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Line

In this topic

  1. Summary
  2. Discussion
  3. Syntax
  4. Properties
  5. Method Overview
  6. Methods
  7. Code sample

Summary

Line charts allow you to visualize change over a continuous range, such as time or distance. Visualizing change with a line chart allows for the overall trend to be displayed at once, and for multiple trends to be compared simultaneously.

Learn more about line charts in ArcGIS Pro

Discussion

When creating a chart object, optional arguments for the class constructor must be specified using the argument name; they cannot be specified by argument position. See the code sample section for an example of how to specify arguments using keywords.

Syntax

Line (x, {y}, {splitCategory}, {multiSeriesDisplay}, {miniChartsPerRow}, {showPreviewChart}, {aggregation}, {timeIntervalUnits}, {timeIntervalSize}, {timeAggregationType}, {trimIncompleteTimeInterval}, {nullPolicy}, {rotated}, {title}, {description}, {xTitle}, {yTitle}, {dataSource}, {displaySize})
ParameterExplanationData Type
x

The field name for the x-axis variable. The field must be a numeric or date field.

String
y

The field names for the y-axis variables. The value must be a numeric field or a list of numeric fields.

String
splitCategory

A categorical field that adds a separate series or line for each unique value in the field.

String
multiSeriesDisplay

The display type for a line chart with multiple series. Valid options are singleChart and grid.

String
miniChartsPerRow

Sets the number of mini-charts that will be shown per row. The number of rows will be determined by the total number of series divided by the miniChartsPerRow value.

Integer
showPreviewChart

Indicates whether the preview chart is visible for grid charts. True displays the preview chart. False hides the preview chart.

(The default value is False)

Boolean
aggregation

The statistical calculation applied to values aggregated into each temporal bin. Supported statistics are COUNT, SUM, MEAN, MEDIAN, MIN, and MAX. No aggregation means that each value will be plotted on the chart regardless of overlap or recurring values.

String
timeIntervalUnits

The time unit that corresponds to the timeIntervalSize. Valid options include SECONDS, MINUTES, HOURS, DAYS, WEEKS, MONTHS, and YEARS.

String
timeIntervalSize

The span of time that will be binned or aggregated together. This argument must be used in conjunction with timeIntervalUnit.

String
timeAggregationType

The time interval alignment type. Valid options include equalIntervalsFromStartTime and equalIntervalsFromEndTime.

String
trimIncompleteTimeInterval

Determines whether incomplete time intervals at the start or end of the data span (depending on the timeAggregationType) will be removed from the chart. Incomplete intervals on a chart can cause misleading results in which the period in question is under- or overreported due to a different amount of time in the interval. True indicates to trim these incomplete intervals. False does not trim incomplete intervals.

String
nullPolicy

How summarized bins returning a null value are displayed. Supported options are null, zero, and interpolate

String
rotated

Indicates whether lines are viewed horizontally or vertically. Lines display horizontally by default.

(The default value is False)

Boolean
title

Sets the title of the chart. The title text appears at the top of the chart view and is used as the label for the chart in the Contents pane.

String
description

Sets the description of the chart. The description text appears at the bottom of the chart view.

String
xTitle

Sets the title for the x-axis of the chart.

String
yTitle

Sets the title for the y-axis of the chart.

String
dataSource

Sets the data source of the chart. When a chart is exported using the exportToSVG method or displayed in an ArcGIS Notebook, the data source is read and rendered on the chart. Valid data sources include paths to datasets, including local datasets, UNC paths, and service URLs, and arcpy.mp Layer objects.

Object
displaySize
[displaySize,...]

Sets the size of the chart when exported using the exportToSVG method or displayed in an ArcGIS Notebook. The value must be specified as a two-item list, where the first item is the width of the chart and the second item is the height of the chart.

List

Properties

PropertyExplanationData Type
aggregation
(Read and Write)

The statistical calculation applied to values aggregated into each temporal bin. Supported statistics are COUNT, SUM, MEAN, MEDIAN, MIN, and MAX. No aggregation means that each value will be plotted on the chart regardless of overlap or recurring values.

String
dataSource
(Read and Write)

Sets the data source of the chart. When a chart is exported using the exportToSVG method or displayed in an ArcGIS Notebook, the data source is read and rendered on the chart. Valid data sources include paths to datasets, including local datasets, UNC paths, and service URLs, and arcpy.mp Layer objects.

Object
description
(Read and Write)

Sets the description of the chart. The description text appears at the bottom of the chart view.

String
displaySize
(Read and Write)

Sets the size of the chart when exported using the exportToSVG method or displayed in an ArcGIS Notebook. The value must be specified as a two-item list, where the first item is the width of the chart and the second item is the height of the chart.

List
legend
(Read and Write)

Sets the properties of the chart legend.

  • visible—Indicates whether the legend is visible in the chart view. True displays the legend. False hides the legend.
  • title—The title to display for the legend.
Object
miniChartsPerRow
(Read and Write)

Sets the number of mini-charts that will be shown per row. The number of rows will be determined by the total number of series divided by the miniChartsPerRow value.

Integer
multiSeriesDisplay
(Read and Write)

The display type for a line chart with multiple series. Valid options are singleChart and grid.

String
nullPolicy
(Read and Write)

How summarized bins returning a null value are displayed. Supported options are null, zero, and interpolate.

String
rotated
(Read and Write)

Indicates whether the chart is viewed vertically or horizontally. The chart displays vertically by default. True rotates the chart horizontally. False displays the chart vertically.

