The document discusses the conceptual modeling of stratigraphic relationships in archaeology, emphasizing digital stratigraphy and the need for clarity in analysis processes. It highlights challenges such as variability in digital data, the complexities of stratigraphic grouping, and different temporalities in archaeological contexts, particularly using examples from Çatalhöyük. The document also calls for improved standards in digital recording and visualization to enhance understanding and communication of spatiotemporal relationships.

1. When Harris met Allen
in the Matrix
Keith May,
Historic England |
& University of South Wales |
How can the conceptual modelling of stratigraphic relationships
facilitate deeper understanding of archaeological space and time?
Steve Roskams & James Taylor
| Department of Archaeology,
| University of York

2. Digital Stratigraphy:
Digital Tools
Harris Matrix Composer
Bonn/ArchEd - Matrix layout

3. Digital Stratigraphy:
Principles
Stratigraphic laws/analysis are fundamental
methodological approach in many recording
systems.
Harris (1979) asserts three main areas of study:
● Theories and laws
● Recording
● Post-excavation analysis
“As stratigraphic sequences are abstractions, they can be demonstrated in writing or by
schematic diagrams.” (Harris 1979, 111)
Harris 1979 - Fig 2

4. Digital Stratigraphy:
Practice
But...
● Limited consistency in digital stratigraphic data
● Less consistency for higher order grouping
○ (especially phasing)
● Problems with representation of analytical
groups
○ (relationship between phases groups & contexts)
“Turning next to data manipulation after excavation, there is a great need to sort out the
concepts used in stratigraphic analysis … to match the systematization which has been
developed in the production of the site record. For the most part what is needed is
intellectual clarity in defining concepts and then labelling them” (Roskams 2001, 278-279)

5. ● Variability of
stratigraphic data
held in digital archive
● Site Matrices and
Grouping and
Phasing information
● Multiple forms and
mixed explicit data
What sort of Information is (re)useful to
others?

6. The Process of Analysis: Stratigraphic Correlation
We rarely describe how we go about this.
Summarise Descriptive
Information
e.g. Code by soil
types/inclusions.
Correlate
Horizontally
e.g.
Construction/Occupation/
Destruction.
Commonly below another.
Consider linkage strengths.
(etc.)
Correlate
Vertically
e.g. New activity?
Block together
common activities.
Higher-Order
Interpretations
Noting rationale (again
based upon physical,
stragitgraphic & spatial
considerations).
Plot Spatially
Revisit the plans (or GIS).
This may strengthen/deny
previous reasoning (if latter,
reiterate).
We often assume that the most certain interpretations exist at the start of stratigraphic
analysis and become less so ‘higher up’. The opposite can be true.

7. The Process of Analysis: Stratigraphic Grouping
● The ‘grouping process’ tries to understand how lowest order, individual actions can make up
an activity.
○ The latter may have no exact chronological implications - activities can be quick or can
last centuries.
○ Whatever form groups take, not all stratigraphic units will belong to any one with equal
certainty.
Section through Çatalhöyük's Building 5 that the
highlights the need for grouping of features. Note the
difference in complexity between a post retrieval pit
and a platform (with associated burials) and
remodelling events that are represented by the steps
in the platform (highlighted with arrows), and which
are often grouped (as in this example) as the same
feature

8. The Process of Analysis: Higher Temporalities
Periodisation
● If groups make up periods (defined as site-wide activities [?]), then the number of such periods
will vary depending on how big an exposure is being analysed.
○ e.g. in the whole of London, only 3 big fires would form periods (and even that does
not work across all sites - as at Çatalhöyük).
Knowing when something is thought to be site wide, and when it is not, matters - scale of
correlation
Plan and section of Çatalhöyük
showing the shifting pattern of
occupation in the excavated area,
as interpreted by Mellaart in 1967

9. Space and Time
Aim for ‘land-use’
diagrams e.g. Carthage
Certainty
Representing different degrees of
certainty of linkage (was one
layer, exactly contemporary,
broadly contemporary)
Duration of Processes
Stretch boxes to represents
events vs. processes vs.
gaps
Representing more than just sequence.

