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DataClock

In this topic

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

Summary

The DataClock class creates data clocks. Data clocks visually summarize temporal data into two dimensions to reveal seasonal or cyclical patterns and trends over time.

Learn more about data clocks in ArcGIS Pro

Discussion

When creating this 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

DataClock (dateField, {numberField}, {timeUnitsRingWedge}, {aggregation}, {nullPolicy}, {classificationMethod}, {classCount}, {title}, {description}, {dataSource}, {displaySize}, {theme})
ParameterExplanationData Type
dateField

The name of the date field that is used to create the chart.

String
numberField

The name of the field that is aggregated and used to determine the color of the chart cells.

String
timeUnitsRingWedge

Specifies the time-unit pair that is supported in the data clock chart.

  • YEARS_MONTHS—Display years on the ring axis and months on the wedge axis.
  • YEARS_WEEKS—Display years on the ring axis and weeks on the wedge axis.
  • YEARS_DAYS—Display years on the ring axis and days on the wedge axis.
  • WEEKS_DAYS—Display weeks on the ring axis and days on the wedge axis.
  • DAYS_HOURS—Display days on the ring axis and hours on the wedge axis.
String
aggregation

Specifies the statistical calculation that will be applied to values aggregated into each cell.

  • COUNT—The total number of records will be identified.
  • SUM—The sum of all values will be calculated.
  • MEAN—The mean of all values will be calculated.
  • MEDIAN—The median of all values will be calculated.
  • MIN—The minimum value will be identified.
  • MAX—The maximum value will be identified.
String
nullPolicy

Specifies how summarized cells returning a null value will be displayed.

  • null—Cells will be displayed as null.
  • zero—Cells will be displayed as zero.
String
classificationMethod

Specifies the classification method that will be used to visualize cell color and classify data.

  • equalIntervals—The equal interval method will be used.
  • geometricalIntervals—The geometric interval method will be used.
  • naturalBreaks—The natural breaks method will be used.
  • quantiles—The quantiles method will be used.
String
classCount

The number of classes used in the classification method.

Integer
title

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

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

String
dataSource

The data source of the chart. When a chart is exported using the exportToSVG method or displayed in ArcGIS Notebooks, the data source will be read and rendered on the chart. Valid data sources include the following:

  • Paths to datasets, including local datasets, UNC paths, and service URLs
  • Apache Arrow table objects
  • Layer or Table objects

Object
displaySize
[displaySize,...]

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

List
theme

Specifies the theme that will be applied to the chart.

  • Light—The Light theme will be applied.
  • Medium—The Medium theme will be applied.
  • Dark—The Dark theme will be applied.
String

Properties

PropertyExplanationData Type
aggregation
(Read and Write)

Specifies the statistical calculation that will be applied to values aggregated into each cell.

  • COUNT—The total number of records will be identified.
  • SUM—The sum of all values will be calculated.
  • MEAN—The mean of all values will be calculated.
  • MEDIAN—The median of all values will be calculated.
  • MIN—The minimum value will be identified.
  • MAX—The maximum value will be identified.
String
classCount
(Read and Write)

The number of classes used in the classification method.

Integer
classificationMethod
(Read and Write)

Specifies the classification method that will be used to visualize cell color and classify data.

  • equalIntervals—The equal interval method will be used.
  • geometricalIntervals—The geometric interval method will be used.
  • naturalBreaks—The natural breaks method will be used.
  • quantiles—The quantiles method will be used.
String
dataSource
(Read and Write)

The data source of the chart. When a chart is exported using the exportToSVG method or displayed in an ArcGIS notebook, the data source will be read and rendered on the chart. Valid data sources include the following:

  • Paths to datasets, including local datasets, UNC paths, and service URLs
  • Apache Arrow table objects
  • Layer or Table objects

Object
dateField
(Read and Write)

The name of the date field that is used to create the chart.

String
description
(Read and Write)

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

String
displaySize
(Read and Write)

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 in which the first item is the width of the chart and the second item is the height of the chart.

List
legend
(Read and Write)

The properties of the chart legend.

