Antonella Guidazzoli, Luigi Calori
VIS.I.T Visual Information Technology CINECA
Scientific visualization procedures have been one of the major advances in archaeological practice over the last few years, as they are an invaluable tool for an easier comprehension of various hypotheses on the analysis of territory.
The Research Areas of Prehistory and Archaeology of the Department of Territory and Historical Heritage of the University of Jaén have been working for the last three years on the above techniques for their application to visualization the Iberian oppida known as 'Puente Tablas' and 'Giribaile'.
This work eventually resulted in navegations of the territory of the hinterland of these oppida. Such navegations were later improved during the last work period at the CINECA.
The video originally produced for the oppidum of Puente Tablas in 1994, to which the results obtained from the survey of building lands in the town of Jaén had previously been incorporated, has been improved with a closer view of the settlement. To this end, the Department of Education of the Andalusia Regional Council ('Consejería de Cultura de la Junta de Andalucía') funded a photogrametric reconstruction of the site, with an accuracy between contour lines of 1 m. A black and white aerial photography of the site was then placed on top for a better resolution.
This gradual approach to the oppidum clearly shows the selection criteria of a particular location for a settlement, both in itself and in relation with other settlements, in particular with the oppidum 'Santa Catalina', of which more and more archaeological evidence is being found in the excavations of the original city centre of Jaén.
It is our intention to go deeper into this visualization model in the near future, in order to focus on more and more specific aspects of 'Puente Tablas', such as the wall and the town planning, which have already been partly excavated.
As for the oppidum 'Giribaile', the already existing video made in 1995 has been improved by colouring the aerial photography with an artificial palette, and integrating a 3D Studio model of the settlement 'La Monaria'.
The proposed recreation of these oppida efficiently accounts for two of the various settlement patterns described for the evolution of Iberian populations in the Upper Gualdaquivir. The continuity of the archaeological sequence from the origins of the Iberian world to the definitive establishment of romanization can thus be easily understood.
Another aim was to make use of the possibilities of Internet as a quick and efficient medium for the diffusion of archaeological documentation. Interactive demonstrative models were therefore designed as a complement of each video using VRML and offered as a site in the web.
Navegation on the oppidum 'Giribaile' is particularly illustrative, as visitors can visualize all the settlements in the plain, as well as gain access to their respective databases by selecting the appropriate vectors. These databases contain, among other aspects, the name of each site and further archaeological and topographic characterizations.
A similar, although more complete database will be designed for the oppidum 'Puente Tablas'. This other database will offer an overall view of the excavated part of the site, such that visitors of the site may virtually move around the settlement and get to know the everyday details of the life of inhabitants of an Iberian oppidum of the first half of the IVth ct. B.C. in the area known as 'Campiña de Jaén'.
Once the territory of these settlements has been properly dealt with, it seems to us that it is of great interest to extend our work to the interior of the dwellings of each site, thus reaching the archaelogical analysis of more and more specific aspects of the settlement.
Research on the Iberian culture in Jaén thus benefits from such powerful resources as visualization programmes and scientific analysis, which are a most appropriate stage previously to the actual recreation of these settlements in museums.
Archaeological surveying has certainly been one of the most important centers of attention in the historical research conducted in the province of Jaén over the last few years.
Our interest in achieving better and more detailed results has boosted a continuous technical and methodological innovation, of which our research during the year 1996 under an EU grant at the CINECA is but one example.
Our major aim was to learn about the possibilities of digital processing of satellite images for archaeological teledetection. To this end, we used a Panchromatic SPOT scene, which we treated with Ermapper as the base programme. The quick work with pre-established algorithms and filters of the above programme, as well as its automatic classification of images, were especially fruitful.
On the other hand, the high resolution of the Panchromatic SPOT can accurately identify the edge of paths and fields, thus allowing for the interpretation of Roman 'centuriae' on the basis of previous well-known studies of a similar kind.
One-way filters (e.g., NE-SW) and 'light and shade' effects on images were successfully applied to the representation of such regular pattern in a particular direction. Identification of Iberian fortifications proper to the oppida of the Upper Guadalquivir are also programme-assisted, as walls appear as very steep slopes after texture-mapping the images.
This approach to teledetection confirmed the highly-predictive capacity of this method for location of archaeological sites still unknown in our research area.
Statistical analyses are also of great help for this task, as they can show numerically discontinuities of images caused by existing archaeological features. It is also possible to identify and segment frequencies responsible for noise in images, especially if it is caused by tree plantations like the abundant ones of olive trees in the province of Jaén.
Finally, Ermapper is particularly versatile for work with file annotation, rasters and vectorials, and also offers some very promising possibilities for image equalization and enhancement, thus being capable of revealing archaeological phenomena difficult to locate by the mere visual examination common in techniques based on photointerpretation.
BIBLIOGRAPHY
GUTIÉRREZ, L.M. (en prensa): Poblamiento ibérico en el curso medio del río Guadalimar. Tesis Doctoral. Universidad de Jaén. Microfichas.