R: Apply Scalar Dilation

scalardilate {spatstat.geom} | R Documentation

## Apply Scalar Dilation

### Description

Applies scalar dilation to a plane geometrical object, such as a point pattern or a window, relative to a specified origin.

### Usage

      scalardilate(X, f, ...)

      ## S3 method for class 'im'
    scalardilate(X, f, ..., origin=NULL)

      ## S3 method for class 'owin'
    scalardilate(X, f, ..., origin=NULL)

      ## S3 method for class 'ppp'
    scalardilate(X, f, ..., origin=NULL)

      ## S3 method for class 'psp'
    scalardilate(X, f, ..., origin=NULL)

      ## Default S3 method:
    scalardilate(X, f, ...)

### Arguments

`X` | Any suitable dataset representing a two-dimensional object, such as a point pattern (object of class `"ppp"`), a window (object of class `"owin"`), a pixel image (class `"im"`) and so on.
`f` | Scalar dilation factor. A finite number greater than zero.
`...` | Ignored by the methods.
`origin` | Origin for the scalar dilation. Either a vector of 2 numbers, or one of the character strings `"centroid"`, `"midpoint"`, `"left"`, `"right"`, `"top"`, `"bottom"`, `"topleft"`, `"bottomleft"`, `"topright"` or `"bottomright"` (partially matched).

### Details

This command performs scalar dilation of the object `X` by the factor `f` relative to the origin specified by `origin`.

The function `scalardilate` is generic, with methods for windows (class `"owin"`), point patterns (class `"ppp"`), pixel images (class `"im"`), line segment patterns (class `"psp"`) and a default method.

If the argument `origin` is not given, then every spatial coordinate is multiplied by the factor `f`.

If `origin` is given, then scalar dilation is performed relative to the specified origin. Effectively, `X` is shifted so that `origin` is moved to `c(0,0)`, then scalar dilation is performed, then the result is shifted so that `c(0,0)` is moved to `origin`.

This command is a special case of an affine transformation: see `affine`.

### Value

Another object of the same type, representing the result of applying the scalar dilation.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`affine`, `shift`

### Examples

    plot(letterR)
    plot(scalardilate(letterR, 0.7, origin="left"), col="red", add=TRUE)

[Package spatstat.geom version 2.3-2 Index]