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.
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.
See Also
affine
,
affine.owin
,
affine.psp
,
affine.im
,
flipxy
,
rotate
,
shift
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))))
Community examples
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