The Currency of Cost GIS Cost Surface Analysis and Environmental Bias Terry Beaulieu, PhD Candidate...

The Currency of CostGIS Cost Surface Analysisand Environmental Bias

Terry Beaulieu, PhD Candidate17 May 2014

FACULTY OF ARTSDepartment of Archaeology

Canadian Archaeological Association: Currency of Cost

Least Cost Path Overview: Raster

17 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



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

Least Cost Path Analysis is a measure of economic efficiency

We are bombarded daily with messages extolling the virtues of maximizing efficiency




The two most common currencies employed by archaeologists conducting Leas Cost Path analysis

Time— e.g. Tobler’s Hiking Function

06

255.335.05.125.1

035.05.125.12

222

22

slopeforW

GLW

V

LWVGVGVLWW

LW

slopeforVGVLWWLLWW

M watts

05.05.26 SeW

Energy— e.g. Pandorf et al’s and Santee et al’s Metabolic rate

formulas



Least Cost Path Bias: Terminology

‘Cost’ and ‘friction’ are negative terms

Evoke ideas that restrict and constrain travel and present barriers to movement

Tends to result in the privileging of environmental variables over more cultural measures

More to movement than simply avoiding physical obstacles



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



Study Area



Modern Example: Rosemary to Gem



Prehistoric Example: Trail Junction to Hunting Hill



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



Thank You


The Currency of Cost GIS Cost Surface Analysis and Environmental Bias Terry Beaulieu, PhD Candidate...

Documents

Transcript of The Currency of Cost GIS Cost Surface Analysis and Environmental Bias Terry Beaulieu, PhD Candidate...