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Photography in archaeology
#41
Jack Wrote:Looked at the photos. Am I understanding correct that the strimmed area is over an experimental ditch recently dug and filled in. Is that the light stripe that shows up on the near IR image and less well on the thermal image?

There is no thermal image. The thermal stills and 24hr thermal videos are at Leeds University being analysed in relation to all the other data that has been gathered.
Details will be posted on http://dartproject.info/WPBlog/?p=1578

Looking at this near IR shot:
[Image: dart12.jpg]
you have the overgrown infilled ditch and immediately below this area is:
[Image: dart13.jpg]
which is the strimmed bit with the left side of the infilled ditch just visible.
http://www.armadale.org.uk/dart.htm

You can also pick out old dig trenches:
[Image: kinneil01.jpg]
from over 30 years ago. The two horizontal parallel features to the right.
http://www.armadale.org.uk/kinneil.htm
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#42
Oxbeast Wrote:@Kevin, that link doesn't work for me, I get a '404 not found' from their server. It sounds really interesting, and certainly up my street.

I'm pretty impressed by the photos of the open area excavation showing features under UV. That could be useful on a massive stripped site, you could even mosiac the photos. Has it been tried since 1985 though?

My question exactly, hence my original posting.
The photographer, Christopher Brooke is still about http://www.linkedin.com/pub/christopher-.../5/958/107 and still active being Convenor of http://rspsoc.org/information-zones/sigs/archaeology/

Forum members may also be interested in the work of http://www.univie.ac.at/aarg/php/cms/about/about-aarg
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#43
Jack Wrote:But to get back to the photography stuff...........John, where do you see your experiments leading to is my burning question?

A greater understanding of aerial images?
Prospecting for sites before excavation?
Or the identification of individual unexcavated features on an already stripped area from the ground?
Or as an aid to show already excavated features more vividly?

Or all of the above?

I think there may have been an initial misunderstanding of your questions
'Have any readers photographed areas of an excavation outside the visible spectrum (near UV and near IR), with a normal digital camera on a tripod and appropriate filters?
Has anyone used a thermal imaging camera with any success? '

Most amateur archaeology groups go digging. For us, digging is a last resort and our trust has been set up with that implied: www.wlatrust.org.uk
Digging a site is obviously damaging.
My original questions had come from wondering what work was being done to get as much information as possible from a site before any data was irretrievably lost, especially of artefacts that may be mere 'shadows' in the ground....as some features are 'shadows' in the landscape with little left in the ground.

My present view:
A greater understanding of [LOW LEVEL] aerial images YES AND THE DEVELOPMENT OF TECHNIQUES FOR USE WITH KITES. For a more academic overview see the rigourous work of Geert Verhoeven. Our approach is pragmatic.
Prospecting for sites before excavation - YES TO PROSPECTION BUT IN LIMITED AREAS OF KNOWN POTENTIAL, POSSIBLE EXCAVATION BY OTHERS.
The identification of individual unexcavated features on an already stripped area from the ground - NORMALLY NO, UNLESS WE ARE INVITED TO A SITE.
As an aid to show already excavated features more vividly - OR TO SEE FEATURES OUTSIDE THE VISIBLE SPECTRUM and TO SEE ANYTHING MISSED IN THE LOCALITY.

Our original intentions are still posted on:
http://www.armadale.org.uk/archaeologyintro.htm

We moved to Scotland from the archaeologically rich Cotswolds in 2004 where I had had no interest in archaeology.
We settled in the post-industrial, archaeological black hole of West Lothian with shallow soils on volcanic hills and soggy fields.
On our first sites, where we brought in the Edinburgh Archaeological Field Society (Yes, they gave us the kick start) soil resistance and magnetometry were not always productive.
Kite aerial work was........so, when archaeologist Jim Knowles wandered onto one of our sites in 2008 and had a go with one of our kites, it was not long before the West Lothian Archaeology Group was formed.

Ultimately, the responsibility for the direction of the Group depends on Jim.
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#44
John Wells Wrote:Maybe its something for the future when resolution improves and experiments have ironed out issues.

