Views of Carnac: applications of visibility analysis and dynamic visualisation for understanding the Neolithic monuments of southern Brittany

The Neolithic monuments of the Carnac area of southern Brittany are of international importance. However, archaeologists have tended to study the monuments as individual sites, rather than investigating their landscape settings. This is in part because the landscape is difficult to explore in the field. Modern houses and conifer plantations obscure views; earthen structures have been significantly reduced in size, indeed some have been entirely levelled. As it is difficult to conduct fieldwork in this landscape, digital techniques are particularly informative. The landscape is a subtle one, and environmentally deterministic interpretations are implausible. However, this does not mean that topography was unimportant to the choices of monument location. The visual characteristics of locales can vary greatly even in relatively slight topography. Small rises can obscure features near by, or give considerable prominence over longer distances. This article explores the potential of visibility analysis and dynamic visualisation for investigating the visual context of two of the monument types, the earthen long mounds and angled passage graves. Traditional viewshed maps allow direct quantitative comparisons to be made between sites. The effect of monument dimensions is explored. However, as has been discussed in earlier articles in Internet Archaeology (e.g. Gillings and Goodrick 1996), viewshed analysis does not represent the whole of human visual experience. Therefore, visualisations have been used to explore the landscape further. A dynamic visualisation of a journey up the Crac'h estuary provides a more subjective view of the landscape settings of the monuments. The VRML version of the landscape model provides the opportunity for readers to explore the landscape themselves, and expand on the interpretations offered. However, the visualisations are limited in their resolution, and thus it is important to refer back to the viewshed maps for specific information. Through using complementary techniques, our understanding of the landscape is extended beyond that which is possible from a single approach