R: Plot Result of Scan Test

plot.scan.test {spatstat} | R Documentation

## Plot Result of Scan Test

### Description

Computes or plots an image showing the likelihood ratio test statistic for the scan test, or the optimal circle radius.

### Usage

     ## S3 method for class 'scan.test'
    plot(x, ..., what=c("statistic", "radius"),
                   do.window = TRUE)

     ## S3 method for class 'scan.test'
    as.im(X, ..., what=c("statistic", "radius"))

### Arguments

`x,X` | Result of a scan test. An object of class `"scan.test"` produced by `scan.test`.
`...` | Arguments passed to `plot.im` to control the appearance of the plot.
`what` | Character string indicating whether to produce an image of the (profile) likelihood ratio test statistic (`what="statistic"`, the default) or an image of the optimal value of circle radius (`what="radius"`).
`do.window` | Logical value indicating whether to plot the original window of the data as well.

### Details

These functions extract, and plot, the spatially-varying value of the likelihood ratio test statistic which forms the basis of the scan test.

If the test result `X` was based on circles of the same radius `r`, then `as.im(X)` is a pixel image of the likelihood ratio test statistic as a function of the position of the centre of the circle.

If the test result `X` was based on circles of several different radii `r`, then `as.im(X)` is a pixel image of the profile (maximum value over all radii `r`) likelihood ratio test statistic as a function of the position of the centre of the circle, and `as.im(X, what="radius")` is a pixel image giving for each location u the value of `r` which maximised the likelihood ratio test statistic at that location.

The `plot` method plots the corresponding image.

### Value

The value of `as.im.scan.test` is a pixel image (object of class `"im"`). The value of `plot.scan.test` is `NULL`.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`scan.test`, `scanLRTS`

### Examples

       if(interactive()) {
         a <- scan.test(redwood, seq(0.04, 0.1, by=0.01),
                        method="poisson", nsim=19)
       } else {
         a <- scan.test(redwood, c(0.05, 0.1), method="poisson", nsim=2)
       }
       plot(a)
       as.im(a)
       plot(a, what="radius")

[Package spatstat version 1.63-3 Index]