How to build an area chart

Like line charts, area charts are a good way to show trends over time.

Here we have some US census population data for several states.

Let’s plot this data in an area chart.

To start off, I’ll just select data for Arizona, and create a new area chart.

Now, if I try Recommended Charts, we’ll see an area option that looks good.

But notice it’s actually a stacked area chart, not a basic area chart.

The resulting chart clearly shows Arizona’s population has grown rapidly.

Next I’ll add data for Florida.

Now you’re able to see why plot order matters.

When plotted second, Florida completely obscures Arizona.

If I add more states…we see Iowa, since Iowa plots after Florida.

But California blocks out everything else.

One way to fix this is to rearrange the plot order with Select Data.

Notice however when you customize plot order, Excel no longer highlights source data.

Now another way to fix things is to sort the source data first, and then make the chart.

If I convert the data to a Table first, it will be easier to sort.

To simplify the vertical axis, I’ll set display units to millions.

Now let’s look again at the stacked area chart option.

I’ll duplicate this chart, then switch the second chart to stacked area.

Notice data series are plotted in the same order, starting with California, and ending with Arizona.

However, in the second chart, data series are stacked, one on top of the other.

While stacking has a key benefit of keeping all series visible all the time, it has consequences.

First, we can no longer easily read populations for each state.

In the stacked area chart, this is hard to see.

Second, a stacked area chart implies a part-to-whole relationship.

The bottom line is a stacked area chart only makes sense when you want to show a part-to-whole relationship.