Find an empty space on a plot

Try to find the largest empty rectangle on a plot.

Usage

emptyspace(x,y=NULL)

Arguments

x,y

x and y positions of the points on the plot.

Details

emptyspace searches the pairs of points on the plot to find the largest rectangular space within which none of the points lie. It does not guarantee that the space will be large enough to fit a legend or text.

Two alternatives are the largest.empty function in the Hmisc package and the maxEmptyRect function. While maxEmptyRect will generally outperform emptyspace, emptyspace will sometimes find a slightly smaller, but "squarer" rectangle.

Value

The x and y coordinates of the center of the rectangle found.

Author

Ray Brownrigg

Examples

 x<-rnorm(100)
 y<-rnorm(100)
 plot(x,y,main="Find the empty space",xlab="X",ylab="Y")
 es<-emptyspace(x,y)
 # use a transparent background so that any overplotted points are shown
 boxed.labels(es,labels="Here is the\nempty space",bg="transparent")