KnowledgeGraphSublayer | References | ArcGIS Maps SDK for JavaScript

import KnowledgeGraphSublayer from "@arcgis/core/layers/knowledgeGraph/KnowledgeGraphSublayer.js";

Inheritance:: KnowledgeGraphSublayer→Layer→Accessor

Since: ArcGIS Maps SDK for JavaScript 4.26

A KnowledgeGraphSublayer is a sublayer of a KnowledgeGraphLayer or LinkChartLayer that contains all instances of a named type. For example, lets say a knowledge graph has Supplier, Part, and Manufacturer as entity types and buys_part and makes_part as relationship types.

When knowledge graph data is added to a map, each of the named types is a sublayer in the KnowledgeGraphLayer. Each sublayer contains all of the Entity or Relationship instances for that named type. Sublayers of spatial entity types contain features that will be added to the map or displayed in geographic layout on a link chart.

See also

Example

//to access individual sublayers in a KnowledgeGraphLayer
knowledgeGraphLayer.layers.items.forEach((sublayer)=>{
 sublayer.popupTemplate = new PopupTemplate({
  title: "{common_name}",
  content: [{
    type: "text",
    text: "Scientific Name: {name}"
  }]
 });
})

Constructors

Constructor

Parameters

Parameter	Type	Description	Required
properties	`KnowledgeGraphSublayerProperties`

See the properties table for a list of all the properties that may be passed into the constructor.

Properties

Any properties can be set, retrieved or listened to. See the Watch for changes topic.

Property	Type	Class
`blendMode` inherited	`BlendMode`	BlendLayer
`capabilities` readonly	`FeatureLayerCapabilities`
`declaredClass` readonly inherited	`string`	Accessor
`defaultPopupTemplate` readonly	`PopupTemplate \| null \| undefined`
`definitionExpression`	`string \| null \| undefined`
`displayFilterEnabled` inherited	`boolean`	DisplayFilteredLayer
`displayFilterInfo` inherited	`DisplayFilterInfo \| null \| undefined`	DisplayFilteredLayer
`effect` inherited	`Effect \| null \| undefined`	BlendLayer
`elevationInfo`	`ElevationInfo \| null \| undefined`
`featureEffect` inherited	`FeatureEffect \| null \| undefined`	FeatureEffectLayer
`featureReduction` inherited	`FeatureReductionUnion \| null \| undefined`	FeatureReductionLayer
`fields` readonly	`Field[]`
`fieldsIndex` readonly	`FieldsIndex<Field>`
`formTemplate`	`FormTemplate \| null \| undefined`
`fullExtent` inherited	`Extent \| null \| undefined`	Layer
`geometryFieldName` readonly	`string \| null \| undefined`
`geometryType` readonly	`FeatureGeometryType \| null \| undefined`
`graphType`	`"entity" \| "relationship"`
`hasM` readonly	`boolean`
`hasZ` readonly	`boolean`
`id` readonly	`string`
`labelingInfo`	`LabelClass[] \| null \| undefined`
`labelsVisible`	`boolean`
`legendEnabled`	`boolean`
`listMode` inherited	`LayerListMode`	Layer
`loaded` readonly inherited	`boolean`	Layer
`loadError` readonly inherited	`EsriError \| null \| undefined`	LoadableMixin
`loadStatus` readonly inherited	`"not-loaded" \| "loading" \| "failed" \| "loaded"`	LoadableMixin
`loadWarnings` readonly inherited	`any[]`	LoadableMixin
`maxScale`	`number`
`minScale`	`number`
`objectIdField`	`string`
`objectType`	`GraphObjectType`
`opacity` inherited	`number`	Layer
`orderBy` inherited	`OrderByInfo[] \| null \| undefined`	OrderedLayer
`parent` inherited	`Map \| Basemap \| Ground \| GroupLayer \| CatalogDynamicGroupLayer \| CatalogLayer \| null \| undefined`	Layer
`parentCompositeLayer`	`LinkChartLayer \| KnowledgeGraphLayer`
`persistenceEnabled` readonly	`boolean`
`popupEnabled`	`boolean`
`popupTemplate`	`PopupTemplate \| null \| undefined`
`refreshInterval` inherited	`number`	RefreshableLayer
`renderer`	`RendererUnion \| null \| undefined`
`templates`	`FeatureTemplate[] \| null \| undefined`
`timeExtent` inherited	`TimeExtent \| null \| undefined`	TemporalLayer
`timeInfo` inherited	`TimeInfo \| null \| undefined`	TemporalLayer
`timeOffset` inherited	`TimeInterval \| null \| undefined`	TemporalLayer
`title` inherited	`string \| null \| undefined`	Layer
`type` readonly	`"knowledge-graph-sublayer"`
`uid` readonly inherited	`string`	IdentifiableMixin
`useViewTime` inherited	`boolean`	TemporalLayer
`visibilityTimeExtent` inherited	`TimeExtent \| null \| undefined`	Layer
`visible` inherited	`boolean`	Layer

blendMode

inherited Property

Type: BlendMode

Inherited from: BlendLayer

Blend modes are used to blend layers together to create an interesting effect in a layer, or even to produce what seems like a new layer. Unlike the method of using transparency which can result in a washed-out top layer, blend modes can create a variety of very vibrant and intriguing results by blending a layer with the layer(s) below it.

When blending layers, a top layer is a layer that has a blend mode applied. All layers underneath the top layer are background layers. The default blending mode is normal where the top layer is simply displayed over the background layer. While this default behavior is perfectly acceptable, the use of blend modes on layers open up a world of endless possibilities to generate creative maps.

The layers in a GroupLayer are blended together in isolation from the rest of the map.

In the following screenshots, the vintage shaded relief layer is displayed over a firefly world imagery layer. The color blend mode is applied to the vintage shaded relief and the result looks like a new layer.

Known Limitations

In 3D SceneViews, the blendMode is supported on BaseTileLayer, ImageryTileLayer, OpenStreetMapLayer, TileLayer, VectorTileLayer, WCSLayer, WebTileLayer, WMTSLayer and GroupLayer.
When working with GroupLayers in a 3D SceneView, the blendMode is only applied to the sublayers that support it.
The blendMode is not supported in the Legend.
See print for known printing limitations.

The following factors will affect the blend result:

Order of all layers
Layer opacity
Opacity of features in layers
Visibility of layers
By default, the very bottom layer in a map is drawn on a transparent background. You can change the MapView's background color.

Blend mode	Description
normal	The top layer is displayed over the background layer. The data of the top layer block the data of background layer where they overlap.
average	Takes the mathematical average of top and background layers. Result of `average` blend mode is often similar to the effect of setting the layer's opacity to 50%.

