Photogrammetry as a Tool for Mitigating Climate Change Threats to Heritage

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Hello, my name is Nick Mason and I’m the Archaeology Officer for the North York Moors National Park in England. I’ve been dabbling with photogrammetry and digital recording techniques since I was a Maritime Archaeology master’s student in 2015. Whilst the basic methodology is nothing new to archaeology, we are finding new uses for the technology all the time: aerial surveying, artefact recording and museum interpretation, digital reconstruction… and increasingly as a response to climate change threats to heritage.

Second World War D-Day landing craft, part of MSc research.

Tools for the Job?

I was recently at a conference discussing mitigation options for coastal erosion cases, and the question was asked: should sites at risk be recorded by volunteers? For me, the answer is a definite yes. Whilst we don’t all have high-quality DSLRs, drones, or archaeological training, the great thing about photogrammetry is that it can be accomplished by anyone with a camera phone and determination. Let me be clear: I don’t think 3D modelling should be used as a replacement for traditional interpretive recording, or as stand-in for professionals when available. However, I have frequently made models of features and scenes which are now the sole record of that archaeology, and that is surely better than nothing. I’d love to prove that effective data can be collected with simple digital tools. The models presented here were captured with everything from high-end drones down to second-hand camera phones and knock-off action cams, and everything processed with Agisoft Photoscan/Metashape.

CITiZAN Science

Stone-cut ‘Viking’ graves, from a CITiZAN photogrammetry workshop.

I first came across photogrammetry being taught as a citizen science and engagement tool when working with the Coastal and Intertidal Zone Archaeology Network, hosted by Museum of London Archaeology. One of the project’s aims is to encourage people to take ownership of local coastal heritage by reporting on the condition of foreshore sites. To assist with this they have a dedicated mobile app, so for those using the app taking additional photos with a phone camera seemed an obvious step. Various photogrammetry workshops were organised, and were well attended. Soon afterwards, thousands of photos started to arrive in our inboxes. As you might expect, the resulting modelling quality varied wildly, but the majority of models were useable. Local people monitoring and reporting on the condition of nearby sites is fantastic for often resource-limited archaeologists, and adding photogrammetry to the toolkit is an extra bonus to crowd-sourced data.

Starting them Young

Here’s a more recent case study showing the ease of teaching the basics. Alongside the Land of Iron industrial heritage project, the National Park hosts a North Yorkshire and Teesside branch of the Young Archaeologists’ Club. Last month we decided to run a session with our aspiring archaeologists (ages 8–16) on the recording technique, as we thought it might be useful for them to get a head start on a method they’ll probably be using at some point if they look to heritage as a profession. Of course the children picked up the essentials and rapidly went rogue, starting to model biscuits, traffic cones and each other’s heads, to name but a few. The model above is a great example of the quality they were able to achieve with just an hour’s guidance, even if it’s not strictly archaeological material. Given the children also recently learned offset recording techniques on wreck material, I hope in the future we can combine all these skills and start some wreck monitoring together.

Climate Change: We’re All in This Together

Climate change will bring many challenges to us all over the coming years. One challenge will be the inevitable loss of physical cultural heritage. The most obvious symptom of this will be around threatened coastlines, but other pressures include increasing frequency and power of storms, heightened fire risk (particularly felt in moorland areas), changing land use, and more. Luckily, this fact has been realised and heritage professionals are increasingly working to protect, or in the worst cases simply record, archaeology before it is lost.

The section of timber shipwreck above washed ashore last autumn at Teesside, northeast England. The likelihood is we will see an increase in the amount of wreck material on our foreshores in the future, due to more storms exposing and breaking up wrecks on the seabed. In this case I had no preparation other than a few ranging poles in the back of the car and my phone. By the time I reached the site, looters had already sawn some framing away, and by the next week it was gone. Fifteen minutes on the beach and this basic record was made. The speed possible when making a quick model is invaluable when facing the tide, weather, or more human threats.

One of the many cliffs of North Yorkshire actively eroding.

As well as speedy recording, here at the National Park we are also hoping to use photogrammetry as an efficient monitoring tool. We have several large-scale industrial archaeology Scheduled Monuments (a legal status which can protect heritage in the UK) sitting right on the top of cliffs, facing some significant erosion risks. Various work has been done in the past, but deterioration means that excavation is no longer an option in some areas without extreme Health and Safety measures. A cheaper alternative is to use drones to monitor the stretches on a regular basis. Comparison of survey datasets should allow us to both observe erosion or accretion and find out where it is most serious, and record features in section as they appear in the cliff face. This is increasingly becoming a standard methodology in coastal areas as it has the benefits of being safe, relatively cheap, and the last recourse of preservation by record. There are some great examples out there, including the recent work of the CHERISH project in Wales.

No Magic Wand Yet…

This is not all to say that photogrammetry is without problems. Anyone who has tried to scan a car or vase will understand the issues that reflective surfaces present, and one of the problems with coastal archaeology is that it can be quite wet. I have struggled with underwater photogrammetry in particular, as without a high-end waterproof camera or even a red filter, my diving adventures typically look something like the SS Thistlegorm detail above: mysterious colours and murky. Another problem that many archaeologists are struggling with today is the practicalities of digital preservation. Can we afford to store hundreds of thousands of photographs, and will they even be accessible in 50 years’ time?

Get Out There!

I don’t want to end this brief exploration of archaeological modelling on a down note, though. I got into the art of photogrammetry first and the science second, and have fun playing around with it as a hobby. I enjoy finding out what will and won’t model, what cameras will do in a pinch, standing about waiting for a cloud to roll over, trying to explain what I’m doing to passers-by, and publishing the sometimes odd results online. My Sketchfab page is a pretty eclectic mix, and I’m firmly working under the banner of ‘All sorts of archaeology’ (I’ve recently developed a habit for modelling historic pub features: if that’s not important British archaeology I don’t know what is). It’s a wonderful platform for projects, organisations and individuals to disseminate information, but also show off what they’re up to. We all like to see pretty pictures and models, and hopefully we can also stimulate discussion and inspire others to start reacting to climate issues and other threats.

I know I haven’t covered half of what archaeologists can do with photogrammetry, but I hope this was a good whistle-stop tour of my experiences to those who are discovering heritage modelling for the first time. Go and take pictures of rusty bits of metal: it’s fun.


About the author

Nick Mason

Nick Mason is an archaeologist at the North York Moors National Park Authority, with interests in coastal and climate change heritage matters, diving, and Land Rovers. You can get in touch via his Sketchfab page for any queries.

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