spatstat (version 1.3-2)

affine.ppp: Apply Affine Transformation To Point Pattern

Description

Applies any affine transformation of the plane (linear transformation plus vector shift) to a point pattern.

Usage

affine.ppp(X, mat=diag(c(1,1)), vec=c(0,0), ...)

Arguments

X
Point pattern (object of class "ppp").
mat
Matrix representing a linear transformation.
vec
Vector of length 2 representing a translation.
...
Ignored

Value

  • Another point pattern (of class "ppp") representing the result of applying the affine transformation.

Details

The point pattern, and its window, are subjected first to the linear transformation represented by mat (multiplying on the left by mat), and are then translated by the vector vec. The argument mat must be a nonsingular $2 \times 2$ matrix.

This is a method for the generic function affine.

See Also

affine, affine.owin, rotate, shift

Examples

library(spatstat)
  data(cells)
  # shear transformation
  X <- affine(cells, matrix(c(1,0,0.6,1),ncol=2))
  plot(X)
  # rescale y coordinates by factor 1.3
  plot(affine(cells, diag(c(1,1.3))))