shannonF: Spatial Shannon index

In antiphon/spatialsegregation: Segregation Measures for Multitype Spatial Point Patterns

Description

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

Usage

shannonF(X, r = NULL, v2 = FALSE, ...)

shannon.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.
v2	If TRUE, use the real number of types in neighbourhoods as the log-base instead of total population type count.
...	Further parametes for the function segregationFun.
spatial	If FALSE, return the classical aspatial index value.

Details

The form of Shannon index is H = 1 - E(o)/E(N), where E(N) is the global entropy and E(o) is the local entropy calculated as E(o)= - sum pi_tau log(pi_tau), where the sum is over the different types present in the pattern, and pi_tau is the expected frequency of type tau points in a neighbourhood of a typical point of the pattern.

The function shannonF is the calculation function. Uses function segregationFun.

The function shannon.index is a shortcut to get the non-spatial Shannon index.

Value

Returns an fv-object, see spatstat for more information. The index returns a scalar.

Functions

• shannon.index: Traditional index.

References

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

Reardon, O'sullivan: Measures of spatial segregation. Sociological methodology, 34:121-162, 2004.

antiphon/spatialsegregation documentation built on Nov. 21, 2020, 10:39 p.m.