LiDAR Forest

Welcome to LiDAR Forest. This online workshop aims to share some of the fascinating aspects of optical physics, including celebrating Mary Sommerville, a leading light in Scottish Physics, and the work of Dr Valerie Thomas, a main player in the development of the Landsat programme.

Dr Valerie Thomas

Dr Valerie Thomas next to a stack of early Landsat Computer Compatible Tapes, 1979, NASA.

Mary Sommerville

The first person to be called a ‘scientist’ in writing! The popular phrase in 1830’s Britain was ‘a man of science’ but, not happy with this term, William Whewell used the term ‘scientist’ when reviewing her book ‘On the Connexion of Physical Sciences’.

She was a famous mathematician, her book ‘The Mechanisms of the Heaven’ expanded on previous works and helped explain the mathematical principles at work behind the solar system. She shared her love of mathematics, tutoring Ada Lovelace and the two became friends. They remained in contact and it was said that when perplexed by a mathematical problem then she would sometimes pop round to Mary’s house for a cup of tea and to discuss the matter.

But it’s Mary’s understanding of the nature of light which we are most interested in with LiDAR Forest. She was fascinated by electromagnetism and rather poetically described the nature of light as a wave:

Anyone who has observed the reflection of the waves from a wall on the side of a river after the passage of a steam-boat, will have the perfect idea of the reflection of sound and light’  

Explore the nature of light with these handy demonstrations from the Institute of Physics.

And here’s proof that Mary was right and that light really does travel in waves.

Now we know a little bit more about the nature of light, let’s look at it’s practical applications, including taking a look at the work of Dr Valerie Thomas.

Dr Valerie Thomas

Dr Valerie Thomas is a scientist, inventor and all round good egg. Amongst her inventions are ‘The Illusion Transmitter’, a device which uses parabolic mirrors and projects a 3D image. This device has since been adapted for use in surgery and the production of television screens.

Thomas worked for NASA, she was a main player in the development of Landsat. Landsat is a series of satellite missions that have been imaging the earth for decades. It has been an incredible tool for allowing us to see our impact on the planet.

Her role was managing the development of the early Landsat image processing software system. She worked at NASA’s Goddard Space Flight Center, where she became the resident expert in Computer Compatible Tapes (as seen in the image above), which were used to store the imagery collected by Landsat programme.

Since retiring in 1995 she has kept herself busy volunteering her time as a physics teacher in public schools. But it’s her work on the Landsat programme that relates to and in some ways has inspired the LiDAR forest.


Having seen the value of Landsat, other scientists have looked to find new ways to use satellites and other technologies to collect data on remote places, so that we can monitor and protect these important ecosystems

LIDAR is a technique for scanning environments using lasers and can be used to create 3D models of rainforests, including every single branch.

A pulse of laser light is sent to points on the object to be scanned, the time taken for each pulse to travel to the chosen point is timed and used to calculate exactly how far away each point on the chosen object is located. This can then be used to create incredibly complicated and detailed models. Scanning a rainforest tree requires around 1 million measurements per tree!

But why make models of trees?

Once a tree has been measured and an accurate model produced, this can be used to assess all sorts of information. Researchers can use it to ‘weigh’ the tree, by calculating its volume and then weight. This can enable them to calculate how much carbon dioxide is stored within it. By scanning whole sections of forest they can see the impact of logging as the surrounding flora responds to the loss of a tree.

How Much Carbon is in a Tree? Hands on activity

Harry Carstairs, PHD student and researcher at Edinburgh University has created a rather handy and fun guide so that you can calculate approximately how much carbon dioxide is stored in trees.

Don’t worry if you don’t have a scientific background or fancy apparatus, all you require is something to write with and a calculator (or phone with a calculator app).

LiDAR Forest was created by artist Johnathan Elders and Harry Carstairs in partnership with the University of Edinburgh and Edinburgh Napier University’s Centre for Interaction Design. Supported by the Institute of Physics Scotland, Creative Edinburgh, Creative Informatics, Made with Numbers, and Edinburgh Remakery.