  • alignment—Specifies the alignment of the legend. Alignment options are left, bottom, top, and right.
  • title—The title of the legend.
  • visible—Specifies whether the legend will be displayed in the chart view. True displays the legend, and False hides the legend.
Object
nullPolicy
(Read and Write)

Specifies how summarized cells returning a null value will be displayed.

  • null—Cells will be displayed as null.
  • zero—Cells will be displayed as zero.
String
numberField
(Read and Write)

The name of the field that is aggregated and used to determine the color of the chart cells.

String
theme
(Read and Write)

Specifies the theme that will be applied to the chart.

  • Light—The Light theme will be applied.
  • Medium—The Medium theme will be applied.
  • Dark—The Dark theme will be applied.
String
timeUnitsRingWedge
(Read and Write)

Specifies the time-unit pair that is supported in the data clock chart.

  • YEARS_MONTHS—Display years on the ring axis and months on the wedge axis.
  • YEARS_WEEKS—Display years on the ring axis and weeks on the wedge axis.
  • YEARS_DAYS—Display years on the ring axis and days on the wedge axis.
  • WEEKS_DAYS—Display weeks on the ring axis and days on the wedge axis.
  • DAYS_HOURS—Display days on the ring axis and hours on the wedge axis.
String
title
(Read and Write)

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
type
(Read Only)

The string value indicating the chart type.

String

Method Overview

MethodExplanation
addToLayer (layer_or_layerfile)

The addToLayer method adds the chart object to a layer or table view.

exportToJPEG (path, width, height)

The exportToJPEG method exports a chart to JPEG format.

exportToPNG (path, width, height)

The exportToPNG method exports a chart to PNG format.

exportToSVG (path, width, height)

The exportToSVG method exports a chart to SVG format.

updateChart ()

The updateChart method 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. This argument can be a Layer or Table object.

Object

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

Add a chart to an existing layer.

import arcpy

# Insert creation of chart object here
...

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)
exportToJPEG (path, width, height)
ParameterExplanationData Type
path

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

String
width

The width of the output graphic.

Integer
height

The height of the output graphic.

Integer

The chart is exported to a .jpg file that can be shared and viewed outside of ArcGIS Pro. JPEG is a raster image format that uses lossy compression to reduce file size.

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

import arcpy

# Insert creation of chart object here
...

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.exportToJPEG('theftsPerBeat.jpg', 800, 600)
exportToPNG (path, width, height)
ParameterExplanationData Type
path

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

String
width

The width of the output graphic.

Integer
height

The height of the output graphic.

Integer

The chart is exported to a .png file that can be shared and viewed outside of ArcGIS Pro. PNG is a raster image format that uses lossless compression to preserve image quality.

Access an existing chart from a layer, update the title, and export it to a .png file.

import arcpy

lyr = arcpy.mp.ArcGISProject('current').listLayers()[0]

# Retrieve the first chart belonging to the layer
chart = lyr.listCharts()[0]

# Update chart title
chart.title = 'Voter Turnout by State'

# Save the chart to PNG file with dimensions width=800, height=600
chart.exportToPNG('populationByState.png', 800, 600)
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

The chart is exported to an .svg file that can be shared and viewed outside of ArcGIS Pro. SVG is a vector image format that allows for editing and infinite scaling of the graphic without a loss in quality.

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

import arcpy

# Insert creation of chart object here
# ...

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

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

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

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

You can also modify the properties of the original chart instead of starting 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 allows 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.

import arcpy

# Insert creation of chart object here
...

chart.addToLayer(myLayer)

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

Code sample

Create a data clock chart using a layer in the current project and export the chart to an .svg file. 


import arcpy
lyr = arcpy.mp.ArcGISProject("current").listMaps()[0].listLayers("car_accidents")[0]
chart = arcpy.charts.DataClock(dateField="Date", aggregation="count", 
                               timeUnitsRingWedge="WEEKS_DAYS", dataSource=lyr)
chart.exportToSVG("data_clock.svg", width=750, height=500)

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