Karen Nichols's blog

Recording Experiment at Bulford

A comparison between geo-rectified photography and photogrammetry to record human remains.

In late 2015 Wessex Archaeology started the excavation of a large Anglo-Saxon cemetery at Bulford which presented the opportunity to carry out some tests to investigate the best, most cost-effective and efficient way to record burials. We wanted to understand the differences and economic viability of some of the most popular techniques on the market: geo-rectified photography and photogrammetry. 
 

3422

After permission was granted by site manager Simon Cleggett, in December 2015 the WA Geomatics team, Damien Campbell Bell and myself gathered at Bulford to carry out this field experiment. 
 
For the work, we used a Leica Netrover Viva GPS and a Pentax K50 digital SLR camera for the photogrammetry and the geo-rectified photography. Additional accessories included a ladder and lots of targets. 
 
The type of camera we used (a Pentax K50) is a weather-resistant digital SLR camera with approximately 16.49 Mega pixels and mounting 18-55 mm lens. We normally use this type of camera in the field. A Leica Viva GPS was also employed to record the position of the targets used in the photos. 
 
For the success of both the photogrammetry and the geo-rectified photography, targets were placed both on the base of the graves and on top at ground level.
 
With photogrammetry, we can produce a 3D model using a set of photos taken from every angle of the subject. With the Pentax K50 we took approximately 23 photos for each grave; the shots were taken all around the grave cut, on top and at the sides aiming to get complete coverage. These photos were later post-processed to obtain a photogrammetry 3D model. We tried to keep the number of photos below 50 so that the processing would be faster.

 

As for the geo-rectified photography, each burial was photographed from the top in one single shot. Geo-rectified photography only requires one image, but for it to work it needs to be taken on the same plane as the subject, with the camera in a horizontal position. If these two important conditions are not met, the photo can be distorted and would be unusable. This operation required the photographer to climb on a ladder as to make sure that the whole grave was in the photo frame, this also contributed to the photo being less detailed because of the distance. Afterwards, the middle point of each target was recorded with a Leica Netrover Viva GPS with accuracy settings set below 0.02 m. 
 
For both photogrammetry and geo-rectified photography, to measure the position of the targets with a GPS or Total station is essential as this will provide the constrains for the 3D model and will also accurately locate the burials within the national coordinate system.  
 
Back in the office, the data from these various sources were post-processed and compared to each other using the photogrammetry models and the metric surveys as references. These different methodologies were analysed according to level of accuracy achieved, time of execution, least potential damage/disruption caused to the archaeology, time of post-processing and cost for the project. 
 
The results of these techniques were very good but photogrammetry was most successful, the 3D models produced were highly accurate. Unfortunately, some of the photos taken for geo-rectification had to be discarded, highlighting one of the problems with the geo-rectified photography: the shot must be on point and horizontal to minimise any distortion; if the shot is taken too far away many small details will not be clear. In addition to this, another problem that we encountered was the lack of space inside the grave to place the targets. Still, despite some problems in post-processing, the geo-rectified photography gave good accurate results, the photos were rectified and geo-located to be then digitised in the office. The records obtained with geo-rectified photography worked out to be the fastest technique while photogrammetry requires powerful computers and can take a long time to process.

 

For both of these methods used there are pros and cons so that one might be better than the other, depending on what level of accuracy is required and how much time is available on site. 
 
It was really instructive and fun to experiment with these methods on site and to compare them; the results obtained are going to be very useful to plan future archaeological works, allowing us to consider different methodologies according to specific site conditions and project budgets. 
 

Kent Jones Interviews - Guillermo Santamaria

Welcome to the first of our Kent Jones interviews. As with many people Kent is fascinated by world archaeology but loves the archaeology of the UK. He has been interested in how different countries do archaeology and how skills and expertise are shared between countries to better understand archaeology.
 
Here at Wessex Archaeology we are fortunate to have archaeologists working for us who have worked and trained internationally, which provides Kent the opportunity to speak to archaeologists about their experiences within the UK and abroad. The first of Kent’s interviews is with Guillermo (Will) Santamaria, a field archaeologist from Spain.
 

