ACEPoly: A function to compute the Massey and Denton Polycentric...

In OasisR: Outright Tool for the Analysis of Spatial Inequalities and Segregation

A function to compute the Massey and Denton Polycentric Absolute Centralisation Index

Description

The absolute centralization index measures a group spatial distribution compared to the distribution of land area around the city center. The function can be used in two ways: to provide an area vector and a vector containing the distances between spatial units centroids and the central spatial unit or a external geographic information source (spatial object or shape file).

Usage

ACEPoly(x, a = NULL, dc = NULL, center = 1, 
spatobj = NULL, folder = NULL, shape = NULL)

Arguments

x	an object of class matrix (or which can be coerced to that class), where each column represents the distribution of a group within spatial units. The number of columns should be greater than 1 (at least 2 groups are required). You should not include a column with total population, because this will be interpreted as a group.
a	a numeric vector containing spatial unit areas
dc	a numeric matrix containing the distances between spatial units centroids and the central spatial units
center	a numeric vector giving the number of the spatial units that represent the centers in the table
spatobj	a spatial object (SpatialPolygonsDataFrame) with geographic information
folder	a character vector with the folder (directory) name indicating where the shapefile is located on the drive
shape	a character vector with the name of the shapefile (without the .shp extension).

Value

A numeric vector containing the Massey and Denton absolute polycentric centralisation index values for each group

References

Massey D. S. and Denton N. A. (1988) The dimensions of residential segregation. Social Forces 67(2), pp. 281-315.

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

See Also

ACE, RCE,

RCEPoly, RCEPolyK,

ACEDuncan, ACEDuncanPoly,

ACEDuncanPolyK

Examples

x <- segdata@data[ ,1:2]
ar<-area(segdata)
foldername <- system.file('extdata', package = 'OasisR')
shapename <- 'segdata'

ACEPoly(x, spatobj = segdata, center = c(28, 83) )

ACEPoly(x, folder = foldername, shape = shapename, center = c(28, 83))

center <- c(28, 83)
polydist <- matrix(data = NA, nrow = nrow(x), ncol = length(center))
for (i in 1:ncol(polydist))
  polydist[,i] <- distcenter(spatobj = segdata, center = center[i])
ACEPoly(x, a = ar, dc = polydist)

distmin <- vector(length = nrow(x))
for (i in 1:nrow(polydist)) distmin[i] <- min(polydist[i,])
ACE(x, a = ar, dc = distmin)

OasisR documentation built on April 3, 2025, 5:58 p.m.