Tag Archives: Scottish Lidar

Achnasoul and Medieval Earthwork Castles in Ross Revisited

by Meryl Marshall

The moated homestead in Achnasoul Wood (NGR NH 48808 51821 Canmore ID: 274702 Highland Council (HC) HER MHG29192) 4kms west of Muir of Ord was visited by NOSAS members on a winter walk in February 2020 just before “lockdown”. The visit renewed my interest in the medieval period in this area and I began some research into the two homesteads of Davids Fort and Achnasoul with the intention of producing a blog for the NOSAS website. It wasn’t long before I realized what a complex topic I had taken on so I decided to split it into two; the first part, on Davids Fort, appeared on the NOSAS website in May 2020, this piece, focusing on Achnasoul, is part two.

The eastern half of the site showing the ditch and double banks with the mound on the right – looking SE

The Achnasoul site is a ringed earthwork with a central mound which was originally interpreted as a “moated homestead” but recently confirmed (on Canmore) as a motte and bailey. It is remarkably well preserved and has been one of my favourite local sites for many years. NOSAS carried out a planetable survey on a cold, wintery day in 2005 (report on NOSAS website at: www.nosas.co.uk/siterecords.asp.) The site remains something of a mystery and seems out of place; clearly it is fortified as it has substantial double banks enclosing a ditch but yet it is situated in low lying ground with higher knolls surrounding it – not a particularly defendable position!

In 2017 the site was scheduled by Historic Environment Scotland (HES) – SM13629. The description in the scheduling document says:               

The monument is a large earthwork enclosure comprising a ditch and two concentric banks which enclose a sub-circular area measuring around 43m northwest-southeast by 39m northeast-southwest within which is a raised mound. The ditch defining the enclosure measures 4m to 5m in width and 1.5m in depth and is broken by two causeways on the northwest and southeast. The outer bank of the ditch is complete and varies in height, reaching a maximum of 2m… Internally, the raised mound lies in the northern part of the enclosed area and is c25m diameter at its base, reaching a maximum height of 2m. The summit is encircled by a fragmentary bank, which encloses an area of around 11m diameter.

The size and form of the visible remains… represents a rare survival of a moated homestead of medieval date.

A processed image of the Achnasoul site from a lidar survey (contains public sector information licensed under the Open Government Licinse v3.0)
Continue reading
Advertisement

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).

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

Continue reading