The Matrix: Using Archaeological Stratigraphic Data
Keith May
Dr James Taylor
Ceri Binding
Connecting and reusing digital records and archives of archaeological investigations.
Stratigraphy is created freely and is everywhere… in chains
Stratigraphic data form the backbone of archaeological records from most excavated sites and, along with the phasing and interpretive information derived through stratigraphic analysis, are essential for chronological modelling, broader synthesis of inter-site phases and periods and, we argue here and elsewhere, should be a required component in digital archives of the growing body of archaeological data and reports generated through the commercial archaeological sector in the UK and internationally (May, Taylor, Binding 2023).
The stratigraphic record that quantifies, characterizes and sequences the different types of stratigraphic units (see Figure 1) is a primary piece of 'evidence' for how, and in what order, a site was excavated.
Stratigraphy helps understand a site’s life story
Not every site has complex stratigraphy, but understanding the nature of the stratigraphy, be that deep or shallow, complex or otherwise, enables researchers to piece together the underlying details of how the excavator(s) arrived at the interpretations they have made about the site.
A short explanation of the importance of stratigraphy and the use of stratigraphic Laws and Principles in archaeology, as set out by Dr Edward Harris from the 1970s onwards (Harris 1989), is provided in this video animation.
Exploring issues in archaeological digital archives
Because an archaeological excavation cannot be repeated, archaeologists have long been concerned that the records of excavations should be published, archived and preserved safely for future research.
Once the archaeology in the ground is dug away then increasingly the digital records and reports held on computers may be all that remains to enable future researchers to find out and understand what has been discovered.
Such digital records remain at some risk, unless that information is deposited in digital repositories such as the Archaeology Data Service and the reports and metadata are made available through online reporting systems such as OASIS - the online system for reporting archaeological investigations in the UK. But many archive records are often still only held on paper and frequently the analytical phasing data used to support the interpretations presented in written reports is not digitally archived consistently, if at all.
This results in key archive records, such as scanned copies of matrix diagrams being, at best, siloed and re-buried in repositories, else unfindable and unsearchable, and most often requires lengthy and wasteful re-keying of data.
#Inform – The Matrix Research Questions
The Matrix project directly addresses two topics from the Historic England Research Agenda (#inform). The first aim is to encourage the sharing, re-use and interoperability of archaeological data and information derived from the commercial sector. The second aim is to ensure the consistent development, application and enforcement of technical information and data standards. The overall aim is to maximize public value and enhance the research potential of the archaeological data being recorded and preserved.
'FAIR' Principles for archaeological data
The Matrix project findings suggest that archaeological records of our stratigraphic data should be archived in a manner that is ‘Findable, Accessible, Interoperable and Reusable’ (FAIR Principles) and ideally openly available too. But ‘ Findable, Accessible, Interoperable and Reusable- FAIR’ data isn’t currently the norm in commercial archaeology, as digital archiving is only now just becoming a requirement in some development control practice and “open data” even less so.
The Open Data Institute defined open data as:
Open data is data that anyone can access, use or share. Simple as that. When big companies or governments release non-personal data, it enables small businesses, citizens and medical researchers to develop resources which make crucial improvements to their communities
Data Management Plans are also not commonly used (yet) by the commercial archaeological sector, or even consistently in academia, despite the good work identifying their importance in the recent publication of the Chartered Institute for Archaeologists Dig Digital guidance. The Matrix project team, along with other authors, have identified the need for a cross-sector set of common guidelines (including, e.g. A data package for stratigraphic and chronological data) to reflect and enshrine best practice in post-excavation analysis work.
The Matrix: Some key outcomes and results
The Matrix has highlighted several areas of archaeological practice where stratigraphic data needs to be queried, revisited, updated, and integrated into new datasets or otherwise re-used, re-mixed and recycled (Huggett 2018).
1. Greater transparency: Evidence in data for interpretations in publications.
Where the stratigraphy is pivotal to the interpretation of excavation data, there is a professional ethical imperative on archaeologists to make the ‘raw’ stratigraphic data available in the digital archive. This goes hand in hand with a scientific responsibility for any related stratigraphic analysis data about a site to be made more ‘Findable, Accessible, Interoperable and Reusable’ in order to lay bare the evidence for our interpretations of the ‘raw’ stratigraphy.
2. Reinterpretation: revisiting and reusing multiple digital data sets
The recent increase in large-scale infrastructure projects (e.g. HS2, Crossrail, etc.) with associated digital project management systems has emphasised the need for better ‘joined up’ data at a landscape scale. These inter-site project management methods are currently more commonly used on urban development sites, and more often enable broader synthetic publications.
3. Deposit Modelling: a need for interoperable stratigraphy
Deposit modelling, especially in urban environments, has effectively become a requirement within planning policy guidance to mitigate and monitor the effects of large-scale developments (Figure 4). Reliable, and ‘Findable, Accessible, Interoperable and Reusable’, stratigraphic data is increasingly important alongside deposit modelling to cost-effectively assess the potential for archaeological remains on development sites.
