nestsplit: Nested Split

In spatstat.geom: Geometrical Functionality of the 'spatstat' Family

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 \spatstatAuthors.

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)

spatstat.geom documentation built on Sept. 18, 2024, 9:08 a.m.