Archaeological 3D GIS

Nicolò Dell’Unto, Giacomo Landeschi, Nicolò Dell'Unto

• Publisher: Routledge
• Year: 2022
• eBook ISBN: 9781000554304
• Edition: 1
• Topic: Social Sciences
• Subtopic: Archaeology
• Index: Social Sciences

Archaeological 3D GIS provides archaeologists with a guide to explore and understand the unprecedented opportunities for collecting, visualising, and analysing archaeological datasets in three dimensions.

With platforms allowing archaeologists to link, query, and analyse in a virtual, georeferenced space information collected by different specialists, the book highlights how it is possible to re-think aspects of theory and practice which relate to GIS. It explores which questions can be addressed in such a new environment and how they are going to impact the way we interpret the past. By using material from several international case studies such as Pompeii, Çatalhöyük, as well as prehistoric and protohistoric sites in Southern Scandinavia, this book discusses the use of the third dimension in support of archaeological practice.

This book will be essential for researchers and scholars who focus on archaeology and spatial analysis, and is designed and structured to serve as a textbook for GIS and digital archaeology courses.

The Open Access version of this book, available at www.taylorfrancis.com, has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license.

1Geographical information systems in archaeology

DOI: 10.4324/9781003034131-2

1.1 GIS and archaeological theory

If we put together the definitions provided by established and commonly cited authors (Aldenderfer and Maschner 1996; Chapman 2006), Geographical Information Systems (GIS) can be defined as a set of spatial digital tools for managing, manipulating, and analysing information, spatially referenced according to geographical coordinates represented in a Cartesian space defined by x and y (and sometimes z, and even a time variable t) axes. GISs have a longstanding tradition in archaeology, and this subchapter will summarise some of the key points that represented a breakthrough for the discipline from a theoretical and methodological perspective.

An unquestioned point when one thinks about GIS is its impact on archaeology as it has been recalled by Chapman (2006:9). So far, examples of archaeological applications of GIS are countless. The big question that arises is whether GIS can still be considered a method in search of theory (Church et al. 1999) or whether it has developed into something more than a methodology, with its own theoretical culture and infrastructure of discussion; in the words of Gillings and Goodrick (1996), a real place to think. There are several definitions of GIS that have already been formulated and, for the sake of brevity, here we shall simply point out three key aspects that have been highlighted by authors referring to the archaeological application of the toolset. One is the spatial dimension of the phenomena that are described and analysed: by its very nature archaeology is a discipline where the material manifestation of the past is examined in its contextual relationship with the surrounding environment. Spatiality thus becomes a pivotal aspect for describing any piece of archaeological information. Structured information, typically represented by Database Management Systems (DBMS), is another key element that characterises any GIS platform, and its conceptual framework has long been employed to manage archaeological data of very heterogeneous nature. A third important aspect is data processing, defined by the system capability of manipulating existing data to create new informative layers. This “heuristic” component is obviously crucial for an analytic approach to the study of an archaeological context/landscape, and this is an additional reason why GIS had and still has a great impact on the discipline. Interestingly, these three points reflect the concepts of space, representation, and reasoning highlighted in a recent article by Lock and Pouncett (2017), which are the key components of any individual’s spatial thinking.

From a theoretical point of view, GIS developed in what can be termed as the “processual” era, a period characterised by a movement known as “New Archaeology” (Binford and Binford 1968; Clarke 1968), with strong emphasis on quantitative and inferential methods, and inspired by the methodological strands introduced by New Geography (Kohn 1970). These methods started to play an increasingly prominent role in the study of the archaeological record, making several authors (Wescott and Brandon 2003) describe GIS as the most powerful tool to be applied to archaeology since the introduction of radiocarbon dating systems. Again, following Harris and Lock (1990) quoting a British government report, the impact of GIS in archaeology was defined as “the biggest step forward in the handling of geographic information since the invention of the map”.

As it has been pointed out several times, spatiality is a significant component of archaeology as a discipline, and the issue of data representation has always been one source of big concern among specialists. Mapping is a very typical example of data representation, and this concept is tightly connected to another keyword of this volume: modelling.

