We discussed:

• the allocation of tasks to Armin Schmidt (Weather analysis, IMKO analysis and GPR analysis)
• the future of the IMKO probes (after fixing they will be returned to Van Walt)
• the equipment reolocation (will happen some time after April – in the hands of Dan and Ant)
• the workshop in September (arranged for the 17th – watch this space for further details)
• The repository ingest functionality
• the AHRC follow on fund application

There was a discussion led by the PhD students (Chris standing in for Rob) around their problems.

Action points

• Dan: Get costs to install the equipment from the lab in Quarry Field
• Dan: Give Ant specifications of the equipment and cabling in Diddington so we can organise the removal
• Ant: Pay Van Walt bill
• Ant: Add a reuest through to the Auger (soil science community)
• Ant: Book BIG room for the workshop
• Ant: Invite Cranfield to the workshop
• Keith and Chris: Decide about the Van Walt probe
• Derek: Give a list of people to invite (Data mining and vision)
• Derek: Will discuss with Dan about modelling variations between temperature and soil moisture
• Derek: Can provide curve fitting signal advice to David (and something on the way the derivatives are calculated)
• All: Pass your presentations to ARB

The minutes of the meeting can be found here.

sorry…. on the 12/12/12 a ‘virtual’ meeting was held. The virtual meetings are designed to provide the DART investigating team with updates of general progress. This is crucial as the investigating team is distributed between a number of different universities. Prior to the meeting the student provide progress reports so we have a document such elements as progress, problems, outputs and achievements.

No one from Birmingham could make the meeting. The bulk of the discussion at this meeting covered the data anlysis techniques that David and Rob have introduced. There was also some concern about the readings from the TDR. Nicole Metje has been asked to look into these. The data server is up and all students have been asked to transfer their data to the WebDav framework. Ant Beck is modelling the back-end in UML. Everyone has been asked to look at the Agenda for the meeting on the 10th and 11th of January

A follow up meeting to discuss Birmingham issues has been suggested for the 20th December.

The monthly student updates can be found here.

The minutes of the meeting can be found here.

The notes from the virtual meeting on the 14th November are also here

This issue represents an important landmark for those undertaking ‘open’ approaches within archaeology. It brings together a number of researchers and leaders from around the to share their experiences and perspectives.

The abstract for our paper is as follows:

By unblocking knowledge bottle-necks and enhancing collaborative and creative input ‘open’ approaches have the potential to revolutionize science, humanities and arts. ‘Open’ has captured the Zeitgeist, but what is it all about? Is it about providing clear and transparent access to knowledge objects: data, theories and knowledge (open access, open data, open methods, open knowledge)? Is it about providing similar access to knowledge acquisition processes (open science)? Obviously it is; however, this is not the whole story. Open approaches require active engagement. This is not just engagement from the ‘usual suspects’ but engagement from a broader societal base. For example, primary data creators need the appropriate incentives to provide access to Open Data – these incentives will vary between different groups: contract archaeologists, curatorial archaeologists and research archaeologists all have different drivers. Equally important is that open approaches raise a number of issues about data access and downstream data reuse. This paper will discuss these issues in relation to the current situation in the UK and in the context of the DART project: an Open Science research project.

THANKS TO ALL

The project summary is as follows:

Rural landscapes across Europe are being transformed by land management, climate change and urban expansion. These threaten our rural heritage at all scales from individual buried remains to the entire historic landscape. The threats are made worse by our unreliable knowledge of this heritage and the uneven approach to the management and monitoring of its condition across Europe. Responding to the threats effectively and efficiently is challenging. Decision-makers and other stakeholders need access to reliable science-based information in order to frame cost-effective and sustainable responses, especially in a complex area such as agricultural policy.

THEMATIK is a pan-European project which will improve our understanding of the environmental and anthropogenic processes which threaten our landscape heritage. From this new methods will be developed for monitoring, detecting and characterising heritage landscapes, their state and their risks. Web-based tools and services will allow stakeholders to assess heritage resources. Reliable and accessible heritage knowledge are key to maintaining flexible and cost effective strategies.