Boolean
showPreviewChart
(Read and Write)

Indicates whether the preview chart is visible for grid charts. True displays the preview chart. False hides the preview chart.

Boolean
splitCategory
(Read and Write)

A categorical field that adds a separate series or line for each unique value in the field.

String
timeAggregationType
(Read and Write)

The time interval alignment type. Valid options include equalIntervalsFromStartTime and equalIntervalsFromEndTime.

String
timeIntervalSize
(Read and Write)

The span of time that will be binned or aggregated together. The property must be used in conjunction with timeIntervalUnit.

String
timeIntervalUnits
(Read and Write)

The time unit that corresponds to the timeIntervalSize. Valid options include SECONDS, MINUTES, HOURS, DAYS, WEEKS, MONTHS, and YEARS.

String
title
(Read and Write)

Sets the title of the chart. The title text appears at the top of the chart view and is used as the label in the Contents pane on the List By Drawing Order tab List By Drawing Order.

String
trimIncompleteTimeInterval
(Read and Write)

Determines whether incomplete time intervals at the start or end of the data span (depending on the timeAggregationType) will be removed from the chart. Incomplete intervals on a chart can cause misleading results in which the period in question is under- or overreported due to a different amount of time in the interval. True indicates to trim these incomplete intervals. False does not trim incomplete intervals.

String
type
(Read Only)

The string value indicating the chart type.

String
x
(Read and Write)

The field name for the x-axis variable. The field must be a numeric or date field.

String
xAxis
(Read and Write)

Sets the properties of the x-axis.

  • field—The field name for the x-axis variable. The field must be a numeric or date field.
  • logarithmic—Indicates whether the axis is logarithmic. True displays the logarithmic axis. False displays the linear axis.
  • maximum—The maximum axis bound.
  • minimum—The minimum axis bound.
  • sort—This property is not supported for the Line class.
  • title—The label of the axis that displays on the chart.
Object
y
(Read and Write)

The field name or names for the numeric field or fields. Must specify a single field name or a list of field names.

String
yAxis
(Read and Write)

Sets the properties of the y-axis.

  • field—The field name or names for the numeric field or fields. Must specify a single field name or a list of field names.
  • logarithmic—Indicates whether the axis is logarithmic. True displays a logarithmic axis. False displays a linear axis.
  • maximum—The maximum axis bound.
  • minimum—The minimum axis bound.
  • sort—This property is not supported for the Line class.
  • title—The label of the axis that displays on the chart.
Object

Method Overview

MethodExplanation
addToLayer (layer_or_layerfile)

Adds the chart object to a layer or stand-alone table.

exportToSVG (path, width, height)

Exports the chart to SVG format.

updateChart ()

Updates chart properties to sync changes between the object and the chart previously added to a layer.

Methods

addToLayer (layer_or_layerfile)
ParameterExplanationData Type
layer_or_layerfile

The chart will be added to the target object. The layer_or_layerfile argument can be a Layer or a Table object.

Object

Often the final step after defining chart properties is to add the chart object to a layer or table using the addToLayer method.

Add a chart to an existing layer.

import arcpy

aprx = arcpy.mp.ArcGISProject("current")
map = aprx.listMaps()[0]
censusLayer = map.listLayers('Census Block Groups')[0]

# Add chart object to a layer
chart.addToLayer(censusLayer)
exportToSVG (path, width, height)
ParameterExplanationData Type
path

The path where the chart will be exported in SVG format.

String
width

The width of the output graphic.

Integer
height

The height of the output graphic.

Integer

In some cases, you may want to save the chart as a graphic that can be shared and viewed outside of ArcGIS Pro. Exporting to the SVG graphic format is beneficial, as the chart elements and text are stored as vector elements that can be independently modified in a vector graphics software. An SVG graphic can also be resized to any scale without pixelation or loss in quality.

Export a chart that has a project layer data source to an .svg file.

import arcpy

aprx = arcpy.mp.ArcGISProject('current')
censusLayer = aprx.listMaps()[0].listLayers('Census Block Groups')[0]

# Set data source of chart object to a layer within current project
chart.dataSource = censusLayer

# Save the chart to file with dimensions width=500, height=500
chart.exportToSVG('populationByState.svg', 500, 500)

Export a chart that has a feature service data source to an .svg file.

featureServiceURL = r'https://services1.arcgis.com/hLJbHVT9ZrDIzK0I/arcgis/rest/services/CrimesChiTheft/FeatureServer/0'

# Set data source of chart object to a feature service URL
chart.dataSource = featureServiceURL

# Save the chart to file with dimensions width=800, height=600
chart.exportToSVG('theftsPerBeat.svg', 800, 600)
updateChart ()

Often the final step after defining chart properties is to add the chart object to a layer using the addToLayer method.

To further modify the chart properties, you can modify the properties of the original chart instead of starting from scratch with a new chart. You can then use the updateChart method to synchronize any changes into the chart that was added to the layer. This will allow the changes you make to be presented in the Chart properties pane and chart view.

Use the updateChart method to synchronize chart property changes into a layer.

chart.addToLayer(myLayer)

# Further modification is necessary
chart.description = "Data from the U.S. Census Bureau"
chart.updateChart()

Code sample

Create a line chart and add it to a layer in the current project.

import arcpy
lyr = arcpy.mp.ArcGISProject("current").listMaps()[0].listLayers()[0]
chart = arcpy.charts.Line(x="date", y="aqi", aggregation="mean")
chart.addToLayer(lyr)

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In this topic
  1. Summary
  2. Discussion
  3. Syntax
  4. Properties
  5. Method Overview
  6. Methods
  7. Code sample