R: Pairwise distances between two different three-dimensional...

crossdist.pp3 {spatstat} | R Documentation

## Pairwise distances between two different three-dimensional point patterns

### Description

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

### Usage

      ## S3 method for class 'pp3'
    crossdist(X, Y, ..., periodic=FALSE, squared=FALSE)

### Arguments

`X,Y` | Point patterns in three dimensions (objects of class `"pp3"`).
`...` | Ignored.
`periodic` | Logical. Specifies whether to apply a periodic edge correction.
`squared` | Logical. If `squared=TRUE`, the squared distances are returned instead (this computation is faster).

### Details

Given two point patterns in three-dimensional space, 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 three-dimensional point patterns (objects of class `"pp3"`).

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.

### 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)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

based on code for two dimensions by Pavel Grabarnik.

### See Also

`crossdist`, `pairdist`, `nndist`, `G3est`

### Examples

       X <- runifpoint3(20)
       Y <- runifpoint3(30)
       d <- crossdist(X, Y)
       d <- crossdist(X, Y, periodic=TRUE)

[Package spatstat version 1.54-0 Index]