getellipse {shape} | R Documentation |
calculates x-y values for (part of) an ellipse; the ellipse can be rotated
getellipse(rx=1, ry=rx, mid=c(0,0), dr=0.01, angle=0, from=-pi, to=pi)
rx |
long radius of ellipse |
ry |
short radius of ellipse |
mid |
midpoint of ellipse |
dr |
size of segments, in radians, to specify ellipse (decrease for smoother) |
angle |
rotation angle, degrees |
from |
starting angle for ellipse segment, radians |
to |
final angle for ellipse segment, radians |
rx and ry are the horizontal and vertical radiusses of the ellipses.
Here "horizontal" and "vertical" denote the position BEFORE rotation
a 2-column matrix with x-y values of the ellipse
Karline Soetaert <k.soetaert@nioo.knaw.nl>
plot(getellipse(1,from=0,to=pi/2),type="l",col="red",lwd=2,main="getellipse") lines(getellipse(0.5,0.25,mid=c(0.5,0.5)),type="l",col="blue",lwd=2) lines(getellipse(0.5,0.25,mid=c(0.5,0.5),angle=45),type="l", col="green",lwd=2) emptyplot(main="getellipse") col <-femmecol(90) for (i in seq(0,180,by=2)) lines(getellipse(0.5,0.25,mid=c(0.5,0.5),angle=i), type="l",col=col[(i/2)+1],lwd=2)