Line Charts

A line chart or line graph is a type of graph displaying a series of data points connected together with a line. Used to to help understanding the underlying patterns that those values represent. Mostly, color is used to indicate the different sets of data in the chart. The chart usually includes a legend which matches sets of data to their corresponding colored lines.

Problems arise when there is no clear method of matching two or more colors of the lines in the chart to their corresponding values and category names in the legend. This confuses color blind and sometimes makes it impossible to use the chart.

Solutions should focus on preventing confusion and mistakes by adding information about the available or picked colors. This can be done in multiple ways. Combining these solutions works even better.

Solution 1: Incorporate the legend in the chart

By placing the labels from the chart next to the corresponding lines, color blind have a better visual connection between the chart and data. The color blind can now rely on something other than color alone.

Solution 2: Use mouse-over hints to connect the legend to the chart

While one of the more technologically involved solutions, this leaves the chart intact but gives an mouse-over with extra information when needed. During the mouse-over, the legend gets matched to the line in the chart the user is hovering over at that moment. This can be a label in the chart with the name of the segment, lighting up the color in the chart and legend, or another way to clarify the link between the chart and the legend.

Solution 3: Use different shapes and icons

By using shapes or icons for the plotted points, color blind now have something other than color to rely on. Doesn’t work for every chart, as some don’t use plotted points.

Solution 4: Use colors easy to distinguish

Use very clear colors with good contrast. Most of all, try to avoid the high priority confusion colors. More information »