The idea of drawing and placing on a map what has been observed in the field goes far back in time, as archaeologists have always been concerned with formal rules and conventions on how to graphically represent the results of a field survey or excavation (Adkins and Adkins 1989). In this context, GIS provided archaeologists with new opportunities to represent and analyse data collected in the field and dramatically contributed to promote an “explanatory” turn of the discipline, where quantitative approaches and spatial/statistical analysis were employed in support of the study of settlement patterns and site formation.

In this respect, there is a vast literature describing the application of predictive models between the 1980s and the early 1990s (Larralde and Chandler 1982; Kvamme 1983; Pilgram 1983; Brandt et al. 1992; Kvamme 1992) which made GIS gain momentum. Indeed, an increasing number of archaeologists both in academia and in contract archaeology started to use these models for creating maps of archaeological risk (or potential) and defining areas that were more likely to contain archaeological material and so more exposed to the risk of destruction in case of new development. In this respect, predictive models have been traditionally divided into two main categories, focused on quite different scopes: cultural resource management (CRM) and research-oriented or explanatory models.

As a further step, and partially due to the harsh critiques raised by post-processualists, an increasing number of GIS models were developed during the 1990s with the idea of trying to combine the analysis of ecological/environmental factors with the quantitative assessment of human behaviours/cultural elements that had long been discarded in the processual era. A significant example is given by Gaffney and Stancic’s work on the island of Hvar, where multiple GIS-based methods were employed to investigate the settlement patterns connected to the chronological phases of habitation in a diachronic perspective. Remarkably, this work constitutes one of the first examples of combined use of predictive modelling techniques together with methods such as least-cost path and viewshed analysis (Gaffney and Stancic 1991).

In this debate, visibility studies and the role of cognition had a prominent part. Several authors within archaeology noted the importance for archaeology to reflect on the centrality of human actors in shaping the past landscape and argued for prioritising the perception and experience of past peoples in any GIS-based analysis. According to several authors (Llobera 1996, Wheatley 2004), one of the main purposes of GIS-based studies should be to foster an understanding of the past landscape through the analysis of this space as a lived-in, meaningful environment where human agency and interaction with the natural ecosystem is a pivotal element. This is one of the reasons why sight, which typically belongs to any human being, was introduced as a possible means by which to investigate the perceptual properties of an archaeological space.

In this context, one of the main limitations has been the inadequacy of conventional data representation schemes (Llobera 2012), where traditional GIS vector primitives (point, line, polygons), and raster datasets are not capable of dealing with the complexity of the landscape under scrutiny. As a consequence, the post-processual discourse has dismissed or at least underplayed the importance and potential of GIS due to the difficulties it has in representing aspects of past realities that this school considered important (Thomas 2000; Tilley 2008). In a recent article (2018) Verhagen stressed the necessity to adopt a different approach, following the proposed distinction between representational and non-representational GIS (Hacıgüzeller 2012). According to this principle, which also draws upon the long-debated problem of developing a more “critical” approach to GIS (Barceló and Pallarés 1996; Pavlovskaya 2018; Perry et al. 2018), one of the main benefits of GIS is to provide archaeologists with multiple models or scenarios that can be built upon the collected data and used for fostering new interpretations with a multi-vocal approach where research questions are continuously posed to the system and problematised based on a combined use of modelling tools. This contrasts very much with the traditional mapping approach, where a detached, immanent representation of a static space is offered and a reductionist view of the landscape is proposed.

Lock and Pouncett (2017) recently highlighted the importance for archaeologists of focusing more on spatial thinking and reflecting on what real contribution GIS can provide to archaeological reasoning. While GIS undoubtedly provides users with an extraordinary amount of tools for managing spatial information, it is not always the case that users are fully aware of the way selected algorithms and geoprocessing tools actually work. The risk is that archaeological questions are subordinated to the available tools and these, in turn, depend on the GIS software in use in a certain project. This can, in turn, make archaeologists shape their spatial questions based on the available toolkits and not adequately identify the real research priorities.

