Tag Archives: recording and surveying

Experiments using a Quadcopter for Archaeological Aerial Photography

by Alan Thompson (NOSAS)

Introduction

I’ve had my Quadcopter for over a year now, had great fun flying it, and have produced many interesting images.  I recently showed a selection of images at a NOSAS evening, and was asked if I would write this blog and share some of the things I’ve learned along the way.

Of course the pictures are what it’s all about and even if you’re not interested in my comments, I hope you enjoy looking at them.

Background

Inspired by some of the wonderful aerial photos (APs) I’ve seen (for example on Canmore) I have long thought how good it would be to be able to take such pictures of our own archaeological sites.

For several years I have been interested in photogrammetry and experimented with that, especially of rock art where the production of a 3D surface and use of computer generated lighting and shadows can give some great effects.

In 2013 I began to investigate kite aerial photography (KAP) but the possibility of using a Quadcopter also emerged and I realised that technology and prices were moving so quickly that it might be a better option.  In early 2014 I decided that the only way to learn was to buy one.

The Quadcopter – getting ready to fly

Most amateur Quadcopters are sold with very wide angle cameras, with the intention of video recording, and also providing a pilot’s view (called first person view or FPV).  This is less than satisfactory for archaeological aerial photography, and so I bought a Quadcopter without a camera, with a view to fitting my own.

The camera is obviously critical, and it needed to be light (ideally <300g including battery), robust, of good enough quality, and with an interval timer.  Unfortunately I could find no such camera.  All those with interval timers are heavier, for example those used for kite aerial photography.  A solution can however be found in that a group of people spend their time hacking the software of Canon cameras (google CHDK) and provide a hacked version for some models which enables an interval timer to be run.

Having bought and hacked my camera and got the interval timer working I had to fit it to the Quadcopter.  The main problem is the high frequency vibration from the rotors which renders the pictures useless.  A suitable anti-vibration mounting was needed, all within the weight limit.

Next, to prepare for the first test flight.  The web (YouTube) is full of videos of alarming crashes and fly-aways.  The Quadcopter instructions are daunting saying that a first flight should be from the middle of a large field, with no wind and no people about.  There is also the matter of insurance (it could certainly hurt someone badly), and the possible need for a CAA licence.  The regulations here are changing quickly but at present as a hobby flier I can insure through the British Model Flying Association (BMFA), and (unlike a professional archaeologist) have no need of a CAA licence provided I fly within line of sight, avoid certain areas (eg near airports) and limit the height.  I would again emphasise that this is all very much in the news and changing and my observations here will quickly be out of date.

Quadcopter flying

The first flight is bit nerve-racking, but set to auto mode the Quadcopter uses its own GPS and compass and is set so that (more or less) if you let go of the controls it just hovers where it is.  Flying in this mode is reasonably straightforward.  I have not dared try any of the advanced modes as yet.

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A Cross Stone found in Rosemarkie

by Tim Blackie (NOSAS)

Rosemarkie Cross Stone (Tim Blackie)

Rosemarkie Cross Stone (Tim Blackie)

This intriguing carved, reworked and relatively portable piece of sandstone (0.32 x 0.38 x 0.15m) was originally located in a rockery in the garden of 1 High Street, Rosemarkie.

Neither the owners of the house nor the local community have any knowledge of its provenance. The find location at 1 High Street is at the south west top of the High Street close to Rosemarkie Church and ancient graveyard where many Pictish and medieval stones have been discovered. The owners were selling their house and offered it to me as I was intrigued with its most unusual design.

The front of the stone appears to bear the design of a cross carved in relief and the rear is flat. It may have originally been rectangular (possibly square or close to it) with a broad chamfered margin on at least three sides. The very prominent chamfer could be a feature of a cross slab associated with the early medieval Pictish centre at Rosemarkie but could equally point to being an architectural fragment with a later date. The fact that the chamfer has been partly removed and an arc cut out of the stone shows that the stone has been perhaps reworked and re-used for another purpose.

