# affine

From spatstat v1.4-3
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.

- Keywords
- spatial

##### 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

```
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))))
```

*Documentation reproduced from package spatstat, version 1.4-3, License: GPL version 2 or newer*

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