Tag Archives: photogrammetry

Droning on about Tarradale

by Andy Hickie

Drone image of Tarradale Through Time barrow cemetery dig, as featured in “Current Archaeology” November 2019.

Back in 2017, I caved in to the demands of consumerism, and purchased a new quadcopter, a Phantom 3 Advanced, which is equipped with a camera and GPS unit. I flew multiple flights around Avoch but, after a while, the novelty of seeing one’s house from the air at different angles and altitudes begins to wear thin, and I began to wonder what I could actually do with a drone. Having always had an interest in archaeology and, spurred on by seeing some of the images Alan Thompson of NOSAS had created, I decided to carry out a few experiments of my own.

My first flights took in locations such as the distillery and settlement at Mulchaich, and the features of Kinbeachie castle – sites which had already been mapped by Alan by drone, the results of which I could use as a ‘benchmark’ against which I could compare those of my own.

At the same time, I began experimenting with various flight planning apps which allow for off-line autonomous flight planning, as well as online platforms for image processing. I found that “DroneDeploy” and “Mapsmadeasy” combined provided a fairly user-friendly pipeline, whereby image capture and photogrammetry can produce georeferenced photomosaics and digital surface models (DSMs). These can then be imported into software such as QGIS for further processing.

Having found the software which satisfied my needs, I then turned my attention to potential sites which I could map – and decided on the cropmarks of the Barrow Cemetery at Tarradale. At this point, my intent was purely to satisfy my own curiosity – just to see what I could see, and how it would compare with the archaeology found at the forthcoming 2019 dig.

And so, on 10 June 2018, accompanied by my daughter Emma to act as co-pilot and “spotter”, I visisted Tarradale to map the area with the drone. I can still recall the excitement I felt as the images began to appear on the monitor of the remote controller, which showed the cropmarks were developing. However, my satisfaction was tempered somewhat when I got home and began to process the photographs. Although the cropmarks were indeed evolving, the crop was insufficiently ripe, and many of the details remained hidden (see image below).

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Pictish Eagles and the Strathpeffer Stone

by John Wombell (NOSAS)

There are 12 known Pictish Eagle carvings, all in the RCAHMS publication of 2008 ‘The Pictish Symbol Stones of Scotland’.  They vary considerably and by far the best known and the best preserved is on the Clach an Tiompain at Strathpeffer (HER MHG43542) meaning the ‘sounding stone’ but known more widely as the Eagle Stone.

There are many images of it in circulation but a week ago I took a new set of photos which Alan Thompson kindly processed for me using photogrammetry (see images above and below, as well as on Sketchfab).  The reason behind this was that I wanted to try to produce an engraving of it on wood and needed to see more detail that is not visible to eye or touch at the stone.

The Eagle Stone has had several lumps bashed off it in the past removing part of the horse shoe symbol and the eagle’s rear end.  Otherwise damage to the carving is minimal with only part of the eagle’s leading leg either fallen or bashed off.

My dilemma was whether to give the eagle a tail or not.  I feel sure that unlike most Pictish eagles this one was drawn from a live eagle depicted walking.  It is correct in a lot of detail even though the carving is full of symbolism.  I decided to give my version a short dipped tail represented as two feathers after one of the Orkney eagles. Continue reading

A Year of Highland Archaeology

by James McComas (NOSAS)

A Year of Highland Archaeology book cover, showing Tarradale Through Time excavation trench with the settings of a possible stone hut. The same trench yielded several rare antler tools.

NOSAS has just published A Year of Highland Archaeology: A Collection of the Projects and Activities of the North of Scotland Archaeological Society . This new book includes 10 articles which explore some of the diverse recent projects that we has been involved with. These range from large scale funded excavations through to group surveys and small scale research projects. They highlight Highland locations from the west to the east coast, from Speyside to Sutherland.

Projects featured include the lottery funded Tarradale Through Time Project, which in 2017 saw 6000 year old antler tools uncovered near Muir of Ord on the Black Isle.  These very rare finds included the remains of a harpoon point and two “T axes” left behind by hunter gatherers on the shores of the Beauly Firth. The T axes are two of only five examples so far known in the whole of Scotland. The trench where these were found also tantalisingly revealed the possible stone setting of a Mesolithic hut. Tarradale Through Time continues in Autumn 2019 with the excavation of potentially one of the largest barrow cemeteries in Scotland (further information at www.tarradalethroughtime.co.uk).

One of rare antler “T axes” found during Tarradale Through Time’s 2017 excavations.

Another chapter focuses on Torvean Hillfort, a neglected structure on the edge of Inverness. Torvean was perhaps constructed more than 2000 years ago, but it is today sadly under threat from persistent trail bike damage. A different chapter tells the much more positive story of how a collection of 400 historic maps relating to the Lovat Highland Estates, covering extensive areas west of Inverness, have now been scanned and made available online.

