ResampleTest: A function to test segregation indices by resampling

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

A function to test segregation indices by resampling

Description

Resampling tests for segregation indexes.

Usage

ResampleTest(
  x,
  fun,
  var = NULL,
  simtype = "MonteCarlo",
  sampleunit = "unit",
  samplesize = NULL,
  perc = c(0.05, 0.95),
  outl = FALSE,
  outmeth = "bp",
  sdtimes = 2,
  IQRrange = 1.5,
  proba = NULL,
  nsim = NULL,
  spatobj = NULL,
  folder = NULL,
  shape = NULL,
  delta = 0.5,
  exact = FALSE,
  d = NULL,
  c = NULL,
  a = NULL,
  ck = NULL,
  f = "exp",
  b = NULL,
  p = NULL,
  spatmat = "c",
  queen = FALSE,
  distin = "m",
  distout = "m",
  diagval = "0",
  fdist = "e",
  itype = "multi",
  dc = NULL,
  center = 1,
  polorder = 4,
  pred = NULL,
  K = 2,
  ptype = "int",
  variant = "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.
fun	a character vector with the segregation function to be tested
var	vector with the variables to be tested
simtype	a character vector with the type of simulation. If simtype = 'Boot', the function generates bootstrap replications If simtype = 'Jack', the function generates jackknife replications If simtype = 'MonteCarlo', the function produces a randomization test using Monte Carlo simulations
sampleunit	= 'unit' (by default) when the sampling unit is the spatial/organisational unit and sampleunit = 'ind' for individual sampling
samplesize	the size of the sample used for bootstraping. If null, the samplesize equals the number of spatial/organizational units(sampleunit = 'unit') or the total total population (sampleunit = 'ind')
perc	the percentiles for the bootstrap replications
outl	logical parameter for jackknife simulations, if TRUE the function provides the outliers obtained by jackknife iterations
outmeth	- a character vector designing the outliers detection method: outmeth = 'bp' (by default) for boxplot method, outmeth = 'sd' for standard deviation method, outmeth = 'z' for normal scores method, outmeth = 't' for t Student scores method, outmeth = 'chisq' for chi-squared scores method, outmeth = 'mad' for median absolute deviation method. The estimations based on scoring methods are obtained using outliers package
sdtimes	multiplication factor of the standard deviation used for outliers detection with jackknife simulations (2 by default)
IQRrange	determines the boxplot thresholds (1.5 by default) as multiplication of IQR (Inter Quartile Range)
proba	for Monte Carlo simulations, proba is a vector with location probabilities. If proba = NULL, the vector is equiprobable. If outliers are determined with jackknife technique, proba indicates the probability (confidence interval) for scoring tests.
nsim	the number of simulations
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).
delta	an inequality aversion parameter
exact	a logical variable to specifiy the index version: exact = FALSE (by default) for the approximate version of the index, and exact = TRUE for the exact version
d	a matrix of the distances between spatial unit centroids
c	a standard binary contiguity (adjacency) symmetric matrix where each element Cij equals 1 if i-th and j-th spatial units are adjacent, and 0 otherwise.
a	a numeric vector containing spatial unit areas
ck	a list containing contiguity matrices coresponding to each order (from 1 to K)
f	the distance function, f = 'exp' (by default) for negative exponential function and f = 'rec' for reciprocal function
b	a common boundaries matrix where each element Bij
p	a numeric vector containing spatial units perimeters.
spatmat	the method used for spatial calculations: 'c' for the contiguity matrix (by default) or any other user spatial interaction matrix and 'd' for the inverse exponential function of the distance.
queen	logical parameter defining criteria used for contiguity matrix computation, TRUE for queen, FALSE (by default) for rook
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)
fdist	the method used for distance interaction matrix: e' for inverse exponential function (by default) and 'l' for linear.
itype	a character string defining the index type: itype = 'multi' (by default) for the multigroup index (White, 1986) or itype = 'between' for the between groups version (White, 1983)
dc	a numeric vector containing the distances between spatial units centroids and the central spatial unit
center	a numeric value giving the number of the spatial unit that represents the center in the table
polorder	order of the polynomial approximation (4 by default)
pred	a numerical vector with percentiles to be predicted.
K	the order of the contiguity matrix
ptype	a string variable giving two options for perimeter calculation when a spatial object or shapefile is provided: 'int' to use only interior boundaries of spatial units, and 'all' to use entire boundaries, including the boundaries to the exterior
variant	a character variable that allows to choose the index version: variant = 's' for the dissimilarity index adjusted for contiguous spatial units boundary lengths and perimeter/area ratio (by default) and variant = 'w' for the version without perimeter/area ratio
...	other specific parameters

Value

A list including: the index's name, the simulation type, the summary statistics of the simulations, the simulated index distribution, the simulated population distribution, a matrix with outliers (jackknife), a list with outliers values (jackknife)

References

Efron, B., and Tibshirani, R. J. (1993). An Introduction to the Bootstrap. New York, Chapman and Hall

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

ResamplePlot

Examples

x <- segdata@data[ ,1:2]

xtest <- ResampleTest (x, fun ='ISMorrill', simtype = 'MonteCarlo', 
                       sampleunit = 'ind', spatobj = segdata)
xtest$Summary

xtest <- ResampleTest (x, fun ='ISMorrill', simtype = 'Boot', 
                       sampleunit = 'unit', spatobj = segdata)
xtest$Summary

xtest <- ResampleTest (GreHSize@data[,3:5], fun='ISDuncan', simtype = 'Jack', 
                       sampleunit = 'unit',  spatobj = GreHSize, 
                       outl = TRUE, outmeth = 'sd', sdtimes = 3)
xtest$Summary
xtest$OutliersVal

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