THEMATIK outputs will inform many policy processes ensuring that decisions on how best to adapt to pressures are based on solid scientific analysis. THEMATIK’s integrated assessment approach will enable stakeholders to explore, assess and understand the interactions between different sectors and how they could affect European landscape change and impact on heritage environments. This contributes to the development of more robust European policy by building the capacity of decision-makers to understand cross-sectoral vulnerability and how it might be reduced by various adaptations. The integrated approach to landscape management at the heart of the European Landscape Convention demands cross-sector thinking to better inform sustainable policy responses.

The bulk of the discussion at this meeting discussed general progress and problems with the TDR station (resolved by Dan – well done).  This was followed by a discussion about the excavation strategy to validate features (not the ditch) in the area covered by the geophysical surveys. Rob will examine the data and suggest recommendations based upon the need to characterise potential archaeological features that ARE NOT the ditch feature.

The monthly student updates can be found here.

The minutes of the meeting can be found here.

The following action points were noted:

RF: produce summary for excavation

All: reconvene handover meeting (Led by availability of Nicole and Dan)

Attendees:

Ant Beck

David Stott

Laura Pring

Robert Fry

Keith Wlkinson

Tony Cohn

Apologies

Armin Schimdt

Dan Boddice

Doreen Boyd

Nicole Metje

Chris Gaffney

These measurements are taken during my monthly multiplexed-twin probe Earth Resistance readings (using a Geoscan RM15 data logger, with  multiplexer attached to a PA20 frame – allowing for twin probe measurements at a= 0.25m, 0.5m, 0.75, and 1m respectively.  - The increasing ‘a’ spacing can be equated with increasing depth of investigation beneath the ground – but I digress..).  The results shown demonstrate the collected readings at a=0.5m which is generally the standard spacing for most twin-probe archaeological surveys.

The investigation of what we continuously term ‘seasonality’ has apparently failed this year.  The weather has behaved in a way we could not foresee – in essence – we haven’t had ‘seasons’.  One major risk with only having C.15 months of survey time over our ditch features supposed that the years of 2011-2012 would be ‘normal’ 0r at least ‘seasonal’.  Instead we ended up with one of the hottest summers in 2011, the warmest and driest winter on record, drought (and associated hosepipe bans) in January and February – followed by the wettest April and June (and I suspect July) on record.  It wouldn’t surprise me if Summer 2011- Autumn 2012 will end up being one of most unpredictable and extreme years on record.  One thing this does offer, however is an intriguing look into one of the wildest years there has been, and how this has changed the way we can (or cannot) detect the archaeology. – after all – that’s what DART is all about, right?  These extreme conditions may well be a catalyst in determining further the causes and effects of the environment on some aspects of archaeological detection.

This effect of the environment can be seen in the graph below.  The data is comprised of taking the average of twenty Earth Resistance traverses taken over the ditch feature at Cherry Copse – 12 months apart (readings have been taken every month of the year, but are not presented here).

From the graph it is quite apparent that the two months do not show the same or even similar anomalies over the ditch feature – even though they are both taken at the height of summer, at the end of June.  The general background resistivity of the site has decreased by around 60 Ohms  over a year – indicating that the soil composition is vastly different to the same month a year ago.  Compared to June 2011, the June 2012 readings show that the soil  is almost at a state of saturation.  Our anomaly, although still visible in the dataset, has shrunk dramatically, and is only visible as a contrast of around 5 Ohms compared to the background response.   As a short post, I do not intend to go into the detail of weather histories and the like – or any further statistical analysis (for that you’ll have to read the DART publication at the end of the project – or my PhD Thesis) however, I feel it does illustrate our core problem which we will hopefully be able to find at least some answers for.

Comments are of course welcome.

Rob.

We proposed a thermal imaging experiment at the RAC in Cirencester. This was originally instigated after viewing the diurnal temperature variations from the embedded probes and wondering what the impact of the vegetation canopy would be on any sensor. This was given life with follow up conversations with John and Rosie Wells (West Lothian Archaeology).

