R: Determine Duplicated Points in a Spatial Point Pattern

duplicated.ppp {spatstat.geom} | R Documentation

## Determine Duplicated Points in a Spatial Point Pattern

### Description

Determines which points in a spatial point pattern are duplicates of previous points, and returns a logical vector.

### Usage

     ## S3 method for class 'ppp'
    duplicated(x, ..., rule=c("spatstat", "deldir", "unmark"))

     ## S3 method for class 'ppx'
    duplicated(x, ...)

     ## S3 method for class 'ppp'
    anyDuplicated(x, ...)

     ## S3 method for class 'ppx'
    anyDuplicated(x, ...)

### Arguments

`x` | A spatial point pattern (object of class `"ppp"` or `"ppx"`).
`...` | Ignored.
`rule` | Character string. The rule for determining duplicated points.

### Details

These are methods for the generic functions `duplicated` and `anyDuplicated` for point pattern datasets (of class `"ppp"`, see `ppp.object`, or class `"ppx"`).

`anyDuplicated(x)` is a faster version of `any(duplicated(x))`.

Two points in a point pattern are deemed to be identical if their x,y coordinates are the same, and their marks are also the same (if they carry marks). The Examples section illustrates how it is possible for a point pattern to contain a pair of identical points.

This function determines which points in `x` duplicate other points that appeared earlier in the sequence. It returns a logical vector with entries that are `TRUE` for duplicated points and `FALSE` for unique (non-duplicated) points.

If `rule="spatstat"` (the default), two points are deemed identical if their coordinates are equal according to `==`, and their marks are equal according to `==`. This is the most stringent possible test. If `rule="unmark"`, duplicated points are determined by testing equality of their coordinates only, using `==`. If `rule="deldir"`, duplicated points are determined by testing equality of their coordinates only, using the function `duplicatedxy` in the package deldir, which currently uses `duplicated.data.frame`. Setting `rule="deldir"` will ensure consistency with functions in the deldir package.

### Value

`duplicated(x)` returns a logical vector of length equal to the number of points in `x`.

`anyDuplicated(x)` is a number equal to 0 if there are no duplicated points, and otherwise is equal to the index of the first duplicated point.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`ppp.object`, `unique.ppp`, `multiplicity.ppp`

### Examples

       X <- ppp(c(1,1,0.5), c(2,2,1), window=square(3))
       duplicated(X)
       duplicated(X, rule="deldir")

[Package spatstat.geom version 2.2-0 Index]