spatstat (version 1.33-0)

duplicated.ppp: 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, \dots, rule=c("spatstat", "deldir"))

Arguments

x

A spatial point pattern (object of class "ppp").

...

Ignored.

rule

Character string. The rule for determining duplicated points.

Value

• A logical vector of length equal to the number of points in x.

Details

This is a method for the generic function duplicated for point pattern datasets (of class "ppp", see ppp.object).

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), duplicated points are determined by testing equality of their coordinates and marks using ==. This is the most stringent possible test. If rule="deldir", duplicated points are determined 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.

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")