Extract.layered: Extract or Replace Subset of a Layered Object

Description

Extract or replace some or all of the layers of a layered object, or extract a spatial subset of each layer.

Usage

# S3 method for layered
[(x, i, j, drop=FALSE, ...)
  # S3 method for layered
[(x, i) <- value
  # S3 method for layered
[[(x, i) <- value

Arguments

A layered object (class "layered").

Subset index for the list of layers. A logical vector, integer vector or character vector specifying which layers are to be extracted or replaced.

Subset index to be applied to the data in each layer. Typically a spatial window (class "owin").

drop

Logical. If i specifies only a single layer and drop=TRUE, then the contents of this layer will be returned.

…

Additional arguments, passed to other subset methods if the subset index is a window.

value

List of objects which shall replace the designated subset, or an object which shall replace the designated element.

Value

Usually an object of class "layered".

Details

A layered object represents data that should be plotted in successive layers, for example, a background and a foreground. See layered.

The function [.layered extracts a designated subset of a layered object. It is a method for [ for the class "layered".

The functions [<-.layered and [[<-.layered replace a designated subset or designated entry of the object by new values. They are methods for [<- and [[<- for the "layered" class.

The index i specifies which layers will be retained. It should be a valid subset index for the list of layers.

The index j will be applied to each layer. It is typically a spatial window (class "owin") so that each of the layers will be restricted to the same spatial region. Alternatively j may be any subset index which is permissible for the "[" method for each of the layers.

Examples

Run this code

# NOT RUN {
 D <- distmap(cells)
 L <- layered(D, cells,
              plotargs=list(list(ribbon=FALSE), list(pch=16)))

 L[-2]
 L[, square(0.5)]

 L[[3]] <- japanesepines
 L
# }