4. The Bayesian Chronological Modelling 'revolution'
The so-called Bayesian Revolution continues to have a profound impact on archaeological dating. When dealing with scientific dating of specific sites, Bayesian chronological modellers regularly seek to drill down into legacy stratigraphic data for those sites, so ‘Findable, Accessible, Interoperable and Reusable’ access to that stratigraphic data is particularly important to them.
Recent PhD work in Heritage Data Analytics (Moody et al. 2021) as part of an Arts and Humanities Research Council funded Collaborative Doctoral Partnership between Historic England and Sheffield University School of Maths and Statistics has shown the considerable problems caused for Bayesian Chronological modellers, by a lack of standardized approaches to the archiving of stratigraphic data (see Figure 3 – with thanks to Bryony Moody).
Partnership Research as an Independent Research Organisation
The Matrix project has developed a very successful partnership between Professor Keith May on behalf of Historic England, Dr James Taylor, lecturer in the Archaeology Department of the University of York, and Ceri Binding, a senior researcher, lecturer, and computer programmer at The University of South Wales. The Matrix project builds on earlier successful research in partnership with the Hypermedia Research Unit at the University of South Wales to research and develop computing technologies for searching for information and data written in different natural languages (different semantics), and reasoning about spatial and temporal relationships (spatiotemporality) in archaeological data (Tudhope et al. 2011).
Conclusions and Further Work - What Next?
Feedback from The Matrix project consultations suggests that a collective approach, amongst archaeologists, to tackling the digital archiving issues would be most effective in delivering a sustainable and 'FAIR' outcome.
A successful application has been made by May and Taylor to the Arts and Humanities Research Council for Follow-on Funding of a new project to investigate how a consortium of archaeological organizations might address some key issues. The new project, ‘The Archaeologist’s Guide to Good Practice – Handbook’ (AG2GP-Handbook), is due to begin in May 2023.
The AG2GP-Handbook project (AH/X006735/1) will combine the collective expertise of archaeological contractors across the UK to produce an online handbook of common archaeological methods used during post-excavation activities, focused initially on stratigraphic analysis.
The project team, in consultation with other stakeholders from the sector such as the Federation of Archaeological Managers and Employers (FAME) and the Chartered Institute for Archaeologists (CIfA), will build a consensus on what online documentation, tools and resources are needed to support best working practice. The project will also make recommendations to develop a sustainable Community of Practice that can maintain the best practice guidance and online tools while investigating the potential for e-learning resources to be used in Continuing Professional Development and for teaching students. To make such a Code of Practice most widely applicable across archaeological fieldwork worldwide, the project is also aiming to draft an International Convention on Archaeological Stratigraphic and Chronological Methods and Data.
Acknowledgements
This work was supported by the Arts and Humanities Research Council via funding under their Leadership Fellowship grant (ref AH/T002093/1).
The authors would like to thank Professor Doug Tudhope, Professor Caitlin Buck, Dr Holly Wright, Tim Williams and Barney Sloane, for their helpful inputs as the project’s Advisory Panel along with Dr Edward Harris, Steve Roskams, Dr Tom Dye, and Dr Jen Heathcote who have helped with invaluable advice along the way. Particular thanks to Bryony Moody, whose complementary Collaborative Doctoral Partnerships PhD research has often helped inform the directions we have taken. Likewise, thanks to the staff at ADS who have helped to track down various data items we could not find or helped confirm what were the “known unknowns” in the ADS archive. Special thanks to the team at MoLA for so diligently archiving the outputs of their work, particularly on the XSM10 project, in ways that enabled FAIR play with their data.
We would also like to sincerely thank the numerous other workshop participants and various consultees, including several colleagues in Historic England, whose participation and feedback was essential for our research, both in understanding disciplinary needs and evaluating prototypes of the 'Phaser' software.
Further information: reading list
Harris, E. C. (1989) Principles of Archaeological Stratigraphy. 2nd ed. London: Academic Press.
Huggett, J. (2018) 'Reuse, Remix, Recycle: Repurposing Archaeological Digital Data'. Advances in Archaeological Practice DOI: https://doi.org/10.1017/aap.2018.1
May, K. (2020) 'The Matrix: Connecting Time and Space in Archaeological Stratigraphic Records and Archives', Internet Archaeology 55. DOI: https://doi.org/10.11141/ia.55.8
May, K., Taylor, J.S. and Binding, C. (2023) 'The Matrix: Connecting and Re-using Digital Records and Archives of Archaeological Investigations', Internet Archaeology 61. DOI: https://doi.org/10.11141/ia.61.2
Moody, B.C., Dye, T., May, K., Wright. H., Buck, C. (2021) 'Digital Chronological Data Reuse in Archaeology: Three Case Studies with Varying Purposes and Perspectives'. Journal of Archaeological Science: Reports 40(11) DOI: https://doi.org/10.1016/j.jasrep.2021.103188
Moody, B.C. (2019) Heritage Data Analytics Year 1 Report: The Quality and Utility of Resources in Digital Heritage Repositories. Historic England unpublished internal report
Tudhope, D., May, K., Binding, C. and Vlachidis, A. (2011) 'Connecting Archaeological Data and Grey Literature via Semantic Cross Search', Internet Archaeology 30. DOI: https://doi.org/10.11141/ia.30.5