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Glenarigolach Abandoned Township, Wester Ross

by Anne McInnes (NOSAS)

Glenarigolach meaning ‘ glen of the forked shieling ‘ is accessed by a stalkers path leading up the hill on the E side of the Gruinard river. The area is centred on NG 98237 89963 and lies at a height of 100m. The glen was once well populated and Glenarigolach lies between the smaller settlements of Ridorcha and Craigour (See HER Record).

looking down the glen

Looking down the glen at Glenarigolach

During the Highland Archaeology Festival 2014 NOSAS led a walk to the site on their second visit to the area. We were not quite so lucky with the weather as in April, but still enjoyed exploring the ruins and features, although some were submerged in bracken (see also our earlier post on the nearby settlement of Keppoch, which was recorded in April 2014).

There is little documented detailed history on the area, but Meryl Marshall (NOSAS) is on the case so all will eventually be revealed!  She has found that Glenarigolach is marked on the Pont 4 map 1583–96 as Ary Gaulach. We do know that the glen was cleared for a sheep run around 1840.

Jim Buchanan has mapped the visible walls in the area using aerial photographs, and a walkover survey with Anne and Terry Doe has so far listed 33 buildings and features. An extensive muir burn in 2013 has revealed more walls and field boundaries and a roundhouse, so further surveying will hopefully take place in early 2015 before everything is once again submerged in grass and bracken.

glenarigolach

Aerial View of Glenarigolach

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Old routes through Ross-shire: Luib, near Achnasheen, to Scardroy in Strathconon

by Meryl Marshall (NOSAS)

A six mile stretch of rough moorland, west of Achnasheen, is traversed by what was once a well made road generally 3 metres in width. Although it has fallen into disuse and is travelled only by the occasional walker, possibly doing a coast to coast trip, the road today is very distinct and forms a pleasant days’ ramble, especially when combined with an outward journey to Achnasheen on the Kyle of Lochalsh train (with homeward transport parked at Scardroy). But what are the origins of the road? and why did it fall out of use?

A route through Strathconon to Loch Carron had been in existence for centuries; it linked the east and west coast lands of the Clan Mackenzie. The Roy map of 1750 has the road passing NW from Scardroy to Luib on Loch Gowan, 3kms west of Achnasheen, and the first mention of an Inn at Luib, or Luibgargan as it is sometimes known, is on the Dorret map of 1750. A 1798 list of householders has John Macdonald, described as “vintner”, residing there and in 1814 Donald Sage passed this way: “Leaving Attadale in the morning I breakfasted at Luibgargan, proceeded on foot down Strathconan and rested during the night at Garve” (Memorabilia Domestica, Donald Sage, 1899 p191). Both the road and the Inn appear on other early maps too, the Ainslie map of 1789, Arrowsmith of 1807 and Thomson of 1830. It also appears on a Strathconon estate map of 1825 where it is annotated “the road from Loch Carron”. So quite clearly this was a route of some importance; how did it come to be abandoned?

Dorret Map

Dorret Map 1750 (detail; click on map for wider view)

Ainslie Map 1789

Ainslie Map 1789 (detail; click on map for wider view)

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Belladrum Excavation, 31st August – 7th September 2014

by Roland Spencer-Jones (NOSAS)

The Belladrum drama has a Prologue and two Acts, three main protagonists, and a horde (sic) of extras.

The Prologue:

Enter first Joe Gibbs, landowner at Belladrum and host to the annual August Tartan Heart Festival.

During clearing his fields after the Festival, he employs a metal detectorist to identify and get rid of all the left-behind tent pegs. Enter next that said detectorist, Eric Soane, who in August 2009 scanned the site and discovered a scatter of Roman denarii and some mediaeval coins. Enter third, Fraser Hunter, a principal Curator at the National Museum of Scotland, with an interest in hoards and Roman coins. He excavated the site in October 2012 to see if there were any more coins and to identify any obvious archaeology. Enter last, the cast of thousands – well, maybe 20-30 – human diggers from around Scotland.

