ISMorrillK: A function to compute K-th order Morrill's segregation index

Description

This function computes an adaptation of Morrill's segregation index which takes into account the interactions between spatial units defined by K-th ordered contiguity matrix. The index can be used in two ways: to provide a contiguity units defined by K order contiguity matrix. The function can be used in two matrix or a external geographic information source (spatial object or shape file).

Usage

ISMorrillK(x, ck = NULL, queen = FALSE, spatobj = NULL, folder = NULL, 
shape = NULL, K = 2, f = 'exp', beta = 1, prec = NULL)

Value

a matrix with Generalized Morrill's dissimilarity index values

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 greaterTR 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.
ck: - a list containing contiguity matrices coresponding to each order (from 1 to K)
queen: - logical parameter defining criteria used for contiguity matrix computation, TRUE for queen, FALSE (by default) for rook
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 driveis located.
shape: - a character vector with the name of the shapefile (without the .shp extension).
K: - the order of the contiguity matrix
f: - the distance function, f = 'exp' (by default) for negative exponential function and f = 'rec' for reciprocal function
beta: - distance decay parameter
prec: - precision parameter. If not NULL, the function stop computing the spatial interaction when the impact on the indice is bellow 10 ^ (-prec)

References

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

Examples

Run this code

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

ISMorrillK(x, spatobj = segdata, queen = FALSE, K = 3)

ISMorrillK(x, folder = foldername, shape = shapename, K = 4, f = 'rec')