Utilisation d'un système d'information géographique pour l'étude de la localisation des dolmens et des menhirs. Application aux monuments de la planèze de Saint-Flour (Cantal)

摘要

When doing some previous research work on the Auvergne megalithic monuments, we were able to show clearly that the location of dolmens and menhirs had not been, in most cases, dictated by favourable geological conditions. On the contrary, the choice of the site was the result of the deliberate will of the megalith builders, which had meant great efforts for them. The builders had looked for some prominent position which would offer the monuments a wide visibility. In order to find out which elements exactly had determined the location of the monuments, we have used a geographical information system. We have worked on the "planèze" (volcanic plateau) of St Flour (Cantal) where most of the Auvergne menhirs and chiefly the dolmens are concentrated. Of course, many factors must be taken into account, among which are the original size of the monuments and the nature of the existing vegetation at the time of their construction. The latter factor has not been considered on account of our very imprecise knowledge of the paleoenvironment. We can notice that the monuments are distributed quite regularly across the central part of the "planèze", called low planèze, where arable land could be found. Apart from two dolmens which are nearly next to each other, the other monuments are stationed along perimeters of roughly the same area. And so, in some way, we can say that they "marked the boundaries" of the territory. When analysing the fields of visibility, we have noticed that they are nearly contiguous (if not taking the vegetation into account). Quite clearly, this factor, whether of actual or symbolic nature, played an important part in the location of megalithic monuments. As a result, we can suggest that because the visibility fields were not overlapping one another, most of the monuments must have been used or even built at the same period. Then it could be suggested that they were distributed along the distinctive territories of small communities of farmers/cattle breeders. Some monuments are wholly different from the others, which might imply a different age or function. Finally, no clear distinction could be seen between dolmens and menhirs, the latter being in very small number.