periodify {spatstat} | R Documentation |
Given a spatial pattern (point pattern, line segment pattern, window, etc) make shifted copies of the pattern and optionally combine them to make a periodic pattern.
periodify(X, ...) ## S3 method for class 'ppp' periodify(X, nx = 1, ny = 1, ..., combine=TRUE, warn=TRUE, check=TRUE, ix=(-nx):nx, iy=(-ny):ny, ixy=expand.grid(ix=ix,iy=iy)) ## S3 method for class 'psp' periodify(X, nx = 1, ny = 1, ..., combine=TRUE, warn=TRUE, check=TRUE, ix=(-nx):nx, iy=(-ny):ny, ixy=expand.grid(ix=ix,iy=iy)) ## S3 method for class 'owin' periodify(X, nx = 1, ny = 1, ..., combine=TRUE, warn=TRUE, ix=(-nx):nx, iy=(-ny):ny, ixy=expand.grid(ix=ix,iy=iy))
X |
An object representing a spatial pattern (point pattern, line segment pattern or window). |
nx,ny |
Integers.
Numbers of additional copies of |
... |
Ignored. |
combine |
Logical flag determining whether the copies should be superimposed
to make an object like |
warn |
Logical flag determining whether to issue warnings. |
check |
Logical flag determining whether to check the validity of the combined pattern. |
ix, iy |
Integer vectors determining the grid positions of the copies
of |
ixy |
Matrix or data frame with two columns, giving the
grid positions of the copies of |
Given a spatial pattern (point pattern, line segment pattern, etc)
this function makes a number of shifted copies of the pattern
and optionally combines them. The function periodify
is
generic, with methods for various kinds of spatial objects.
The default is to make a 3 by 3 array of copies of X
and
combine them into a single pattern of the same kind as X
.
This can be used (for example) to compute toroidal or periodic
edge corrections for various operations on X
.
If the arguments ix
, iy
or ixy
are specified,
then these determine the grid positions of the copies of X
that will be made. For example (ix,iy) = (1, 2)
means a
copy of X
shifted by the vector (ix * w, iy * h)
where
w,h
are the width and height of the bounding rectangle of X
.
If combine=TRUE
(the default) the copies of X
are
superimposed to create an object of the same kind as X
.
If combine=FALSE
the copies of X
are returned as a list.
If combine=TRUE
, an object of the same class as X
.
If combine=FALSE
, a list of objects of the same class as X
.
Adrian Baddeley Adrian.Baddeley@csiro.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
data(cells) plot(periodify(cells)) a <- lapply(periodify(cells$window, combine=FALSE), plot, add=TRUE,lty=2)