Map of Torvean Hillfort, Inverness showing destructive trail bike tracks

A different chapter still focuses on the NOSAS’s work with Scotland’s Rock Art Project. ScRAP aims to log as many as possible of the mysterious carved “cup marks” which appear on Scotland’s boulders and rock faces over a 5 year project. The precise date of these carvings, of which there are many good examples in the Highlands, is unknown but they are thought to have been mainly created in the Neolithic period around 6,000 to 4,000 years ago. Other archaeological locations explored in the book include Ormond Castle in Avoch, a prehistoric roundhouse landscape in Glen Urquhart, and Gruinard Island in Wester Ross.

3D Photogrammetry model of cup marked stone at Kinmylies, Inverness

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Buntait, Glenurquhart: A Bronze Age Landscape?

by James McComas (NOSAS)

The larger barrow at Buntait – feature ‘X’ on the map below.

Although I have lived in Glen Urquhart for some years, it was only comparatively recently that I first visited Buntait, a hamlet just to the north of the Clava type chambered cairn at Corrimony. This was despite me hearing from a number of local people about the amount of upstanding archaeology that was there. I think I must have presumed that because there are no scheduled monuments there it could not be that interesting – an assumption I will not be making in the future. Later research confirmed that Buntait is in fact full of prehistoric (and post medieval) features – including hut circles, field systems, burnt mounds and rock art. Not only are the field systems extensive and some of the hut circles very well preserved, but also there are a couple of ditched barrow features. Locally, only Garbeg is comparable in terms of prehistoric remains.

GIS map of Buntait annotated with huts, barrows, cairn fields, dykes and other archaeological features.

Consequently Buntait became the subject of three archaeological field trips in 2017; two led by NOSAS, and one as part of the Archaeology Scotland Summer School planned with the assistance of NOSAS. There were also numerous smaller sorties for quadcopter flying, polecam photogrammetry, rock art recording (for SCRAP) and general investigation.

OS map of Buntait annotated with huts, barrows and buildings in red, cairns in green and dykes in brown. Blue dots show the location of records on Canmore. BM = burnt mound.

NOSAS field visit to Buntait January 2017

“The Glenurqhuart Story” by Alistair Mackell published in 1982, provides a useful if perhaps now outdated introduction:

Not far from the Corrimony Burial Cairn, on Buntait lands, was a settlement of some considerable size where clearly marked hut circles and cairns suggest a community practising primitive agriculture and a boundary wall, which can still be traced, may have served to protect domestic animals from prowling wolves or other marauding wild animals. Some of these circles are 30 feet in diameter and in the centre of at least one, is a depression which may have been a fireplace. These circles are low banks of stones covered with grass or heather about 2 feet high and 4 feet wide at the base. It is difficult to imagine one large roof covering such an expanse, but if so, it would probably have been formed of wattles and thatched with heather or turf, giving, when complete, a dome – shaped appearance. In each case there is a break in the circle at the south east which indicates the entrance. In other parts of Scotland where these structures have been carefully examined, hearth paving stones have been discovered, but we are unable to reconstruct much of the everyday life of the people of these long bygone days, and we can merely conjecture that they combined hunting with their primitive agriculture, for the Highlands were rich in wildlife.

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Digging in to digital – A summer of photogrammetry in Orkney

by Jim Bright

Standing in Structure 1 while undertaking photogrammetry

I have just completed undertaking an MSc in Archaeological Practice at the Archaeology Institute, University of the Highlands and Islands. This entails completing a placement and as my specialisation and undergraduate dissertation has been researching the use of digital techniques to record and disseminate our heritage, the placement would offer an ideal opportunity to test some techniques in the field.

After discussions with site directors Martin Carruthers and Nick Card, I was offered the opportunity to work throughout the season at both The Cairns and Ness of Brodgar excavations. This would enable me to make 3D models of trenches and structures during different phases of excavation. I could also develop my skills with creating models of small finds, the idea being that there could be 3D models of items made just as they have been excavated, or while in-situ. I wanted to identify the value of having what could be termed as a ‘digital archaeologist’ on a site for the entire duration of an excavation, primarily using the photogrammetry technique, and working on these sites throughout the summer would provide the opportunity to do this.

Before I go in to detail about how I undertook the digital work at both sites, I’ll give a little bit of background information into the excavations. The Cairns was the first excavation where I was to undertake digital work. These excavations overlook Windwick Bay in South Ronaldsay, Orkney, and were undertaken from 12th June to 7th July 2017 with previous excavations having taken place from 2006-2010 and 2012-2015.

View from inside the broch during excavation season 2017 at The Cairns

Initially, excavations took place in order to confirm the presence of a souterrain which had been described in a 1903 text, and during the 2006 excavation season, evidence of what is described as a ‘massive roundhouse’ was uncovered, which today is considered to be a broch or broch like building. The excavation is primarily concerned with the Iron Age period, however evidence of Neolithic activity is also present.

