affine.ppp {spatstat.geom} | R Documentation |
Apply Affine Transformation To Point Pattern
Description
Applies any affine transformation of the plane (linear transformation plus vector shift) to a point pattern.
Usage
## S3 method for class 'ppp'
affine(X, mat=diag(c(1,1)), vec=c(0,0), ...)
Arguments
X |
Point pattern (object of class |
mat |
Matrix representing a linear transformation. |
vec |
Vector of length 2 representing a translation. |
... |
Arguments passed to |
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.
Author(s)
Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner rolfturner@posteo.net
See Also
affine
,
affine.owin
,
affine.psp
,
affine.im
,
flipxy
,
rotate
,
shift
Examples
# shear transformation
X <- affine(cells, matrix(c(1,0,0.6,1),ncol=2))
if(interactive()) {
plot(X)
# rescale y coordinates by factor 1.3
plot(affine(cells, diag(c(1,1.3))))
}