Draw circle with a given radius
Draws a filled circle with a certain radius (in existing plot's units) using polygon
and sin
circle(x, y, r, locnum = 100, ...)
x
: x coordinate of points, numeric value of length 1y
: y coordinater
: radius of the circle in units of current plot. Can have two values for an ellipse.locnum
: number of calculated points on the circle (more means smoother but slower). DEFAULT: 100...
: further arguments passed to polygon
, like col, border, lwddata.frame of coordinates, invisible
If circles look like ellipsis, use plot(... asp=1)
plot(1:20, type="n", asp=1) circle(5,5, r=3) # 1:1 aspect shows they're really circles and not ellipses. circle(15,10, r=4, locnum=12, col=2, border=4, lwd=3) # can not be vectorized: x <- sample(1:20, 15) ; y <- sample(1:20, 15) ; r <- runif(20)*3 circle(x,y,r, col=rgb(1,0.5,0,alpha=0.4), border=NA) for(i in 1:15) circle(x[i],y[i],r[i], col=rgb(1,0.5,0,alpha=0.4), border=NA)
symbols
, polygon
Berry Boessenkool, berry-b@gmx.de , 2012