The second excavation where digital recording took place was at The Ness of Brodgar, situated on an isthmus between the Standing Stones of Stenness and the Ring of Brodgar, in Stenness, Orkney. This site is positioned between the lochs of Stenness and Harray and lies within the inner buffer zone of the World Heritage Site known as the ‘Heart of Neolithic Orkney’. I expect many will be familiar with this site due to its numerous appearances on the television, most recently on the BBC documentary, Britain’s Ancient Capital: Secrets of Orkney. Excavations have taken place here since 2003, after geophysical surveys in 2002 revealed the extent of a large structure and areas of interest. Today the Ness of Brodgar is arguably the most significant Neolithic site in Britain. Continue reading

Scotland’s Rock Art Project (ScRAP) – Progress so far

SCRAP banner

The story of the Project and NOSAS’s involvement up to the end of May 2017

by Alan Thompson (NOSAS)

Background to the Project and NOSAS involvement

Scotland’s Rock Art Project is a five-year project to record and research prehistoric rock art. The scheme is run by Historic Environment Scotland (HES) and funded by the Arts and Humanities Research Council.

The aim of the project is to improve understanding and awareness of Scotland’s rock art through research.  In order to research the carvings, we need to first develop a comprehensive, detailed record of where they are and what they look like.

As many of you will already know, NOSAS is a partner in this project.  Our specific role in 2017 is to work with Tertia Barnett and her team to pilot and test the recording methods to be used.  Beyond that we will be one of a number of Community groups recording rock art across Scotland.

As with all such projects, there is a challenge in ensuring that small groups, working independently in the field, make their records in a sufficiently consistent and comprehensive way that the results are meaningful for analysis by Tertia and her academic partners.

Tertia has extensive experience in recording rock art in England, including in the Northumberland and Durham Rock Art Project (NADRAP).  At that time photogrammetry was still somewhat specialised and could only be used selectively, but despite that some great results were obtained demonstrating that rock art is an ideal subject for photogrammetry.  The progress of technology since then means that our project will major on the use of photogrammetry – we intend that all panels (each discrete exposure of a piece of rock art is called a panel) should be recorded this way.

Tertia also plans an App for recording, the idea being similar to that used by the Scharp/Scape project which some of you have used.  That will take a little time to specify and program, and so in the meanwhile (for the pilot work) we are using paper forms.

Discussing how to record this CMS. (Photo Anne Cockroft)

NOSAS Involvement in the Pilot Project

NOSAS has committed to work with Tertia to record enough panels in our local area in 2017 to fully test the methods she is developing.  35 members have indicated an interest and most of these have already become involved.  If other members are interested they should contact John Wombell or Alan Thompson.

Progress to date

The project is now underway.  We have held two ‘familiarisation’ afternoons at Clava, plus training sessions with Tertia at Dingwall and Drumore. Continue reading

Kinbeachie Castle or “Kinbeachies House”?

by Meryl Marshall (NOSAS)

NOSAS members carried out a measured survey of a site at Kinbeachie on the Black Isle using planetables at the beginning of March, the project also included photographing the site using an aerial drone fly-over. The site is known as “Kinbeachie Castle”; it includes not only the amorphous linear banks thought to be the castle but also a farmstead of 4 buildings and a horse-gang. The remains of the farmstead were obvious, but our initial investigations of Canmore and the HC Historic Environment Record indicated that there was also a typical 18th century “lairds house” there; see photo below, taken in 1959. So was there a castle or a house at the site?Kinbeachie typical 18th century “lairds house”

The small estate of Kinbeachie, amounting to “a half davoch”, is located in the northwest part of the Black Isle overlooking the Cromarty Firth. Today it is productive arable land but in the 16th century there are references to “the King (James IV) hunting in the woodland along the Kinbeakie Burn”.  The area of Kinbeachie has almost certainly been associated with the Urquhart family of Cromarty from this time and the family of Urquhart of Kinbeachie itself from the mid-17th century. Research into this family was to be part of the project.

Brief Description of the site

The site covers an area, 70m x 50m, of rough grassland in the corner of a field. It comprises 2 parts;

  1. The central part thought to be the site of the castle; the remains here are most substantial in the NW part where the footings of two walls up to 1m in height are at right angles to one another. To the SE there are two indistinct parallel banks which terminate in linear stone settings
  2. The farmstead comprises the footings of 4 (possibly 5) rectangular buildings, a horse gang and a semi-circular yard. The buildings have turf covered stone walls up to 0.5-0.7m height and measure between 10-14m x 4m internally. The horse gang platform is 11.5m diameter. The semi-circular yard is 50m NW-SE x 25m NE-SW and bounded on its curving SW side by a discontinuous sloping retaining wall which has stone facing in places and is generally 0.7m in height.

1st Edition OS map

The site viewed from the SE

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