3421

Why do you prefer being called Will? Is it because some British people can’t pronounce Guillermo?
I know it is a bit tricky so I decided to ask people to call me William, which in fact I like more than my Spanish name. It also reminds me when I was a child. My grandparents always wanted to give me an English education so they sent me to a British school where everyone called me Will. 
 
Tell us a little about yourself and the training have you had?
Thanks for giving me the opportunity to talk about me and my professional career. I was born in Madrid but I used to live in Galicia, a region in north-west Spain. Living there was like being in a small England as the weather, landscape and the archaeology are very similar. 
 
I don’t know why but I have always been interested in archaeology so when I turned 16 I went to my first excavation with a university research group that was carrying out an investigation on a Bronze Age settlement. Since then, every summer I spent part of the time digging around Spain. I once had the opportunity to travel to Israel where I spent a couple of months digging a Tell (a mound made of the accumulated remains from settlements). I must say that some of the experienced archaeologists I came across tried hard to dissuade me from doing archaeology, as the future was uncertain at that time. However, I finally ended up studying archaeology at the Uni in Madrid and Santiago de Compostela. At that time (I think nowadays things have changed) we didn’t receive much training as every course was theoretical so it was quite common that students tried to gain experience and money working for commercial units while they were studying.  After finishing my degree, I started working − I wouldn´t say intensely as jobs were limited − for different commercial units until I decided to start up my own small business. Nothing really big as I was just self-employed but sometimes I had my own clients on small projects or collaborated with large archaeological units. Things went from worse to worst when the financial crisis hit Spain. The lack of public and private investment on new developments and consequently archaeological interventions, wiped off the map most of the units and of course me. So, I had to pack everything and come to the only place that could offer good opportunities to continue archaeology...  
 
How does archaeology in Spain differ from archaeology in the UK?
As in the UK the earlier limited protection was extended, in the 90s, when each county implemented new laws that should be included in the local planning application, tending to protect and include new sites. 
 
According with these new laws, depending on the impact of development and proximity to archaeological sites different type of interventions would be required. These types of interventions differ slightly from the ones we do in the UK. To begin with, watching briefs are basically the same. When further investigations are required, to assess potential archaeology on site, we usually do a number of sondages (commonly 2 x 2 m) by hand depending on how big the area is. I think evaluations trenches done by machine are not a common practice in Spain − definitely not where I used to work in Galicia. If archaeology was found in the sondages, the next phase of work would be an open area excavation. In the same way as evaluation trench project could result in an excavation at the end. Although the strategy is different as everything should be 100% dug and the methodology followed single context recording used by MOLA. 
 
Will also went on to praise the UK’s approach to H&S, career development and the professional standards that are employed in the heritage sector.
 
Is there anything you miss about working in archaeology in Spain?
I miss being more in touch with the research part of archaeological intervention. Most of the time as part of the field team we just go to site, strip it, retrieve all the information we can and move to the next project. I would like to have more time to do some research and analyse the artefacts as I used to do in Spain.
 
What challenges have you faced working in the UK?
Working here there are many challenges. Not only the language barrier but each project is different and that keeps you interested.  
 
Interventions are different to the type of interventions I used to carry out in Spain. They are much larger, with more people involve, machinery, H&S issues, etc... so the pressure is higher and the level of responsibility too. 
 
Do you think working in archaeology in Spain and the UK has given you a better understanding of how people lived in the past?
What I come to realise is that people since the beginning of time have been doing the same things here and there. There are some variations on how society was organised and how it reflects on the archaeological remains but at the end the purpose is the same. It´s amazing discovering that same cultural patterns are repeated through the time in places as distant as Spain and UK. I would say that the north and north-west of Spain basically experienced the same cultural evolution as UK and Ireland. The south and south-east is a different world and had a lot of influences from Mediterranean cultures.
 
