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spatialsegregation (version 2.40)

shannonF: Spatial Shannon Index

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.
spatial
If FALSE, return the classical aspatial index value.
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.

Value

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

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.

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.