Section 2: A brief introduction to GIS and Archaeology

2.4 Landscapes, present and past

The archaeological awakening to GIS and the resulting rapid increase in applications started with the publication of Interpreting Space (Allen et al.) in 1990. Since then, in very general terms, there have been two streams of development which can be categorised as Cultural Resource Management (CRM) and landscape analysis. While any definition of GIS will undoubtedly emphasise analytical capabilities (Martin 1996 for an introduction), it must be recognised that a major strength of the software lies in its ability to integrate and manage large and diverse data-sets. The integration and georeferencing of different types of spatial data over large geographical areas, typically a region or even a whole country, together with textual databases is a central concern of CRM. This is usually based on statutory obligations and frequently involves the integration of data sources at a range of varying scales. As a result of the flexibility and strength of these data management capabilities it is not surprising that in the majority of cases, though by no means exclusively, analysis is relegated to a secondary role.

The potential of GIS in CRM was recognised by many countries at a conference in 1991 (Larsen 1992), and has since been realised by some of them, for example France (Guillot and Leroy 1995), The Netherlands (Roorda and Wiemer 1992) and Scotland (Murray 1995). The adoption of GIS by national and regional CRM organisations is a complex business, often embroiled within a range of concerns including information strategies (not least upgrading from an existing system), communications and standards, politics and funding. There has been a great deal of published discussion about these wider issues including European Union initiatives (van Leusen 1995), various data models (Arroyo-Bishop and Lantada Zarzosa 1995; Lang and Stead 1992) and the issues involved in the restructuring of an existing database (Robinson 1993).

While CRM systems are usually based upon a vector data model, they often need to incorporate a number of raster data layers into the database, for example the integration of aerial photographs into the Scottish National Monuments Record ( Murray and Dixon 1995). Other common raster data-layers that could be encountered include the results of geophysical survey (a good example of this, although not strictly CRM, is the Wroxeter Hinterland Project (Gaffney, van Leusen and White 1996)) and satellite imagery (Cox 1992; Gaffney, Ostir, Podobnikar and Stancic 1996).

Within the field of non-CRM landscape applications there are a considerable number that utilise the mapping capabilities of GIS rather than any of its analytical functionality. Even so, analysis can be central to GIS-based landscape studies, as demonstrated by the early case-study of the island of Hvar (Gaffney and Stancic 1991; 1992) and the seminal paper by van Leusen (1993), where the archaeological analyses engage a battery of techniques including various statistics and distance functions. Such applications served to generate a vigorous debate on the underlying epistemology of GIS and the symbiotic relationship between GIS and archaeological theory. This is a debate that raged in geography several years ago (Taylor and Johnston 1995, for an overview) and surfaced in archaeology as an argument against a return to positivism and environmental determinism (Wheatley 1993), both parts of an outdated theoretical stance long since rejected by the majority of archaeologists (Gaffney and van Leusen 1995).

Reactions to this debate have focused on attempts to integrate current theoretical notions of landscape within GIS functionality involving various ways of effectively humanising the landscape. Initially these approaches attempted to comment on the perception and cognition of an individual situated in the landscape based on visibility and intervisibility studies involving line-of-sight and viewshed routines (for example, Gaffney et al. 1995; Lock and Harris 1996). This resulted in the development of a new technique specifically of interest to archaeology, cumulative viewshed analysis (Wheatley 1995).