4 April 2026
Explore Historic Sites with LiDAR Map Overlays
We've added two new map overlays to Visit History: LiDAR DSM and LiDAR DTM. These use laser-scanned elevation data to reveal buried earthworks and archaeological features that are completely invisible at ground level.
What is LiDAR?
LiDAR stands for Light Detection and Ranging. It works by firing rapid pulses of laser light from an aircraft and measuring how long each pulse takes to bounce back. By recording millions of these measurements across a flight path, it's possible to build up an extraordinarily detailed picture of the ground surface below.
The result is an elevation model — essentially a 3D map of the landscape — accurate to within centimetres. For anyone interested in history and archaeology, this is transformative. Features that have been ploughed over, overgrown, or simply eroded over hundreds of years leave subtle bumps and hollows in the ground that are invisible when you're standing in a field, but show up clearly in LiDAR data.
Prehistoric burial mounds, Roman field systems, medieval ridge and furrow patterns, deserted village earthworks — all of these and more can be spotted in LiDAR imagery. It has become one of the most powerful tools available to archaeologists and heritage professionals, and now it's available to everyone directly in Visit History.
DSM — Digital Surface Model
The Digital Surface Model captures the elevation of everything on the ground surface, including trees, buildings, hedgerows, and other vegetation. It gives a complete picture of what the landscape looks like today, including all the objects sitting on top of it.
LiDAR DSM at Stonehenge, showing the surface including surrounding vegetation and structures.
DTM — Digital Terrain Model
The Digital Terrain Model takes the DSM and strips away all surface objects — trees, buildings, anything sitting above bare ground — leaving only the underlying terrain. This is the more powerful overlay for archaeology, as it reveals the subtle shape of the land itself. Notice how the trees along the left edge of the DSM are hiding a clear depression that only becomes visible when you switch to the DTM layer.
Slight rises and dips that are invisible in person can show up clearly in a DTM: the banks of a hillfort, the outline of a Roman road, the humps of a medieval fishpond. If you want to really understand the landscape around a historic site, this is the overlay to use.
LiDAR DTM at Stonehenge, with surface objects removed to reveal the bare terrain.
LiDAR data for England is provided by the Environment Agency at 1 metre resolution and is available under the Open Government Licence.
How to Use It
The map overlay switcher is available directly on the map view in Visit History. Try switching between DTM and Satellite while looking at a scheduled monument — the contrast between what you can see on the ground and what the LiDAR reveals is often remarkable.
We hope these overlays add a new dimension to how you explore the historic sites around you. As always, if you have feedback or suggestions, we'd love to hear from you.