Tom Goskar is an independent archaeologist based in Penzance, Cornwall. He is a prehistorian dabbling in the early middle ages, and a specialist in 3D capture, reconstruction and analysis.

Medieval Priories, Medieval Stones, Historic Photos, and Deep Dreaming

This week has been a busy week. Last Sunday I volunteered for the Tywardreath Priory open day as part of the Festival of British Archaeology. I am one of the archaeologists on the team in the early planning stages of a community archaeology project. It aims to search for, research, and excavate the site of Tywardreath Priory, a Benedictine priory established in the second half of the 11th century. We know the rough area where the priory ought to be, but very little is known for certain.

The open day was very successful, with over 100 visitors to the farm in the village. My role was to explain something of the history and wider landscape context of the site, and to demonstrate LiDAR data to show how the estuary had silted up, cutting off the Priory’s access to the sea.

Tom Goskar demonstrating LiDAR and landscape archaeology at the Tywardreath Priory open day. Photo by Josh Taylor.

Tom Goskar demonstrating LiDAR and landscape archaeology at the Tywardreath Priory open day. Photo by Josh Taylor.

I also showed some 3D captures of decorated medieval stonework taken from the Priory and now situated in the nearby churchyard, and how we can enhance the data to show the decorations more clearly.

For the first half of the week I have switched gear to working with historic photos. I looked at the wonderful glass lantern slides of an excavation at Magor Farm near Redruth in Cornwall during the 1930s held at the Morrab Library in Penzance. They have a fantastic archaeology collection which they hope to digitise later this year if a funding application is successful, which I will be helping with if all goes well.

Being a self-employed archaeologist it pays to widen your horizons to gain work. I’ve been honing my web technology skills and am building a website to host a collection of over 25,000 historic photos, films and audio recordings from around Cornwall. It’s going to be a great resource, complete with ways to get data out of the site in interesting ways. Lots of archaeologists are going to find it useful for desk-based research, not to mention local historians and societies.

And today, the Day of Archaeology itself, has seen me mainly writing and researching. I have an article deadline coming up for my work on 3D capture and enhancement of early medieval sculpture at Gulval near Penzance which I am co-writing with Prof. Michelle Brown an expert in early medieval manuscripts.

Earlier in the day I had a phone call from Prof. Charles Thomas to discuss some work we have done recently on the early medieval ‘Ignioc Stone’ at St Clement near Truro. We’re using 3D techniques to try to see if the accepted transcription of the inscription is correct and to see if the data can help us understand better how this tall stone was reshaped and repurposed.

As a distraction amidst writing and planning a trip to London next week to visit the Society of Antiquaries library, I have been playing with Google’s Deep Dream neural network visualisation (or perhaps, hallucination) engine. It shares some code used by Google Photos to identify the content of photographs (in itself interesting for curators of historic photographs) and produces very strange results as it recursively tries to identify then display what it ‘sees’. A riot of colourful psychedelic nonsense, or an exercise in the study of perception applicable to shamanism, hallucinogenic states and rock art? You choose. For fun, here’s one of the trilithons at Stonehenge like you’ve never seen before.

Stonehenge trilithon visualised with the Google Deep Dream neural art network.

Stonehenge trilithon visualised with the Google Deep Dream neural art network.


Reconstructing a dolmen

Today is a busy one for me. I’m writing this on an overcrowded train to London on the first stage of a journey to the USA. It’s for pleasure not work, although as many archaeologists will tell you, at times the division is a blurry one.

For the past few months I’ve been working on a number of interesting projects. I have been working with Sustrust on the Giants Quoit project. For the last four years they have been working tirelessly with the Cornwall Council Historic Environment Service to excavate the site of Carwynnen Quoit near Camborne in Cornwall.

The dolmen (an entrance grave with three orthostats, or uprights, topped with a large flat capstone) fell down In 1842, and being a popular local landmark it was re-erected shortly afterwards. Unfortunately, in 1966, after an alleged earth tremor, it fell down once again. This time, the stones remained in a pile, and memories of the Quoit faded. In 2009 Sustrust bought the five acre field where the remains of the dolmen lay, and began to hatch plans to re-erect it.

My involvement came earlier this year, 2014, when I was asked to virtually reconstruct Carwynnen Quoit from existing laser scans of the individual stones and to investigate a number of other stones that had the potential to contain rock art. Armed with large quantities of 3D and excavation data and a number of historic photos from different angles, I busied myself with moving the modelled stones around on screen. One of the decisions made early on by the whole team was to reconstruct the quoit as it could have appeared thousands of years ago. Our historic images of the monument show the orthostats leaning at dangerous angles, having spent millennia being persuaded by gravity to cease trying to defy it, gradually tilting before collapsing.