Lighten blend modes:

The following blend modes create lighter results than all layers. In lighten blend modes, pure black colors in the top layer become transparent allowing the background layer to show through. White in the top layer will stay unchanged. Any color that is lighter than pure black is going to lighten colors in the top layer to varying degrees all way to pure white.

Lighten blend modes can be useful when lightening dark colors of the top layer or removing black colors from the result. The plus, lighten and screen modes can be used to brighten layers that have faded or dark colors on a dark background.

Blend mode	Description
lighten	Compares top and background layers and retains the lighter color. Colors in the top layer become transparent if they are darker than the overlapping colors in the background layer allowing the background layer to show through completely. Can be thought of as the opposite of `darken` blend mode.
lighter	Colors in top and background layers are multiplied by their alphas (layer opacity and layer's data opacity. Then the resulting colors are added together. All overlapping midrange colors are lightened in the top layer. The opacity of layer and layer's data will affect the blend result.
plus	Colors in top and background layers are added together. All overlapping midrange colors are lightened in the top layer. This mode is also known as `add` or `linear-dodge`.
screen	Multiplies inverted colors in top and background layers then inverts the colors again. The resulting colors will be lighter than the original color with less contrast. Screen can produce many different levels of brightening depending on the luminosity values of the top layer. Can be thought of as the opposite of the `multiply` mode.
color-dodge	Divides colors in background layer by the inverted top layer. This lightens the background layer depending on the value of the top layer. The brighter the top layer, the more its color affects the background layer. Decreases the contrast between top and background layers resulting in saturated mid-tones and blown highlights.

Darken blend modes:

The following blend modes create darker results than all layers. In darken blend modes, pure white in the top layer will become transparent allowing the background layer to show through. Black in the top layer will stay unchanged. Any color that is darker than pure white is going to darken a top layer to varying degrees all the way to pure black.

The multiply blend mode is often used to highlight shadows, show contrast, or accentuate an aspect of a map. For example, you can use multiply blend mode on a topographic map displayed over hillshade when you want to have your elevation show through the topographic layer. See the intro to layer blending sample.

The multiply and darken modes can be used to have dark labels of the basemap to show through top layers. See the darken blending sample.

The color-burn mode works well with colorful top and background layers since it increases saturation in mid-tones. It increases the contrast by tinting pixels in overlapping areas in top and bottom layers more towards the top layer color. Use this blend mode, when you want an effect with more contrast than multiply or darken.

The following screenshots show how the multiply blend mode used for creating a physical map of the world that shows both boundaries and elevation. multiply-blend

Blend mode	Description
darken	Emphasizes the darkest parts of overlapping layers. Colors in the top layer become transparent if they are lighter than the overlapping colors in the background layer, allowing the background layer to show through completely.
multiply	Emphasizes the darkest parts of overlapping layers by multiplying colors of the top layer and the background layer. Midrange colors from top and background layers are mixed together more evenly.
color-burn	Intensifies the dark areas in all layers. It increases the contrast between top and background layers, by tinting colors in overlapping area towards the top color. To do this it inverts colors of the background layer, divides the result by colors of the top layer, then inverts the results.

Contrast blend modes:

The following blend modes create contrast by both lightening the lighter areas and darkening the darker areas in the top layer by using lightening or darkening blend modes to create the blend. The contrast blend modes will lighten the colors lighter than 50% gray ([128,128,128]), and darken the colors darker than 50% gray. 50% gray will be transparent in the top layer. Each mode can create a variety of results depending on the colors of top and background layers being blended together. The overlay blend mode makes its calculations based on the brightness of the colors in the background layer while all of the other contrast blend modes make their calculations based on the brightness of the top layer. Some of these modes are designed to simulate the effect of shining a light through the top layer, effectively projecting upon the layers beneath it.

Contrast blend modes can be used to increase the contrast and saturation to have more vibrant colors and give a punch to your layers. For example, you can duplicate a layer and set overlay blend mode on the top layer to increase the contrast and tones of your layer. You can also add a polygon layer with a white fill symbol over a dark imagery layer and apply soft-light blend mode to increase the brightness in the imagery layer.

The following screenshots show an effect of the overlay blend mode on a GraphicsLayer. The left image shows when the buffer graphics layer has the normal blend mode. As you can see, the gray color for the buffer polygon is blocking the intersecting census tracts. The right image shows when the overlay blend mode is applied to the buffer graphics layer. The overlay blend mode darkens or lightens the gray buffer polygon depending on the colors of the background layer while the census tracts layer is shining through. See this in action.

Normal blend mode	Overlay blend mode

Blend mode	Description
overlay	Uses a combination of `multiply` and `screen` modes to darken and lighten colors in the top layer with the background layer always shining through. The result is darker color values in the background layer intensify the top layer, while lighter colors in the background layer wash out overlapping areas in the top layer.
soft-light	Applies a half strength `screen` mode to lighter areas and half strength `multiply` mode to darken areas of the top layer. You can think of the `soft-light` as a softer version of the `overlay` mode.
hard-light	Multiplies or screens the colors, depending on colors of the top layer. The effect is similar to shining a harsh spotlight on the top layer.
vivid-light	Uses a combination of `color-burn` or `color-dodge` by increasing or decreasing the contrast, depending on colors in the top layer.

Component blend modes:

The following blend modes use primary color components, which are hue, saturation and luminosity to blend top and background layers. You can add a feature layer with a simple renderer over any layer and set hue, saturation, color or luminosity blend mode on this layer. With this technique, you create a brand new looking map.

The following screenshots show where the topo layer is blended with world hillshade layer with luminosity blend mode. The result is a drastically different looking map which preserves the brightness of the topo layer while adapting the hue and saturation of the hillshade layer.

Blend mode	Description
hue	Creates an effect with the hue of the top layer and the luminosity and saturation of the background layer.
saturation	Creates an effect with the saturation of the top layer and the hue and luminosity of the background layer. 50% gray with no saturation in the background layer will not produce any change.
luminosity	Creates effect with the luminosity of the top layer and the hue and saturation of the background layer. Can be thought of as the opposite of `color` blend mode.
color	Creates an effect with the hue and saturation of the top layer and the luminosity of the background layer. Can be thought of as the opposite of `luminosity` blend mode.

Composite blend modes:

The following blend modes can be used to mask the contents of top, background or both layers.

Destination modes are used to mask the data of the top layer with the data of the background layer.
Source modes are used to mask the data of the background layer with the data of the top layer.

The destination-in blend mode can be used to show areas of focus such as earthquakes, animal migration, or point-source pollution by revealing the underlying map, providing a bird's eye view of the phenomenon. Check out multiple blending and groupLayer blending samples to see composite blend modes in action.

The following screenshots show feature and imagery layers on the left side on their own in the order they are drawn in the view. The imagery layer that contains land cover classification rasters. The feature layer contains 2007 county crops data. The right image shows the result of layer blending where destination-in blendMode is set on the imagery layer. As you can see, the effect is very different from the original layers. The blended result shows areas of cultivated crops only (where both imagery and feature layers overlap).

