spatstat.geom (version 3.3-2)

cut.im: Convert Pixel Image from Numeric to Factor

Description

Transform the values of a pixel image from numeric values into a factor.

Usage

# S3 method for im
cut(x, ...)

Value

A pixel image (object of class "im") with pixel values that are a factor. See im.object.

Arguments

x

A pixel image. An object of class "im".

...

Arguments passed to cut.default. They determine the breakpoints for the mapping from numerical values to factor values. See cut.default.

Author

Adrian Baddeley

and Rolf Turner

Details

This simple function applies the generic cut operation to the pixel values of the image x. The range of pixel values is divided into several intervals, and each interval is associated with a level of a factor. The result is another pixel image, with the same window and pixel grid as x, but with the numeric value of each pixel discretised by replacing it by the factor level.

This function is a convenient way to inspect an image and to obtain summary statistics. See the examples.

To select a subset of an image, use the subset operator [.im instead.

See Also

cut, im.object

Examples

  # artificial image data
  Z <- setcov(square(1))

  Y <- cut(Z, 3)
  Y <- cut(Z, breaks=seq(0,1,length=5))

  # cut at the quartiles
  # (divides the image into 4 equal areas)
  Y <- cut(Z, quantile(Z))