A combo chart is a combination of two column charts, two line graphs, or a column chart and a line graph. You can make a combo chart with a single dataset or with two datasets that share a common string field.
Combo charts can answer questions about your data, such as: What are the trends for the same categories?
An environmental organization is tracking the drought conditions in Southern California and wants to compare temperatures and precipitation to determine which cities are most vulnerable. The organization uses a combo chart to show both the total precipitation and the average temperature for each city in one chart.
Create a combo chart
Combo charts can be created with a single dataset, or with two datasets that share a common string field.
A single dataset
To create a combo chart with a single dataset, complete the following steps:
- Select a string field and two number or rate/ratio fields .
- Create the combo chart using the following steps:
- Drag the selected fields to a new card.
- Hover over the Chart drop zone.
- Drop the selected fields on Combo Chart.
You can also create charts using the Chart menu above the data pane or the Visualization type button on an existing card. For the Chart menu, only charts that are compatible with your data selection will be enabled. For the Visualization type menu, only compatible visualizations (including maps, charts, or tables) will be displayed.
Two datasets with a common string field
To create a combo chart on top of an existing column chart or line graph, complete the following steps:
- Select one of the following data options:
- A number or rate/ratio field from the same dataset as the existing chart.
- A string field that corresponds to the existing chart's string field plus a number or rate/ratio field from a different dataset than the one used in the existing chart.
- Drag the selected fields to the existing column chart or line graph.
- Drop the fields on the Combo Chart drop zone.
The field must be dropped on the body of the chart. Dropping the field on the y-axis of the chart will update the numeric field for the existing chart, rather than create a combo chart.
- Optionally change the type of chart using the Line Graph button or Column Chart button on the vertical axes.
The Layer options button opens the Layer options pane. You can use the Layer options pane to view the legend, change the chart options, and update the chart style.
The Legend tab displays the symbols for the column chart and line graph. The pop out legend button displays the legend as a separate card on your page. If unique symbols are used, the legend can be used to select data on the column chart. To change the color associated with a category, click the symbol and choose a color from the palette or enter a hex value.
The Options tab is used to change the Symbol type to Unique symbol for the columns, smooth the line for the line graph, synchronize the y-axes, and turn labels on or off.
The Synchronize y-axes check box can be used to change both axes to the same scale. Using the same scale for both y-axes is useful in cases where your variables are already using a similar scale, or you want to analyze the magnitude of difference between variables.
Labels display the number values associated with the chart. The following configurations are available for labels:
- Decimal places — You can choose a number of decimal places from zero to five, or choose Default or Auto for the labels. Default will abbreviate large numbers, while Auto will choose an appropriate precision.
- Label alignment — Three alignment options are available for combo charts: Horizontal, outside, Vertical, outside, and Angled.
- Context label — Characters, such as a symbol or unit, can be added to the label. The context label can be placed to the left (default) or right of the value.
The Style tab is used to change the symbol color for both the column chart (single symbol only) and the line graph, change the outline color of the column chart, and change the pattern and thickness of the line graph.
The value of each bar and the trend of the line can be symbolized as a count of features in each category on the x-axis, or as a number or rate/ratio field. If a field is used, the values can be calculated as a sum, minimum, maximum, average, percentile, or median of values from the field for each category.
The Column chart button and Line graph button on the y-axes can be used to switch the visualizations between column charts and line graphs. If both axes are set to column chart, the columns will be subgrouped within each category.
When you create a combo chart, result datasets with the string and number fields used to create the charts will be added to the data pane. The result dataset can be used to find answers with nonspatial analysis using the Action button .