Despite the peculiarities of each region the prehistory and protohistory from an artefactual, occupational and social point of view are very similar. You can find the same artefacts, similar settlements and social organisation on each period here and north-west Spain. The way the Roman occupation changed the culture in England doesn´t differ at all with the way it did in Spain. The Iron Age is well represented in this country by hill forts as it is in the Spain and Portugal and during the Bronze Age henges, cromlechs, roundhouses, were erected, and although they are less monumental they are essentially the same as the 'British' ones. Similar archaeology can be seen across the Atlantic Area − starting from Portugal, through France and arriving in Ireland − when different cultures developed similar ways of life.
 
 
 

Chartered Institute for Archaeologists Conference

Newcastle 2017

Extending across three days, the annual Chartered Institute for Archaeologists (CIfA) conference provides an opportunity for those involved in all areas of the industry (commercial, academic, curatorial and statutory) to come together to explore aspects of the discipline. This year, the conference was held in Newcastle and the theme was Archaeology – A Global Profession
 
Staff from Wessex Archaeology provided a strong contribution to this years’ programme. On the Thursday, Angela Batt and Alexandra Grassam delivered a talk entitled ‘From equality and diversity to fairness and respect’ as part of a session for the CIfA Equality and Diversity group called ‘How are we making archaeology accessible for all and are we doing it well enough?’. The presentation provided a summary of the diversity survey recently undertaken by WA, and outlined the approach to the survey, the issues encountered and the actions initiated so far. 

3419

The talk also included information on guidance prepared with a view to supporting staff with autism, which has been drawn up in conjunction with a member of staff with the condition. The talk concluded by outlining the route Wessex Archaeology intends to take to make a transition from the concept of ‘Equality and Diversity’ towards ‘Fairness, Inclusion and Respect’.  
 
On the Friday two members of Wessex Archaeology Scotland gave presentations at a session ‘Maximising the research potential from infrastructure projects’. The two talks given demonstrated Wessex’s leading role in marine archaeology and the range of backgrounds our staff have. Dr Dan Atkinson ran through a marine perspective on the topic, giving the audience a summary of work completed around the British Isles and the research potential that has come from that. This included a look at large-scale wind farm developments, marine dredging and ports/harbour development. All of these have allowed Wessex Archaeology’s Coastal & Marine team to conduct funded research into topics such as the palaeogeography of the North Sea (Area 240 − marine aggregate dredging), wrecks, WWI aircraft (Junkers 88 engine found during the London Gateway development) and the sinking of the SS Mendi. It also gave Dan an opportunity to promote the successful Marine Antiquities Scheme, launched by Wessex last year.
 
Ben Saunders then gave a presentation on the rescue excavations on prehistoric tombs along the route of the centre sections of the Batinah Expressway, in northern Oman. This stretch of roadway cut through the Batinah Plain, an area of Oman that, until very recently, had seen little archaeological investigation, despite every ridge and hill having a rash of stone burial cairns across their slopes and crests. While our initial responsibility was to purely record the archaeology that was on the ground, we also made contact with researchers at Durham University and Sultan Qaboos University who were working slightly further south on the Rustaq-Batinah Archaeological Survey, allowing them to use our data in return for contextualisation of our findings. The result was an important step in learning more about the prehistory of northern Oman, particularly looking at the poorly understood Iron Age period, and has resulted in a publication through the British Foundation for the Study of Arabia.
 
All who attended the conference enjoyed the opportunity to share best practice and discuss issues related to the archaeological sector.
 
By Alexandra Grassam and Ben Saunders
 

Clay and Cake

Spring PCRG meeting at Salisbury

On Saturday 13 May 2017, the Salisbury office hosted the Prehistoric Ceramics Research Group’s AGM and Spring Meeting. In the morning, the AGM touched upon many of the challenges regarding capacity, standards and sustainability that face the wider profession. We were also pleased to welcome several new members on the day. 
 

