dojo.require("esri.layers.LabelClass");
Description
(Added at v3.6)
Use label classes to restrict labels to certain features or to specify different label fields, symbols, scale ranges, label priorities, and sets of label placement options for different groups of labels.
Samples
Search for
samples that use this class.
Constructors
Properties
Constructor Details
Creates a label class, used for formatting parameters, symbols, date, etc.
Parameters:
<Object > json |
Optional |
Various options to configure this LabelClass . Any property can be passed into this object. |
Sample:
Property Details
An array of objects representing field information to label. This is used for formatting Date/Time and Number. It is not necessary if working with string types. See the fieldInfos specifications table below for additional information. (Added at v3.14)
Object Specifications: <fieldInfos
>
<String > fieldName |
Optional |
The name of the field to label. This should only be used when working with Date/Time and Number field types. |
<Object > format |
Optional |
This object can be used with numerical or date fields to provide more detail about how values should be displayed in labels. NOTE: Only applies to date or number fields, (for example float, double, integer). The format object contains the following properties:
- dateFormat: A string used with date fields to specify how the date should appear in labels. Acceptable values can be found in this help topic.
- digitSeparator: Used with the
places property below. It is a boolean used with numerical fields. A value of true allows the number to have a digit (or thousands) separator when the value appears in labels. Depending on the locale, this separator is a decimal point or a comma. A value of false means that no separator will be used.
- places: Used with the
digitSeparator property above. An integer used with numerical fields to specify the number of supported decimal places that should appear in labels. Any places beyond this value are rounded.
Sample snippet showing various formats.
"fieldInfos": [
{ fieldName: "created_date",
format: { dateFormat: "shortDate"}
},
{
fieldName: "last_edited_date",
format: { dateFormat: "longDate"}
},
{
fieldName: "eventtype",
format: { places: 6, digitSeparator: true }
}
]
|
Adjusts the formatting of labels. See the
Labeling Objects section of the ArcGIS REST API documentation for available options.
NOTE: Currently
labelExpression
is not supported with
FeatureLayer types, please use
labelExpressionInfo
instead. This supports using a combination of attribute fields and simple text. If working with
ArcGISDynamicMapServiceLayer layers, please continue to use
labelExpression
.
Sample:
"Name: {CITY_NAME} Area: {CITY_AREA}"
Use this property when working with
FeatureLayer layer types. See the object specification table for
labelExpressionInfo below for more details. If working with
ArcGISDynamicMapServiceLayer layers, use
labelExpression
since
labelExpressionInfo
is not supported.
(Added at v3.12) Object Specifications: <labelExpressionInfo
>
<String > expression |
Required |
An 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: "$feature.CITY_NAME" . Expressions can be more sophisticated and use logical functions. This may be useful if you want to use classed labels. For example, "IIF($feature.POPULATION > 10000, $feature.NAME + ' city', $feature.NAME + ' town')" . |
<String > value |
Optional |
Deprecated at v3.19. Use the expression property instead. The text used to label the feature. Field values may be referenced using the following syntax: "{FIELD_NAME}" . For example, to label points representing city's with their name and population in parentheses, you would use the following string: labelExpressionInfo.value = "{CITY_NAME} ({POP_2012})" |
The position of the label. Available values for various feature types:
- Point: "above-center", "above-left", "above-right", "below-center", "below-left", "below-right", "center-center", "center-left", "center-right"
- Polyline/Line: "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"
- Polygon: "always-horizontal"
The maximum scale to show labels. Note: the number of maxScale
should always be less than the number of minScale
.
The minimum scale to show labels. Note: the number of minScale
should always be greater than the number of maxScale
.
If this is defined, the symbol size changes proportionally. See the object specifications table below for a list of its available properties. (Added at v3.11)
Object Specifications: <sizeInfo
>
<String > field |
Required |
Required name of the feature attribute field that contains the data value. |
<Number > maxDataValue |
Required |
The maximum data value. |
<Number > maxSize |
Required |
Maximum symbol size (in pixels). |
<Number > minDataValue |
Required |
The minimum data value. |
<Number > minSize |
Required |
The symbol size (in pixels) to use for a feature for a minimum data value. |
Sets the Rendering symbol for the label.
Sample: labelClass.symbol = new TextSymbol({
font: new Font("12",Font.STYLE_NORMAL, Font.VARIANT_NORMAL,Font.WEIGHT_BOLD,"Helvetica"),
color: new Color("#666633")
});
When true, show the fields in the labelExpression
that have domains using the domain's name.
Known values: true | false
A where clause determining which features are labeled. When specified, only features that match this clause will be labeled. Only very basic SQL is supported.
Sample: labelClass.where = "STATE_NAME = 'California'";