1.1.1 Issue of scale

The problem of the complexity of past realities, and how they struggle to be grasped with the available media, is tightly connected to the issue of scale. Scale deals with the problem of humans’ perceptual limitation to connect themselves with phenomena taking place at micro and macro level (Lock and Molyneaux 2006). In regards to archaeological spatial analysis, one common problem relates to the type of representation that is needed to allow archaeologists to grasp the historical/archaeological meaning of a certain space. For example, if the purpose of the analysis is to make a distribution map for all of the classical temples located in a particular region and dated to a specific period, they can be represented as dots on a map. In this case, the vector point primitive is an adequate entity for fulfilling the expectations of a map user who wants to know about quantity and spatial location for the category of classical temples in that region, for instance. In this case, it is the spatio-relational nature of the temple that is under scrutiny, making it possible to investigate their agency in the surrounding space. On the other hand, if one takes the same temple and starts examining the architectural features of which it is composed, it is apparent that such an object is a palimpsest of actions characterised by several temporal phases identified by elements such as columns, plinths, capitals, and so on. The same entity thus becomes a constructed space in which activities took and still take place, a living environment for social encounters. In terms of computer graphics, the vector point primitive will no longer be the right symbol to represent it, and it would be more appropriate to use a 3D boundary model instead to cope with this geometrical complexity. As a consequence, what has been previously analysed as an object-in-a-space can be now examined as an object-as-a-place, following Tuan’s definition of place (1977). The multiscalar nature of today’s GIS allows such an approach, in which the same entity is represented either as a dot in a landscape or as a 3D/4D space defined by its own x, y, z, and t coordinates (Landeschi 2019).

1.1.2 High-definition vs. Multi-resolution

In present-day archaeology, one of the big questions is posed by the large amount of information that archaeologists collect from the field, something that has been exacerbated by the introduction of innovative techniques and methods for data acquisition (UASs, image-based 3D Modelling, LIDAR, SONAR data, etc.), more efficient hardware and software solutions (3D GIS, 3D modelling software, game engines, BIMs) and high-performance network/cluster computers (Landeschi et al. 2020). One of the recurring themes in the current agenda is what has been termed as “High-Definition” (HD) archaeology. The term high-definition usually designates digital systems capable of handling data with a very high level of detail. When it comes to archaeological applications (Gowlett 1997), HD was first introduced to define a methodological approach in which the archaeological record is investigated with a significantly high level of detail thanks to the contributions given by analytic methods borrowed from natural sciences. Archaeological excavation is the perfect environment where one can examine sediments and sets of artefacts and ecofacts at micro-scale together with units and stratigraphic layers at middle/macro-scale. The higher the number of intervals in which a single phenomenon can be divided into, the higher its resolution or definition. Such a concept is tightly related to the stances of the 1960s’ New Archaeology, when quantitative approaches and statistical methods had a great impact on the discipline. More recently, formal methods of archaeological investigation have been systematically combined so as to broaden the range of material qualities of artefacts and contexts that can be examined. This has led to a new general rethinking of the term “high-definition” archaeology and its proposal as the ultimate goal of important interdisciplinary projects (Raja and Sindbaek 2018).

In this context, the role played by GIS is becoming even more relevant than before. In a posthumanist perspective, where the reality of the past is examined as a continuum where humans, animals and the natural environment are interacting (see Fredengren 2013; Thomas 2015; Braidotti 2016; Díaz-Guardamino and Morgan 2019), it becomes essential to collect, organise, and process data that describe this complex reality in a way that can account for multiple actors and narratives.

An example of this is given by the Çatalhöyük research project, where a GIS geodatabase has been put at the core of the system to manage different types of data including archive reports, older excavation plans, and even field sketches and notes by the excavator during a certain field campaign (Berggren et al. 2015). The combinati...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• List of illustrations
• Foreword
• Preface
• Acknowledgements
• List of abbreviations
• Introduction
• 1 Geographical information systems in archaeology
• 2 3D models and knowledge production
• 3 3D GIS in archaeology
• 4 Deploying 3D GIS at the Trowel’s edge
• 5 Surface and subsurface analysis
• 6 3D visibility analysis
• 7 Volumes
• 8 Future developments
• References
• Index