R: Interactively join vertices on a plot

clickjoin {spatstat} | R Documentation

## Interactively join vertices on a plot

### Description

Given a point pattern representing a set of vertices, this command gives a point-and-click interface allowing the user to join pairs of selected vertices by edges.

### Usage

      clickjoin(X, ..., add = TRUE, m = NULL, join = TRUE)

### Arguments

`X` | Point pattern of vertices. An object of class `"ppp"`.
`...` | Arguments passed to `segments` to control the plotting of the new edges.
`add` | Logical. Whether the point pattern `X` should be added to the existing plot (`add=TRUE`) or a new plot should be created (`add=FALSE`).
`m` | Optional. Logical matrix specifying an initial set of edges. There is an edge between vertices `i` and `j` if `m[i,j] = TRUE`.
`join` | Optional. If `TRUE`, then each user click will join a pair of vertices. If `FALSE`, then each user click will delete an existing edge. This is only relevant if `m` is supplied.

### Details

This function makes it easier for the user to create a linear network or a planar graph, given a set of vertices.

The function first displays the point pattern `X`, then repeatedly prompts the user to click on a pair of points in `X`. Each selected pair of points will be joined by an edge. The function returns a logical matrix which has entries equal to `TRUE` for each pair of vertices joined by an edge.

The selection of points is performed using `identify.ppp` which typically expects the user to click the left mouse button. This point-and-click interaction continues until the user terminates it, by pressing the middle mouse button, or pressing the right mouse button and selecting `stop`.

The return value can be used in `linnet` to create a linear network.

### Value

Logical matrix `m` with value `m[i,j] = TRUE` for every pair of vertices `X[i]` and `X[j]` that should be joined by an edge.

### Author(s)

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

### See Also

`linnet`, `clickppp`

[Package spatstat version 1.63-3 Index]