Turtle Station

Nickleodeon’s  Next Generation take on the Teenage Mutant Ninja pizza scoffers has taken over in our house from last week’s obsession with werewolves. Meanwhile, at work I have been introducing our new UCLan Young Researcher, Steph, to surveying. These two events are completely connected in my head because when I worked at Glamorgan-Gwent Archaeological Trust in the early 90s I had a Geordie boss. Try saying ‘total station’ in an Auf Wiedersehen Pet accent and you will see where the title of this post comes from.

Steph is with us for two weeks to experience what university research is all about (coffee drinking is obviously an important component). We spent Tuesday learning about basic total station survey around the campus and moving between the map data in QGIS and measuring points in the real world. Yesterday we took this knowledge out into the field. We had two jobs to complete this week, both of them geared to making the start of the dig on Monday go a smoothly as possible. One was to move all the equipment out of the stores and into our temporary base at New Laund Farm. The other was to lay out some of the proposed trenches on the ground so that we can start digging them straight away. It’s always tempting to leave this job until the day you actually start but this inevitably leads to there being some slight unsuspected problem with the survey data. Then you end up with twenty bored excavators standing around watching as two people frantically do sums in their heads and argue about the answer.

IMAG0268

Karl nobly gave us a hand with both the kit-shifting and survey. He is the invisibly small one holding the reflective target in amongst the dairy herd in the middle distance. The job we had to do is simple, but it is absolutely vital to get it right. Our QGIS files record the position of known archaeology and, since the other week, the positions of trenches which should coincide with that known archaeology. We can save these positions as OS grid-references into the memory of the total station. We then use the total station to put markers down on the ground at the same co-ordinates and, hopefully, there are our trenches, right on top of the features we want to investigate.

For this to work the total station needs to be located at some known point on the national grid. In practice it is easiest to do this by a process known as resectioning. To resection you use the total station to measure distances to and angles between a series of other known points. We are using the corners of field boundaries here but anything big and immobile that has been previously surveyed by the OS will do. The total station then calculates the point where all these lines intersect and that allows it to work out both where it is in the field and which way north is – all the information you need to then survey any other point within sight. Depressingly, it also tells you what the margin of error in the calculation is. The photo shows us on our second attempt at setting up by Trench K because we didn’t like the errors the first time around.

trench location NL13

We have trench K and Trench H laid out ready for the start of work on Monday. The weather forecast is supernaturally good and I don’t think we have forgotten anything essential for the first week. Today we have been back in the university, partly because the whole school had been invited to meet the new Vice-Chancellor, but also to get our final coffees from David’s Caffeine Rush concession which ran out of contract today. Anyone in the vicinity of Kirkby Longsdale should check out his new business Mia Italia, the coffee will be fantastic.

Rick

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