An area chart is an extension of a line chart. The area chart shows the line of the measure but fills the area below the line to emphasize on the value of the measure. A special case of area chart is a stacked area chart, which shows a line per measure and the area between the lines is filled. Tableau's implementation of area charts uses one date variable and one or more measures.
Let's use the sample file Sample – Superstore Sales (Excel)
. Open a new worksheet and select Sample – Superstore Sales (Excel) as the data source.
Once the data is loaded on the new worksheet, perform the following steps to create an area chart:
When we added Order Date for the first time, Tableau, by default, aggregated the date field by year; therefore, we added Order Date again to create aggregation by quarter of the Order Date. We also added Region to create facets on the regions that provide trends of order quantity over time.
A blog post by visual.ly
, an information graphics company, discusses the key differences between line charts and area charts. You can find this post at http://blog.visual.ly/line-vs-area-charts/.