OasisR (version 1.0.0)

Delta: A function to compute Delta index

Description

Delta index compares the relative density of a spatial unit with the proportion of a group living in the same unit. The function can be used in two ways: by providing a vector with spatial units area, or a geographic source (spatial object or shape file) wich will be used to compute the area vector within the function

Usage

Delta(x, a = NULL, spatobj = NULL, folder = NULL, shape = NULL)

Arguments

x

- an object of class matrix (or that can be coerced to that class), where each column represents the distribution of a population group, within spatial units. The number of columns should be greater than one (at least two population groups are require

a

- a vector with areas of spatial units

spatobj

- a spatial object (SpatialPolygonsDataFrame)

folder

- a character vector with the folder (directory) where the shapefile is

shape

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

Value

• A vector with Delta index

References

Duncan O. D., Cuzzoert and Duncan B. (1961) Problems in analyzing areal data. Statistical geography, Glencoe, Illinois: The free press of Glencoe

See Also

Absolute Concentration Index: ACO Relative Concentration Index: RCO

Examples

x <- slot(GreHSize, 'data')[ ,3:5]
ar <- area(GreHSize)
foldername <- system.file('extdata', package = 'OasisR')
shapename <- 'GreHSize'

Delta(x, a = ar)

Delta(x, spatobj = GreHSize)

Delta(x, folder = foldername, shape = shapename)