable farming in Todenham, Gloucestershire. These earthworks, known as ridge and furrow, survive in fields that are now used for pasture. In places, modern ploughing has flattened the remains, but aerial photographs taken in the 1940s show that ridge and furrow once extended across most of the parish. 27345_010 17-NOV-201. © Historic England. Photographer: Damian Grady


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