acc | R Documentation |
Destination accessibility or centrality or competition is a variable that when added to a destination choice model forms the competing destinations choice model. A simple formula for this variable is:
A_j = \Sigma ( W_m / D_{jm} ) | m<>j
where A_j
is the potential accessibility of destination j
to all other potential destinations m
, W_m
is a weight generally measured by population, and D_{jm}
is the distance between j
and m
.
acc(X, Y, Pop, Power=1)
X |
a numeric vector of x coordinates |
Y |
a numeric vector of y coordinates |
Pop |
a numeric vector of the weights, usually a population variable |
Power |
a power of the distance; default is 1 |
AccMeasure |
a single column numeric matrix of accessibility scores |
X,Y should be Cartesian coordinates for the distances to be measured in meters. In the sample dataset GR.Municipalities the projection used is the EPSG:2100 (GGRS87 / Greek Grid)
Stamatis Kalogirou <stamatis@lctools.science>
Kalogirou, S. (2003) The Statistical Analysis and Modelling of Internal Migration Flows within England and Wales, PhD Thesis, School of Geography, Politics and Sociology, University of Newcastle upon Tyne, UK. https://theses.ncl.ac.uk/jspui/handle/10443/204
Kalogirou, S. (2016) Destination Choice of Athenians: an application of geographically weighted versions of standard and zero inflated Poisson spatial interaction models, Geographical Analysis, 48(2),pp. 191-230. DOI: 10.1111/gean.12092 https://onlinelibrary.wiley.com/doi/abs/10.1111/gean.12092
data(GR.Municipalities)
attr<-GR.Municipalities@data
aMeasure<-acc(attr$X[1:100], attr$Y[1:100],attr$PopTot01[1:100],1)
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