plot (ggplot ?) smooth + color area between 2 curves

Question

I have a question for you please :

My data :

    Nb_obs <- as.vector(c( 2,  0,  6,  2,  7,  1,  8,  0,  2,  1,  1,  3, 11,  5,  9,  6,  4,  0,           


        

Answer 1

This produces the plot with shaded areas using base R graphics.
The trick is to pair the x values with the y values.

plot(data$Nb_obst, data$Nb_obs, type = "n",  xlab = "Number obst", ylab = "number obs", ylim = c(0, 25))

lines(data$Nb_obst, data$inf20, col = "dark red")
lines(data$Nb_obst, data$sup20, col = "dark red")

lines(data$Nb_obst, data$inf40, col = "red")
lines(data$Nb_obst, data$sup40, col = "red")

lines(data$Nb_obst, data$inf60, col = "dark orange")
lines(data$Nb_obst, data$sup60, col = "dark orange")

lines(data$Nb_obst, data$inf90, col = "yellow")
lines(data$Nb_obst, data$sup90, col = "yellow")

with(data, polygon(c(Nb_obst, rev(Nb_obst)), c(inf90, rev(sup90)), col = "yellow"))
with(data, polygon(c(Nb_obst, rev(Nb_obst)), c(inf60, rev(sup60)), col = "dark orange"))
with(data, polygon(c(Nb_obst, rev(Nb_obst)), c(inf40, rev(sup40)), col = "red"))
with(data, polygon(c(Nb_obst, rev(Nb_obst)), c(inf20, rev(sup20)), col = "dark red"))

The code for a ggplot graph is a bit longer. There is a function geom_ribbon perfect for this.

g <- ggplot(data)
g + geom_ribbon(aes(x = Nb_obst, ymin = sup60, ymax = sup90), fill = "yellow") + 
    geom_ribbon(aes(x = Nb_obst, ymin = sup40, ymax = sup60), fill = "dark orange") + 
    geom_ribbon(aes(x = Nb_obst, ymin = sup20, ymax = sup40), fill = "red") + 
    geom_ribbon(aes(x = Nb_obst, ymin = inf20, ymax = sup20), fill = "dark red") + 
    geom_ribbon(aes(x = Nb_obst, ymin = inf40, ymax = inf20), fill = "red") + 
    geom_ribbon(aes(x = Nb_obst, ymin = inf60, ymax = inf40), fill = "dark orange") + 
    geom_ribbon(aes(x = Nb_obst, ymin = inf90, ymax = inf60), fill = "yellow")

Data.

I will redo your dataset, simplifying its creation. You don't need as.vector and if you are creating a data.frame there is no need for the data.frame method of cbind, data.frame(.) is enough.

Nb_obs <- c( 2,  0,  6,  2,  7,  1,  8,  0,  2,  1,  1,  3, 11,  5,  9,  6,  4,  0,  7,  9)
Nb_obst <- c(31, 35, 35, 35, 39, 39, 39, 39, 39, 41, 41, 42, 43, 43, 45, 45, 47, 48, 51, 51)
inf20 <- c(2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 3, 4, 4, 3, 5, 4)
sup20 <- c(3, 4, 4, 4, 5, 4, 4, 5, 4, 4, 5, 5, 5, 6, 5, 6, 6, 5, 7, 6)
inf40 <- c(1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 3, 3, 3, 4, 3)
sup40 <- c(4, 5, 5, 5, 6, 5, 5, 6, 5, 5, 6, 6, 6, 7, 6, 7, 7, 7, 9, 7)
inf60 <- c(1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 2)
sup60 <- c(5, 6, 6,  6,  8,  7,  7,  7,  7,  7,  7,  7,  8,  9,  8,  9,  9,  9, 11,  9)
inf90 <- c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1)
sup90 <- c(10, 11, 11, 11, 15, 13, 13, 14, 12, 13, 13, 13, 14, 17, 15, 17, 17, 16, 21, 18)

data <- data.frame(Nb_obs, Nb_obst, inf20, sup20, inf40, sup40, inf60 , sup60, inf90 , sup90)