affine
From spatstat v1.9-1
by Adrian Baddeley
Apply Affine Transformation
Applies any affine transformation of the plane (linear transformation plus vector shift) to a plane geometrical object, such as a point pattern or a window.
Usage
affine(X, mat=diag(c(1,1)), vec=c(0,0))
Arguments
- X
- Any suitable dataset representing a two-dimensional
object, such as a point pattern (object of class
"ppp"
), or a window (object of class"owin"
). - mat
- Matrix representing a linear transformation.
- vec
- Vector of length 2 representing a translation.
Details
This is generic. Methods are provided for
point patterns (affine.ppp
)
and windows (affine.owin
).
First the linear transformation represented by
mat
is applied (multiplying on the left by mat
),
and then the result is translated by the vector vec
.
The argument mat
must be a nonsingular $2 \times 2$
matrix.
Value
- Another object of the same type, representing the result of applying the affine transformation.
synopsis
affine(X, ...)
See Also
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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