Blend mode	Description
destination-over	Destination/background layer covers the top layer. The top layer is drawn underneath the destination layer. You'll see the top layer peek through wherever the background layer is transparent or has no data.
destination-atop	Destination/background layer is drawn only where it overlaps the top layer. The top layer is drawn underneath the background layer. You'll see the top layer peek through wherever the background layer is transparent or has no data.
destination-in	Destination/background layer is drawn only where it overlaps with the top layer. Everything else is made transparent.
destination-out	Destination/background layer is drawn where it doesn't overlap the top layer. Everything else is made transparent.
source-atop	Source/top layer is drawn only where it overlaps the background layer. You will see the background layer peek through where the source layer is transparent or has no data.
source-in	Source/top layer is drawn only where it overlaps with the background layer. Everything else is made transparent.
source-out	Source/top layer is drawn where it doesn't overlap the background layer. Everything else is made transparent.
xor	Top and background layers are made transparent where they overlap. Both layers are drawn normal everywhere else.

Invert blend modes:

The following blend modes either invert or cancel out colors depending on colors of the background layer. These blend modes look for variations between top and background layers. For example, you can use difference or exclusion blend modes on two imagery layers of forest covers to visualize how forest covers changed from one year to another.

The invert blend mode can be used to turn any light basemap into a dark basemap to accommodate those who work in low-light conditions. The following screenshots show how setting the invert blend mode set on a feature layer with a simple renderer turns the world Hillshade into a dark themed basemap in no time.

Blend mode	Description
difference	Subtracts the darker of the overlapping colors from the lighter color. When two pixels with the same value are subtracted, the result is black. Blending with black produces no change. Blending with white inverts the colors. This blending mode is useful for aligning layers with similar content.
exclusion	Similar to the `difference` blend mode, except that the resulting image is lighter overall. Overlapping areas with lighter color values are lightened, while darker overlapping color values become transparent.
minus	Subtracts colors of the top layer from colors of the background layer making the blend result darker. In the case of negative values, black is displayed.
invert	Inverts the background colors wherever the top and background layers overlap. The invert blend mode inverts the layer similar to a photographic negative.
reflect	This blend mode creates effects as if you added shiny objects or areas of light in the layer. Black pixels in the background layer are ignored as if they were transparent.

See also

Layer blending samples

Default value: "normal"

capabilities

readonly Property

Type: FeatureLayerCapabilities

Describes the layer's supported capabilities.

Example

// Print the maximum number of features that will be returned per server request.
layer.when(() => {
  console.log(`Maximum number of records: ${layer.capabilities.query.maxRecordCount}`);
}

declaredClass

readonlyinherited Property

Type: string

Inherited from: Accessor

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

defaultPopupTemplate

readonly Property

Type: PopupTemplate | null | undefined

The definition of the default popup template for the sublayer.

definitionExpression

Property

Type: string | null | undefined

The SQL where clause used to filter features on the client. Only the features that satisfy the definition expression are displayed in the View. A definition expression is different from an inclusion list because it is applied after the parent KnowledgeGraphLayer is returned. Setting a definition expression is useful when the dataset is large and you don't want to bring all features to the client for analysis.

Example

// Set the definition expression directly on sublayer instance to only suppliers with more than 50 employees.
knowledgeGraphLayer.layers.items[0].definitionExpression = "employee_count > 50";

displayFilterEnabled

inherited Property

Type: boolean

Inherited from: DisplayFilteredLayer

Since: ArcGIS Maps SDK for JavaScript 4.32

Indicates whether the layer's displayFilterInfo is applied when rendering the layer in the view. If false, the layer's display filter is ignored and all features are rendered without filtering. To ignore display filters across all layers in the view, set the view's View.displayFilterEnabled property to false.

Default value: true

displayFilterInfo

autocast inherited Property

Type: DisplayFilterInfo | null | undefined

Inherited from: DisplayFilteredLayer

Since: ArcGIS Maps SDK for JavaScript 4.32

Information related to a display filter associated with a layer. Display filters control which features are visible on the map. They allow you to display a subset of features while retaining access to all features for querying and analysis. Unlike FeatureLayer.definitionExpression, which filters data at the source level, display filters only affect visibility on the map. Therefore display filters should be ignored when querying data to present to users. Display filters can be disabled for all layers in the map by setting the view's View.displayFilterEnabled property to false.

Notes: To optimize memory usage for rendering, display filters may be appended to the layer's FeatureLayer.definitionExpression when querying the service. As a result, the filtered features may not be available on the client for executing layer view queries. To determine if all features are available in the view, check the layer view's FeatureLayerView.hasAllFeaturesInView property when layer view's FeatureLayerView.dataUpdating is false. If false, the layer view does not have all features in the view and you should query the layer instead.

See also

Example

// set a scale-dependent display filter on a layer
const layer = new FeatureLayer({
  portalItem: {
    id: "28dbd58ad90e4a47ab0e0334d2b69427"
  },
  minScale: 0,
  maxScale: 0,
  outFields: ["*"],
  // set scale-dependent display filters to declutter the display at different scales.
  // Show more streams as user zooms in and less as user zooms out.
  displayFilterInfo: new DisplayFilterInfo({
    mode: "scale",
    filters: [
      {
        title: "streamOrder >= 8",
        minScale: 0,
        maxScale: 18_489_297.737236,
        where: "streamOrder >= 8"
      },
      {
        title: "streamOrder >= 6",
        minScale: 18_489_297.737236
        maxScale: 9_244_648.868618,
        where: "streamOrder >= 6"
      },
      {
        title: "streamOrder >= 4",
        minScale: 9_244_648.868618,
        maxScale: 577790.5542885
        where: "streamOrder >= 4"
      },
      {
        title: "all",
        minScale: 577790.5542885,
        maxScale: 0
      }
    ]
  })
});

effect

inherited Property

Type: Effect | null | undefined

Inherited from: BlendLayer

Effect provides various filter functions that can be performed on the layer to achieve different visual effects similar to how image filters work. This powerful capability allows you to apply css filter-like functions to layers to create custom visual effects to enhance the cartographic quality of your maps. This is done by applying the desired effect to the layer's effect property as a string or an array of objects to set scale dependent effects.

Notes

Set featureEffect property on a layer if different effects need to be applied features that meet or fail a specified filter. If all of the following four properties are applied, then they will be applied in this order: featureEffect, effect, opacity and blendMode.

Known Limitations

The effect is not supported in 3D SceneViews.
The effect cannot be applied to a layer with a heatmap renderer.
The effect is not supported in layers with FeatureLayer.featureReduction of type cluster enabled.
See print for known printing limitations.

