# affine.ppp

From spatstat v1.17-0
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.
- ...
- Ignored

##### 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

##### 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 1.17-0, License: GPL (>= 2)*

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