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WORKING DRAFT. DO NOT CITE WITHOUT AUTHORS PERMISSION. 2014.
Practice and Method in Creating 3D Models in Archaeology
for
Digital Archaeological Practice
A Workshop on the use of Technology in the Field
February 6 - 7, 2014
University of Massachusetts Amherst
William R. Caraher
University of North Dakota
Introduction
As anyone who has heard me talk over the last few years -- including many of the people in the
room here -- knows Im both an enthusiastic supporter of digital methods in archaeology, and
deeply curious about how they are transforming archaeological practice. Today I want to consider
how the use of 3D imaging from photographs (structure-from-motion imaging) transforms certainaspects of archaeological practice and, as a result, forms part of a larger trend in how the discipline,
as a community of practice, is changing.
Most of my observations here come from two perspectives. First, my background is in survey
archaeology, and I have only come lately and reluctantly to excavation. [SLIDE]One of the major
conversations in survey involves methodology, and, in particular, the ability of "inexperienced" field
walkers to make "simple" identifications of material in the field. Part of the efficiency required (and
touted!) by intensive survey projects comes from the ability to make use of relatively untrained
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[SLIDE]Yet, despite careful attention to processes and procedures, there has been little
reflection on the practice of collecting 3D data. Like methods associated with survey archaeology,
scholars have recognized recent improvements in 3D imaging as a boon to field efficiency and way
to produce archaeological illustrations that are more accurate, consistent, and efficient than
traditional field recording practices. By simply following Brandon's step-by-step procedure even the
most clueless project director (or undergraduate!) can produce highly accurate and detailed 3D
images of stratigraphic relationships, architecture, or landscapes. This interest in efficiency and
streamlining the archaeological data collection process, then, follows a pattern visible in botharchaeological survey practice as well as in recent uses of iPads to replace traditional excavation
notebooks.
Practices
While advocates of 3D methods are quick to point out that producing "structure-from-motion"
images of a trench or a building is just one step in collecting and interpreting archaeological data, itis nevertheless true that this change in field practices will contribute to how archaeological
knowledge is produced and consumed. The primary concern in my paper today is how the practices
associated with producing "structure-from-motion" image, recently facilitated by remarkably easy
software like Agisoft Photoscan, continue a trend toward simplifying and "de-skilling" in-field data
collection.
In this context, I should clarify what I mean by deskilling. I am not referring to specific
archaeological skills in the field (nor that individual excavators have become less skillful), but rather
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revising archaeological descriptions longhand. [SLIDE] I have wondered, for example, whether the
ease with which a user can edit, revise, and delete data in some of the most recent implementations
of trench-side data collecting might undermine traditional best-practices which require trench
supervisors to strike through and initial revisions in their notebooks rather than deleting them
completely. It will be interesting to understand how later revisionssay of an error in instrument
height or in interpretationwill appear in digital notebooks. It is easy to imagine a system that
preserves all changes to an entry, of course, but Ive yet to see a system where a wiki-like interface
exists.
My Luddite perspectives could easily extend from a genuine concern about data integrity to the
more elusive realm of changing archaeological experience. [SLIDE] Data collected through GPS
units, remote sensing, and increasingly automated and regularized methods in the field threaten to
erode less structured engagement with the environment and to isolate the essentially haptic
experience of walking through the landscape from the work of formal archaeological data collection.
As an example, my long-time collaborator David Pettegrew found it necessary to return to the
Isthmus of Corinth where he had conducted a three-year rigorously systematic intensive pedestriansurvey to attempt to understand the experience of moving and living in the landscape. During the
formal field seasons, David kept his head inclined toward his clipboard and forms while mapping
new units, collecting environmental data from each 3000 sq. m. unit, and recording artifact counts
on highly-specific paper forms. In his return trips to the same region, he maintained an unstructured
notebook to record many large-scale observations that he missed during the structured field seasons.
This is no fault of Davids, but a typical byproduct of intensive survey methods that privilege both
highly granular approaches to space as well as the methods used to document this space. In fact,
Richard Blanton has referred to this almost-atomic focus on intensive data collection as
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preserved in the exposed trench. [SLIDE] Plans are sometimes festooned with interpretative notes
and contribute to the first steps in archaeological interpretation.
[SLIDE]While the number, detail, and frequency of trench plans vary according to project,
typically each context receives a plan. Drawing the plan represents a pause in the hectic routine of
excavation and an opportunity to clarify features in the trench and the excavation process. Like
maintaining the trench notebook, the act of drawing is slow and methodical, encouraging the kind of
scrutiny that can inform later excavation decisions and produce features and relationships obscured
by visual noise or revealed through careful measurement. Depending on the size of the trench, thenumber of features, the scale, and the amount of detail, trench plans can take anywhere from 20
minutes to an hour to illustrate.
