LabelClass
require(["esri/layers/support/LabelClass"], function(LabelClass) { /* code goes here */ });
esri/layers/support/LabelClass
Defines label expressions, symbols, scale ranges, label priorities, and label placement options for labels on a layer.
Known Limitations
FeatureLayer only supports label placement for Point and Polygon geometries in 2D MapViews.
- See also:
Constructors
- new LabelClass(properties)
- Parameter:properties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Property Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
String | The name of the class. more details | more details | Accessor | |
String | Defines the content of label text for MapImageLayer. more details | more details | LabelClass | |
Object | Defines the content of label text for FeatureLayer. more details | more details | LabelClass | |
String | The position of the label. more details | more details | LabelClass | |
Number | The maximum scale (most zoomed in) at which labels are visible in the view. more details | more details | LabelClass | |
Number | The minimum scale (most zoomed out) at which labels are visible in the view. more details | more details | LabelClass | |
TextSymbol | LabelSymbol3D | Defines the symbol used for rendering the label. more details | more details | LabelClass | |
Boolean | Indicates whether to use domain names if the fields in the labelExpression or labelExpressionInfo have domains. more details | more details | LabelClass | |
String | A SQL where clause used to determine the features to which the label class should be applied. more details | more details | LabelClass |
Property Details
- Since: ArcGIS API for JavaScript 4.7
The name of the class. The declared class name is formatted as
esri.folder.className
.
- labelExpressionString
Defines the content of label text for MapImageLayer. If working with FeatureLayer, use labelExpressionInfo instead.
Attribute values may be included in labels using SQL syntax. To include an attribute value in a label, wrap the name of the field in square brackets
[]
. See the example snippet below.Example:// For Spokane County, WA, label will display: "Spokane County, Washington" labelClass.labelExpression = '[COUNTY_NAME] CONCAT " County, " CONCAT [STATE_NAME]';
- labelExpressionInfoObject
Defines the content of label text for FeatureLayer. If working with MapImageLayer, use labelExpression instead.
- Properties:
- optionalvalue String
The SQL expression defining the content of the label text.
Deprecated as of v4.5. Use
expression
instead.expression StringAn Arcade expression that evaluates to a string used to label features in the layer. The most simple expressions return field values. For example, to label a layer of cities with their names, simply reference the field value with the global variable:
$feature.CITY_NAME
. Expressions can be more sophisticated and use logical functions. This may be useful if you want to use classed labels. For example, the following expression appendscity
to the end of the label if the feature's population field contains a number greater than 10,000. Otherwise,town
is appended to the end of the label. Additionally, you can useTextFormatting.NewLine
to add a new line to the label.IIF($feature.POPULATION > 10000, $feature.NAME + ' city', $feature.NAME + ' town')
Example:// For Spokane County, WA, label will display: "Spokane County, Washington" labelClass.labelExpressionInfo = { expression: "$feature.COUNTY_NAME + ' County, ' + $feature.STATE_NAME" };
- labelPlacementString
The position of the label. Possible values are based on the feature type. This property requires a value.
Possible Values (Points): above-center | above-left | above-right | below-center | below-left | below-right | center-center | center-left | center-right
Possible Values (Polylines): above-after | above-along | above-before | above-start | above-end | below-after | below-along | below-before | below-start | below-end | center-after | center-along | center-before | center-start | center-end
Possible Values (Polygons): always-horizontal
Known Limitations
- Currently, if the label has a line callout in a 3D SceneView, then only
above-center
is supported. - Label placement only applies to Point layers in 3D SceneViews.
- FeatureLayers only support labeling for Point and Polygon geometries.
- Default Value:null
Example:labelClass.labelPlacement = "above-right";
- Currently, if the label has a line callout in a 3D SceneView, then only
- maxScaleNumber
The maximum scale (most zoomed in) at which labels are visible in the view. A value of
0
means the label's visibility does not have a maximum scale. The maxScale value should always be smaller than the minScale value.- Default Value:0
- minScaleNumber
The minimum scale (most zoomed out) at which labels are visible in the view. A value of
0
means the label's visibility does not have a minimum scale. The minScale value should always be larger than the maxScale value.- Default Value:0
Defines the symbol used for rendering the label.
Example:labelClass.symbol = { type: "label-3d", // autocasts as new LabelSymbol3D() symbolLayers: [{ type: "text", // autocasts as new TextSymbol3DLayer() material: { color: "black" }, size: 15 }] };
- useCodedValuesBoolean
Indicates whether to use domain names if the fields in the labelExpression or labelExpressionInfo have domains.
- whereString
A SQL where clause used to determine the features to which the label class should be applied. When specified, only features evaluating to
true
based on this expression will be labeled.Known Limitations
Only very basic SQL is currently supported.
Example:labelClass.where = "CITYNAME = 'Redlands'";
Method Overview
Name | Return Type | Summary | Class | |
---|---|---|---|---|
LabelClass | Creates a deep clone of the LabelClass. more details | more details | LabelClass | |
* | Creates a new instance of this class and initializes it with values from a JSON object generated from a product in the ArcGIS platform. more details | more details | LabelClass | |
Object | Converts an instance of this class to its ArcGIS portal JSON representation. more details | more details | LabelClass |
Method Details
- clone(){LabelClass}
Creates a deep clone of the LabelClass.
Returns:Type Description LabelClass A deep clone of the object that invoked this method. Example:// Creates a deep clone of the graphic's first symbol layer var label = layer.labelingInfo[0].clone();
- 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 ObjectA 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.