R: Extract or Replace Subset of Tessellation

Extract.tess {spatstat.geom} | R Documentation

## Extract or Replace Subset of Tessellation

### Description

Extract, change or delete a subset of the tiles of a tessellation, to make a new tessellation.

### Usage

      ## S3 method for class 'tess'
    x[i, ...]
      ## S3 replacement method for class 'tess'
    x[i, ...] <- value

### Arguments

`x` | A tessellation (object of class `"tess"`).
`i` | Subset index for the tiles of the tessellation. Alternatively a window (object of class `"owin"`).
`...` | 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 `"owin"`) or `NULL`.

### Details

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.

For `[.tess` only, the subset index can also be a window (object of class `"owin"`). The tessellation `x` is then intersected with the window.

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.

### Value

A tessellation (object of class `"tess"`).

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk

### See Also

`tess`, `tiles`, `intersect.tess`.

### Examples

       A <- tess(xgrid=0:4, ygrid=0:3)
       B <- A[c(1, 3, 7)]
       E <- A[-1]
       A[c(2, 5, 11)] <- NULL

[Package spatstat.geom version 2.3-2 Index]