[R] to draw a smooth arc Dear R-list members, I would like to draw a smooth arc. I can draw an arc parametrically, but this produces an arc too coarse, even allowing for different increments in sequence t in the example below. Function "symbols" (graphics) does produce a smooth circle, but it cannot produce an arc. Please see the following example, drawing complete circles: plot(-5:5,-5:5,type='n') ## draws circle with function symbols (package graphics) ## - inner circle is very smooth: symbols(0,0,circles=2,add=TRUE) ## draws circle parametrically - outer circle is too coarse: pi <- 4*atan(1) t <- seq(0,2*pi,0.02) lines(4*cos(t),4*sin(t)) Package "plotrix" has a function "draw.arc", but arcs produced with this function are also either too coarse or too polygonal, depending on the number of polygons used to approximate the arc. Is there a way to harness the characteristics of function "symbols" (graphics) to draw a smooth arc, not just a complete circle? I am using R 2.5.0, running under Windows XP. Thank you very much. Paulo Barata ----------------------------------------------------------------- Paulo Barata Fundacao Oswaldo Cruz (Oswaldo Cruz Foundation) Rua Leopoldo Bulhoes 1480 - 8A 21041-210  Rio de Janeiro - RJ Brazil E-mail: pbarata@infolink.com.br ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.