Quarry Field Diurnal Temperature variations from the 10cm probes

Between the 18th and 22nd June 2012 two diurnal measurement experiments were conducted at the Harnhill study site in Cirencester. Diurnal refers to patterns or activities that occur over a daily cycle. In this instance we are interested in solar insolation, how this is emitted in the thermal wavelengths and how this varies throughout the day. It was hypothesised that different surface and subsurface thermal variations throughout the diurnal cycle will lead to different readings with different sensors. We proposed to study this by conducting diurnal measurements with thermal imaging and video cameras and diurnal measurements with the ERT. The former experiment will examine how emitted radiation at the thermal wavelengths changes with the diurnal cycles and if this can be used to detect archaeological features. The latter experiment will look at how subsurface temperature variations in conjunction with the electrolytic medium change electrical resistance conditions which in turn impact on the sensor readings. This experiment will be reported by Rob Fry.

The conditions for the experiment were far from ideal. Torrential rain was forecast. Fortunately the rain only started in earnest from midnight on the Wednesday.

Experimental design

The aim of the experiment was fourfold:

1. to collect temperature variations throughout a diurnal cycle to understand the impact on temperature dynamics on archaeological detection.
2. to determine the impact of the crop canopy on the detection of archaeological features.
3. to evaluate the use of Fourier Transform Infra-red on archaeological detection.
4. to compare the imaging measurements with the results from in-situ subsurface and ambient temperature sensors.

Three sensors were used to measure the thermal infra-red: a low cost auto-ranging thermal video camera (30Hz NTSC Flir PathFindIR, Model 334-0001-00) , a quantitative thermal imaging camera (model Tetso 875?) and a FTIR (described in a subsequent post). The PathFindIR thermal camera was provided by the West Lothian Archaeological Trust. This imaging camera has a capture resolution of 320 x 240 pixels, a field of view of 36 x 27 degrees and a spectral range of 8-14 micrometre. Whilst this camera is not designed for quantitative use it has a quoted radiometric resolution of 0.1°C which means  that it can adequately detect the relative temperature variations observed in the probes in Quarry Field. The thermal sensitivity of the PathFindIR is given as 100mK at + 25°C. Further details on the PathFindIR can be found here.  This camera is also light (360g excl. battery): this means it can be easily deployed on either a UAV or kite. The video output from this camera was captured on a dedicated hard drive DVR (with a small PVR used as a monitor) meaning that video was captured for the full diurnal cycle.

The Tetso 875 (model 1 or 2) thermal imaging camera was provided by XXXX at Kings College, London. This imaging camera has a capture resolution of X by Y pixels, a field of view of Z and a spectral range of A. This camera is designed for quantitative scientific analysis, is calibrated and has a radiometric resolution of B. This camera is manually triggered with images taken at half hour intervals. Images are stored in a proprietary format on an internal SD card. The ***** FTIR was provided by NERC Field Spectroscopy Facility (FSF). This device collects a single pixel thermal hyperspectral stack covering wavelengths (A, B, C). If has a Z field of view. Data is stored…..

In order to examine contrast between the sub-surface archaeological feature and the surrounding soils it is important to achieve an Instantaneous Field of View (IFOV) that encompasses both the archaeological feature and the surrounding matrix. Based upon the field of view of the imaging cameras and guidance on safe operating height a height of approximately 8m is required to collect a 5m wide image on the ground. In addition it is necessary to compare changes over time so it is important to co-register images taken at different time frames. With these two factors in mind it was decided to employ a scaffolding tower to provide both elevation and a stable platform for repeat measurements and to place ground control markers for rectification. Candles in jars provided this purpose. Three lit candles were placed over known points for a period of 10 minutes and removed prior to taking readings. This warmed the soil providing both rectification points and a target to focus the camera. After thinking about this, and recognising that the thermal camera measurements are based on the emmisivity of the objects under study. Emissivity is a dimensionless quantity: in general, the duller and blacker a material is, the closer its emissivity is to 1. The more reflective a material is, the lower its emissivity. The emmisivity values for bare metal is significantly different from soil and vegetation. Hence, we just inverted the tealights and recorded the different value of the aluminium base.

One of the other concerns was that after removal of the crop the soil would take some time to return to it’s nominal diurnal dynamic temperature range (i.e. there would be a lag after strimming while the soil achieved it’s normal operating temperature range). We therefore decided to strim 50% of the IFOV to provide the maximum amount of time for the soil to get back up to temperature. After strimming the soil was raked to remove the majority of vegetation. A full day of recording would take place over the 50/50 split. The equipment would then be transferred to the other field to conduct the same measurements whilst the other 50% of vegetation was removed. The following day the monitoring equipment would be returned to the original location.

