LiDAR
LiDAR images are a great starting point for anyone interested in undertaking an archaeological survey.
LiDAR (light detection and ranging) is a survey technique involving a plane flying over the landscape and using laser beams to ‘map’ the ground surface.
The images generated show the ground surface with most of the vegetation stripped away. The contours of the landscape are shown clearly, making it possible to see the gradient of hills and valleys and to pick out rivers and streams. Man-made features, such as buildings, roads, and railway tracks, show up well.
LiDAR reveals archaeological features that are hidden by trees in aerial photos or are hard to spot on the ground. It is therefore particularly helpful for researching archaeology in the heavily wooded High Weald. The images show up many of the features listed on our Archaeology page.
Weald Forest Ridge LiDAR images
We surveyed the Weald Forest Ridge area of the High Weald using LiDAR in 2011, thanks to a grant from the National Heritage Lottery Fund.
The map to the right shows the area surveyed; it ran from Horsham in the west to Tunbridge Wells in the east.
To download the LiDAR images generated as as a result of this project visit our Publications library.
If you’re looking for images of a particular part of the Weald Forest Ridge area, please get in touch and we’ll help you locate them.
Making sense of LiDAR
The LiDAR is, in simple terms, an image of the ground surface with most of the vegetation stripped away.
The contours of the landscape are shown clearly, enabling you to see the gradient of hills and valleys and to pick out the streams which wriggle their way through them. Man-made features, such as buildings, roads and railway tracks, show up well.
LiDAR uses lasers to measure the difference in height of the ground surface. It cannot reveal archaeology under the ground unless the buried remains are causing the ground surface to rise.
Irregular brown areas on the image are where the lasers have been unable to penetrate. This often happens where evergreens grow – large holly trees, stands of young conifer and patches of rhododendron. Lakes and ponds can also appear brown, although sometimes they are the same colour as the surrounds, but look completely even. Gorse makes the LiDAR look ‘lumpy’ and lack detail.
LiDAR can show very subtle features which are invisible on the ground. Features in lines, such as banks and ditches, show clearly. Using our LiDAR images and our specially-developed toolkits, you can discover more about the archaeology of the Weald Forest Ridge.
LiDAR images work best when printed out at A3. At this size you can see both the overall shape of the landscape and the individual features more clearly.
Always look at the LiDAR print with north at the top as turning it upside-down will make valleys look like ridges and mounds look like hollows.
Other sources of LiDAR
Another place to find LiDAR is from the Environment Agency. Areas flown by the Environment Agency are mainly near rivers and along the coast.
LiDAR images can be downloaded freely for personal non-commercial use from the Defra data services platform.