See also

Examples

// the following effect will be applied to the layer at all scales
// brightness will be applied first, then hue-rotate followed by contrast
// changing order of the effects will change the final result
layer.effect = "brightness(5) hue-rotate(270deg) contrast(200%)";

// set a scale dependent bloom effect on the layer
layer.effect = [
  {
    scale: 36978595,
    value: "drop-shadow(3px, 3px, 4px)"
  },
  {
    scale: 18489297,
    value: "drop-shadow(2px, 2px, 3px)"
  },
  {
    scale: 4622324,
    value: "drop-shadow(1px, 1px, 2px)"
  }
];

elevationInfo

autocast Property

Type: ElevationInfo | null | undefined

Specifies how features are placed on the vertical axis (z). This property may only be used in a SceneView. See the ElevationInfo sample for an example of how this property may be used.

Known Limitations

KnowledgeGraphServices do not currently support Z-values. If the elevation info is not specified, the effective elevation depends on the context and could vary per graphic.

featureEffect

autocast inherited Property

Type: FeatureEffect | null | undefined

Inherited from: FeatureEffectLayer

The featureEffect can be used to draw attention to features of interest. It allows for the selection of features via a filter, and an includedEffect and excludedEffect are applied to those features that respectively pass or fail the filter requirements.

Notes

Set the effect property if the effect needs to be applied to the entire layer.

If the featureEffect is set on the layer, it will be inherited by layerView.featureEffect unless the developer overrides it on the layer view. The layerView.featureEffect will take precedence over layer.featureEffect if both properties are set.

If all of the following four properties are applied, then they will be applied in this order: featureEffect, effect, opacity and blendMode.

Known Limitations

FeatureEffect is not supported in the following scenarios:

In 3D SceneViews
When FeatureReductionCluster is enabled
See print for known printing limitations.

See also

Examples

// gray out features that fall outside of the 3 mile buffer of the mouse's location
// by setting feature effect on excluded features
layer.featureEffect = new FeatureEffect({
  filter: new FeatureFilter({
    geometry: filterGeometry,
    spatialRelationship: "intersects",
    distance: 3,
    units: "miles"
  }),
  excludedEffect: "grayscale(100%) opacity(30%)"
});

// Apply a drop-shadow feature effect to the features that intersect the borough boundaries,
// while applying blur and brightness effects to the features that are excluded from filter criteria.
// The resulting map will make it easier to spot if the residents are more likely to experience deprivation
// if they live on a borough boundary.
const featureFilter = new FeatureFilter({
  where: "BoroughEdge='true'"
});
layer.featureEffect = new FeatureEffect({
  filter: featureFilter,
  includedEffect: "drop-shadow(3px, 3px, 3px, black)",
  excludedEffect: "blur(1px) brightness(65%)"
});

featureReduction

autocast inherited Property

Type: FeatureReductionUnion | null | undefined

Inherited from: FeatureReductionLayer

Configures the method for reducing the number of features in the view. By default this property is null, which indicates the layer view should draw every feature.

There are three types of feature reduction: selection, cluster, and binning.

Selection only applies to points in a SceneView and involves thinning overlapping features so no features intersect on screen. This has been available since version 4.4.
Cluster groups points, lines, or polygons in a MapView into clusters defined in screen space. Each cluster is a point geometry whose size is proportional to the number of features within the cluster. This has been available since version 4.14.
Binning spatially groups points, lines, or polygons in a MapView into bins, clearly defining the area aggregating features in map space. Each bin is a polygon geometry typically rendered so its color represents the number of features within the bin. This has been available since version 4.24.

See also

Examples

// clusters features based on their spatial proximity to other features
layer.featureReduction = {
  type: "cluster",
  clusterRadius: 100
};

// thins features in the view
layer.featureReduction = {
  type: "selection"
};

// Aggregates features to bins
layer.featureReduction = {
  type: "binning",
  renderer: {
    type: "simple",  // autocasts as new SimpleRenderer()
    symbol: {
      type: "simple-fill",  // autocasts as new SimpleFillSymbol()
      outline: {  // autocasts as new SimpleLineSymbol()
        width: 0.5,
        color: "white"
      }
    },
    visualVariables: [{
      type: "color",
      field: "aggregateCount",
      stops: [
        { value: 1, color: "white" },
        { value: 1000, color: "blue" }
      ]
    }]
  },
  popupTemplate: {
    content: "This bin contains <b>{aggregateCount}</b> features.",
    fieldInfos: [{
      fieldName: "aggregateCount",
      format: {
        digitSeparator: true,
        places: 0
      }
    }]
  }
};

fields

readonly Property

Type: Field[]

An array of fields in the layer. Each field represents an attribute that may contain a value for each feature in the layer.

Example

// define each field's schema
const fields = [
 new Field({
   name: "ObjectID",
   alias: "ObjectID",
   type: "oid"
 }), new Field({
   name: "description",
   alias: "Description",
   type: "string"
 }), new Field ({
   name: "title",
   alias: "Title",
   type: "string"
 })
];

fieldsIndex

readonly Property

Type: FieldsIndex<Field>

A convenient property that can be used to make case-insensitive lookups for a field by name. It can also provide a list of the date fields in a layer.

Example

// lookup a field by name. name is case-insensitive
const field = layer.fieldsIndex.get("SoMeFiEld");

if (field) {
  console.log(field.name); // SomeField
}

formTemplate

autocast Property

Type: FormTemplate | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.34

The template used in an associated layer's FeatureForm. All of the properties and field configurations set on the layer's FeatureForm are handled via the FormTemplate.

Example

// Create the Field Elements to pass into the template
const fieldElement1 = new FieldElement({
  fieldName: "firstname",
  label: "First name",
  description: "First name of emergency contact"
});

const fieldElement2 = new FieldElement({
  fieldName: "lastname",
  label: "Last name",
  description: "Last name of emergency contact"
});

// Create the form's template
const formTemplate = new FormTemplate({
  title: "Emergency information",
  description: "In case of emergency, update any additional information needed",
  elements: [fieldElement1, fieldElement2] // pass in array of field elements from above
});

// Pass the template to the layer
knowledgeGraphSublayer.formTemplate = formTemplate;

// Pass the layer to the FeatureForm
const form = new FeatureForm({
  container: "form", // html div referencing the form
  layer: knowledgeGraphSublayer
})

fullExtent

autocast inherited Property

Type: Extent | null | undefined

Inherited from: Layer

The full extent of the layer. By default, this is worldwide. This property may be used to set the extent of the view to match a layer's extent so that its features appear to fill the view. See the sample snippet below.

The fullExtent property is always null for GroupLayer.

