spatstat (version 1.16-3)

shift.ppp: Apply Vector Translation To Point Pattern

Description

Applies a vector shift to a point pattern.

Usage

## S3 method for class 'ppp':
shift(X, vec=c(0,0), ..., origin=NULL)

Arguments

X

Point pattern (object of class "ppp").

vec

Vector of length 2 representing a translation.

...

Ignored

origin

Character string determining a location that will be shifted to the origin. Options are "centroid", "midpoint" and "bottomleft". Partially matched.

Value

• Another point pattern (of class "ppp") representing the result of applying the vector shift.

Details

The point pattern, and its window, are translated by the vector vec. This is a method for the generic function shift.

If origin is given, then it should be one of the character strings "centroid", "midpoint" or "bottomleft". The argument vec will be ignored; instead the shift will be performed so that the specified geometric location is shifted to the origin. If origin="centroid" then the centroid of the window will be shifted to the origin. If origin="midpoint" then the centre of the bounding rectangle of the window will be shifted to the origin. If origin="bottomleft" then the bottom left corner of the bounding rectangle of the window will be shifted to the origin.

See Also

shift, shift.owin, rotate, affine

Examples

data(cells)
  X <- shift(cells, c(2,3))
  plot(X)
  # no discernible difference except coordinates are different
  plot(cells, pch=16)
  plot(shift(cells, c(0.03,0.03)), add=TRUE)

  shift(cells, origin="mid")