Interactively Define a Polygon
Allows the user to create a polygon by point-and-click in the display.
clickpoly(add=FALSE, nv=NULL, np=1, ...)
- Logical value indicating whether to create a new plot
add=FALSE) or draw over the existing plot (
- Number of vertices of the polygon (if this is predetermined).
- Number of polygons to create.
- Arguments passed to
locatorto control the interactive plot, and to
polygonto plot the polygons.
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
representing the polygon.
This function uses the Rcommand
input the mouse clicks. It only works on screen devices such as
pch (plotting character),
cex (character expansion
col (colour). See
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.
- A window (object of class
"owin") representing the polygon.