linearpcf
Linear Pair Correlation Function
Computes an estimate of the linear pair correlation function for a point pattern on a linear network.
- Keywords
- spatial, nonparametric
Usage
linearpcf(X, r=NULL, ..., correction="Ang")Arguments
- X
- Point pattern on linear network (object of class
"lpp"). - r
- Optional. Numeric vector of values of the function argument $r$. There is a sensible default.
- ...
- Arguments passed to
density.defaultto control the smoothing. - correction
- Geometry correction.
Either
"none"or"Ang". See Details.
Details
This command computes the linear pair correlation function from point pattern data on a linear network.
The pair correlation function is estimated from the
shortest-path distances between each pair of data points,
using the fixed-bandwidth kernel smoother
density.default,
with a bias correction at each end of the interval of $r$ values.
To switch off the bias correction, set endcorrect=FALSE.
If correction="none", the calculations do not include
any correction for the geometry of the linear network. The result is
an estimate of the first derivative of the
network $K$ function defined by Okabe and Yamada (2001).
If correction="Ang", the pair counts are weighted using
Ang's correction (Ang, 2010). The result is an estimate of the
pair correlation function in the linear network.
Value
- Function value table (object of class
"fv").
References
Ang, Q.W. (2010) Statistical methodology for spatial point patterns on a linear network. MSc thesis, University of Western Australia. Ang, Q.W., Baddeley, A. and Nair, G. (2012) Geometrically corrected second-order analysis of events on a linear network, with applications to ecology and criminology. Scandinavian Journal of Statistics 39, 591--617. Okabe, A. and Yamada, I. (2001) The K-function method on a network and its computational implementation. Geographical Analysis 33, 271-290.
See Also
Examples
data(simplenet)
X <- rpoislpp(5, simplenet)
linearpcf(X)
linearpcf(X, correction="none")