R: Pairwise distances between two different point patterns

crossdist.ppp {spatstat} | R Documentation

## Pairwise distances between two different point patterns

### Description

Computes the distances between pairs of points taken from two different point patterns.

### Usage

      ## S3 method for class 'ppp'
    crossdist(X, Y, ..., periodic=FALSE, method="C", squared=FALSE)

### Arguments

`X,Y` | Point patterns (objects of class `"ppp"`).
`...` | Ignored.
`periodic` | Logical. Specifies whether to apply a periodic edge correction.
`method` | String specifying which method of calculation to use. Values are `"C"` and `"interpreted"`.
`squared` | Logical. If `squared=TRUE`, the squared distances are returned instead (this computation is faster).

### Details

Given two point patterns, this function computes the Euclidean distance from each point in the first pattern to each point in the second pattern, and returns a matrix containing these distances.

This is a method for the generic function `crossdist` for point patterns (objects of class `"ppp"`).

This function expects two point patterns `X` and `Y`, and returns the matrix whose `[i,j]` entry is the distance from `X[i]` to `Y[j]`.

Alternatively if `periodic=TRUE`, then provided the windows containing `X` and `Y` are identical and are rectangular, then the distances will be computed in the ‘periodic’ sense (also known as ‘torus’ distance): opposite edges of the rectangle are regarded as equivalent. This is meaningless if the window is not a rectangle.

The argument `method` is not normally used. It is retained only for checking the validity of the software. If `method = "interpreted"` then the distances are computed using interpreted R code only. If `method="C"` (the default) then C code is used. The C code is faster by a factor of 4.

### Value

A matrix whose `[i,j]` entry is the distance from the `i`-th point in `X` to the `j`-th point in `Y`.

### Author(s)

Pavel Grabarnik pavel.grabar@issp.serpukhov.su and Adrian Baddeley Adrian.Baddeley@curtin.edu.au

### See Also

`crossdist`, `crossdist.default`, `crossdist.psp`, `pairdist`, `nndist`, `Gest`

### Examples

       data(cells)
       d <- crossdist(cells, runifpoint(6))
       d <- crossdist(cells, runifpoint(6), periodic=TRUE)

[Package spatstat version 1.63-3 Index]