This blog is written by John Howell, a geologist who wants to share his passion for rocks with everyone. He has worked all over the world and his favourite place for fieldwork is Utah. He lives on a small farm on the coast south of Aberdeen and keeps rare breed sheep. You can contact John @virtualgeol on Twitter.
In 1815 a surveyor called William Smith published a map that changed our understanding of the Earth. Smith invented the concept of the “geological map”, and then to prove it was a really great idea, he went and single-handedly mapped the whole of England and Wales, on horseback! His revolutionary idea, like many of the best scientific breakthroughs, was actually quite simple; you take a regular map and add a layer on top that shows the geology. This results in a very colourful map that shows the geology at any location and, to the trained eye, provides a 3D view of the subsurface.
It’s hard to fully appreciate the magnitude of Smith’s achievement. Firstly, the idea was so powerful that it revolutionised our understanding of the structure and layers within the Earth’s crust. Secondly, his map bears a striking resemblance to modern versions, which have involved years of work by thousands of geologists. Finally, Smith was not part of the establishment; he was an outsider. It took years before the brilliance of his idea was recognised and he was duly acknowledged as the Father of modern Geology.
A comparison of Smith’s original map and a modern geological map
This is important to our story here because Smith’s achievements were so monumental that for the next two hundred years no one came up with a better way of recording rocks in the field and displaying the data. Even today, every geology student in the UK will spend 5 or 6 weeks making a map. They will head out, just as Smith did, with a base map, a compass and a bunch of coloured pencils. They will wander their chosen area and record the geology on to the map, tracing where the layers of strata meet the ground’s surface. At least today the horse is optional.
It was not until the start of the 21st Century that alternative methods for collecting field data started to appear, and it’s only within the last 5 years that these methods have been widely adopted by the geoscience community. Unlike Smith’s maps, the development of these new methods isn’t the result of the brilliance of one person; it’s the result of a fortuitous emergence of several different technologies that have aligned to produce a second revolution in geological fieldwork – “the Virtual Geoscience Revolution”.
Virtual Outcrops
Virtual Geoscience is based around the collection of Virtual Outcrops. A virtual outcrop is a photorealistic, 3D model of a cliff section in a computer. Initially, these models were collected using special laser scanners (called lidar) and the technique was limited to a few specialist research groups. It is only within the last 5 or 6 years that methods have been developed that allow these types of models to be acquired by anyone and everyone. The new methods involve using drones to take hundreds or even thousands of photos which are then combined to produce the 3D models using a process called photogrammetry.
A unique view of some classic British geology. This is a virtual outcrop model of Kilt Rock in Skye, where giant columns of basalt associated with the opening of the Atlantic Ocean make cliffs 60 m high
Photogrammetry is based on the idea that every photo is a 2D representation of a 3D scene. If you take two photos of the same scene from different angles, it is possible to reconstruct the object in 3D by picking lots of common points between the photos. This concept has been around for almost as long as photography- but only in the last few years have there been software algorithms that can rapidly analyse hundreds of photos and pick the millions of points needed to produce models of complex objects like big cliffs. The widespread adoption of these fancy software also had to wait for the development of computers fast enough to run the algorithms in a reasonable time.
Luckily, the emergence of the new software and faster computers occurred along with the appearance of consumer drones capable of taking high quality photos of cliffs from optimal angles to build really great models. Now anyone with a relatively cheap drone, a decent laptop and some low-cost software can create an amazing 3D model of a geological outcrop. And they are, adoption of the technique has literally exploded! Almost everyone doing geological fieldwork is now taking a drone and creating virtual outcrops, and this is fundamentally changing the way in which geologists work. Now, instead of having to make all the observations in the field and missing out the parts of the cliffs you can’t get to, the geologist simply flies the drone, processes the 3D model and then goes back to the lab where they can make all the measurements that they want from the comfort of their desk. Virtual outcrops give modern geologists two key advantages. Firstly, we can collect data faster, more efficiently and more accurately than scrambling about on the rocks and secondly, there are data that simply cannot be collected by a person on the ground. Once they are collected and processed these virtual outcrops have a wide range of uses.
The author in his natural environment, collecting virtual outcrop data with a drone in Utah
The Uses of Virtual Outcrops
In teaching, there is an old saying that “the best geologist is the one who has seen the most rocks”. Seeing those rocks typically involves lots of travelling and can take a lifetime. With virtual outcrops it is possible to get around the world, see the best examples of different features and gain that experience much faster. This is especially true when we are not able to travel due to lock-down, and also at a time when we might like to cut down on travel to reduce our CO2 impact. Virtual fieldtrips are an amazing way to visit world-class sections and see the best geology in an immersive way. They are as relevant to children studying geology for the first time as they are to experienced geoscientists trying to expand their understanding
Virtual outcrops are also used extensively in research. They supplement traditional fieldwork, so that students and researchers who might normally spend a few weeks or even months in their study area can take that study area home, digitally. There are also new methods coming out of virtual geoscience. For example, our research group recently flew a series of drones over Stromboli, an active volcano in the Mediterranean. By collecting both regular and thermal images we were able to build the first 3D thermal model of a volcano (see this Youtube video). The potential applications for virtual geosciences are only limited by our imagination.
As more and more individuals and groups start collecting and working with virtual outcrops it is essential that we are able to share data, both amongst scientists and also with the wider public. The website v3geo.com was recently launched to allow anyone to view virtual outcrops and visit important geological sites around the world. It is freely available for anyone to view and in the near future it will also be open for anyone to upload and share their data as well. It is an amazing resource for teachers and anyone who wants to understand geology better.
Two hundred years ago, William Smith literally put geology on the map and revolutionised our understanding of the Earth. Whether this latest revolution has such a seismic impact remains to be seen, but it is certainly a very exciting time to working on virtual geoscience.