R: Envelope of K1hat-K2hat from random labelling of two point...

Kenv.label {splancs} | R Documentation

## Envelope of K1hat-K2hat from random labelling of two point patterns

### Description

Compute envelope of K1hat-K2hat from random labelling of two point patterns

### Usage

    Kenv.label(pts1,pts2,poly,nsim,s,quiet=FALSE)

### Arguments

`pts1` | First point data set.
`pts2` | Second point data set.
`poly` | Polygon containing the points.
`nsim` | Number of random labellings to do.
`s` | Vector of distances at which to calculate the envelope.
`quiet` | If FALSE, print a message after every simulation for progress monitoring. If TRUE, print no messages.

### Details

The two point data sets are randomly labelled using `rLabel`, then `Khat` is called to estimate the K-function for each resulting set at the distances in `s`. The difference between these two estimates is then calculated. The maximum and minimum values of this difference at each distance,over the `nlab` labellings is returned.

### Value

A list with two components, called `$upper` and `$lower`. Each component is a vector like `s`.

### References

Rowlingson, B. and Diggle, P. 1993 Splancs: spatial point pattern analysis code in S-Plus. Computers and Geosciences, 19, 627-655; the original sources can be accessed at: http://www.maths.lancs.ac.uk/~rowlings/Splancs/. See also Bivand, R. and Gebhardt, A. 2000 Implementing functions for spatial statistical analysis using the R language. Journal of Geographical Systems, 2, 307-317.

### See Also

`rLabel`,`ikhat`

### Examples

    data(okwhite)
    data(okblack)
    okpoly <- list(x=c(okwhite$x, okblack$x), y=c(okwhite$y, okblack$y))
    K1.hat <- khat(as.points(okwhite), bboxx(bbox(as.points(okpoly))), seq(5,80,5))
    K2.hat <- khat(as.points(okblack), bboxx(bbox(as.points(okpoly))), seq(5,80,5))
    K.diff <- K1.hat-K2.hat
    plot(seq(5,80,5), K.diff, xlab="distance", ylab=expression(hat(K)[1]-hat(K)[2]),
    ylim=c(-11000,7000), type="l", main="Simulation envelopes, random labelling")
    env.lab <- Kenv.label(as.points(okwhite), as.points(okblack),
    bboxx(bbox(as.points(okpoly))), nsim=29, s=seq(5,80,5))
    lines(seq(5,80,5), env.lab$upper, lty=2)
    lines(seq(5,80,5), env.lab$lower, lty=2)

[Package splancs version 2.01-40 Index]