R: Random Thinning of Clumps

rthinclumps {spatstat.core} | R Documentation

## Random Thinning of Clumps

### Description

Finds the topologically-connected clumps of a spatial region and randomly deletes some of the clumps.

### Usage

    rthinclumps(W, p, ...)

### Arguments

`W` | Window (object of class `"owin"` or pixel image (object of class `"im"`).
`p` | Probability of retaining each clump. A single number between 0 and 1.
`...` | Additional arguments passed to `connected.im` or `connected.owin` to determine the connected clumps.

### Details

The argument `W` specifies a region of space, typically consisting of several clumps that are not connected to each other. The algorithm randomly deletes or retains each clump. The fate of each clump is independent of other clumps.

If `W` is a spatial window (class `"owin"`) then it will be divided into clumps using `connected.owin`. Each clump will either be retained (with probability `p`) or deleted in its entirety (with probability `1-p`).

If `W` is a pixel image (class `"im"`) then its domain will be divided into clumps using `connected.im`. The default behaviour depends on the type of pixel values. If the pixel values are logical, then the spatial region will be taken to consist of all pixels whose value is `TRUE`. Otherwise, the spatial region is taken to consist of all pixels whose value is defined (i.e. not equal to `NA`). This behaviour can be changed using the argument `background` passed to `connected.im`.

The result is a window comprising all the clumps that were retained.

### Value

Window (object of class `"owin"`).

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au.

### See Also

`rthin` for thinning other kinds of objects.

### Examples

      A <- (distmap(cells) < 0.06)
      opa <- par(mfrow=c(1,2))
      plot(A)
      plot(rthinclumps(A, 0.5))
      par(opa)

[Package spatstat.core version 2.3-1 Index]