3417

Over 20 people attended to listen to talks by Matt Leivers (Wessex Archaeology) and Lisa Brown (Oxford Archaeology) who spoke about the new discoveries found at the DIO sites on Salisbury Plain and at Thame (Oxfordshire, a joint project between Oxford Archaeology and Cotswold Archaeology) respectively. Both talks included unexpected discoveries of early Neolithic causewayed enclosures, and it was a great opportunity to see and handle the different styles of pottery found at both sites.  Richard Massey (Cotswold Archaeology) talked about the Deverel-Rimbury Bronze Age cremation cemetery at Heatherstone Grange on the edge of the New Forest, a site that had produced an impressive number of urns of different types including a striking number of finely made Barrel Urns. Grace Jones had kindly brought over many of these pots for people to view and Elaine Morris was on hand to share her ideas about the assemblage. Phil Andrews (Wessex Archaeology, Breaking Ground Heritage & DIO) spoke about the investigations at the East Chisenbury midden, perhaps the most impressive of all such sites in Wessex and beyond. The midden represents a massive refuse dump that accumulated during the 9th to 6th centuries BC, which today forms an extensive artificial mound some 3 m in height. Later in the day there was a chance to examine some of the fine and highly decorated pottery and compare this with a similar assemblage from a recently excavated settlement found at King’s Gate, Amesbury (Wiltshire).    
 
The afternoon workshop with its impressive array of prehistoric pots and associated finds provided much scope for discussion and the opportunity to examine and handle the many fine pots.   Between talks and pots, there was a fine array of home baked cakes to consume. 
 
If you would like to find out more about the PCRG please check our Twitter feed @PrehistCeramics
 

Forwards to the West

Three years of Wessex Archaeology West

Wessex Archaeology is one of the largest and longest-established archaeological contractors in the UK. Wessex Archaeology West is increasing WA’s geographic coverage, along with other regional offices in Kent, Yorkshire, Wales and Scotland.

3415

Three years ago, Wessex Archaeology West began with a small windowless office and tool store in the centre of the city and a team of technicians (diggers!). Within one year we were working from Warwickshire to Cornwall and from South Wales to the London fringe, becoming a regional office within two years. Increased turnover meant the need for physical expansion and a move in January 2016 to bigger premises at the newly built Filwood Green Business Park. Today Wessex Archaeology West boasts a much larger fieldwork team, Heritage specialists, multi-skilled Project Managers, Geophysical Survey and Community services. Recognising Bristol city’s maritime heritage, most recently we have been joined by a Senior Officer from the Wessex Coastal & Marine team.
 
In addition to delivering commercial archaeological projects and heritage advice to clients, Wessex Archaeology West has given talks and presentations to local history societies, community groups, appeared on local media and developed strong links with Bristol Culture for the annual Festival of Archaeology.
 
Several members of our team specialise in deep urban archaeology with a successful major excavation and building recording of a former slum area in Bath. Highlights of this high-profile project included locating part of the city’s medieval defensive ditch, uncovering a previously unknown 17th/18th-century footbridge, and fully excavating the remains of 40 buildings associated with Bath’s 18th-century quayside. The buildings were identified as a mixture of warehouses, factories, pubs, a public wash house known as Milk Street Baths and several brothels. 
 
Wessex Archaeology West have also assisted renovation works at Holy Trinity Church in Bradford on Avon. Our team identified a series of burials, scientifically dated to the 9th and 10th centuries, supporting the hypothesis that the medieval church stands on the site of a lost Saxon Minster. At the neighbouring 10th-century Church of St Laurence, our Reflectance Transformation Imaging (RTI) photography has captured the most detailed image yet taken of a Saxon relief-carved alter piece. RTI has since been rolled out across other Wessex Archaeology projects.
 
Highlights of our more rural projects include the excavation of several prehistoric and Romano-British settlements near Swindon, finding evidence for Saxon continuation of occupation close to Hucclecote Roman Villa in Gloucester and assisting our head office during the excavation of a previously unknown large Romano-British roadside settlement near Beanacre, Wiltshire.
 
Wessex Archaeology West is currently involved with major infrastructure programmes in and around Bristol, Somerset, Devon and the Midlands, as well as large-scale housing developments in Gloucestershire and Wiltshire. We are also assisting the expansion of the new Wessex Welshpool office’s involvement with renewable energy schemes in South and West Wales. In 2017 staff from Wessex Archaeology West are looking forwards to working as far afield as Shetland, Europe and the Channel Islands and appearing on national media. Watch this space…..or follow us on twitter @wessexwest to find out more about our exploits!
 
