spatstat (version 1.47-0)

affine.lpp: Apply Geometrical Transformations to Point Pattern on a Linear Network

Description

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

Usage

"affine"(X, mat=diag(c(1,1)), vec=c(0,0), ...)
  "shift"(X, vec=c(0,0), ..., origin=NULL)
  "rotate"(X, angle=pi/2, ..., centre=NULL)
  "scalardilate"(X, f, ...)
  "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<-

Value

Another point pattern on a linear network (object of class "lpp") representing the result of applying the geometrical transformation.

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.

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))