# plot.scan.test: Plot Result of Scan Test In spatstat: Spatial Point Pattern Analysis, Model-Fitting, Simulation, Tests

## Description

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

## Usage

 ```1 2 3 4 5 6``` ``` ## 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)

and \rolf

`scan.test`, `scanLRTS`

## Examples

 ```1 2 3 4 5 6 7 8 9``` ``` 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") ```

### Example output

```Loading required package: nlme