 
 
3416

New Heritage Consultant in Bristol

3407

Wessex Archaeology West is pleased to welcome Ruth Humphreys, our latest recruit, joining us as a Senior Heritage Consultant based at our Bristol Office. Ruth’s experience covers a broad range of sites and archaeological environments of different periods. Since 2007 she has worked for several archaeology units across the Midlands, whilst also contributing to a number of international projects in Egypt, Sudan and Greece. Since 2013 Ruth has predominantly worked on heritage assessments, including the River Thames Scheme which involved collating information on over 3000 heritage assets across several unitary authorities.
 
Ruth remains passionate about African archaeology, and enjoys expanding her understanding of the wide variety of approaches taken to heritage conservation across the globe. She recently presented a paper on early-stage archaeological intervention within the UK Planning process at a conference in Slovenia.
 

Medieval Pottery Conference

3405

This year’s Medieval Pottery Research Group (MPRG) conference has been organised jointly with the Centre for Historical Archaeology and the University of Leicester. Lorraine Mepham of WA has been acting for MPRG to help set up the conference programme. The conference is on the subject of ‘Ceramics and Drink’, and will take place at the University of Leicester on 2 and 3 June 2017
 
Ceramic containers were a preferred way of producing, storing, transforming, and consuming liquid beverages, and form a significant part of archaeological assemblages across Europe in the medieval and post-medieval periods. They are associated with a wide range of human activity from large-scale transnational trade, to ceremonial consumption, to intimate daily rituals within the home. This conference aims to explore the important social and economic roles that were filled by the ceramics of drink.
 
The programme features an excellent line-up of speakers, whose topics include post-medieval London pub assemblages, Lithuanian drinking innovations, Roman Catholic tea-drinkers in the Netherlands, Cambridge coffee houses and Portuguese water containers. There will also be practical demonstrations led by expert potter John Hudson. All are welcome to attend the conference, whether specialist or non-specialist - you can download the programme and registration form here
 
 

The Packhorse Inn

3404

South Stoke, Bath

The Packhorse Inn was one of the Bath area’s oldest and much-loved pubs. The 17th-century building, set in a large garden, is full of character: with flagstone floors, original timber beams and inglenook fireplaces. It was a refuge valued by locals and walkers alike. A cosy, friendly and quintessentially British pub!
 
The Packhorse was closed in 2012, when the brewery sold it to a private developer, but has recently been bought back by the local community after they ran successful campaign to secure the future of their village pub.  It is currently undergoing a huge transformation and refurbishment and they hope re-open later this year.
 
The pub is set within a landscape rich in history, and extensive Romano-British occupation is known in the immediate vicinity of the site.  Wessex Archaeology is currently undertaking a watching brief on groundworks in the carpark to make sure that all historic assets are correctly recorded taking the local community one step closer to re-opening.
 
Fundraising is still on-going and there are regular events and ‘pop-ups’ which are proving very popular in the area.  If you want to find out more and support this community effort you can find them on Facebook ‘Save the Packhorse’ and join them in the twittersphere @PackhorseBath
 
 
 
 

Tunnels at Larkhill

Two weeks ago we talked about the compelling WWI history of our Larkhill site with its practice trenches, tunnels and personal stories of the men that trained there. Excavations here have been undertaken by Wessex Archaeology, on behalf of WYG, for the Defence Infrastructure Organisation
This week we want to share an example of the names written onto the walls of tunnels by Australian and British soldiers trained at Larkhill. Much like the chalk block we shared last week, this collapsed tunnel intersection was recorded using photogrammetry. This area of the tunnels was discovered collapsed and was machine excavated to reveal as much as was safe.
 

3395

Due to the limitations of sharing a model of this size online we have had to reduce the texture quality and decimate the mesh. The result is that it is not possible to read the writing on this Sketchfab model, though it is identifiable. The screenshot below shows what is visible in our fully detailed model. Amongst the names in this tunnel are Privates Baird, Dunn, Fleming, Organ and Watson. We are continuing to research the lives and military careers of all of the named individuals we have come across at Larkhill and intend to release more details in the future.
 
