R: Divide a Measure into Parts

split.msr {spatstat.core} | R Documentation

## Divide a Measure into Parts

### Description

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

### Usage

      ## S3 method for class '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.

### 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`.

### Value

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

### Author(s)

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

### See Also

`msr`, `[.msr`, `with.msr`

### Examples

      ## 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

[Package spatstat.core version 2.3-1 Index]