What does lidar provide?

Lidar is seen by some as a tool that will record all aspects of the historic environment, meaning we no longer need other techniques, especially as it is often described as being able to 'see through trees'. This is not true and comes from a misunderstanding of how lidar works. The key element of lidar is light, and as such it cannot see 'through' trees or anything else. However, in the right conditions, gaps in the woodland canopy can make it possible to record the ground surface below, by a technique that is known as vegetation removal. What lidar can provide is accurate locational and height data that allows the creation of a 3-dimensional model of the land surface, or digital terrain model (DTM). This can be examined to identify historic features that exhibit some form of surface topographic expression, although how effective this is depends on the resolution of the data and on other factors described in detail below. The intensity of the reflection of the laser pulse can sometimes also provide useful information.

A brief history of lidar

Airborne lidar technology

Height data from lidar

Lidar intensity data