spatstat (version 1.46-1)

plot.leverage.ppm: 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

"plot"(x, ..., showcut=TRUE, col.cut=par("fg"), multiplot=TRUE)
 "persp"(x, ..., main)

Arguments

x

Leverage measure (object of class "leverage.ppm") computed by leverage.ppm.

...

Arguments passed to plot.im or contour.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.

multiplot

Logical value indicating whether it is permissible to display several plot panels.

main

Optional main title.

Value

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

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.im. 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.

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)