10. Example of Çatalhöyük
Konya Region Turkey
Neolithic and Chalcolithic ‘Tell Site’.
Occupied for approximately 2200 years,
from c.7500-5700BC.
Covers approximately 33.5 acres and
20m deep stratigraphic sequence.
Only c.4% of the Neolithic mound
excavated.
Presents some interesting spatiotemporal challenges

11. Example of Çatalhöyük: Principles (Temporal Units)
Basic Stratigraphic Unit
A unit, equivalent to a ‘context’
in British field archaeology,
represents the basic recording
element.assigned a unique
identifying number and is
recorded on a Unit Sheet.
Unit
● Ideally a single identifiable
depositional event.
● Some units may represent
multiple depositional events that
it is impossible to excavate
separately
● Some depositional events may be
subdivided into multiple units.
Higher Order Spatial
Grouping
A feature represents a group of
related units recorded on a
Feature Sheet. These are
hybrid stratigraphic groups.
Feature
● Not all units need belong to
features.
● Assigned to any group of related
units that need to be described
● Or because the existence of a
feature number is helpful when
referring to the entity
● Feature system is fluid,
potentially including any
conceivable group of units
Higher Order Temporal
Grouping
Phasing of units relates to the
occupation sequence of a
building or external area, as
illustrated in the Harris matrix
for each building* and space*.
*Separate spatial groupings.
Phase
● Recorded on the Space sheets as
‘occupation phases’
● Represent major changes in the
life history of a building or space
while subphases indicate minor
changes.
Highest Order Temporal
Grouping
Level
● Typical of old school ‘Tell’ Site
methodology
● Problematic because Tells are
neat temporally neat.
A level is a group of one or
more spaces of buildings that
are at least partially
contemporary with one
another. Inhereited and
modified from James Mellaart
1960’s division of the area he
excavated into 15 successive
building ‘levels’ from 0 to XIII.

12. Example of Çatalhöyük: Practice (Matrix Notation)
Phases: horizontal
line through the
matrix
Units: standard
stratigraphic
matrix cell
Features: nested
brackets around
units
All these elements, as well as the spatial groupings of Space and Building are reflected in the
relational data structure of the project database.

13. Example of Çatalhöyük: Common Spatiotemporal Issues

14. Example of Çatalhöyük: Common Spatiotemporal Issues

15. Example of Çatalhöyük: Visualising Spatiotemporality
Animation showing spatial
distribution of obsidian
projectile density through
time in Çatalhöyük
Buildings 65 & 56,
alongside cumulative
distribution.

16. Modeling the Matrix
Example: Silbury Hill

17. Allen - Temporal Operators
Relation Inverse
Before (precedes) < After (preceded by) >
Meets m Met by mi
Overlaps o Overlapped by oi
During d Contains di
Starts s Started by si
Finishes f Finished by fi
Equals =
Allen Operators (Allen 1983):
temporal relation
classifications that
acknowledge the implicit
spatiotemporality of
stratigraphic relationships in
Harris (e.g. Superposition)
along with other less explicit
temporality seen in other
archaeological records.
Modeling the Matrix

18. Modeling the 4D nature of Phase/Period
Potentials of a
semantic approach to
stratigraphic analysis
Search and analysis of
associated finds and
samples using extra
temporal relations
Presenting outputs and
re-use of data
enhanced for temporal
cross search
Fig4. temporal relations on spatiotemporal volumes A and B

19. Modeling the Matrix
“The problem of representing temporal
knowledge and temporal reasoning arises
in a wide range of disciplines including
computer science, philosophy,
psychology, and linguistics. In computer
science, it is a core problem of
information systems, program verification,
artificial intelligence, and other areas
involving process modeling”
(Allen 1983, 832)
(Image: Binding 2011, 14)
STAR Semantic Query Browser
Implicit temporal relationships in the
diagrams that are not formalized in the
digital records

