EDfunc {SegEnvIneq}R Documentation

A function to compute environmental dissimilarity index

Description

Environmental Dissimilarity index measures the dissimilarity between the distribution of a population group x and the one of an environmental (dis-)amenity a among spatial units. The environmental dissimilarity index has several versions: "standard" aspatial version based on Duncan & Duncan (1955) segregation index; adjusted versions with spatial interactions matrices based on contiguities (Morrill, 1991; Tivadar, 2019), boundaries, or shapes (Wong, 1998; Tivadar, 2019); or defined by the user.

Usage

EDfunc(x, a, vers = "standard", w = NULL, ar = NULL, per = NULL,
b = NULL, folder = NULL, shape = NULL, spatobj = NULL, queen = TRUE,
ptype = "int", K = 1, f = "exp", beta = 1)

Arguments

x

a vector of the population/group distribution across spatial units

a

a vector of the environmental variable spatial distribution

vers

the index version: "standard" (by default) for aspatial environmental dissimilarity index (Duncan); "contig" for adjusted index with a contiguity spatial interactions matrix (Morrill); "bound" for adjusted index with a boundaries spatial interactions matrix (Wong); "shape" for adjusted index with a boundaries and shape spatial interactions matrix (Wong); "user" for adjusted index with any user spatial interactions matrix

w

an optional spatial weights matrix. If necessary and not provided, it will be computed in the function

ar

an optional vector of spatial units area. If necessary and not provided, it will be computed in the function

per

an optional vector of spatial units perimeter. If necessary and not provided, it will be computed in the function.

b

an optional shared border matrix. If necessary and not provided, it will be computed in the function.

folder

a character vector with the folder (directory) name indicating where the shapefile with geographical info is located on the drive if the interactions matrix is computed in the function

shape

a character vector with the name of the shapefile (without the .shp extension)

spatobj

a spatial object (SpatialPolygonsDataFrame) with geographic information as alternative for the shapefile, if the interactions matrix is computed in the function

queen

logical parameter defining criteria used for contiguity matrix computation, TRUE for queen (by default), FALSE for rook

ptype

a string variable giving two options for perimeter calculation for Wong's indices: "int" to use only interior borders of spatial units and "all" to use entire borders, including to the exterior of the area

K

the order of contiguity matrix if "contig" version is chosen (K = 1 by default)

f

spatial decay function of contiguity matrix when K > 1, with f = "exp" (by default) for exponential function of contiguity "distance" exp(beta*(1-k))

beta

spatial decay intensity parameter (equal to 1 by default), used only when the version with contiguity is chosen and K > 1

Value

The value of the environmental dissimilarity index

References

Schaeffer Y. and Tivadar M. (2019) Measuring Environmental Inequalities: Insights from the Residential Segregation Literature. Ecological Economics, 164, 106329

Tivadar M. (2019) OasisR: An R Package to Bring Some Order to the World of Segregation Measurement. Journal of Statistical Software, 89 (7), pp. 1-39

Duncan O. D. and Duncan B. (1955) Residential Distribution and Occupational Stratification. American Journal of Sociology, 60 (5), pp. 493-503

Morrill B. (1991) On the measure of geographic segregation. Geography research forum, 11, pp. 25-36.

Wong D. W. S. (1998) Measuring multiethnic spatial segregation. Urban Geography, 19 (1), pp. 77-87.

See Also

ECfunc, EnvResampleTest, EnvResamplePlot

Examples

data(segdata, package = "OasisR")
# segdata - theoretical distributions on a 10x10 grid map
# We consider A1 - population distribution and A2 - amenity distribution
EDfunc (segdata@data$A1, segdata@data$A2)
EDfunc (segdata@data$A1, segdata@data$A2, vers = "contig", spatobj =segdata, queen = FALSE)
EDfunc (segdata@data$A1, segdata@data$A2, vers = "contig", spatobj =segdata, queen = FALSE, K = 3)
EDfunc (segdata@data$A1, segdata@data$A2, vers = "bound", spatobj =segdata)
EDfunc (segdata@data$A1, segdata@data$A2, vers = "shape", spatobj =segdata, ptype = 'all')

[Package SegEnvIneq version 1.2 Index]