Setting the stones upright by archaeologically studying the sockets in the ground and wear on the capstone meant that the Giants Quoit (as it is locally known) could stand again for, hopefully, millennia. It will never be exactly the same as the quoit was when originally built some 4500 years ago, but close, and importantly, safe, so that people can enjoy and engage with the monument.

I visited Carwynnen Quoit on a rainy day back at the beginning of May and it was a hive of activity. A school visit was in progress with a large marquee was set up as an outdoor classroom, with demonstrations of ancient technology such as honeysuckle rope construction, pottery, and theories about how the stones were originally moved. Lessons in poetry and art were planned for later in the day. I’m sure that day will have an influence on them for years to come – considering that local schools were also involved in the excavations of previous years, I wouldn’t be surprised if the seeds of a few embryonic archaeological careers haven’t been sown.

Using photogrammetry I made very detailed 3D models of the stones thought to contain rock art, and got a good feel for the site and how it may have appeared during the late Neolithic. We also crowded around the computer to continue to twist and move stones to help inform the reconstruction. It was decided to make a triangular wooden template to make sure that the orthostats would be positioned correctly.

Back at the office I processed the images of the rock art stones – the “Shield Stone” and “Coffin Stone” – into 3D point clouds and began to use a number of techniques to enhance details cut into the surface of the stones. I came to the conclusion that the marks on the Coffin Stone were mainly natural, although human-influenced, perhaps as a result of ploughing, dragging or even an attempt to dress it at some point. It is tempting to see a series of intersecting lines which form uneven diamond or lozenge patterns as deliberate, but they’re easily formed unintentionally.

The Shield Stone is interesting. The markings are deliberate, but I remain to be convinced that they were part of a singular design.

Photogrammetry of the reconstructed orthostats

Photogrammetry of the reconstructed orthostats

The 3D point clouds allow all kinds of analysis to take place that you cannot do physically, such as colouring the stone by depth to enhance details cut into the stone (they show up as a different colour to flatter parts) and removing distracting details such as the natural colours of the stone.

To match one of the historic photos of Carwynnen Quoit, an Edwardian picnic is being organised where participants will dress in period costume, eat lunch, and pose for a real plate photograph. Sadly, I’ve just had to reply to the invitation explaining that I’ll still be in the USA when it happens – I’d never normally turn away the opportunity for a ‘proper’ antiquarian day out!

Below are a few of the images that I created for the project. Visit the Giants Quoit website to find out more, and be sure to come back to the Day of Archaeology site to explore more of the amazing posts submitted today.

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Simulated glass plate image of the 3D reconstruction

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Laser scanned orthostats placed upon the excavation plan


Enhancing worn inscriptions and the Day of Archaeology 2012

My name is Tom Goskar and I am one of the organisers of the Day of Archaeology, as well as being a freelance archaeologist who specialises in applying digital techniques to different aspects of the discipline. My day today has been rather mixed, but predictably involved being at the proverbial digital coalface of archaeology in two aspects.

At 8am I checked my email to catch up with the behind-the-scenes talk between the eight organisers of the Day of Archaeology, and log into this website to begin moderating the posts that were by then flowing thick and fast. By 11am I had been on a Google Hangout with Pat and Jess, and we had re-jigged the homepage to make it easier to explore, as well as temporarily excluding posts from last year to highlight the new contributions. It looked much better afterwards. I have been dipping into the website on and off all day, making sure that posts looked good, and expanding and linking the occasional acronym to help readers know what they are. The DoA moderators have been hard at work in the engine room!

In between, for a personal project I have been processing 3D data from a medieval cross close to where I live, here in Penzance, Cornwall, as well as helping to refurbish a soon-to-be-open digital arts space in the town centre.

The Penzance Market Cross, made in the 11th century, is decorated and has many inscriptions. These are very eroded and most people do not notice them. Unless you happen to see the stone in just the right glancing sunlight, the sides of the cross appear to just have some panels of dots and a few lines, not much else. Nothing could be farther from the truth. Using photogrammetric techniques, I have been examining the cross to see if how well 3D capture techniques can enhance the inscriptions and decorations, with the aim of comparing my results with drawings made using traditional techniques (rubbings, chalking, torchlit photos).

In the spirit of the Day of Archaeology, below is a working illustration showing the north east elevation of the Market Cross, which I produced for this blog post. In the centre of the image is the cross as the casual visitor may see it. To the left, the colour information has been removed (which can sometimes be distracting), leaving the shape of the stone artificially coloured grey, with a virtual light source moved to show some of the decoration. To the right, a Radiance Scaling shader has been applied, which colours concavities and convexities to help reveal details on the stone.

