linearpcfcross
Multitype Pair Correlation Function (Cross-type) for Linear Point Pattern
For a multitype point pattern on a linear network, estimate the multitype pair correlation function from points of type $i$ to points of type $j$.
- Keywords
- spatial, nonparametric
Usage
linearpcfcross(X, i, j, r=NULL, ..., correction="Ang")Arguments
- X
- The observed point pattern,
from which an estimate of the $i$-to-any pair correlation function
$g_{ij}(r)$ will be computed.
An object of class
"lpp"which must be a multitype point pattern (a marked point pattern whose - i
- Number or character string identifying the type (mark value)
of the points in
Xfrom which distances are measured. Defaults to the first level ofmarks(X). - j
- Number or character string identifying the type (mark value)
of the points in
Xto which distances are measured. Defaults to the second level ofmarks(X). - r
- numeric vector. The values of the argument $r$ at which the function $g_{ij}(r)$ should be evaluated. There is a sensible default. First-time users are strongly advised not to specify this argument. See below for important conditions o
- correction
- Geometry correction.
Either
"none"or"Ang". See Details. - ...
- Arguments passed to
density.defaultto control the kernel smoothing.
Details
This is a counterpart of the function pcfcross
for a point pattern on a linear network (object of class "lpp").
The argument i will be interpreted as
levels of the factor marks(X).
If i is missing, it defaults to the first
level of the marks factor.
The argument r is the vector of values for the
distance $r$ at which $g_{ij}(r)$
should be evaluated.
The values of $r$ must be increasing nonnegative numbers
and the maximum $r$ value must not exceed the radius of the
largest disc contained in the window.
Value
- An object of class
"fv"(seefv.object).
Warnings
The argument i is interpreted as a
level of the factor marks(X). Beware of the usual
trap with factors: numerical values are not
interpreted in the same way as character values.
References
Baddeley, A, Jammalamadaka, A. and Nair, G. (to appear) Multitype point process analysis of spines on the dendrite network of a neuron. Applied Statistics (Journal of the Royal Statistical Society, Series C), In press.
See Also
Examples
data(chicago)
g <- linearpcfcross(chicago, "assault")