Closing the lines in a ggplot2 radar / spider chart

Question

I need a flexible way to make radar / spider charts in ggplot2. From solutions I\'ve found on github and the ggplot2 group, I\'ve come this far:

library(ggpl         


        

Answer 1

Using the new ggproto mechanism available in ggplot2 2.0.0, coord_radar can be defined as:

coord_radar <- function (theta = "x", start = 0, direction = 1) 
{
 theta <- match.arg(theta, c("x", "y"))
 r <- if (theta == "x") 
        "y"
      else "x"
 ggproto("CoordRadar", CoordPolar, theta = theta, r = r, start = start, 
      direction = sign(direction),
      is_linear = function(coord) TRUE)
}

Not sure if the syntax is perfect but it is working...