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What archaeology looks like on LiDAR
Many kinds of earthwork have a recognisable shape on a LiDAR terrain model. This guide describes the common ones, with the modern features they are most often confused with.
Hillforts
One or more banks (ramparts) with ditches enclosing a hilltop or promontory, often with entrances where the banks overlap or turn inwards. Most date from the late Bronze Age and Iron Age. On LiDAR the circuits are usually clear even under woodland, which has made LiDAR a main source for new hillfort records.
Barrows and cairns
Round barrows are circular mounds, some with a surrounding ditch, usually of the early Bronze Age; they are often in groups or lines along a ridge. Long barrows are elongated mounds of the Neolithic, often with side ditches. Ploughed barrows can survive only as a low rise or a ring. Confusions: spoil heaps, tree throws, landscaping mounds and bomb craters (which are hollows with a rim).
Roman roads
A low raised bank (the agger) running on long straight alignments, sometimes with side ditches, and changing direction at high points. Where the road is under a modern road it may not show; where it crosses fields it may survive as a faint linear rise or a line of field boundaries. The Roman Roads Research Association's routes in Waystone carry its grade of evidence for each length.
Ridge and furrow
Parallel ridges, usually several metres apart, made by ploughing in strips in the medieval and post-medieval periods. They often run in blocks (furlongs) with a slight reversed-S curve, and end in headlands. Confusion: modern drainage or narrow steam-ploughed ridges, which are straighter and more regular.
Deserted medieval villages
Hollow ways (sunken lanes), rectangular house platforms, and plots (tofts and crofts) bounded by banks, often beside a church or manor site and surrounded by ridge and furrow.
Enclosures and field systems
Banks and ditches forming rectangular, curvilinear or irregular enclosures, and the lynchets and banks of prehistoric and Roman field systems on chalk and limestone downland.
Mining and quarrying
Bell pits show as rings of spoil around a central hollow, often in clusters; open quarries as steep-sided hollows with tips. These are archaeology too, and many are recorded.
Twentieth-century features
Practice trenches, gun emplacements, anti-aircraft sites, bomb craters and the footings of camps survive widely, and many are not recorded.
Before you draw a conclusion
- Check the heritage records and the aerial archaeology layer near the feature.
- Check the Ordnance Survey six-inch maps of 1843–1913: many earthworks were drawn on them, and many apparent earthworks are later.
- Look at it with two different readings (see LiDAR visualisations explained).
- Scheduled monuments are protected by law; visit on public rights of way and report new finds to the local Historic Environment Record.
Related
Sources
- Environment Agency, National LIDAR Programme and LIDAR Composite DTM (1 m), Open Government Licence. © Environment Agency copyright and/or database right.
- Natural Resources Wales and Welsh Government LiDAR (1 m), Open Government Licence. Contains Natural Resources Wales information © Natural Resources Wales and Database Right.
- Historic England (2018). Using Airborne Lidar in Archaeological Survey: The Light Fantastic. Swindon: Historic England.
- Hesse, R. (2010). LiDAR-derived Local Relief Models: a new tool for archaeological prospection. Archaeological Prospection 17(2), 67–72.
- Zakšek, K., Oštir, K. and Kokalj, Ž. (2011). Sky-View Factor as a relief visualization technique. Remote Sensing 3(2), 398–415.
- Kokalj, Ž. and Somrak, M. (2019). Why not a single image? Combining visualizations to facilitate fieldwork and on-screen mapping. Remote Sensing 11(7), 747.
Last updated 2026-10-16.