Penzance Market Cross

Penzance Market Cross, captured in 3D with photogrammetry, and enhanced using digital filters.

 

As you can see from the Radiance Scaling image to the right, there is definitely more going on than first meets the eye. The figure in the second panel from the top is clearly visible, as are the letters and glyphs in the lower two panels. As I type, I am processing a mesh with a much higher level of detail, and look forward to the results which will be ready in the early hours of tomorrow morning. Comparing the results to the accepted interpretations made by Professor Charles Thomas will be interesting, whether they differ or help to confirm what we already know.

So, my Day of Archaeology has been a busy and varying one, and it’s not over yet. Time to publish this post, and return to the list of posts to publish some more from around the globe, so that we can all show to the world what archaeologists really get up to in our own words. I hope that it helps people today and in the future to understand just how exciting and relevant archaeology is to us all.

You can follow my archaeology musings over at my blog Past Thinking.

Archaeology on the web

My name is Tom Goskar, and I am Wessex Archaeology‘s web manager. I am also one one of the team behind the Day of Archaeology, an international online event which has taken months in the planning.

Like the rest of the Day of Archaeology team, my day has been an incredibly busy one. Essentially it began in earnest yesterday evening (if that’s not cheating) putting the final touches to the DoA website, through to seeing the first post from the Guardian’s Maev Kennedy go online.

After some sleep, I have been helping to keep the website well-oiled and ticking along. I have been doing this whilst publishing and planning web content for Wessex Archeology, who have helped to support the Day of Archaeology by providing some of my time during the day to help run it. Today, I have published some updates about a large excavation that is happening in the heart of Dorchester, the Roman town of Durnovaria. I’ve also been following back people who have recently started following Wessex on Twitter, planning some future web content for an industrial site that we are working on in the north of England, and looking at ideas for publishing some of our content as e-books (in EPUB format) and how we might fit that into our existing design workflows. There are some promising tools out there, and it’s exciting to think of the possibilities of publishing content that will look good on devices from smartphones to Kindles, iPads, etc. Especially when you have a back-catalogue of titles which are now out of print. We could give some publications a new lease of life. Specialist books which when printed are only ever available to a small number of people could have global distribution and benefit many more. Keep your eyes on the Wessex Archaeology website, there’s lots of exciting things planned for the future.

Today I have also just finished an article for a forthcoming publication based upon a talk I gave earlier this year as part the Centre for Audio-Visual Study and Practice in Archaeology (CASPAR) “Archaeologists & the Digital: Towards Strategies of Engagement” workshop in May 2011 at UCL in London. My paper is called Wessex Archaeology and the Web, a simple title, but one that explores how the organisation’s website has grown from a small nine page brochure-style website in 2001 to the  socially connected 4000+ page site that it is today. Major archaeological discoveries, such as the Amesbury Archer and the Boscombe Bowmen amongst others were catalysts to expand and change the way we published information online. We’ve been earlier adopters of many “Web 2.0” (despite my hating that term) technologies and web services, as well as starting the first archaeology podcast, Archaeocast. Many other heritage organisations have looked to us for trying things out first, so we have been in the spotlight on many occasions. It’s been some journey since I relaunched the website in May 2002, and it still feels like this is just the beginning.

My philosophy has always been that archaeology is all about people; as archaeologists we have a duty to make our work available to as many people as possible, otherwise there is little point in what we do. We run the risk of becoming irrelevant to society if we do not broaden access to the information that we uncover. The web is instrumental to helping us to help people learn about their pasts, and the Day of Archaeology is a fantastic way of showing the sheer diversity of work that goes on inside archaeology, and how exciting and relevant it all is.

It has been wonderful to, throughout the day, read many of the posts as they have been published. It makes me excited to see so much happening in the world (literally – see the map of posts!) of archaeology, and that so many people have been passionate enough about their subject to tell the world about it through the Day of Archaeology website. I do hope that it inspires more archaeologists to shout about their work (we’re often quite shy) and see the benefits of the web, and that it inspires readers of this site to follow up the projects that they see here. Maybe some will be moved to take up archaeology in some way, maybe as a volunteer, joining a local dig, or even thinking about archaeology as a profession.

So, a big thank you to all who have contributed an entry to the Day of Archaeology so far, and to fellow organisers Lorna, Matt, Dan, Jess, Stu, and Andy. And thank you, dear reader, for supporting us by visiting and reading all about a day in the life of what is now 422 archaeologists.

It’s been a fun journey, and fingers crossed, there will be a Day of Archaeology 2012!