Plan of areas for thermal measurements

As the weather conditions were against us, rather than taking measurements on different days with and without the crop it was decided to strim half the IFOV prior to measurement to directly measure the contrast between soil and crop. The rationale was based on the lag effect that would occur after the crop was harvested which means that the subsurface soils would take some time to achieve the ambient dynamic temperature range of bare soils throughout the diurnal cycle. It was, therefore, proposed that any site would have two batches of diurnal measurements: one with the crop half removed from the IFOV and the other with the crop fully removed from the IFOV.

Fieldwork

Fieldwork commenced on the 18th June 2012. The survey areas in Cherry Copse and Quarry Field were set out. The appropriate segments were strimmed with the surface raked to clear vegetation to leave stubble and bare soil exposed. The scaffolding towers were erected and generators installed. Thermal video and imaging measurements commenced at Cherry Copse at 16:15 on Monday the 18th June and concluded at 16:20 on the 19th June. The weather was clear for the duration of the experiment. The remaining part of the area in Cherry Copse was strimmed and the surface raked. The equipment was re-established at Quarry Field with thermal video and imaging measurements commencing at 17:45 on the 19th June. The ditch feature was easily identified in the crop on the first thermal image. Detecting features in heavy, clay, soils represents the largest gain to the archaeological community. As the weather forecast predicted rain on the Thursday it was decided to continue measurements at Quarry Field. The first diurnal cycle measurements concluded at 17:45 on the 20th June. At this time the remaining part of the area in Cherry Copse was strimmed and the surface raked. Measurements continued in Quarry Field until 17:45 on the 21st June.

The weather conditions were too poor to continue in Cherry Copse. However, the initial readings from Quarry Field did not provide the same degree of differential measurements as predicted from the in-situ temperature probes. This could be due to a number of factors that includes: the change in conditions between the probes and the measurement sites, the attenuation of the soil and crop on thermal emmissions, differences in wavelength sensitivity of the different measuring devices (probes, thermal imager and thermal video), trampling of the exposed surface impacting on temperature ?????, not enough time was given to (work this up later). To address this further thermal imaging readings were taken at exposed holes adjacent to the subsurface probes. These holes, excavated to provide topsoil and sub-soil for the plant growth experiments, were situated over the archaeology and in the natural soil. Measurements were taken with the thermal imaging camera between the hours of solar noon and 3 pm which represent the period of maximum temperature differential between the archaeological sediments and the surrounding soil matrix from the subsurface temperature probes.

Analysis

We will be working on the data preparation and analysis and will post further information here. John and Rosie have posted some images on the West Lothian Archaeology website: http://www.armadale.org.uk/dart.htm

Thanks

This experiment was a real team effort thanks are due to a whole range of people including:

David Stott

Rob Fry

Tony Norris (and everyone else on the RAC Harnhill estate)

Rosie and John Wells (also thanks for getting a picture of the UAV before I crashed it!)

Tom Overbury

Nicola Cannon

Doreen Boyd

Graham Ferrier

Tom Smith

The scaffolders

RAC and Leeds University finance offices (for being understanding)

Three sensors were used to measure the thermal infra-red: a low cost auto-ranging thermal video camera (30Hz NTSC Flir  PathFindIR, Model 334-0001-00) , a quantitative thermal imaging camera (model Tetso 875?) and a FTIR (described in a subsequent post). The PathFindIR thermal camera was provided by the West Lothian Archaeological Trust. This imaging camera has a capture resolution of 320 x 240 pixels, a field of view of 36 x 27 degrees and a spectral range of  8-14?m. Whilst this camera is not designed for quantitative use it has a quoted radiometric resolution of 0.1°C which means that means that it can adequately detect the relative temperature variations observed in the probes in Quarry Field. This camera is also light (360g excl. battery): this means it can be easily deployed on either a UAV or kite. The video output from this camera was captured on a dedicated hard drive DVR (with a small PVR used as a monitor) meaning that video was captured for the full diurnal cycle.

The abstract was entitled ‘Using multi-temporal benchmarking to determine optimal sensor deployment’. You can see a copy of the abstract here.

Well done all.