[R] Is something wrong wiht draw.circle()?

[Jim Lemon]

On 09/08/2012 02:04 AM, Chris82 wrote:
> Hey R users,
>
> I am a little bit confused.
>
>
> require(plotrix)
>
> plot(0,xlim=c(-10,10),ylim=c(-10,10),type="n",xlab="",ylab="")
> draw.circle(0,0,5)
>
> lines(c(0,0),c(0,5))
> lines(c(0,5),c(0,0))
>
>
> This is not really a circle with a radius of 5.
>
Hi Chris82,
If you measure it, you will find that it is indeed a circle, and that 
your two "radii" are not of equal length (see Euclid, -300). The 
draw.circle function attempts to correct for the aspect ratio of the 
plot, but not for the aspect ratio of the device, so there may be slight 
variations on different devices.

Jim