spatstat (version 1.55-0)

split.msr: Divide a Measure into Parts

Description

Decomposes a measure into components, each component being a measure.

Usage

# S3 method for msr
split(x, f, drop = FALSE, …)

Arguments

x

Measure (object of class "msr") to be decomposed.

f

Factor or tessellation determining the decomposition. Argument passed to split.ppp. See Details.

drop

Logical value indicating whether empty components should be retained in the list (drop=FALSE, the default) or deleted (drop=TRUE).

…

Ignored.

Value

A list, each of whose entries is a measure (object of class "msr").

Details

An object of class "msr" represents a signed (i.e. real-valued) or vector-valued measure in the spatstat package. See msr for explanation.

This function is a method for the generic split. It divides the measure x into components, each of which is a measure.

A measure x is represented in spatstat by a finite set of sample points with values attached to them. The function split.msr divides this pattern of sample points into several sub-patterns of points using split.ppp. For each sub-pattern, the values attached to these points are extracted from x, and these values and sample points determine a measure, which is a component or piece of the original x.

The argument f can be missing, if the sample points of x are multitype points. In this case, x represents a measure associated with marked spatial locations, and the command split(x) separates x into a list of component measures, one for each possible mark.

Otherwise the argument f is passed to split.ppp. It should be either a factor (of length equal to the number of sample points of x) or a tessellation (object of class "tess" representing a division of space into tiles) as documented under split.ppp.

See Also

msr, [.msr, with.msr

Examples

# NOT RUN {
  ## split by tessellation
  a <- residuals(ppm(cells ~ x))
  aa <- split(a, dirichlet(runifpoint(4)))
  aa
  sapply(aa, integral)

  ## split by type of point
  b <- residuals(ppm(amacrine ~ marks + x))
  bb <- split(b)
  bb
# }