Interpreting LIDAR data – it’s a question of light

Roy Canham reports on the importance of light:

Back in March Kate reported on the very rapid photographic survey we undertook right across the project area. The purpose was to record the condition of each field so that we had same measure of judging just what ground conditions were current at the time of the airborne LIDAR survey.

Click the photos below to see larger versions.

By chance, a number of the photos show archaeology. One of Kate’s own photos taken near Turleigh is very intriguing, showing a massive earth bank crossing a steep hillside. The LIDAR show this clearly (the arrow indicates the direction of the photo) but leaves us puzzled as to the nature of this huge bank, which clearly curves round as if forming part of a massive enclosure – a prehistoric settlement perhaps?

In the foreground of Kate’s photo is another earthwork, which is not coming through on the LIDAR.

When these photo-like images are ‘developed’ from the LIDAR raw data, we have to make a decision on which direction to place the light-source – remember this whole process is digital! – and a surface feature in line with that source will barely show up. The lesson is to illuminate a series of images from different directions.




Get involved!

There are many ways to get involved with the project: looking at aerial photographs, field walking, helping to plot the findings on maps, to name but a few.  For those interested in helping with the project, we will also be running training sessions on identifying earthworks, and other skills.

If you are interested in getting involved with this exciting project, please contact Roy Canham on 01225 866748 or at

If you’re not sure what you could do to help, read our How To Get Involved blog post.

If you aren’t able to help, but you want to keep up to date, then please follow our blog.  We’ll be holding public talks and other events throughout the year, so look out for announcements here.

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