R: Apply Geometrical Transformations to Point Pattern on a...

affine.lpp {spatstat.linnet} | R Documentation

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

### Description

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, ..., centre=NULL)

      ## S3 method for class 'lpp'
    scalardilate(X, f, ...)

      ## 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.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner r.turner@auckland.ac.nz

### See Also

`lpp`.

Generic functions `affine`, `shift`, `rotate`, `scalardilate`, `rescale`.

### Examples

      X <- rpoislpp(2, simplenet)
      U <- rotate(X, pi)
      V <- shift(X, c(0.1, 0.2))
      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))

[Package spatstat.linnet version 2.3-1 Index]