[SLIDE] In comparison, it took a trench supervisor 10-15 minutes to take a sufficient number
of photographs for a 5 x 5 m. trench to produce an accurate Agisoft Photoscan 3D image at Tel
Akko. The computer time to process these images, of course, was much longer, but this occurred
either simultaneous with field work or at times when field work was not possible. This reflects asubstantial improvement in efficiency when compared with experiments conducted just a few years
earlier at Chersonesos, where a combination of georeferenced photographs and elevation control
points on the features and the surface of the trench took the same amount of time as a trench plan
executed by a skilled illustrator. The improvements in software have eliminated the need to collect
numerous control points as well as photographs, while maintaining a level of spatial control that is
superior to even the most skilled illustrator. At the same time, the issues noted by Adam Rabinowitz
at Chersonesos persist: photographs cannot replace the interpretative aspect of trench side
illustrating. Preparing an illustration from a structure-from-motion model or a georeferenced
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performance to materials. This ecology defines a wide range of social, political, disciplinary,
economic, and personal relationships.
When we reflect on material corollaries for past practices, we would not hesitate to understand
variations in both the practices and materials as keys to understanding how ancient societies
structured certain kinds of social relations. In fact, the act of writing or drawing is often vital to
understanding past communities of practice that embody the relationship between individual
agency and structured social expectations. [SLIDE] Latour is willing to extend the status of agency
even further to include individual objects and pieces of technology that he sees as actors embeddedwithin dense networks (ANT). Ingold, and others, are skeptical, but nevertheless emphasize the role
that technology, practices, and individuals play in constructing the conditions for agency and its
(reciprocating) products. From the perspective of archaeological tools and practices, we can argue
that using a digital camera, iPad, or laptop in the field creates fundamentally different relationships
than using an architects table, clipboard, or field notebook. If we see disciplines as communities of
practice then the changing roles of technology and practices in the field impact the situation of
disciplinary knowledge.
[SLIDE] Maguire and Shanks 1996 article on archaeology as craft provides another context for
understanding archaeology as disciplinary practice. They argue that archaeological knowledge is
produced through a socially engaged practice which is not alienating, which edifies and provides
diverse experience. The character of archaeology as craft grounds it both in experience and resists
the alienating division of labor. This is a romantic notion, that corresponds awkwardly to the realities
of large and complex archaeological projects which rely on increasingly atomized and deskilled
practices that remove the interpretative function from both the space of the field and the purview of
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[SLIDE]Technological changes coincided with the shift from authorizing practices resting in
the individual artisanal archaeologist to our disciplinary discourse. The collection of numerous
photographs to produce a structure-from-motion model of a site, trench, context, or object,
depends less upon the unique abilities of the photographer and more upon a set of established
practices and software algorithms. Even access to photographic equipment is no longer a source of
distinction on the project as relatively high-quality digital cameras are inexpensive, available, and
satisfactory for the production of 3D images.
[SLIDE] Photographic 3D models do not replace illustration entirely, of course, but they move
the act of illustrating from the trench side to the computer lab. The displacement of this part of the
archaeological process from the field to the lab represents a transformation of the haptic aspects of
archaeological inquiry. The computer monitor becomes the trench and the impulse to maximize the
quantity (and resolution) of the data collected in the field moves more time consuming practices of
analysis to the margins of the archaeological field day and, sometimes, the field season. As a result,
(in my somewhat alarmist and apocalyptic perspective) the object of archaeological investigationshifts from the trench to its digital surrogate (using Adam Rabinowitzs term), and the posture of the
archaeologist shifts from stooping at trench side to hunched over a laptop.
[SLIDE] Imagining the future, we can see significant trends in how the locus of authority has
changed as the process of deskilling archaeological practice continues. The use of technology like
Agisoft to document the daily work and stratigraphic context present in each trench frees the trench
supervisors from the responsibilities of trench illustration and corresponding role in the time
consuming interpretative process (as the increasingly form-driven data collection forms replace the
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methodology present a challenge of sorts. It challenges us to become more aware of the relationship
between the practice and the structure of archaeological knowledge.
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Practice and Method in Creating 3D Models in Archaeology
Digital Archaeological Practice
A Workshop on the use of Technology in the Field
William Caraher, University of North Dakota
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Corinth Notebook: 988Field ValueTitle Zygouries Field Notebook
Author Blegen, C.W.Contents Field Notes
Area Agios BasiliosCorinthiaZygouries
Site ZygouriesCity CorinthCountry Greecehttp://...//id/corinth/notebook/988/html
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