Explore the Stonehenge landscape LiDAR survey
The image below is an extract from our 3D visualisation of the Stonehenge landscape. It was created from the LiDAR (Light Distance And Ranging) data collected by the Environment Agency. In this image, the view is from above the World Heritage Site and the terrain is lit from the south-east at a very low angle to highlight the subtle archaeological features on the ground.
Use the slider below the image to zoom closer. Click and drag the image to pan around it, or user the arrow buttons next to the zoom slider.
3D render of the Stonehenge World Heritage Site. Data courtesy the Environment Agency.
LiDAR (Light Detection and Ranging) data is produced by attaching a 3D laser scanner to an aircraft. A cloud of measurement points across the landscape is produced as the laser-beam is fired at the ground and measured when it is reflected back to the aircraft. Depending on how high the aircraft flies and how the raw data is processed, this typically results in a dataset of points spaced between 15cm and 2m apart, with a vertical tolerance of up to 20cm.
The highly detailed terrain models which can be produced from this data are incredibly useful for identifying archaeological features, even those which can barely be seen with the naked eye. In addition to the spatial component of the data, the intensity of the reflected laser beam is also recorded and this can be used to identify buried features where they cause changes in the vegetation cover or soil moisture content and hence the amount of absorption and reflectance of the laser beam.
Q: Why did we light the terrain from the south-east?
A: In the real world this is an unusual direction for low elevation lighting. It shows a view we cannot obtain from aerial photography. The downside is that many people's brains are conditioned to interpret hillshades with the light coming from the NW. If the light appears to come from the SE the majority of people will perceive the topography as inverted. With concentration it is possible to force the brain to undo the inversion. Start with a relatively small and simple shape - such as a barrow - then work out into the wider landscape.