Pathways, Perception and the
development of Place
Computational
approaches to
movement and
perception of
landscape in
prehistory
A 3D reconstruction of the Beckhampton
Avenue, Avebury, Wilts.
Paul Cripps, Postgraduate Research Student,
University of Southampton, School of Humanities; Archaeology

2 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Outline
 Introduction
 Landscape studies
 Visibility analysis
 Abstractions of reality
 Approximations of
the situation
 Moving and seeing
 Movement
 Perception
 Computer based
approaches
 An integrated
approach A 3D reconstruction of the Cove in
Longstones Field, Avebury, Wilts.
 Available tools; GIS
and 3D
 An integrated system

3 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Background & Introduction
 Any landscape can be seen as a snapshot of the
complex continuum of interaction between
humans and their environment
 The formation of landscapes, particularly
significant places within them, can therefore be
seen as a function of this interaction
 This interaction has at its core the notions of
movement and perception, humans being highly
visually attuned, mobile actors
 In the later Neolithic, we see monumental forms
which are linear in nature and may be related to
movement of one kind or another

4 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
e.g. Stonehenge, Wilts.
 Many
archaeological
remains
 Complex sequence
of developments
over a very long
period of time
 Linear monuments
include an avenue
and two cursus

5 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Landscape studies & visibility analysis
 Landscape interpretation comprises functional
aspects (eg Renfrew) and phenomenological
aspects (eg Tilley, Thomas)
 Complementary rather than bipolar
 Visibility analysis fuses these aspects and has
been used successfully to analyse visual
characteristics of landscape built up from the
point of view of individual human actors
 eg Exon, Gaffney, Woodward & Yorston (2000);
investigated intervisibility of sites around
Stonehenge
 eg Wheatley (1995); looked at intervisibility of
long barrows around Avebury and Stonehenge
 eg Llobera; looked at total visual characteristics
of landscape

6 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Abstraction from reality…
 Visibility analysis can only ever provide an
approximation of the situation
 Better approximations can be achieved by
improving the theoretical model used and/or the
source data
 Computers can be used to speed up the process
of calculating lines-of-sight; a viewshed shows all
the lines-of-sight from a location
 A simple binary viewshed can be seen as a
starting point illustrating a single static view but
can also be used as the input to:
 Cumulative, Fuzzy and Dynamic viewshed
techniques used to give an improved
approximation the situation

7 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Approximations of the situation
 But this is still only part of the story!
 Traditionally, visibility analysis dependent on a
purely mathematical approach using Line-Of-Sight
vectors
 What about other factors…?
 Vegetation has a dramatic effect on visibility, as
does weather, colour, relative position and
lighting
 Static viewpoints only give one view, often biased
by the choice of archaeological sites as input
locations

8 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Approximations of the situation
 A mathematical
approach to
visibility
 Processor intensive;
powerful computers
needed
 Many calculations
possible on a
modern computer

9 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Moving and seeing
 So visibility analyses to date, while successful,
have for the most part, ignored effects of
movement and perception
 While there may be significance in particular
static viewsheds, what about humans as dynamic
agents, moving through, seeing and interacting
with the landscape around them…?
 This investigation will draw on theoretical
discourses and make use of the concept of
visibility as a means to investigate this cultural
continuum in terms of movement and perception
 Hence, inferences regarding site location, relative
chronology and functional aspects may be made

10 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Perception
 For the purposes of this investigation, a simplified
perceptual model is used:
 Based on visibility and factors influencing visibility
alone eg effects of colour, lighting, relative
position, environmental factors, etc
 Other senses (aural, haptic, etc) are currently
ignored
 Drawing on interdisciplinary sources eg
psychology and landscape design

11 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Movement
 Humans are dynamic agents capable of moving
and interacting with their environment
 It is through such movements and interactions an
understanding of landscape is constructed
 This understanding is incorporated back into the
landscape continuum by means of human action
eg constructing/destruction of monuments,
reserving ‘special’ places, cultural practices, etc
 Movement is therefore an important factor in the
way humans come to understand the world
around them

