# affine.lpp

From spatstat v1.42-2
by Adrian Baddeley

##### Apply Geometrical Transformations to Point Pattern on a Linear Network

Apply geometrical transformations to a point pattern on a linear network.

##### Usage

```
## S3 method for class 'lpp':
affine(X, mat=diag(c(1,1)), vec=c(0,0), ...)
``` ## S3 method for class 'lpp':
shift(X, vec=c(0,0), ..., origin=NULL)

## S3 method for class 'lpp':
rotate(X, angle=pi/2, \dots, centre=NULL)

## S3 method for class 'lpp':
scalardilate(X, f, \dots)

## S3 method for class 'lpp':
rescale(X, s, unitname)

##### Arguments

- X
- Point pattern on a linear network (object of class
`"lpp"`

). - mat
- Matrix representing a linear transformation.
- vec
- Vector of length 2 representing a translation.
- angle
- Rotation angle in radians.
- f
- Scalar dilation factor.
- s
- Unit conversion factor: the new units are
`s`

times the old units. - ...
- Arguments passed to other methods.
- origin
- Character string determining a location
that will be shifted to the origin. Options are
`"centroid"`

,`"midpoint"`

and`"bottomleft"`

. Partially matched. - centre
- Centre of rotation.
Either a vector of length 2, or a character string
(partially matched to
`"centroid"`

,`"midpoint"`

or`"bottomleft"`

). The default is the coordinate origin`c(0,0)`

. - unitname
- Optional. New name for the unit of length.
A value acceptable to the function
`unitname<-`

##### Details

These functions are methods for the generic functions
`affine`

,
`shift`

,
`rotate`

,
`rescale`

and
`scalardilate`

applicable to objects of class `"lpp"`

.

All of these functions
perform geometrical transformations on the object `X`

,
except for `rescale`

, which simply rescales the units of length.

##### Value

- Another point pattern on a linear network (object of class
`"lpp"`

) representing the result of applying the geometrical transformation.

##### See Also

`lpp`

.
Generic functions
`affine`

,
`shift`

,
`rotate`

,
`scalardilate`

,
`rescale`

.

##### Examples

```
X <- rpoislpp(2, simplenet)
U <- rotate(X, pi)
stretch <- diag(c(2,3))
Y <- affine(X, mat=stretch)
shear <- matrix(c(1,0,0.6,1),ncol=2, nrow=2)
Z <- affine(X, mat=shear, vec=c(0, 1))
```

*Documentation reproduced from package spatstat, version 1.42-2, License: GPL (>= 2)*

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