spatstat.data (version 3.1-9)

hamster: Aherne's hamster tumour data

Description

Point pattern of cell nuclei in hamster kidney, each nucleus classified as either `dividing' or `pyknotic'. A multitype point pattern.

Usage

data(hamster)

Format

An object of class "ppp" representing the point pattern of cell locations. Entries include

x	Cartesian \(x\)-coordinate of cell
y	Cartesian \(y\)-coordinate of cell
marks	factor with levels "dividing" and "pyknotic".

See ppp.object for details of the format.

Notes

These data were presented and analysed by Diggle (1983, section 7.3).

The data give the positions of the centres of the nuclei of certain cells in a histological section of tissue from a laboratory-induced metastasising lymphoma in the kidney of a hamster.

The nuclei are classified as either "pyknotic" (corresponding to dying cells) or "dividing" (corresponding to cells arrested in metaphase, i.e. in the act of dividing). The background void is occupied by unrecorded, interphase cells in relatively large numbers.

The sampling window is a square, originally about 0.25 mm square in real units, which has been rescaled to the unit square.

References

Diggle, P.J. (1983) Statistical analysis of spatial point patterns. Academic Press.

Examples

  if(require(spatstat.geom)) {
  hamster
  ## rescale to microns
  (Ham <- rescale(hamster))
  }