What is LiDAR?

LiDAR (Light Detection And Ranging) is a method of collecting height data by bouncing laser pulses at the ground from and back to an aircraft. The data can be turned into digital elevation models, essentially, high resolution 3d maps of the ground surface, which can be displayed in several ways – one way is to produce artificial shadows or ‘hillshade’, as in the grey background mapping used on this website.

Visualizing landscapes, seeing archaeological sites in context. Here, the ramparts of both hillforts on Earl’s Hill, Pontesbury, are visible, with Lower Camp in the foreground, and the earthworks of the Upper Camp in the background.

Visualizing landscapes, seeing archaeological sites in context. Here, the ramparts of both hillforts on Earl’s Hill, Pontesbury, are visible, with Lower Camp in the foreground, and the earthworks of the Upper Camp in the background.

While LiDAR cannot see through trees, some of the laser pulses will penetrate between branches – particularly when the flying is done in winter and the leaves have fallen. The trees themselves can then be digitally removed from the image, to give some detail of the shape of the ground between the trees. This can sometimes reveal archaeological sites and features that can’t be seen from normal aerial photography.

‘Seeing beneath trees’: the ramparts of the hillfort at Callow Hill is hidden by trees, but becomes very evident in the ‘bare earth’ Digital Terrain Model, created from LiDAR data. Extensive quarrying to the North and East is also visible in this data.

‘Seeing beneath trees’: the ramparts of the hillfort at Callow Hill is hidden by trees, but becomes very evident in the ‘bare earth’ Digital Terrain Model, created from LiDAR data. Extensive quarrying to the North and East is also visible in this data.

The Landscape Partnership Scheme collected 1m resolution LiDAR data for the whole scheme area. It has formed the cornerstone for a number of projects carried out by the scheme. Volunteer surveyors have used it as the basis for site visits and baseline survey of features recorded – revealing detail on the ground, especially of prehistoric and mining-related features in these areas. This information has been used to enhance the Shropshire Historic Environment Record, which continues to use LiDAR
data to identify previously unrecorded features.