This post describes how to build an area chart using base R and the `polygon()`

function. See the area chart section for a `ggplot2`

implementation.

`plot()`

and `polygon()`

Base R also allows to build area charts thanks to the `polygon()`

function. This function requires 2 inputs: `x`

and `y`

.

Note that extreme values of both are added at the beginning and at the end of each vectors to make sure the polygon is closed.

```
# Create data
data.frame(x=seq(1,10), y=sample(seq(1,15),10))
data <-
# Draw line on top
plot(data, col=rgb(0.2,0.1,0.5,0.9), type="o", lwd=3, xlab="", ylab="size",
pch=20)
# Fill the area
polygon(c(min(data$x), data$x, max(data$x)),
c(min(data$y), data$y, min(data$y)),
col=rgb(0.2,0.1,0.5,0.2), border=FALSE)
```