R: Fill the complement of a polygon

antipolygon {GEOmap} | R Documentation

## Fill the complement of a polygon

### Description

Fill a plot with a color outside the confines of a polygon.

### Usage

    antipolygon(x, y, col = 0, corner=1, pct=.4)

### Arguments

`x` | x coordinates of polygon
`y` | y coordinates of polygon
`col` | Fill color
`corner` | Corner on the plot to connect to at the end: 1 = LowerLeft(default) ; 2:UpperLeft 3 = UpperRight; 4=LowerRight
`pct` | Decimal percent of usr coordinates to expand beyond the polygon

### Details

antipolygon uses par("usr") to determine the external bounds of plotting region. Corners are labels from bottom left counter-clockwise, 1-4.

### Value

Used for graphical side effect

### Note

If the figure is resized after plotting, filling may not appear correct.

### Author(s)

Jonathan M. Lees <jonathan.lees@unc.edu>

### See Also

polygon, par

### Examples

    x = runif(100)
    y = runif(100)

    #########  some data points to plot:

    plot(x,y)
    ###########   create polygon:
    pp =list(x=c(0.231,0.316,0.169,0.343,0.311,0.484,0.757,
             0.555,0.800,0.563,0.427,0.412,0.203),
         y=c(0.774,0.622,0.401,0.386,0.138,0.312,0.200,0.459,
            0.658,0.624,0.954,0.686,0.813))

    polygon(pp)

    antipolygon(x=pp$x, y=pp$y,col='blue')
    ####  where as this does not look so good
    plot(x,y)
    antipolygon(x=pp$x, y=pp$y,col='blue', corner=2)

[Package GEOmap version 2.4-0 Index]