R: Plot Leverage Function

plot.leverage.ppm {spatstat} | R Documentation

## Plot Leverage Function

### Description

Generate a pixel image plot, or a perspective plot, of a leverage function that has been computed by `leverage.ppm`.

### Usage

     ## S3 method for class 'leverage.ppm'
    plot(x, ..., showcut=TRUE, col.cut=par("fg"),
                                 args.contour=list(),
                                 multiplot=TRUE)

     ## S3 method for class 'leverage.ppm'
    persp(x, ..., main)

### Arguments

`x` | Leverage function (object of class `"leverage.ppm"`) computed by `leverage.ppm`.
`...` | Arguments passed to `plot.im` or `persp.im` controlling the plot.
`showcut` | Logical. If `TRUE`, a contour line is plotted at the level equal to the theoretical mean of the leverage.
`col.cut` | Optional colour for the contour line.
`args.contour` | Optional list of arguments passed to `contour.default` to control the plotting of the contour line.
`multiplot` | Logical value indicating whether it is permissible to display several plot panels.
`main` | Optional main title.

### Details

These functions are the `plot` and `persp` methods for objects of class `"leverage.ppm"`. Such objects are computed by the command `leverage.ppm`.

The `plot` method displays the leverage function as a colour pixel image using `plot.im`, and draws a single contour line at the mean leverage value using `contour.default`. Use the argument `clipwin` to restrict the plot to a subset of the full data.

The `persp` method displays the leverage function as a surface in perspective view, using `persp.im`.

### Value

Same as for `plot.im` and `persp.im` respectively.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.

### References

Baddeley, A., Chang, Y.M. and Song, Y. (2013) Leverage and influence diagnostics for spatial point process models. Scandinavian Journal of Statistics 40, 86–104.

### See Also

`leverage.ppm`.

### Examples

       X <- rpoispp(function(x,y) { exp(3+3*x) })
       fit <- ppm(X ~x+y)
       lef <- leverage(fit)
       plot(lef)
       persp(lef)

[Package spatstat version 1.54-0 Index]