On their knees in Trench 1

On their knees in Trench 1

There are two possible narratives, Fraser says. The coins were a hoard, a cache. Someone in the Iron Age wanted to find a good safe place to store his (presumably his) treasure. Or, second narrative,  these scattered coins were a votive offering to the gods. There is evidence from other sites such as Birnie, Fraser says, that the hoards of coins do seem to have been placed in special previously holy places.

And, why place the coins here? Birnie and Rhynie had hoards placed within settlement areas. Is there evidence of that at Belladrum? Or, if the coins were a votive offering, what was there at the time to focus the offering? A spring? An ancient site? And, most intriguingly, why 1000 years later were some mediaeval coins placed in the same area?

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Highland Hillforts

by Meryl Marshall (NOSAS)

The Atlas of Hillforts in Britain and Ireland project

Hillforts are one of the most prominent types of prehistoric monument seen across many parts of Britain and Ireland, and this hillfort project has recently been set up with the aim of producing a paper atlas and an online searchable atlas linked to Google Earth. It is a collaborative four year project between the Universities of Oxford and Edinburgh, and contributions from members of the public, either as individuals or as part of local field groups, are welcome.

Several members of NOSAS were interested in this project and a field day took place in May which nine attended. We visited three forts in the Drumnadrochit area which James McComas had suggested. The day was a great success even though the weather didn’t exactly co-operate and the overall impression was “damp” to say the least! The three forts of Dun Scriben, Craig Mony (Craigmonie) and An Torr were very different from each other – we took photos, made rough sketches and filled in the (reputedly) tortuous form provided on the website. The form proved to be not as formidable as we had anticipated and has been submitted to Strat Halliday who is the Scottish and Irish end of the project. If any members are interested in participating in the project or in joining the next NOSAS field day please contact Meryl Marshall.

More information about the project is available on the website

http://www.arch.ox.ac.uk/hillforts-atlas.html

The form to fill in is available at

http://www.arch.ox.ac.uk/files/hillforts/survey%20pro-forma%20web%20final%20v2.pdf

and notes and guidelines are at

http://www.arch.ox.ac.uk/files/hillforts/survey%20notes%20for%20guidance%20web%20final%20v2.pdf

Producing drawings of hillforts

A drawing or sketch of a site, even if it is not precisely to scale, gives so much more information than a written description. Ideally it would be good to produce a plane-table drawing but this is not always a convenient method as it is time consuming and involves carrying heavy equipment to remote and inaccessible places. So when doing the recent surveys at Drumnadrochit we experimented with several methods of survey: using tape and offset, pacing and GPS waymarks. A draft sketch on permatrace was produced but, as usual, it was a bit messy – the words “dog’s breakfast” came to mind! A tidy final drawing was needed, so using a further piece of permatrace and a 4H pencil, I traced the site using hachuring as per RCAHMS guidelines, with annotations to clarify some of the features; I then scanned the result, see sketch of Craig Mony Fort. For me this method of drawing up is new and I have not perfected the technique yet, but Ian Parker of RCAHMS was helpful in giving advice and suggestions, and also his own drawing below.

Craig Mony Fort Meryl Marshall

Craig Mony, Drumnadrochit, by Meryl Marshall

Craig Mony, Drumnadrochit, by Ian Parker

Craig Mony, Drumnadrochit, by Ian Parker

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A Visit to Kinloch Hourn

by Anne Coombs (NOSAS)

The now the familiar road to Kinloch Hourn was a great introduction to the walk led by John Wombell on the 29th June. Henry Birkbeck has always been very generous to NOSAS and once again he offered us the use of the Lodge for the whole weekend. Please don’t get me wrong: the camp site by the riverside is perfectly acceptable but it was much more comfortable and midge free in the Lodge. What resulted was an extended long weekend which turned into a typical KLH event and my apologies to those who were unable to attend but you missed a very good time.

