A serial chart visualizes one or more series of data points along a horizontal (X) axis and a vertical (y) axis. Serial charts get their name from their ability to show more than one series of data. In the below chart, there are two series of data: one showing crime counts by day and the other showing a three-day rolling average of crime counts. Furthermore, each series in a serial chart has a type that determines the way these data points are visualized. In the below example, the series showing crime counts by day has the type of bar and the series showing the three-day rolling average of crime counts has the type of line.
The anatomy of a serial chart is further described below.
- Scrollbar—Controls the number of data categories displayed.
- Hover Text—Displays additional information about a data point while hovering over it with your mouse.
- Grid Lines—Improve chart readability. You can control how horizontal and vertical grid lines are displayed.
- Guides—Provide context to the data being displayed on a chart by representing goals or thresholds. Guides can be lines that represent a single value, or a shaded area that represents a range of values. In addition, serial charts can have multiple guides.
- Legend—Conveys the meaning of colors used in the chart. How you configure the data in the chart determines the position of the chart's legend.
- Label—Describes categories and values. Labels are auto-generated, however, you can override them at design time. For instance, when the category axis shows dates, you can adjust their display through date formatting. You can also control value axis labels through unit prefixing or number formatting.
- Axis Title—Summarizes the types of categories or values shown on the axis. Each axis can have its own title.
- Axis—One axis in a serial chart is used to display the category of each data point, while the other axis is used to represent its numeric value. The category axis can show discrete values, or continuous values such as dates. In the above chart, the categories are displayed along the horizontal axis, and the values are displayed along the vertical axis. However, this setup could be flipped. The vertical bars could be displayed horizontally by changing the orientation of the axes, so that the horizontal axis displays values and the vertical axis displays categories.
Series types include bar, line, or smooth line. Each series type is best suited for a different data type.
On a bar chart, data points in the series are represented by a box where the height of the box is determined by the point's numerical value. Bars can either be horizontal or vertical, depending on the chart's orientation. Bar charts are best used for data with discrete categories, but they can also be used to display data with continuous categories.
In contrast, data with discrete values is not suitable for line and smooth line charts because the data points in these series are connected. These types of charts are most appropriate for data with continuous categories such as dates.
Line and smooth line charts can easily be turned into area charts by increasing their fill opacity.
There are two ways to create multi-series charts. Which method you use depends on how your chart's categories are determined from its data. If your chart's categories are based on grouped values, you can create a multi-series chart by specifying a Split By Field. If your chart's categories are based on features, you can manually include multiple series in the chart through clicking + Series. See Data series for details on how to determine the basis of your chart's categories.
When each of the series in a multi-series chart is of different types, such as the first chart in this topic, it is considered a combo chart. When all the series are the same type, they can be grouped, stacked, or 100% stacked.
Grouped charts are used for showing information about different sub-groups of main categories. A separate bar or line represents each of the sub-groups, which are different colors to distinguish them. When configuring a grouped chart, be sure to limit the amount of information, to ensure it's easy to understand.
Stacking allows series to be placed on top of each other, without overlapping. A stacked chart is similar to a grouped chart because it can be used to display information about sub-groups that compose different categories. In a stacked chart, the data points representing sub-groups are placed on top of each other (or side-by-side when the chart is displayed horizontally). Different colors are used to indicate the contributions of the different sub-groups. The overall value is the total size of the category.
100% stacked charts
A variation of a stacked chart is a 100% stacked chart. This shows relative differences within each category. The total of each column is always 100, and the length of each sub-group is its contribution to the total in terms of percent.