Example

// Once the layer loads, set the view's extent to the layer's full extent
layer.when(function(){
  view.extent = layer.fullExtent;
});

geometryFieldName

readonly Property

Type: string | null | undefined

The name of the geometry field for the sublayer.

geometryType

readonly Property

Type: FeatureGeometryType | null | undefined

The geometry type of features in the sublayer.

graphType

Property

Type: "entity" | "relationship"

Specifies whether the sublayer represents an entity type or relationship type.

hasM

readonly Property

Type: boolean

Indicates whether the features in the sublayer have M (measurement) values. Use the supportsM property in the KnowledgeGraphSublayer's capabilities.data object to verify if M values are supported.

Default value: false

hasZ

readonly Property

Type: boolean

Indicates whether the features in the layer have Z (elevation) values. Refer to elevationInfo for details regarding placement and rendering of features with z-values in 3D SceneViews. Use the supportsZ property in the KnowledgeGraphSublayer's capabilities.data object to verify if Z values are supported.

Known Limitations

KnowledgeGraphService's do not currently support Z-values.

Default value: false

id

readonly Property

Type: string

The unique ID assigned to the layer.

labelingInfo

autocast Property

Type: LabelClass[] | null | undefined

The label definition for this sublayer, specified as an array of label classes. Use this property to specify labeling properties for the sublayer such as label expression, placement, and size.

Multiple Label classes with different where clauses can be used to define several labels with varying styles on the same feature. Likewise, multiple label classes may be used to label different types of features (for example blue labels for lakes and green labels for parks).

See the Labeling guide page for more information and known limitations.

See also

Example

const statesLabelClass = new LabelClass({
  labelExpressionInfo: { expression: "$feature.NAME" },
  symbol: {
    type: "text",  // autocasts as new TextSymbol()
    color: "black",
    haloSize: 1,
    haloColor: "white"
  }
});

knowledgeGraphLayer.layers.items[0].labelingInfo = [ statesLabelClass ];

labelsVisible

Property

Type: boolean

Indicates whether to display labels for this sublayer. If true, labels will appear as defined in the labelingInfo property.

Known Limitations

3D SceneViews only support displaying one LabelClass per feature.

Default value: true

legendEnabled

Property

Type: boolean

Indicates whether the layer will be included in the legend. When false, the layer will be excluded from the legend.

Default value: true

listMode

inherited Property

Type: LayerListMode

Inherited from: Layer

Indicates how the layer should display in the Layer List component. The possible values are listed below.

Value	Description
show	The layer is visible in the table of contents.
hide	The layer is hidden in the table of contents.
hide-children	If the layer is a GroupLayer, BuildingSceneLayer, KMLLayer, MapImageLayer, SubtypeGroupLayer, TileLayer, or WMSLayer, hide the children layers from the table of contents.

Default value: "show"

loaded

readonlyinherited Property

Type: boolean

Inherited from: Layer

Indicates whether the layer's resources have loaded. When true, all the properties of the object can be accessed.

Default value: false

loadError

readonlyinherited Property

Type: EsriError | null | undefined

Inherited from: LoadableMixin

The Error object returned if an error occurred while loading.

loadStatus

readonlyinherited Property

Type: "not-loaded" | "loading" | "failed" | "loaded"

Inherited from: LoadableMixin

Represents the status of a load() operation.

Value	Description
not-loaded	The object's resources have not loaded.
loading	The object's resources are currently loading.
loaded	The object's resources have loaded without errors.
failed	The object's resources failed to load. See loadError for more details.

Default value: "not-loaded"

loadWarnings

readonlyinherited Property

Type: any[]

Inherited from: LoadableMixin

A list of warnings which occurred while loading.

maxScale

Property

Type: number

The maximum scale (most zoomed in) at which the layer is visible in the view. If the map is zoomed in beyond this scale, the layer will not be visible. A value of 0 means the layer does not have a maximum scale. The maxScale value should always be smaller than the minScale value, and greater than or equal to the service specification.

Default value: 0

Examples

// The layer will not be visible when the view is zoomed in beyond a scale of 1:1,000
layer.maxScale = 1000;

// The layer's visibility is not restricted to a maximum scale.
layer.maxScale = 0;

minScale

Property

Type: number

The minimum scale (most zoomed out) at which the layer is visible in the view. If the map is zoomed out beyond this scale, the layer will not be visible. A value of 0 means the layer does not have a minimum scale. The minScale value should always be larger than the maxScale value, and lesser than or equal to the service specification.

Default value: 0

Examples

// The layer will not be visible when the view is zoomed out beyond a scale of 1:3,000,000
layer.minScale = 3000000;

// The layer's visibility is not restricted to a minimum scale.
layer.minScale = 0;

objectIdField

Property

Type: string

The name of an oid containing a unique value or identifier for each feature in the sublayer.

objectType

Property

Type: GraphObjectType

Outlines the type definition for the named type represented by the sublayer.

opacity

inherited Property

Type: number

Inherited from: Layer

The opacity of the layer. This value can range between 1 and 0, where 0 is 100 percent transparent and 1 is completely opaque.

Known Limitations

In a 3D SceneView, modifying opacity is not supported for DimensionLayer, GaussianSplatLayer, IntegratedMesh3DTilesLayer, IntegratedMeshLayer, LineOfSightLayer, PointCloudLayer, ViewshedLayer, and VoxelLayer.

Default value: 1

Example

// Makes the layer 50% transparent
layer.opacity = 0.5;

orderBy

autocast inherited Property

Type: OrderByInfo[] | null | undefined

Inherited from: OrderedLayer

Determines the order in which features are drawn in the view. You can sort features by a field value or the value returned from an Arcade expression in ascending or descending order.

When null (default), features are drawn in the order they are returned from the service or client.

Known Limitations

This property only controls feature drawing order in MapView. Configuring feature drawing order in SceneView is not supported.
This property does not control the drawing order of clusters. It only applies to individual features.
Feature drawing order configurations defined with Arcade expressions cannot be saved to web maps.
Currently, you can only sort features by one field or expression.

See also

Arcade Feature Z Profile

Examples

// Features with smaller population values will
// be rendered on top of larger features.
layer.orderBy = [{
  field: "POPULATION"
}];

// Features with larger population values will
// be rendered on top of smaller features.
layer.orderBy = [{
  field: "POPULATION",
  order: "descending"
}];

// Orders features by date in descending order.
// The most recent features will be rendered
// on top of older features.
layer.orderBy = [{
  field: "Alarm_Date",
  order: "descending"
}];

// Orders features by storm warning duration in descending order.
// Warnings with longer durations
// be rendered on top of warnings with shorter durations.
layer.orderBy = [{
  valueExpression: "DateDiff($feature.Watch_End, $feature.Watch_Start, 'hours' )",
  order: "descending"
}];

// Orders features by data values used in a size visual variable
const sizeVariable = layer.renderer.visualVariables.find( vv => vv.type === "size");
const { field, valueExpression } = sizeVariable;
layer.orderBy = [{
  field,
  valueExpression,
  order: "ascending"
}];

parent

inherited Property

Type: Map | Basemap | Ground | GroupLayer | CatalogDynamicGroupLayer | CatalogLayer | null | undefined

Inherited from: Layer

Since: ArcGIS Maps SDK for JavaScript 4.27

The parent to which the layer belongs.

parentCompositeLayer

Property

Type: LinkChartLayer | KnowledgeGraphLayer

The KnowledgeGraphLayer of which this is a sublayer for a specific entity or relationship type.

persistenceEnabled

readonly Property

Type: boolean

Since: ArcGIS Maps SDK for JavaScript 4.28

Enable persistence of the layer in a WebMap or WebScene.

