Extract a subset of a leverage map, or extract the leverage values at specified locations.
# S3 method for leverage.ppm
[(x, i, ..., update=TRUE)Another object of class "leverage.ppm",
or a vector of numeric values of leverage.
A leverage object (of class "leverage.ppm")
computed by leverage.ppm.
Subset index (passed to [.im).
Either a spatial window (object of class "owin")
or a spatial point pattern (object of class "ppp").
Further arguments passed to [.im,
especially the argument drop.
Logical value indicating whether to update the internally-stored value of the mean leverage, by averaging over the specified subset.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner rolfturner@posteo.net and Ege Rubak rubak@math.aau.dk
An object of class "leverage.ppm" contains the values of the
leverage function for a point process model, computed by
leverage.ppm.
This function extracts a designated subset of the leverage values, either as another leverage object, or as a vector of numeric values.
The function [.leverage.ppm is a method for [ for the
class "leverage.ppm". The argument i should be either
a spatial window (object of class "owin")
determining a region where the leverage map is required.
The result will typically be another leverage map
(object of class leverage.ppm).
a spatial point pattern (object of class "ppp")
specifying locations at which the leverage values are required.
The result will be a numeric vector.
The subset operator for images, [.im, is applied to
the leverage map. If this yields a pixel image, then the result of
[.leverage.ppm is another leverage object. Otherwise,
a vector containing the numeric values of leverage is returned.
leverage.ppm.
fit <- ppm(cells ~x)
lev <- leverage(fit)
b <- owin(c(0.1, 0.3), c(0.2, 0.4))
lev[b]
lev[cells]
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