spatialsegregation (version 2.40)

simpsonF: Spatial Simpson Index

Description

Compute the spatial and aspatial Simpson index for a given multitype point pattern.

Usage

simpsonF(X, r=NULL, ...)
simpson.index(X, spatial=FALSE, ...)

Arguments

X

Multitype point pattern of class ppp (see package 'spatstat')

r

Vector of sizes for neighbourhoods, e.g. geometric graph with different ranges.

spatial

If FALSE, return the classical aspatial index value.

...

Further parametes for the function segregationFun.

Value

Returns an fv-object, see spatstat for more information.

Details

The form of Simpson index is S = 1 - sum pi_tau, where the sum is over the types of the pattern, and pi_tau is like in Shimatani\& Kubota 2004.

The function simpsonF is the main calculation function. Uses function segregationFun.

The function simpson.index is a shortcut to get a single value for the pattern. Uses 4-nn graph by default.

References

Rajala, Illian: A family of spatial biodiversity measures based on graphs, Env. Ecol. Stat. 2012

Shimatani, Kubota: Quantitative assesment of multispecies spatial pattern with high species diversity. Ecological Research, 19, 2004.