spatstat.geom: clickppp – R documentation

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spatstat.geom

clickppp

Interactively Add Points

Description

Allows the user to create a point pattern by point-and-click in the display.

Usage

clickppp(n=NULL, win=square(1), types=NULL, ..., add=FALSE,
    main=NULL, hook=NULL)

Arguments

`n`	Number of points to be added (if this is predetermined).
`win`	Window in which to create the point pattern. An object of class `"owin"`.
`types`	Vector of types, when creating a multitype point pattern.
`...`	Optional extra arguments to be passed to `locator` to control the display.
`add`	Logical value indicating whether to create a new plot (`add=FALSE`) or draw over the existing plot (`add=TRUE`).
`main`	Main heading for plot.
`hook`	For internal use only. Do not use this argument.

Details

This function allows the user to create a point pattern by interactively clicking on the screen display.

First the window win is plotted on the current screen device. Then the user is prompted to point the mouse at any desired locations and click the left mouse button to add each point. Interactive input stops after n clicks (if n was given) or when the middle mouse button is pressed.

The return value is a point pattern containing the locations of all the clicked points inside the original window win, provided that all of the clicked locations were inside this window. Otherwise, the window is expanded to a box large enough to contain all the points (as well as containing the original window).

If the argument types is given, then a multitype point pattern will be created. The user is prompted to input the locations of points of type type[i], for each successive index i. (If the argument n was given, there will be n points of each type.) The return value is a multitype point pattern.

This function uses the R command locator to input the mouse clicks. It only works on screen devices such as ‘X11’, ‘windows’ and ‘quartz’. Arguments that can be passed to locator through ... include pch (plotting character), cex (character expansion factor) and col (colour). See locator and par.

Value

A point pattern (object of class "ppp").

Author(s)

Original by Dominic Schuhmacher. Adapted by Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner r.turner@auckland.ac.nz.