# Filling the area between plots

In *Chapter 7*, *Filling, Clipping, and Shading*, we dealt with filling areas enclosed by TikZ paths. Now we will do the same with plots.

You may remember the integral of a function over an interval: it represents the exact area between the curve and the *x*-axis over the interval. Let’s see how to visualize this.

The `fillbetween`

library provides ways to fill areas between plots and axes. You can load it this way:

\usepgfplotslibrary{fillbetween}

Let’s look at the axes and how we can access them as TikZ paths. `pgfplots`

has its own coordinate system that can be accessed using the `axis cs`

prefix. Using this, the plot coordinate system coordinates are translated to TikZ coordinates. So, in TikZ, we can work with a coordinate `(axis cs:1,2)`

which is the coordinate (1,2) in the plot coordinate system, no matter what its TikZ size is.

In the following example, we give a plot a path name. Then, we define a TikZ path with `axis cs`

coordinates...