df <- expand.grid(x = 1:10, y=1:10) df$angle <- runif(100, 0, 2*pi) df$speed <- runif(100, 0, sqrt(0.1 * df$x)) ggplot(df, aes(x, y)) + geom_point() + geom_spoke(aes(angle = angle), radius = 0.5) ggplot(df, aes(x, y)) + geom_point() + geom_spoke(aes(angle = angle, radius = speed)) Run the code above in your browser using DataLab