Default value: true

popupEnabled

Property

Type: boolean

Indicates whether to display popups when features in the layer are clicked. The layer needs to have a popupTemplate to define what information should be displayed in the popup. Alternatively, a default popup template may be automatically used if Popup.defaultPopupTemplateEnabled is set to true.

See also

Default value: true

popupTemplate

autocast Property

Type: PopupTemplate | null | undefined

The popup template for the sublayer. When set on the sublayer, the popupTemplate allows users to access attributes and display their values in the view's Popup when a feature is selected using text and/or charts. .

A default popup template is automatically used if no popupTemplate has been defined when Popup.defaultPopupTemplateEnabled is set to true.

See also

refreshInterval

inherited Property

Type: number

Inherited from: RefreshableLayer

Refresh interval of the layer in minutes. Value of 0 indicates no refresh.

See also

Default value: 0

Example

// the layer will be refreshed every minute.
layer.refreshInterval = 1;

renderer

autocast Property

Type: RendererUnion | null | undefined

The renderer assigned to the sublayer. The renderer defines how to visualize each feature in the sublayer. Depending on the renderer type, features may be visualized with the same symbol, or with varying symbols based on the values of provided attribute fields or functions.

See also

Styles and data visualization

Example

// all features in the sublayer will be visualized with
// a 6pt black marker symbol and a thin, white outline

//Apply renderer to the first sublayer of the KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];
sublayer.renderer = {
  type: "simple",  // autocasts as new SimpleRenderer()
  symbol: {
    type: "simple-marker",  // autocasts as new SimpleMarkerSymbol()
    size: 6,
    color: "black",
    outline: {  // autocasts as new SimpleLineSymbol()
      width: 0.5,
      color: "white"
    }
  }
};

templates

autocast Property

Type: FeatureTemplate[] | null | undefined

Since: ArcGIS Maps SDK for JavaScript 4.34

An array of feature templates defined in the knowledge graph sublayer.

timeExtent

autocast inherited Property

Type: TimeExtent | null | undefined

Inherited from: TemporalLayer

The layer's time extent. When the layer's useViewTime is false, the layer instructs the view to show data from the layer based on this time extent. If the useViewTime is true, and both layer and view time extents are set, then features that fall within the intersection of the view and layer time extents will be displayed. For example, if the layer's time extent is set to display features between 1970 and 1975 and the view has a time extent set to 1972-1980, the effective time on the feature layer will be 1972-1975.

Examples

if (!layer.useViewTime) {
  if (layer.timeExtent) {
    console.log("Current timeExtent:", layer.timeExtent.start, " - ", layer.timeExtent.end}
  } else {
    console.log("The layer will display data within the view's timeExtent.");
    console.log("Current view.timeExtent:", view.timeExtent.start, " - ", view.timeExtent.end}
  }
}

// set the timeExtent on the layer and useViewTime false
// In this case, the layer will honor its timeExtent and ignore
// the view's timeExtent
const layer = new ImageryLayer({
  url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/ScientificData/SeaTemperature/ImageServer",
  timeExtent: {
    start: new Date(2014, 4, 18),
    end: new Date(2014, 4, 19)
  },
  useViewTime: false
});

// timeExtent is set on the layer and the view
// In this case, the layer will display features that fall
// within the intersection of view and layer time extents
// features within Jan 1, 1976 - Jan 1, 1981 will be displayed
const view = new MapView({
  timeExtent: {
    start: new Date(1976, 0, 1),
    end: new Date(2002, 0, 1)
  }
});
const layer = new FeatureLayer({
  url: myUrl,
  timeExtent: {
    start: new Date(1974, 0, 1),
    end: new Date(1981, 0, 1)
  }
});

timeInfo

autocast inherited Property

Type: TimeInfo | null | undefined

Inherited from: TemporalLayer

TimeInfo provides information such as date fields that store start and end time for each feature and the fullTimeExtent for the layer. The timeInfo property, along with its startField and endField properties, must be set at the time of layer initialization if it is being set for a CSVLayer, GeoJSONLayer or FeatureLayer initialized from client-side features. The fullTimeExtent for timeInfo is automatically calculated based on its startField and endField properties. The timeInfo parameters cannot be changed after the layer is loaded.

TimeInfo's TimeInfo.startField and endField can be date, date-only or timestamp-offset field type for FeatureLayer and MapImageLayer.

Example

// create geojson layer from usgs earthquakes geojson feed
const geojsonLayer = new GeoJSONLayer({
  url: "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_month.geojson",
  copyright: "USGS Earthquakes",
  fields: [
    { "name": "mag", "type": "double" },
    { "name": "place", "type": "string" },
    { "name": "time", "type": "date" }, // date field
    { "name": "depth", "type": "double" }
  ],
  // timeInfo can be used to do temporal queries
  // set the startField and endField.
  // timeExtent is automatically calculated from the
  // the start and end date fields
  // The date values must be in milliseconds number from the UNIX epoch specified in UTC.
  timeInfo: {
    startField: "time"
  }
});

timeOffset

autocast inherited Property

Type: TimeInterval | null | undefined

Inherited from: TemporalLayer

A temporary offset of the time data based on a certain TimeInterval. This allows users to overlay features from two or more time-aware layers with different time extents. For example, if a layer has data recorded for the year 1970, an offset value of 2 years would temporarily shift the data to 1972. You can then overlay this data with data recorded in 1972. A time offset can be used for display purposes only. The query and selection are not affected by the offset.

Example

// Offset a CSV Layer containing hurricanes from 2015 so that they appear in 2019 (+4 years).
let layer = new CSVLayer({
  url: `hurricanes-and-storms-2015.csv`,
  timeOffset: {
    value: 4,
    unit: "years"
  },
  timeInfo: {
    startField: "ISO_time"
  },
  renderer: {
    type: "simple",
    symbol: {
      type: "simple-marker",
      size: 6,
      color: "red",
      outline: {
        width: 0.5,
        color: "black"
      }
    }
  }
});

title

inherited Property

Type: string | null | undefined

Inherited from: Layer

The title of the layer used to identify it in places such as the Layer List component.

