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Function

a!areaChartField(label, instructions, categories, series, xAxisTitle, yAxisTitle, yAxisMin, yAxisMax, stacking, referenceLines, showLegend, showDataLabels, showTooltips, allowDecimalAxisLabels, labelPosition, helpTooltip, showWhen, connectNulls, accessibilityText, colorScheme, height, xAxisStyle, yAxisStyle, data, config, refreshAlways, refreshInterval, refreshOnReferencedVarChange, refreshOnVarChange, refreshAfter)

Displays a series of numerical data as points connected by lines with the area between the line and axis shaded. Use an area chart to visualize trends over time and compare multiple values. If specific values are more important than the trend, consider using a column chart.

See also:

• Chart Color Schemes
• Configure Charts Using Records

Parameters

Configuration

There are two ways to configure an area chart:

1. Set a record type as the data source and define fields to display on the chart.
2. Perform your own query and define lists of data within the categories and series.

If you have a record type that uses a database as the source, or a record type with data sync enabled, we recommend using the record type as the source of your chart. This configuration is easier because Appian will perform the query for you and display the results directly in the chart.

If your record type uses a web service as the source and does not have data sync enabled, use the categories and series to construct the chart manually.

Using record data

Configuring an area chart using a record type as the source requires using two parameters: data and config. Once you provide a record type in the data parameter and provide the fields in the config parameter, the chart displays the results.

See Chart Configuration Using Record Data for details on using a record type as the source. See Build Reports from Records for examples of reports created with different charts.

Using categories and series

When using categories and series, you must provide the list of data labels and values directly to these parameters.

Categories

• The order of items in the categories array determines the display order of categories on the chart with the left-most item in the array appearing on the far left of the x-axis.
• For each null or empty item in the array passed to categories, [Category #] displays on the x-axis with # as the index number in the categories array of the null or empty item. For example, [Category 1].
• The index of each item in the categories array must match with the index of its series data value.

Series

• A single Series item produces a single line with line points for each categories item. Multiple series items produce multiple lines with one line for each series label item displayed in a distinct color.
• Use a!chartSeries() to create the Chart Series array.
• If a series data value is greater than the Max Y-Axis value or less than the Min Y-Axis value, the line line and shaded area will not appear on the chart.
• If the series argument has a non-null label value paired with a 0, null, or empty data value, the data value still displays in the legend.
• If the series argument has a null or empty label value paired with a non-null data value, the label value displays as [Series #] with # as the index number of the data value. For example, [Series 1].

Usage considerations

Using the stacking parameter

• The stacking parameter has three possible values:

  • "NONE" is best for showing an overlapping area chart. This will shade each line from its vertical value to the common baseline (zero). Use this value when you want to compare two values. If you need to compare more than two values, consider using a line chart instead since it may be hard for users to read multiple overlapping areas. See Area charts vs. line charts for other considerations.

  • "NORMAL" is best for showing part-to-whole relationships. This will stack each value on top of each other so the topmost line corresponds to the total of all values. Use this value when you want to see a breakdown of a total.

  • "PERCENT_TO_TOTAL" is best for showing the distribution of categories as part of a whole. The Y-axis will display values starting from 0% (the baseline) to 100%. Use this value when the cumulative total is unimportant.

    Note:  If you've set a Min Y-Axis or Max Y-Axis value, the value will correspond to a percentage. For example, if you set a Min Y-Axis of 20, it will display as 20%.

Area charts vs. line charts

• Area charts are most similar to line charts in that they are great for showing trends over time. So when should you choose an area chart or a line chart?
  • Consider using an area chart to display large differences between multiple data points, or when you need to show how multiple data points relate to a total value.
  • Consider using a line chart to show multiple data comparisons over time.
• For more information on which type of chart to use in your reports, see Charts design guidance.

Chart refresh behavior

• You can define a!refreshVariable parameters directly in the chart without creating additional local variables. The only exception being refreshOnVarChange, which refreshes the chart after a specific local variable has changed.
• When you use a record type as the source of your chart, it's recommended to use the refresh parameters in the chart instead of using local variables and the a!refreshVariable() function. This is because the refresh behavior will automatically apply to the fields specified in the data parameter of the chart.
• If you're not using a record type as the source of your chart, use local variables and the a!refreshVariable() function to define refresh behavior since you won't use the data parameter to configure your chart.

Example

Click EXPRESSION to copy and paste an example into the Interface Definition to see it displayed.

The examples below demonstrate how to configure your charts using categories and series. For examples on using record data, see Chart Configuration Using Record Data.

Multiple series area chart with normal stacking

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{
  a!areaChartField(
    label: "Cases by Month",
    labelPosition: "ABOVE",
    categories: {"Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "Jan", "Feb"},
    series: {
      a!chartSeries(label: "Met SLA", data: {72, 91, 93, 95, 92, 99, 98, 99, 79, 83, 90, 99}),
      a!chartSeries(label: "Missed SLA", data: {12, 55, 26, 61, 30, 29, 49, 37, 62, 51, 33, 29})
    },
    stacking: "NORMAL",
    colorScheme: "SUNSET",
  )
}

Displays the following:

Multiple series area chart with percent to total stacking

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{
  a!areaChartField(
    label: "New Customers by Industry",
    labelPosition: "ABOVE",
    categories: {"2012", "2013", "2014", "2015", "2016", "2017", "2018", "2019", "2020", "2021", "2022"},
    series: {
      a!chartSeries(label: "Retail", data: {69, 54, 81, 74, 73, 64, 74, 52, 64, 63, 72}),
      a!chartSeries(label: "Healthcare", data: {28, 29, 39, 34, 40, 45, 47, 51, 62, 66, 69}),
      a!chartSeries(label: "Real Estate", data: {2, 5, 6, 9, 23, 9, 17, 17, 62, 51, 50}),
      a!chartSeries(label: "Food Services", data: {1, 2, 2, 7, 1, 2, 10, 7, 22, 21, 29})
    },
    stacking: "PERCENT_TO_TOTAL",
    colorScheme: "CLASSIC"
  )
}

Displays the following:

Multiple series area chart with no stacking

To learn how to create this area chart, see the Dynamically Show Sales by Product Category Compared to Total Sales pattern.

Feature compatibility

Related Patterns

The following patterns include usage of the Area Chart Component.

• Dynamically Show Sales by Product Category Compared to Total Sales (Records, Reports, Charts, Filtering): This pattern illustrates how to create an area chart that dynamically displays sales generated by product category compared to total sales.