Dig Diary – Tuesday, August 22, 2017

Day Thirty-Six

The end is nigh…

Final photo clean in Trench T.

Tuesday dawned cold and windy and stayed that way.

The wind is whistling in from the east and the air temperature has dropped several notches and is showing no signs of reviving.

Life, and archaeology, goes on, however, and there is a palpable sense of urgency as the days of this final week run out.

In the Finds Hut, Ann, with a depleted team of helpers, is still cleaning the backlog of pottery which has landed on her desk in recent days, while wondering how it is all going to be safely packed and stowed away.

Outside the hut, Alette has temporarily abandoned her high-tech surveying equipment and is industriously cleaning grubby finds trays.

Where it will all go is another difficult question, as the vast Ness assemblage of all sorts of material and artefacts is already swallowing up our storage place.

Our Finds Supervisor is, however, rarely beaten and seems to have developed a sort of Tardis strategy, which results in large quantities of material disappearing into quite small spaces.

Emma’s latest line in headgear.

Out in the trenches, there is a concentration on final preparations for the beginning of the covering-up process, which will start tomorrow — although the weather forecast does not look promising.

The exception this afternoon was Trench T, where many of the remaining diggers, including site director Nick, were busy cleaning surfaces for a very important event.

Trench T must look its best as Hugo, complete with camera-on-a-pole, took a series of images he will amalgamate into a highly-detailed 3D image of this very large trench.

The result will be on the Sketchfab website in a few days and will complement both Hugo’s earlier work and also some of the images taken this season by Jim Bright (see below).

We could still do with some more volunteers to help cover the site with plastic sheeting and tyres.

This is really vital work as the Orkney stone, of which the buildings are constructed, makes excellent building material but is very liable to disintegrate over the winter if exposed.

It is not the cleanest task, and reasonable fitness would be a help, but this most important task goes more quickly and easily if there are plenty of people to take part.

Just come along any time on Wednesday to Friday (9am), or email Nick at nick.card@uhi.ac.uk.


From the Trenches

Screen grab of vertical shot of the northern entrance area of Structure Eight.

Today’s blogger, Jim.

Hi I’m Jim and I’ve been fortunate enough to work at the Ness of Brodgar this season, creating 3D models of some of the structures around the site.

This is for my Archaeological Practice Masters degree I am undertaking at the University of the Highlands and Islands.

I have been focusing on digital archaeology throughout this degree and my undergraduate degree, which I also completed at UHI.

The main focus for my work was to create 3D models which could not only be used as a form of dissemination, so everyone could see parts of the site online in 3D, but which also could be used as a tool to inform and help the archaeologists throughout the season at the Ness.

This has worked very well and I have been able to create models of structures as an aid to planning them. Indeed, in some cases the models have been used as a replacement to planning parts of the site which would normally be very time consuming.

Much has been learned throughout the season, about how to organise undertaking the photogrammetry with the structure supervisors.

The areas are cleaned back and made to look as tidy as possible before I go in and begin taking hundreds of photographs, which can then be loaded in to software and used to create the models.

The processing of the models can take several hours for larger areas and involves several steps, from aligning the photos to removing bad points and data, to generating mesh and textures for the model.

Once this is done co-ordinates from coded targets are input in order for the model to give accurate measurements down to the nearest millimetre.

Hugo and Woody record the final section through the wall in the side entrance to Structure Fourteen.

This can be a nail-biting time, especially if the structure supervisors are waiting for the result before they can continue to work on the structure, so I need to make sure I have taken as many photos at as many angles on a structure as possible for the model to generate correctly.

Fortunately, all the models created for planning were generated correctly and showing the results to the structure supervisors in the knowledge that they will be used to help with the archaeology is a very rewarding experience.

Screen grabs of the models at certain angles have been made so the supervisors can take them out to the site, draw on them and use them to discuss what to do next.

Much has also been learned about best practice when creating a 3D model, especially from Dr Hugo Anderson-Whymark, an expert in creating models from the Ness of Brodgar, along with other sites and places.

His valuable advice has enabled me to develop my skills and I’ve been able to create 3D models of a vastly superior quality from the work I was producing before I began my placement.

Another aim for my placement at the Ness was to record a structure being removed, in 3D, step by step.

The northern curving, phase two wall, bisecting the building in Structure One was being removed to bring the structure back to its original form and so this was a perfect opportunity to record the wall, in 3D, as it was removed course by course.

This has worked very well, with thanks to the wonderful patience of the structure supervisor Andy Boyer and her team in Structure One, who would clean up the section and wait while I undertook the photogrammetry of sections of the wall each time a new model was required.

We now have a detailed 3D record of this wall as it was removed.

I will be posting more models of the wall removal in different phases, along with other structures on my Sketchfab page www.sketchfab.com/jimbright and on www.virtualpasts.com

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