If the layer is loaded from a portal item, the title of the portal item will be used. If a layer is loaded as part of a webmap or a webscene, then the title of the layer as stored in the webmap/webscene will be used.

type

readonly Property

Type: "knowledge-graph-sublayer"

The layer type provides a convenient way to check the type of the layer without the need to import specific layer modules.

uid

readonlyinherited Property

Type: string

Inherited from: IdentifiableMixin

Since: ArcGIS Maps SDK for JavaScript 4.33

An automatically generated unique identifier assigned to the instance. The unique id is generated each time the application is loaded.

useViewTime

inherited Property

Type: boolean

Inherited from: TemporalLayer

Determines if the time enabled layer will update its temporal data based on the view's timeExtent. When false, the layer will display its temporal data based on the layer's timeExtent, regardless of changes to the view. If both view and layer time extents are set while this property is true, then the features that fall within the intersection of the view and layer time extents will be displayed. For example, if a layer's time extent is set to display features between 1970 and 1975 and the view has a time extent set to 1972-1980, the effective time on the feature layer will be 1972-1975.

Changing useViewTime to false does not affect layer's visibilityTimeExtent.

Default value: true

Example

if (featureLayer.useViewTime) {
  console.log("Displaying data between:", view.timeExtent.start, " - ", view.timeExtent.end);
}

visibilityTimeExtent

autocast inherited Property

Type: TimeExtent | null | undefined

Inherited from: Layer

Since: ArcGIS Maps SDK for JavaScript 4.30

Specifies a fixed time extent during which a layer should be visible. This property can be used to configure a layer that does not have time values stored in an attribute field to work with time. Once configured, the TimeSlider widget will display the layer within the set time extent. In the case that only one of the TimeExtent.start or TimeExtent.end date values are available, the layer remains visible indefinitely in the direction where there is no time value.

Aerial imagery can capture seasonal variations in vegetation, water bodies, and land use patterns. For example, in agricultural regions, aerial imageries taken during different growing seasons provide insights into crop health and productivity. Defining a fixed time extent on imageries from specific time periods provides temporal context and facilitates focused analysis based on specific time periods or events.

See also

Sample - GraphicsLayer with visibilityTimeExtent

visible

inherited Property

Type: boolean

Inherited from: Layer

Indicates if the layer is visible in the View. When false, the layer may still be added to a Map instance that is referenced in a view, but its features will not be visible in the view.

Default value: true

Example

// The layer is no longer visible in the view
layer.visible = false;

// Watch for changes in the layer's visibility
// and set the visibility of another layer when it changes
reactiveUtils.watch(
  () => layer.visible,
  (visible) => {
    if (visible) {
      anotherLayer.visible = true;
    } else {
      anotherLayer.visible = false;
    }
  }
);

Methods

Method	Signature	Class
`fromArcGISServerUrl` inherited static	`fromArcGISServerUrl(params: string \| FromArcGISServerUrlParameters): Promise<Layer>`	Layer
`fromPortalItem` inherited static	`fromPortalItem(params: LayerFromPortalItemParameters): Promise<Layer>`	Layer
`cancelLoad` inherited	`cancelLoad(): this`	LoadableMixin
`createLayerView` inherited	`createLayerView<T extends LayerView = LayerView>(view: View<T>, options?: AbortOptions): Promise<T>`	Layer
`createPopupTemplate`	`createPopupTemplate(options?: CreatePopupTemplateOptions): PopupTemplate \| null \| undefined`
`createQuery`	`createQuery(): Query`
`destroy` inherited	`destroy(): void`	Layer
`emit` inherited	`emit<Type extends EventNames<this>>(type: Type, event?: this["@eventTypes"][Type]): boolean`	EventedMixin
`fetchAttributionData` inherited	`fetchAttributionData(): Promise<any>`	Layer
`getField`	`getField(fieldName: string): Field \| null \| undefined`
`getFieldDomain`	`getFieldDomain(fieldName: string, options?: FieldDomainOptions): DomainUnion \| null \| undefined`
`hasEventListener` inherited	`hasEventListener<Type extends EventNames<this>>(type: Type): boolean`	EventedMixin
`isFulfilled` inherited	`isFulfilled(): boolean`	EsriPromiseMixin
`isRejected` inherited	`isRejected(): boolean`	EsriPromiseMixin
`isResolved` inherited	`isResolved(): boolean`	EsriPromiseMixin
`load` inherited	`load(options?: AbortOptions \| null \| undefined): Promise<this>`	LoadableMixin
`on` inherited	`on<Type extends EventNames<this>>(type: Type, listener: EventedCallback<this["@eventTypes"][Type]>): ResourceHandle`	EventedMixin
`queryExtent`	`queryExtent(query?: QueryProperties \| null \| undefined, options?: RequestOptions): Promise<{ count: number; extent: Extent \| null; }>`
`queryFeatureCount`	`queryFeatureCount(query?: QueryProperties \| null \| undefined, options?: RequestOptions): Promise<number>`
`queryFeatures`	`queryFeatures(query?: QueryProperties \| null \| undefined, options?: RequestOptions): Promise<FeatureSet>`
`queryObjectIds`	`queryObjectIds(query?: QueryProperties \| null \| undefined, options?: RequestOptions): Promise<ObjectId[]>`
`refresh` inherited	`refresh(): void`	RefreshableLayer
`when` inherited	`when<TResult1 = this, TResult2 = never>(onFulfilled?: OnFulfilledCallback<this, TResult1> \| null \| undefined, onRejected?: OnRejectedCallback<TResult2> \| null \| undefined): Promise<TResult1 \| TResult2>`	EsriPromiseMixin

fromArcGISServerUrl

inheritedstatic Method

Signature: fromArcGISServerUrl (params: string | FromArcGISServerUrlParameters): Promise<Layer>

Inherited from: Layer

Creates a new layer instance from an ArcGIS Server URL. Depending on the URL, the returned layer type may be a BuildingSceneLayer, CatalogLayer, ElevationLayer, FeatureLayer, GroupLayer, ImageryLayer, ImageryTileLayer, IntegratedMeshLayer, KnowledgeGraphLayer, MapImageLayer, OrientedImageryLayer, PointCloudLayer, SceneLayer, StreamLayer, SubtypeGroupLayer, TileLayer, or VideoLayer.

This is useful when you work with various ArcGIS Server URLs, but you don't necessarily know which layer type(s) they create. This method creates the appropriate layer type for you. In case of a feature service or a scene service, when the URL points to the service and the service has multiple layers, the returned promise will resolve to a GroupLayer.

Beginning with version 4.17, it is possible to load tables from hosted feature services. This only applies to feature layers, and will successfully load if FeatureLayer.isTable returns true.

The following table details what is returned when loading specific URL types.

