Allows the user to create a polygon by point-and-click in the display.
clickpoly(add=FALSE, nv=NULL, np=1, ..., snap.step=NULL, snap.origin=c(0,0))A window (object of class "owin") representing the polygon.
Logical value indicating whether to create a new plot
(add=FALSE) or draw over the existing plot (add=TRUE).
Number of vertices of the polygon (if this is predetermined).
Number of polygons to create.
Arguments passed to locator to control the
interactive plot, and to polygon to plot the
polygons.
Optional. Spatial coordinates will be rounded to the nearest
multiple of snap.step. A positive number specifying the step
length, or a vector of 2 positive numbers specifying step lengths
for the \(x\) and \(y\) coordinates.
Optional. Numeric vector of length 2. Coordinates of the origin that will be used when rounding coordinates.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner rolfturner@posteo.net.
This function allows the user to create a polygonal window by interactively clicking on the screen display.
The user is prompted to point the mouse at any desired locations
for the polygon vertices,
and click the left mouse button to add each point.
Interactive input stops after nv clicks (if nv was given)
or when the middle mouse button is pressed.
The return value is a window (object of class "owin")
representing the polygon.
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.
Multiple polygons can also be drawn, by specifying
np > 1. The polygons must be disjoint. The result is
a single window object consisting of all the polygons.
If snap.step is given, a grid of lines will be drawn with
the specified spacing, and the clicked locations will be
snapped (rounded) to the nearest grid point.
identify.ppp,
clickbox,
clickppp,
clickdist,
locator