Where To Draw The Line: Line Graph vs. Area Chart
I can honestly say that I have seldom, if ever, used an area chart in the business world. Both a line graph and area chart shows the same type of information, which is data over time. The way Excel 2007 describes the two is by noting:
Line Graph: "display trend over time…. useful when there are many data points and the order is important"
Area Chart: "display the trend of values over time"
Below I have taken two separate data visualizations showing the same type of data. The first is an area chart with the second being a line graph. The data sets are different, but the use is nearly the same – showing a trend of a percent over months or years. There is the Tufte concept of data/ink to consider if you really want to get technical. Me, I just stick to a simple well designed line graph.
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Simply put, I think you can’t go wrong with either of the two above if your intention is to visualize the trend of data over time. Even though I rarely use area charts, I would much rather have someone use one of these over the misuse of trying to fit a column chart in its place. One use of a variation of the area chart that I typically see is to show the range of average temperatures throughout the year, where the area represents the average high and average low temperature. Conversely, I’ve also seen the temperature data represented with two line graphs for the average high/low (www.weather.com uses this method and can be seen here). You can also see an example of an area combination chart on Jon Peltier’s site found here.
Which chart do you prefer when showing data over time, the line graph, area chart or other? Does one sector tend to use area charts over line graphs? My experience in the business world leads me to think lines are preferred over area charts.
May 4th, 2009 at 9:57 am
Lines are preferred. A combination with budget or average or typical values in an area series and actuals in a line (which is displayed in front of the area) is effective.
May 4th, 2009 at 10:53 am
I think both are acceptable, 看你喜好什么，in biz affairs I use line chart more frequently.
I find , in Biz week, they use area chart when there is only one serial,这有一种稳定感， and use line chart when there are two or more serials ，便于比较.
May 4th, 2009 at 3:31 pm
For me, it would depend on context. In a report or dashboard kind of setting, I’d use the line chart to keep things simple and clean. In a presentation, however, I think the area chart is more effective at communicating the size of the area to a large audience. That’s assuming it’s just a single data series as in the examples above. I just think a large audience can grasp the magnitude and changes in the data with the colored area.
May 4th, 2009 at 8:38 pm
Michael -
You’re right, I think the area chart would be more visible to someone in the back row.
May 4th, 2009 at 9:09 pm
I would have to agree with Jon up until I read Michael’s comment. I think that it would depend on the audience and medium that the data visualization would appear.
Thank you all for the feedback!