20. Bayesian chronological modeling
One difference between a Bayesian chronological model and
an archaeological sequence diagram is that the Bayesian
chronological model may include relationships that cannot be
expressed by simple before/after stratigraphy.
The illustration recognizes three possible relationships
between two chronological phases where one is older than
the other (Fig. 7). Only two of these relationships can be
represented stratigraphically.
Overlaps in Time relationship
Meets in Time relationship
A Bayesian chronological model comprises directly-dated events and the start and
end dates of one or more chronological phases. The start and end dates of a
chronological phase typically map directly to an archaeological context
“One chronological phase can be older than the other such that the end date for the
older chronological phase is the same age as the start date for the younger
chronological phase (Fig. 7, middle)”.
Dye & Buck 2015
Fig. 7.

21. Would Process Modeling for Analysis activities help?
Identify common steps
in the Analysis process
Identify and clarify
differing approaches to
process
Enable semantic
mappings between
common concepts and
terms used in Analysis
process(es)

22. Towards a Clearer Spatiotemporality
Our Goals
Querying, Re-Use & Interoperability:
● Ease of use by stratigraphers.
Analytical tools:
● Deeper spatiotemporal understanding and interpretation by
stratigraphers and other specialists
Visualisation:
● Work towards a clearer way of presenting spatiotemporality.
Dissemination:
● Consideration of wider audiences for publication (specialists and academics both inside and outside of
the project, students, or wider audience with an interest in understanding spatiotemporal processes of
archaeology.
Visualisation &
Dissemination
Query & Analysis

23. Conclusions:
Representation of other
Allen relationships
04
● To get at increased spatiotemporal nuance
and complexity
● To enable more complex analysis and
interpretation
Development of new
modes of spatiotemporal
visualisation
03
● Highlighting complexity of spatiotemporal
relationships
● To facilitate understanding and
communication
Standards of expression of
spatiotemporal relations
02
● Practically derived from existing processes
(eg. Harris Matrix) to facilitate ease of use
and re-use
01
● At the level of data structure (ie. CSV as
opposed to images
● To facilitate re-use
Consistent standards for
digital stratigraphic
recording

24. ● Allen, J.F. (1983) 'Maintaining Knowledge about Temporal Intervals'. Communications of the ACM 26, 11,
832-843.
● Harris, E.C. (1979) Principles of Archaeological Stratigraphy (1st Edition). London: Academic Press.
● Rains, M. (2000) 'Review of ArchEd and Stratigraph - Excavation recording and analysis
software[Software]', Internet Archaeology 8. https://doi.org/10.11141/ia.8.9
● Roskams, S. (2001) Excavation. Cambridge: Cambridge University Press.
● Taylor, J.S. (2016) Making Time For Space At Çatalhöyük: GIS as a tool for exploring intra-site
spatiotemporality within complex stratigraphic sequences. PhD thesis, University of York.
● Tudhope, D. et al. (2011) 'Connecting Archaeological Data and Grey Literature via Semantic Cross
Search', Internet Archaeology 30. https://doi.org/10.11141/ia.30.5
● Papadakis, M., Doerr, M. and Plexousakis, D. "Fuzzy times on space-time volumes," eChallenges e-2014
Conference Proceedings, Belfast, 2014, pp. 1-11.
● Dye, T.S. & Buck, C.E. (2015) Archaeological sequence diagrams and Bayesian chronological
models.Journal of Archaeological Science, 63. 84 - 93. ISSN 0305-4403
● Farid, S. & Hodder, I. (2014) 'Excavation, Recording and Sampling Methodologies.', in I. Hodder (ed)
Çatalhöyük Excavations: The 2000-2008 seasons., 35-52. Los Angeles: British Institute at Ankara &
The Cotsen Institute of Archaeology, UCLA.
References