clickpoly(add=FALSE, nv=NULL, np=1, ...)add=FALSE) or draw over the existing plot (add=TRUE).locator to control the
interactive plot."owin") representing the polygon. 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 Rcommand locator to
input the mouse clicks. It only works on screen devices such as
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.
identify.ppp,
clickppp,
locator