The role of visual appreciation of landscape has taken a
leading role in the archaeology of landscape, encouraged both by theoretical
approaches and the utility of GIS softwares for automatic analysis of the
visual characteristics of large landscapes.
Various writers have critiqued GIS studies of visibility and proposed
enhancements to and refinements of visibility studies (eg. Llobera 1996 and 2000; Ogburn
2006). In essence arguments for the refinement
of visibilities studies focus on the need to appreciate the impact of range,
view direction and target size on visibility. Additionally, a number of authors
have pointed out the shortcomings of both theoretical and practical approaches
to visibility studies, in particular the fact that many studies ignore or
misrepresent the potential impact of vegetation and past vegetation patterns on
landscape and visibility.
I have been experimenting with using CryEngine to model
different degrees of visual occlusion of landscape, based on atmospheric fog and rain. Sandbox conveniently allows varying vegetation
scenarios for the same landscape to be stored as layers that may be turned on
and off to explore the visual impact of changes in vegetation. Sandbox's environment controls allow
alteration of the character, density and occlusion distance of atmospheric fog
and addition the impact of rain on visibility may be simulated through particle
effects. The graphics here illustrate CryEngine
simulations of the effect of increasingly dense atmospheric fog (with view distance decreasing from 200m to 500m) and the addition
of rain on visibility of Stonehenge as viewed from The Cursus, a distance of
just over 2km, and can be compared with a traditional GIS-derived
two-dimensional viewshed diagram from the same location.
I think this approach has some potential for exploring changing visibility in landscapes where views and indivisibility are considered significant. I'll be exploring different vegetation patterns in a similar light in the near future.
Llobera, M. 1996. Exploring the topography of mind: GIS, social space and archaeology. Antiquity 70, 612-22.
Llobera, M. 2001. Building past landscape perception with GIS: understanding topographic prominence. Journal of Archaeological Science 28,
1005-14.
Ogburn, D.E. 2006. Assessing the level of visibility of cultural objects in past landscapes. Journal of Archaeological Science 33,
405-13.