Resolution is not a problem in photography, even when working with a 320x240 pixel thermal imager on a kite.
It is better than the usual 1 pixel equivalent per square metre of geophysical surveys.
[/URL]

Our Group archaeologist Jim mentioned that this statement could be misinterpreted as a criticism of geophysical techniques. I am a physicist by training.
I am not comparing methodologies, I am comparing resolutions. There is a tendency to reject low resolution photography without considering the context. The mention of geophysical techniques is simply to give a frame of reference for acceptable levels of resolution in aerial archaeology.
We have a soil resistance meter and look forward to when we can buy a gradiometer ;o)
Jim is responsible for the geophysics.
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#45
We did a little at uni but not much, mostly the photographing of artifacts in the illustration modules. I think the onsite is important though, our fieldwork photograhy was pretty well thought out.
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#46
John Wells Wrote:The image is only intended to illustrate the resolution of our thermal images and I thought that a human body (mine is now a close approximation!) was the best way to illustrated this.

..............<snip>

If you want to see the resolution of a 140 x 140 pixel thermal camera (if I remember correctly, link to paper on http://www.armadale.org.uk/phototech03.htm) have a look at this image of Villa Rustica taken by Uli Kiesow in 2006:
[Image: thermaluli.jpg]? archaeoflug.de 2006
Visible left and thermal right.
This is the image that made me take up kite aerial thermography, although Uli used a microlight.

Have a look at the recent kite aerial thermogram by Larry Purcell at the foot of:
http://www.armadale.org.uk/phototech06.htm
and Larry has only just started this work!

We have had our first thermal imager for a year but have done very little work. Conditions have been atrocious this year for crop marks (including thermal ones) and safe kite work.
Our Group is working in partnership with Dave Cowley of the RCAHMS to look at a Roman site in Falkirk both within and outside the visible spectrum but this project will now only take off with next season's crop.

Cooler!
Now that's impressive.

I can see great potential for commercial work in preliminary site investigation either pre-planning or for site evaluation.

One headache I've noticed in the industry is accurately showing the presence of archaeology on a development site and its extent before any topsoil is removed.
Especially on sites where there are no cropmarks, no know sites/findspots, nothing turned up from fieldwalking, the geophysical surveys failed to pick anything up and the sample trial-trenching failed to find any archaeology.......and yet archaeology is there.

Not trawled through all the links yet (thanks for posting them) but I'm guessing there is a link between how well geophysics works and how well thermal imagery (and near IR photography) works on any given site, am I understanding correctly that its linked to differential wetness? Think I read that's one of the things your studying?
What would be amazing useful in finding (and saving) archaeology is a cheap and quick technique (like kite-base photography) that can spot archaeological features in areas where cropmarks don't show up and geophysics doesn't work well.

.......just seen the last post, Will endeavor to look through the links in detail
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#47
Jack - The thermal work is still in its early days. The important thing is that (unlike in the visible spectrum) thermal crop marks may occur at any time with differential water loss in the crop producing a temperature variation. So, you are not waiting for the crop/flora to mature.
Unfortunately, Jim, Rosie and I are working mainly in West Lothian and, for differential water loss, it helps if it stops raining for more than a few days ;o)
It may be helpful to go through the techniques on our page: http://www.armadale.org.uk/phototech.htm

I would go for visible, near IR and thermal imaging before topsoil is removed but, under general conditions, near IR may be the most useful. For thermal crop marks and thermal variations in the ground, timing is likely to be crucial.
So far, our comparison of techniques is limited eg
http://www.armadale.org.uk/blackness.htm
http://www.armadale.org.uk/archaeology3.htm
http://www.armadale.org.uk/gormyre.htm

There is no doubt that KAP can useful when geophysical techniques are limited by excess moisture, magnetic rocks etc....and vice versa!
Given the chance, we will use all techniques at our disposal. However, we have the advantage of not being a commercial group.
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#48
In the same year that Christopher Brooke took his UV image at Sutton Hoo, this paper on thermal imaging was published:
Aerial Thermography: A Remote Sensing Technique Applied to Detection of Buried Archaeological Remains at a Site in Dalecarlia, Sweden
by Bengt Lund?n 1985
The findings in this paper deal with the non-crop/flora aspects of thermal imaging.

See also Thermal prospecting on vegetation by Ulrich Kiesow (archaeoflug) as mentioned previously.
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