verhagen, p., brughmans, t., nuninger, l. and bertoncello, f. (2012) the long and winding road:...

8/2/2019 Verhagen, P., BRUGHMANS, T., Nuninger, L. and Bertoncello, F. (2012) The long and winding road: combining least cost paths and network analysis techniques for settlement lo

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CAA2012 Southampton, UK 26-30 March 2012

Philip VerhagenVU University Amsterdam (NL)

Tom BrughmansUniversity of Southampton (UK)

Laure NuningerCNRS, UMR6249, Besanon (F)

Frdrique BertoncelloCNRS, UMR6130, Nice (F)

PHC Van Gogh 2010/2011 - Introducing the human (f )actor in predictive modelling for archaeology

Frans-Nederlandse Academie / Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)Ministres des Affaires trangres et europennes (MAEE) / Enseignement suprieur et de la Recherche (MESR).


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predictive modelling mainly based onenvironmental factors

socio-cultural factors too difficult to integrate?

accessibility is a potential factor to include, but how

to define it?


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Llobera (2000) introduced the concept of scale-dependentaccessibility

modification of Shimbel or all-node distance matrix

provides the minimal distance between each node of a network relative distances determined using cost surfaces

time-consuming calculations for larger areas

interest: determine areas where local and regional

accessibility are opposed predicting the possible location of fords and passes, or defendible

positions in the landscape

understanding why certain portions of the landscape are not occupied


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least cost path calculations usually applied to determineroutes between known locations

exception: Whitley and Burns (2008)

paths calculated within a certain radius from a randomly orsystematically selected sample of starting points

creates multiple cost paths for a region at various scale levels

no preferred start or end points

cost distances calculated from starting point

paths tracked back from a sufficiently large number of points at aspecific distance

repeat and overlay for each starting point


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+ + + + + + + ++ + + + + + + ++ + + + + + + ++ + + + + + + ++ + + + + + + ++ + + + + + + ++ + + + + + + ++ + + + + + + ++ + + + + + + ++ + + + + + + +


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cumulative cost paths resemble networks that have

weighted edges

non-directed edges

a large number of nodes

few hubs (nodes with lots of connections)

can network analysis techniques say something more about

the structure? e.g. identify corridors and bottlenecks


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node-based global measures

average degree, heterogeneity, clustering coefficient

local measures

closeness and betweenness centrality

import/export from ArcGIS through .dbf needs from-node, to-node and coordinates of nodes

open source software


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based on space syntax concepts

calculates local (edge-based) measures

choice (=betweenness)

both topological and metric depth

topological/metric radius can be defined

im- and export from ArcGIS through MIF/MID-format

freeware (UCL)


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cumulative cost path based networks contain a lotof noise, need post-processing to extract thegeneral structure

for this exercise:

select 10% and 20% most frequently chosen paths

simplify network structure (expand linear raster featureswith 2 cells) and thin it

convert to polyline


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cumulative cost path based networks are not typical

few hubs, weakly structured

general structure only apparent when selecting the most frequently

chosen paths

some network analysis measures can be interesting forbetter understanding potential foci of movement in thelandscape

in particular betweenness (choice) and control

analysis very sensitive to edge effects


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node-based network analysis packages

do not include metric depth

cannot calculate measures over various scales

space syntax does

but gives no information on the nodes

cannot include relative distances (costs)

how to interpret the results in archaeological terms?

verhagen, p., brughmans, t., nuninger, l. and bertoncello, f. (2012) the long and winding road:...

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