This model also gives us the opportunity to discuss the technique of photogrammetry a bit more and some of the limitations we faced in recording this tunnel intersection.
 
Photogrammetry involves taking multiple photographs of the subject, covering every surface of it which is visible. By ensuring there is sufficient overlap between these photos, and that they contain all of the details that you are interested in you are able to generate a 3D model using photogrammetric software. This functions by identifying common points within different photographs, working out where each of the photographs were taken from based on this information, and then using the photographs to create a three-dimensional mesh. This mesh is then overlain with a texture generated by combining the colour information from all of the photos used in the creation of the model. 
 
As this technique relies on photography, lighting and access are key issues. In the case of this tunnel both were problematic. The bright chalk reflects the sunlight very strongly in exposed areas, whilst the areas still underground are considerably darker. Trying to expose photographs to deal with these two extremes can be tricky, and in order to avoid over exposure in the brighter areas, where soldiers had written their names, it was necessary to leave the darker areas under exposed. In addition to this, health and safety considerations of working in a collapsed tunnel meant that we could not send anyone into the covered areas, limiting our ability to photograph all areas of the tunnel intersection. The result of these two factors is a loss of detail, and some areas not being modelled, leaving holes in the mesh. These have been infilled to create a complete solid, and you will be able to identify areas where this has been done.
 
What this demonstrates however, is that even in the most difficult of circumstances we can produce a high quality model that gives us a better record of our heritage than otherwise available. In this case we have been able to record not just the writing of the soldiers training at Larkhill, but the position of that writing, and a number of other features that tell little stories about how this tunnel intersection was used. It is this extra context that can really bring archaeology to life.
3394
We will be releasing more 3D models in the weeks to come, but for now see if you can find the writing in the model; there are more names we’ve not shown you! If you would like to discuss using Wessex Archaeology’s photogrammetric recording services, please get in touch. 
 

Larkhill Graffiti on ANZAC Day

3384

In preparation for building Service Family Accommodation at Larkhill, Wessex Archaeology has identified and excavated a large array of WWI practise trenches. This complex of trenches is where British and Commonwealth soldiers were trained in advance of their mobilisation to the theatre of war and was in use from 1915 to 1918. The area was later used to train forces in advance of WWII and even into the 1970s.
 
In the process of excavation, archaeologists have identified graffiti left by some of the soldiers and have identified records of the presence of others through archived documents. These included a significant proportion of Australian signatures and details which have allowed us to identify some of the soldiers, research some of their stories, and on some occasions – contact their descendants.
 
The archaeologists have uncovered profound moments in time, written by soldiers before going off to the hell of the trenches on the front line. While many of these soldiers’ lives ended in tragedy, sometimes there is a happy tale to come out of the war. One such example is George John Bayley (identified via archive records) who travelled from country Victoria, Australia to Larkhill and back again. But in the travails of war, he found his sweetheart and took her home. 
 
George John Bayley from Ballarat, Victoria, in southern Australia, enlisted with the 37th Battalion Australian Imperial Force (AIF) and travelled to the UK on HMAT Persic leaving from Melbourne on 3rd June 1916. While training at Larkhill, George met and fell in love with Beatrice Ethel ‘Phyllis’ Parsons from Wilton, Salisbury, UK, and married her after surviving WWI. 
 
George took Phyllis back to Australia after the war and George worked as the Stationmaster for Sheep Hills Railway Station in country north-west Victoria and then Mont Albert Railway Station in the eastern suburbs of Melbourne, Victoria. George and Phyllis lived a long and happy life, blessed with children. On the death of his wife, George went to live with his daughter, Berenice but he died of a ‘broken heart’ about four months later. 
 
The body of data from the Larkhill graffiti is likely to increase as the investigations continue and there are many more stories to tell, particularly those of the Australian and New Zealand Army Corps (ANZAC). In the centenary years of that horrendous conflict, we should all stop to remember those who made such sacrifices. 
 
Lest we forget on this ANZAC Day.
 
Simon Cleggett, Project Manager and Peta Knott, Archaeologist
 
Copyright historic images www.ancestry.co.uk
3385
Syndicate content