# connected.ppp: Connected Components of a Point Pattern In spatstat.geom: Geometrical Functionality of the 'spatstat' Family

## Description

Finds the topologically-connected components of a point pattern, when all pairs of points closer than a threshold distance are joined.

## Usage

 ```1 2 3 4 5``` ```## S3 method for class 'ppp' connected(X, R, ...) ## S3 method for class 'pp3' connected(X, R, ...) ```

## Arguments

 `X` A point pattern (object of class `"ppp"` or `"pp3"`). `R` Threshold distance. Pairs of points closer than `R` units apart will be joined together. `...` Other arguments, not recognised by these methods.

## Details

This function can be used to identify clumps of points in a point pattern.

The function `connected` is generic. This file documents the methods for point patterns in dimension two or three (objects of class `"ppp"` or `"pp3"`).

The point pattern `X` is first converted into an abstract graph by joining every pair of points that lie closer than `R` units apart. Then the connected components of this graph are identified.

Two points in `X` belong to the same connected component if they can be reached by a series of steps between points of `X`, each step being shorter than `R` units in length.

The result is a vector of labels for the points of `X` where all the points in a connected component have the same label.

## Value

A point pattern, equivalent to `X` except that the points have factor-valued marks, with levels corresponding to the connected components.

\spatstatAuthors

.

## See Also

`connected.im`, `im.object`, `tess`

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10``` ``` Y <- connected(redwoodfull, 0.1) if(interactive()) { plot(Y, cols=1:length(levels(marks(Y))), main="connected(redwoodfull, 0.1)") } X <- osteo\$pts[] Z <- connected(X, 32) if(interactive()) { plot(Z, col=marks(Z), main="") } ```

spatstat.geom documentation built on March 22, 2021, 9:09 a.m.