The visual variable base class. See each of the subclasses that extend this class to learn how to create continuous data-driven thematic visualizations.

ColorVariable	SizeVariable	OpacityVariable	RotationVariable

See also:

• SimpleRenderer.visualVariables
• UniqueValueRenderer.visualVariables
• ClassBreaksRenderer.visualVariables

Property Overview

Property Details

declaredClass Stringreadonly inherited

The name of the class. The declared class name is formatted as esri.folder.className.

field String

The name of the numeric attribute field that contains the data values used to determine the color/opacity/size/rotation of each feature.

index String|Number

The index of the visual variable in relation to its position in the visualVariables property of the renderer.

legendOptions Object

An object providing options for displaying the visual variable in the Legend.

Properties:

showLegend Boolean optional Indicates whether to show the visual variable in the legend.

title String optional The title describing the visualization of the visual variable in the Legend. This takes precedence over a field alias or valueExpressionTitle.

type Stringreadonly

The visual variable type.

Possible values: color | opacity | rotation | size

valueExpression String

An Arcade expression evaluating to a number. This expression can reference field values using the $feature global variable and perform mathematical calculations and logical evaluations at runtime. The values returned from this expression are the data used to drive the visualization. This takes precedence over field. Therefore, this property is typically used as an alternative to field in visual variables.

See also:

• Arcade - expression language

valueExpressionTitle String

The title identifying and describing the associated Arcade expression as defined in the valueExpression property. This is displayed as the title of the corresponding visual variable in the Legend in the absence of a provided title in the legendOptions property.

Method Overview

Method Details

fromJSON(json){*}static

Creates a new instance of this class and initializes it with values from a JSON object generated from a product in the ArcGIS platform. The object passed into the input json parameter often comes from a response to a query operation in the REST API or a toJSON() method from another ArcGIS product. See the Using fromJSON() topic in the Guide for details and examples of when and how to use this function.

Parameter:

json Object A JSON representation of the instance in the ArcGIS format. See the ArcGIS REST API documentation for examples of the structure of various input JSON objects.

Returns:

Type	Description
*	Returns a new instance of this class.

toJSON(){Object}

Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() topic in the Guide for more information.

Returns:

Type	Description
Object	The ArcGIS portal JSON representation of an instance of this class.