Extract.tess {spatstat} | R Documentation |
Extract, change or delete a subset of the tiles of a tessellation, to make a new tessellation.
## S3 method for class 'tess' x[...] ## S3 replacement method for class 'tess' x[...] <- value
x |
A tessellation (object of class |
... |
One argument that specifies the subset to be extracted or changed. Any valid format for the subset index in a list. |
value |
Replacement value for the selected tiles of the tessellation.
A list of windows (objects of class |
A tessellation (object of class "tess"
, see tess
)
is effectively a list of tiles (spatial regions) that cover a spatial region.
The subset operator [.tess
extracts some
of these tiles and forms a new tessellation, which of course covers a
smaller region than the original.
The replacement operator changes the selected tiles. The replacement
value
may be either NULL
(which causes the selected tiles
to be removed from x
) or a list of the same length as
the selected subset. The entries of value
may be windows
(objects of class "owin"
) or NULL
to indicate that the
corresponding tile should be deleted.
Generally it does not make sense to replace a tile in a tessellation with a completely different tile, because the tiles are expected to fit together. However this facility is sometimes useful for making small adjustments to polygonal tiles.
A tessellation (object of class "tess"
).
Adrian Baddeley Adrian.Baddeley@csiro.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
tess
,
A <- tess(xgrid=0:4, ygrid=0:3) B <- A[c(1, 3, 7)] E <- A[-1] A[c(2, 5, 11)] <- NULL