spatialsegregation-ISAR {spatialsegregation} | R Documentation |
Compute the Individual Species Area Relationship ( ISAR ), or Local Species Richness, for a given multitype point pattern.
isarF(X, r=NULL, target=NULL, v2=FALSE, ... ) isar.index(X, r=4, ntype="knn", ...)
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 . |
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.
Returns an fv
-object, see spatstat
for more information.
Tuomas Rajala University of Jyvaskyla, Finland tuomas.a.rajala@jyu.fi
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.