spatstat.linnet: connected.lpp – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

connected.lpp

Connected Components of a Point Pattern on a Linear Network

Description

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

Usage

## S3 method for class 'lpp'
connected(X, R=Inf, ..., dismantle=TRUE)

Arguments

`X`	A linear network (object of class `"lpp"`).
`R`	Threshold distance. Pairs of points will be joined together if they are closer than `R` units apart, measured by the shortest path in the network. The default `R=Inf` implies that points will be joined together if they are mutually connected by any path in the network.
`dismantle`	Logical. If `TRUE` (the default), the network itself will be divided into its path-connected components using `connected.linnet`.
`...`	Ignored.

Details

The function connected is generic. This is the method for point patterns on a linear network (objects of class "lpp"). It divides the point pattern X into one or more groups of points.

If R=Inf (the default), then X is divided into groups such that any pair of points in the same group can be joined by a path in the network.

If R is a finite number, then two points of X are declared to be R-close if they lie closer than R units apart, measured by the length of the shortest path in the network. Two points are R-connected if they can be reached by a series of steps between R-close pairs of points of X. Then X is divided into groups such that any pair of points in the same group is R-connected.

If dismantle=TRUE (the default) the algorithm first checks whether the network is connected (i.e. whether any pair of vertices can be joined by a path in the network), and if not, the network is decomposed into its connected components.

Value

A point pattern (of class "lpp") with marks indicating the grouping, or a list of such point patterns.

Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au.

Examples

## behaviour like connected.ppp
   U <- runiflpp(20, simplenet)
   plot(connected(U, 0.15, dismantle=FALSE))

   ## behaviour like connected.owin
   ## remove some edges from a network to make it disconnected
   plot(simplenet, col="grey", main="", lty=2)
   A <- thinNetwork(simplenet, retainedges=-c(3,5))
   plot(A, add=TRUE, lwd=2)
   X <- runiflpp(10, A)
   ## find the connected components
   cX <- connected(X)
   plot(cX[[1]], add=TRUE, col="blue", lwd=2)

spatstat.linnet

Linear Networks Functionality of the 'spatstat' Family

v2.1-1

GPL (>= 2)

Authors

Adrian Baddeley [aut, cre], Rolf Turner [aut], Ege Rubak [aut], Ottmar Cronie [ctb], Tilman Davies [ctb], Greg McSwiggan [ctb], Suman Rakshit [ctb]

Initial release

2021-03-28