The Lodge is self-sufficient with its own water supply which also runs the hydro-electric scheme providing all the electricity for the house. The weather was glorious and had been for some time, and the absence of rain meant that the burn was very low. This resulted in much hilarity as we discussed the various water economies we could employ. Bath sharing suggestions of course produced much nonsense but with a great deal of care we avoided that by just staying dirty!

Loch Hourn

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Excavations on the Tarbat Peninsula: Cnoc Tigh (Iron Age Round House)

by Oskar Sveinbjarnason (University of Aberdeen)

The excavation started as planned on the 22nd June. A 15m long trench and 10m wide was opened over the northern part of the dun. It took 2 days to open up the area (gorse removal and grass) and as the surrounding field was under crop, a JCB was not able to access the site and speed up the opening. It soon became apparent that the site has been largely robbed of stones, likely during the 19th – 20th Century, possibly to make the enclosure which sits on top of the dun. The quarry holes can still be seen. It was a hard task to plan and remove this later enclosure, mainly due to the amount of rubble and the fact that the enclosure was little more than tossed up earth and stone bank (we can firmly assume that this is not the Castle Corbet) and blended in with the dun itself.

outer dun wall at cnoc tigh

Picture showing the surviving outer dun wall. The rubble to the left is a collapse which hid this outer wall face.

In the trench the outer dun wall face was harder to find than we expected and is it due to the large amount of collapse from the dun wall core outwards and collapse from the enclosure on top of it as well. It was towards the end of week 2 when we finally figured out where the outer dun wall was located and which made the site nicer and easier to understand.

The dun wall turned out to be a complex construction with multiple stages of construction now visible. Initially it seems to have started out as a round house with about 1.5m thick wall. Up against this wall, additional 2.5m of extra wall was added, making the wall about 4m thick.

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Keppoch: Recording an Abandoned Township in Wester Ross

By James McComas (NOSAS)

Keppoch Township Apr14ocd

Keppoch is a cleared village near Dundonnell in Wester Ross (NH 09519 88665). I have a visited a few such settlements before but it did not take long to realise that Keppoch was something special. This was partly the situation; overlooking as it does the wide valley floor of Strath Beag near the entrance to Little Loch Broom, with the snowy shoulders of An Teallach looming on the horizon. However the number and extent of the buildings easily identifiable was the real draw. Also poignancy was provided by the historical information we had, largely complied by Cathy Dagg, which showed that the settlement had been apparently cleared of its tenants between the 1820’s and 40’s. Only four households were listed as remaining in the 1841 census; a weaver, a carpenter, a fisher and a cotter.

Anne MacInnes (who originally suggested the site), Meryl Marshall and Beth Blackburn between them had organised a four day programme running across the last weekend of April. Friday and Saturday would be taken up with clearing the site, whilst Sunday would be the meat of recording and drawing the features. Monday was reserved for a trip out to another nearby cleared village at Glenarigolach.

I did not manage to make it down until Saturday lunchtime and by this point clearing operations were well under way with a few newly discovered buildings being added to Meryl’s original drawing. The afternoon was spent disposing of the remaining brambles and gorse, and was finished with a tour of the village during which each building had numbers attached for easy identification the following day. After this everybody was more than happy to get washed and changed before reconvening for a very pleasant meal at the Aultbea Hotel.

Meryl Marshall had prepared a fearsomely comprehensive information booklet for the weekend. This had been emailed to all the attendees with stern warnings to thoroughly digest the contents prior to Sunday. Meryl had actually done a fantastic job of producing a simple but effective guide to recording and surveying a township, including handy “top tips” (the whole manual can be accessed at here and is well worth checking out). It informed us that standard of information to be collected could range from a “one star” up to a “five star” treatment. We were to give Keppoch a four star treatment, which would involve a full written description, photos and a dimensioned sketch of each building.

Meryl in lecture mode at Keppoch

Meryl in lecture mode at Keppoch

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