Poo: A function to compute the mean proximity between persons without regard to group (Poo)

Description

Mean proximity, Poo, computes the mean distance between the individuals in the area with no regard for group. The function can be used in two ways: to provide a distance matrix or a external geographic information source (spatial object or shape file)

Usage

Poo(x, d = NULL, fdist = 'e', distin = 'm',  distout = 'm', diagval = '0', 
itype = 'multi', beta = 1, spatobj = NULL, folder = NULL, shape = NULL)

Value

Poo index value(s)

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.
d: - a matrix of the distances between spatial unit centroids
fdist: - the method used for distance interaction matrix: e' for inverse exponential function (by default) and 'l' for linear.
distin: - input metric conversion, based on bink package and includes conversions from 'm', 'km', 'inch', 'ft', 'yd', 'mi', 'naut_mi', etc.
distout: - output metric conversion, based on bink package and includes conversions to 'm', 'km', 'inch', 'ft', 'yd', 'mi', 'naut_mi', etc.
diagval: - when providing a spatial object or a shape file, the user has the choice of the spatial matrix diagonal definition: diagval = '0' (by default) for an null diagonal and diagval = 'a' to compute the diagonal as 0.6 * square root (spatial/organizational unitsarea) (White, 1983)
itype: - a character string defining the index type: itype = 'multi' (by default) for the multi-group index (White, 1986) or itype = 'between' for the between groups version (White, 1983)
beta: - distance decay parameter
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).

References

White M. J. (1983) The Measurement of Spatial Segregation. American Journal of Sociology, 88, p. 1008-1019

White, M. J. (1986) Segregation and Diversity Measures in Population DistributionE. Population Index 52(2): 198-221.

Examples

Run this code

x <- segdata@data[ ,1:2]
ar<-area(segdata)
dist <- distance(segdata)
diag(dist)<-sqrt(ar) * 0.6
foldername <- system.file('extdata', package = 'OasisR')
shapename <- 'segdata'

Poo(x, spatobj = segdata)

Poo(x, folder = foldername, shape = shapename, fdist = 'l') 

Poo(x, spatobj = segdata, diagval ='a')

Poo(x, d = dist, fdist = 'e')