make the analysis of enormous amounts of data feasible. With the advent of the personal computer as an affordable, fast, and user-friendly analytical tool, it is now possible to process in a very short period of time amounts of data that otherwise would have taken days or even weeks to process.

The sheer size of the databases that archaeologists have to work with, which include archaeological and environmental data, made it extremely difficult, if not virtually impossible, to integrate all the material into a spatial-temporal framework. The best archaeologists could hope for was that through the production of accurate maps of site or artifact distribution, a meticulous visual inspection would reveal any spatial pattern.

Traditionally, maps have been an indispensable tool for archaeology and related disciplines. The basic geographic features are displayed using various visual artifices, such as diverse symbols or colors or text codes, which are explained in the legends. Naturally, the most important limitation these maps have is the amount of information they can effectively communicate, if more information is needed, it would have to be included in another form.

Map production, however, is a very expensive and time-consuming activity. As our scientific knowledge of the earth advances, new information needs to be charted almost immediately, but the effective and prompt assessment of natural resources, meteorological phenomena, and urban growth requires that maps be produced expediently and at low cost.

The demand for detailed map information has put pressure on for the development of better mapping techniques, and naturally, computer applications such as computer assisted design (CAD) and computer assisted mapping (CAM) have been instrumental in meeting this demand. Still, these advantages in map production and the ability of computer applications like CAM or CAD to identify spatial patterns between the mapped features—points, lines, and polygons—are very limited, because they are not linked to a relational database. It is only with the advent of GIS that we are able, for the first time, to link the geographic position of the mapped features with the qualitative and quantitative information that describes them and make queries about them.

In essence, GIS is a spatially referenced database that allow us to store great amounts of data, retrieve it with ease, manipulate it mathematically, and visualize the results within its spatial context. Hence, the core of the analytic power of GIS lies in its ability to handle digital maps to create new information from the preexisting data.

To fully understand this advantage we need to take a closer look at the conceptual changes in maps as a result of the insertion of GIS. Prior to this insertion, the study of the spatial distribution of natural resources and human and plant populations was approached in a qualitative way. The principal aim was to produce inventories of these data, and the enormous amount of information produced forced the cartographer to rely on qualitative methods of classification and mapping.

Consequently, quantitative descriptions were hindered mainly because of a lack of the appropriate mathematical tools needed to describe the spatial variations. With GIS, however, maps underwent a critical transformation because spatial variations could now be rendered as digits. Therefore, maps are no longer conceived as simplified pictorial depictions of the real world but as numbers. This is a major conceptual leap since throughout the approximately 8,000 years of mapmaking, maps have been primarily descriptive, which has limited their application to showing the exact location of things. Increasingly, however, maps are becoming prescriptive, containing the data necessary to assist us in making decisions.

Applications of GIS in Archaeology

GIS technology is relatively recent as the first operational GIS was developed in Canada in 1972, around the same time that the first text on GIS was published. It was not until the 1980s, however, that archaeologists begin applying GIS to their field of study. In 1982, the study of the settlement patterns in relation to the seasonal availability of natural resources in western Arizona was approached using GIS.