# DrawEllipse

##### Draw an Ellipse

Draw one or several ellipses on an existing plot.

- Keywords
- aplot

##### Usage

```
DrawEllipse(x = 0, y = x, radius.x = 1, radius.y = 0.5, rot = 0,
nv = 100, border = par("fg"), col = par("bg"),
lty = par("lty"), lwd = par("lwd"), plot = TRUE)
```

##### Arguments

- x, y
the x and y co-ordinates for the centre(s) of the ellipse(s).

- radius.x
a scalar or a vector giving the semi-major axis of the ellipse.

- radius.y
a scalar or a vector giving the semi-minor axis of the ellipse.

- rot
angle of rotation in radians.

- nv
number of vertices to draw the ellipses.

- border
color for borders. The default is

`par("fg")`

. Use`border = NA`

to omit borders.- col
color(s) to fill or shade the annulus sector with. The default

`NA`

(or also`NULL`

) means do not fill (say draw transparent).- lty
line type for borders and shading; defaults to

`"solid"`

.- lwd
line width for borders and shading.

- plot
logical. If

`TRUE`

the structure will be plotted. If`FALSE`

only the points are calculated and returned. Use this if you want to combine several geometric structures to a single polygon.

##### Details

Use `DegToRad`

if you want to define rotation angle in degrees.

##### Value

The function invisibly returns a list of the calculated coordinates for all shapes.

##### See Also

##### Examples

```
# NOT RUN {
par(mfrow=c(1,2))
Canvas()
DrawEllipse(rot = c(1:3) * pi/3, col=SetAlpha(c("blue","red","green"), 0.5) )
plot(cars)
m <- var(cars)
eig <- eigen(m)
eig.val <- sqrt(eig$values)
eig.vec <- eig$vectors
DrawEllipse(x=mean(cars$speed), y=mean(cars$dist), radius.x=eig.val[1] , radius.y=eig.val[2]
, rot=acos(eig.vec[1,1]), border="blue", lwd=3)
# }
```

*Documentation reproduced from package DescTools, version 0.99.36, License: GPL (>= 2)*