The Currency of Cost GIS Cost Surface Analysis and Environmental Bias Terry Beaulieu, PhD Candidate 17 May 2014 FACULTY OF ARTS Department of Archaeology

Least Cost Path Overview: Raster Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Least Cost Path Overview: Raster Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Least Cost Path Overview: Raster Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Least Cost Path Overview: Raster Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Least Cost Path Overview: Raster Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Least Cost Path: Archaeological Applications  Most applications tend to employ only environmental measures — Slope, elevation, vegetation etc.  Leads to accusations of excessive environmental determinism  Most likely caused by the often unrecognized inherent bias intrinsic to GIS analyses Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Least Cost Path Bias: Economic Efficiency  Fits well with free market economics and neoliberal theory  An often unrecognized source of potential bias in Archaeological Least Cost Path Analysis Canadian Archaeological Association: Currency of Cost  Least Cost Path Analysis is a measure of economic efficiency  We are bombarded daily with messages extolling the virtues of maximizing efficiency 17 May 2014Terry Beaulieu

Least Cost Path Bias: Economic Efficiency Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Least Cost Path Bias: Economic Efficiency  The two most common currencies employed by archaeologists conducting Leas Cost Path analysis  Time — e.g. Tobler’s Hiking Function Canadian Archaeological Association: Currency of Cost  Energy — e.g. Pandorf et al’s and Santee et al’s Metabolic rate formulas 17 May 2014Terry Beaulieu

Least Cost Path Bias: Terminology  ‘Cost’ and ‘friction’ are negative terms  Evoke ideas that restrict and constrain travel and present barriers to movement Canadian Archaeological Association: Currency of Cost  Tends to result in the privileging of environmental variables over more cultural measures  More to movement than simply avoiding physical obstacles 17 May 2014Terry Beaulieu

Least Cost Path Bias: Terminology  Replace ‘Cost Raster’ and ‘Friction Surface’ with ‘Favourability Raster’ or ‘Desirability Surface’  Move beyond limiting factors and consider variables that promote or enhance movement  e.g. a ‘good’ view Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Study Area Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Study Area Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Modern Example: Rosemary to Gem Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Modern Example: Rosemary to Gem Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Modern Example: Rosemary to Gem Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Modern Example: Rosemary to Gem Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Modern Example: Rosemary to Gem Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Modern Example: Rosemary to Gem Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Prehistoric Example: Trail Junction to Hunting Hill Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Prehistoric Example: Trail Junction to Hunting Hill Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Prehistoric Example: Trail Junction to Hunting Hill Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Prehistoric Example: Trail Junction to Hunting Hill 17 May 2014Canadian Archaeological Association: Currency of CostTerry Beaulieu

Prehistoric Example: Trail Junction to Hunting Hill 17 May 2014Canadian Archaeological Association: Currency of CostTerry Beaulieu

Prehistoric Example: Trail Junction to Hunting Hill Canadian Archaeological Association: Currency of Cost17 May 2014Terry Beaulieu

Conclusion  Least Cost Path is a measure of economic efficiency — Currencies used by archaeologists tend to privilege environmental variables over cultural ones  Raster terminology leads to focus on physical barriers — Result is currencies that privilege environmental measures  Appearance of excessive environmental determinism is caused by these unacknowledged GIS biases  Recognition of GIS biases will allow archaeologists to mitigate the negative affects of those biases — Address the charge of environmental determinism — Create richer, more satisfying archaeological models 17 May 2014Canadian Archaeological Association: Currency of CostTerry Beaulieu

Thank You 17 May 2014Canadian Archaeological Association: Currency of CostTerry Beaulieu