R: Nested Split

nestsplit {spatstat.geom} | R Documentation

## Nested Split

### Description

Applies two splitting operations to a point pattern, producing a list of lists of patterns.

### Usage

      nestsplit(X, ...)

### Arguments

`X` | Point pattern to be split. Object of class `"ppp"`.
`...` | Data determining the splitting factors or splitting regions. See Details.

### Details

This function splits the point pattern `X` into several sub-patterns using `split.ppp`, then splits each of the sub-patterns into sub-sub-patterns using `split.ppp` again. The result is a hyperframe containing the sub-sub-patterns and two factors indicating the grouping.

The arguments `...` determine the two splitting factors or splitting regions. Each argument may be:

- a factor (of length equal to the number of points in `X`)

- the name of a column of marks of `X` (provided this column contains factor values)

- a tessellation (class `"tess"`)

- a pixel image (class `"im"`) with factor values

- a window (class `"owin"`)

- identified by name (in the form `name=value`) as one of the formal arguments of `quadrats` or `tess`

The arguments will be processed to yield a list of two splitting factors/tessellations. The splits will be applied to `X` consecutively to produce the sub-sub-patterns.

### Value

A hyperframe with three columns. The first column contains the sub-sub-patterns. The second and third columns are factors which identify the grouping according to the two splitting factors.

### Author(s)

Original idea by Ute Hahn. Code by Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.

### See Also

`split.ppp`, `quantess`

### Examples

      # factor and tessellation
      Nft <- nestsplit(amacrine, marks(amacrine), quadrats(amacrine, 3, 1))
      Ntf <- nestsplit(amacrine, quadrats(amacrine, 3, 1), marks(amacrine))
      Ntf

      # two factors
      big <- with(marks(betacells), area > 300)
      Nff <- nestsplit(betacells, "type", factor(big))

      # two tessellations
      Tx <- quantess(redwood, "x", 4)
      Td <- dirichlet(runifrect(5, Window(redwood)))
      Ntt <- nestsplit(redwood, Td, Tx)
      Ntt2 <- nestsplit(redwood, Td, ny=3)

[Package spatstat.geom version 2.2-0 Index]