spatialsegregation-ISAR {spatialsegregation}R Documentation

Individual Species Area Relationship

Description

Compute the Individual Species Area Relationship ( ISAR ), or Local Species Richness, for a given multitype point pattern.

Usage

isarF(X, r=NULL, target=NULL, v2=FALSE, ... )
isar.index(X, r=4, ntype="knn", ...)

Arguments

X Multitype point pattern of class ppp (see package 'spatstat')
r Vector of sizes for neighbourhoods, e.g. geometric graph with different ranges.
target Default NULL. Calculate only for target type. If NULL compute mean over all types.
v2 Logical. Estimate species/neighbours -ratios instead of just species/1.
ntype Set the default in isar.index to knn neighbourhood type.
... Further parameters for the function segregationFun.

Details

Date: 2009-09-06
License: GPL v2 or later

Extension of ISAR-function introduced in WGGH07. In effect calculates the expected amount of different types present in the neighbourhood of a point in the pattern.

The function isarF is the calculation function for different neighbourhoods. Uses function segregationFun.

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

Value

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

Author(s)

Tuomas Rajala University of Jyvaskyla, Finland tuomas.a.rajala@jyu.fi

References

Rajala, Illian: Graph-based description of mingling and segregation in multitype spatial point patterns. To appear 2009.

Wiegand, Gunatilleke, Gunatilleke, Huth: How individual species structure diversity in tropical forests. PNAS, nov 16, 2007.


[Package spatialsegregation version 2.11 Index]