12 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
An integrated approach
 A holistic approach needed
 GIS cannot adequetely account for the factors
previously mentioned
 3D technologies do not have the sort of analytical
functions found in GIS, but outputs can be
subjected to image analysis.
 Therefore, make use of analytical 2D GIS and
image analysis supported and qualified by 3D
visualisation tools
 Incorporate rich spatial data; terrain models,
lighting/atmospheric models, environmental
evidence, reconstructed archaeological features
and interpretations (eg Neolithic neon)

13 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
GIS based Viewshed Analysis
 Binary viewshed
from the Cove in
Longstones Field,
Avebury, Wilts.
 Pink areas visible,
other areas not
visible

14 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
GIS based Viewshed Analysis
 Probabilistic
viewshed
from
Stonehenge,
Wilts.
 Grey areas
not visible;
darker
shades of
blue indicate
higher
probability of
being visible

15 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
GIS based Viewshed Analysis
 Animated
sequence of
viewsheds along
the path of the
Beckhampton
Avenue,
Avebury Wilts.
 A dynamic
approach to
viewsheds

16 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
3D visualisation
 Animations
 Modern
computers
capable of
real-time high
quality
visualisations
Animation showing the Cove,
Longstones Field, Avebury, Wilts.

17 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
3D visualisation
 High dynamic
range imagery
 Involves
calculating a
range of images
of differing
exposures to
create a more
realistic
composite
 Now possible in
real-time
Render showing the effects of HDR
using Vue 5 Infinite
© Eon Software

18 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
3D visualisation
 Global
Illumination
 Gives realistic
lighting in
outdoor spaces
Render showing the effects of Global
Illumination using Vue 5 Infinite
© Eon Software

19 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
3D visualisation
 Atmospherics
 Complex
particle
systems such
as mist or fog
Render showing the effects of
can be added atmospherics using Vue 5 Infinite
 Interaction © Eon Software
with light
sources can
be controlled

20 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
3D visualisation
 Complex
lighting models;
reflections and
refractions
 Output can be
further
investigated
using image
analysis
techniques
 Demo uses a
range of Animation demonstrating the concept of
Rendering with natural light (Debevec,
techniques in
1998); the latest improved version of this
real-time on ATI
model runs in real-time on the ACRG
graphics cards workstation using OpenGL (Apple Mac G5,
Dual 2.7GHz processors, 8Gb RAM) © ATI

21 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
An integrated system
Image Analysis
(analytical gfx package
Viewsheds Viewsheds
tbc)
(simple, (complex,
Animations Rendered binary) compound)
views
3D model 2D spatial analysis
(Vue Infinite v5) (ArcINFO / Grass)
Dynamic
interaction
(gaming
engine /
OpenGL tbc)
GIS database
(ArcINFO / Grass)
Uni-directional data flow
Bi-directional data flow
Interface interaction

22 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Next steps
 This investigation is still very much work in
progress (first year PhD, studying part-time)
 Hardware set up (ACRG Workstation); Unix based
(OSX; Tiger) 64-bit workstation recently acquired
 System components to be integrated and tested
(due late 2005); Open-source where possible
 Detailed investigations of study areas to follow
(scheduled for 2006), including fieldwork to
validate results

23 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
Acknowledgements & image credits
 Dr. David Wheatley (Supervisor)
 English Heritage; Stonehenge & Avebury World
Heritage Site GIS (archaeological data)
 Archaeological Computing Research Group (support)
http://www.arch.soton.ac.uk/Prospectus/ACRG/
 Eon Software (manufacturers of Vue 5 Infinite)
http://www.e-onsoftware.com/Products/vue5infinite
 ATI (manufacturers of graphics cards)
http://www.ati.com/developer/demos/macss2/

24 Pathways, Perception and the development of Place; Computational approaches to movement and perception of landscape in prehistory
“Exploring Research” - LASS Conference, University of Southampton, Jun 7th 2005
fin
360° Panorama from Windmill Hill, Avebury, Wilts.
 Contact paul.cripps@soton.ac.uk
 See www.soton.ac.uk/~pjc196/research/
for more information
Based on a paper originally presented at
Computer Applications in Archaeology,
Tomar, Portugal, Easter 2005