affine.ppp

From spatstat v1.34-1 by Adrian Baddeley

Apply Affine Transformation To Point Pattern

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

Keywords: spatial, math

Usage

## S3 method for class 'ppp':
affine(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.
...: Arguments passed to affine.owin affecting the handling of the observation window, if it is a binary pixel mask.

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.

Value

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

Examples

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))))

Documentation reproduced from package spatstat, version 1.34-1, License: GPL (>= 2)

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