URL	Returns
Feature service with one layer	FeatureLayer where FeatureLayer.isTable returns `false`.
Feature service with one table	FeatureLayer where FeatureLayer.isTable returns `true`.
Feature service with more than one layer(s)/table(s)	GroupLayer with layers and tables.
Layers with type other than "Feature Layer" are discarded, e.g. Utility Network Layers	N/A

See also

FeatureLayer.isTable

Parameters

Parameter	Type	Description	Required
params	`string \| FromArcGISServerUrlParameters`	Input parameters for creating the layer.

Returns: Promise<Layer>
Returns a promise that resolves to the new Layer instance.

Examples

// This snippet shows how to add a feature layer from an ArcGIS Server URL
// Get an ArcGIS Server URL from a custom function
const arcgisUrl = getLayerUrl();

Layer.fromArcGISServerUrl({
  url: arcgisUrl,
  properties: {
    // set any layer properties here
    popupTemplate: new PopupTemplate()
  }
}).then(function(layer){
  // add the layer to the map
  map.add(layer);
});

// This snippet shows how to add a table from an ArcGIS Server URL
// Get an ArcGIS Server URL from a custom function
const arcgisUrl = getLayerUrl();

Layer.fromArcGISServerUrl({
  url: arcgisUrl
}).then(function(layer){
  // Load the table before it can be used
  layer.load().then(function() {
    // Check that it is the right type
    if (layer.isTable) {
      // Add table to map's tables collection
      map.tables.add(layer);
    }
  });
});

fromPortalItem

inheritedstatic Method

Signature: fromPortalItem (params: LayerFromPortalItemParameters): Promise<Layer>

Inherited from: Layer

Creates a new layer instance of the appropriate layer class from an ArcGIS Online or ArcGIS Enterprise portal item. If the item points to a feature service with multiple layers, then a GroupLayer is created. If the item points to a service with a single layer, then it resolves to a layer of the same type of class as the service.

Note

At version 4.29, MediaLayer can be loaded from portal items.
At version 4.28, GroupLayer and OrientedImageryLayer can be loaded from portal items.
At version 4.25, CSVLayer and GeoJSONLayer can be loaded from CSV and GeoJSON portal items respectively.
At version 4.17, it is possible to load tables from feature service items hosted in ArcGIS Online and ArcGIS Enterprise. This only applies to feature layers, and will successfully load if FeatureLayer.isTable returns true.

The following table details what is returned when loading specific item types.

Item(s)	Returns
Feature service with one layer	FeatureLayer where FeatureLayer.isTable returns `false`.
Feature service with one table	FeatureLayer where FeatureLayer.isTable returns `true`.
Feature service with more than one layer(s)/table(s)	GroupLayer with layers and tables.
Feature collection with one layer	FeatureLayer where FeatureLayer.isTable returns `false`.
Feature collection with one table	FeatureLayer where FeatureLayer.isTable returns `true`.
Feature collection with more than one layer(s)/table(s)	GroupLayer with layers and tables.

Known Limitations

This method does not currently work with OGCFeatureServer portal items.

See also

Parameters

Parameter	Type	Description	Required
params	`LayerFromPortalItemParameters`	The parameters for loading the portal item.

Returns: Promise<Layer>
Returns a promise which resolves to the new layer instance.

Examples

// Create a layer from a specified portal item and add to the map
Layer.fromPortalItem({
  portalItem: {  // autocasts new PortalItem()
    id: "8444e275037549c1acab02d2626daaee"
  }
}).then(function(layer){
  // add the layer to the map
  map.add(layer);
});

// Create a table from a specified portal item and add it to the map's tables collection
Layer.fromPortalItem({
  portalItem: { // autocasts new PortalItem()
    id: "123f4410054b43d7a0bacc1533ceb8dc" // This is a hosted table stored in a feature service
  }
}).then(function(layer) {
  // Necessary to load the table in order for it to be read correctly
  layer.load().then(function() {
    // Confirm this reads as a table
    if (layer.isTable) {
      // Add the new table to the map's table collection
      map.tables.add(layer);
    }
  });
});

cancelLoad

inherited Method

Signature: cancelLoad (): this

Inherited from: LoadableMixin

Cancels a load() operation if it is already in progress.

Returns: this

createLayerView

inherited Method

Signature: createLayerView <T extends LayerView = LayerView>(view: View<T>, options?: AbortOptions): Promise<T>

Type parameters: <T extends LayerView = LayerView>

Inherited from: Layer

Called by the views, such as MapView and SceneView, when the layer is added to the Map.layers collection and a layer view must be created for it. This method is used internally and there is no use case for invoking it directly.

See also

Sample - Custom WebGL layer view

Parameters

Parameter	Type	Description	Required
view	`View`	The parent view.
options	`AbortOptions`	An object specifying additional options. See the object specification table below for the required properties of this object.

Returns: Promise
Resolves with a LayerView instance.

createPopupTemplate

Method

Signature: createPopupTemplate (options?: CreatePopupTemplateOptions): PopupTemplate | null | undefined

Creates a popup template for the layer, populated with all the fields of the layer.

Parameters

Parameter	Type	Description	Required
options	`CreatePopupTemplateOptions`	Options for creating the popup template.

Returns: PopupTemplate | null | undefined
The popup template, or null if the layer does not have any fields.

createQuery

Method

Signature: createQuery (): Query

Creates query parameter object that can be used to fetch features that satisfy the layer's configurations such as definitionExpression,. It will return Z and M values based on the layer's data capabilities. It sets the query parameter's Query.outFields property to ["*"]. The results will include geometries of features and values for all available fields for client-side queries or all fields in the layer for server side queries.

Returns: Query
The query object representing the sublayer's definition expression and other configurations.

Example

// Get a query object for the layer's current configuration
// queryParams.outFields will be set to ["*"] to get values
// for all available fields.

//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];
const queryParams = sublayer.createQuery();
// set a geometry for filtering features by a region of interest
queryParams.geometry = extentForRegionOfInterest;
// Add to the sublayer's current definitionExpression
queryParams.where = queryParams.where + " AND TYPE = 'Extreme'";

// query the sublayer with the modified params object
sublayer.queryFeatures(queryParams).then(function(results){
  // prints the array of result graphics to the console
  console.log(results.features);
});

destroy

inherited Method

Signature: destroy (): void

Inherited from: Layer

Destroys the layer and any associated resources (including its portalItem, if it is a property on the layer). The layer can no longer be used once it has been destroyed.

The destroyed layer will be removed from its parent object like Map, WebMap, WebScene, Basemap, Ground, or GroupLayer.

See also

Returns: void

emit

inherited Method

Signature: emit <Type extends EventNames<this>>(type: Type, event?: this["@eventTypes"][Type]): boolean

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters

Parameter	Type	Description	Required
type	`Type`	The name of the event.
event	`this["@eventTypes"][Type]`	The event payload.

Returns: boolean
true if a listener was notified

fetchAttributionData

inherited Method

Signature: fetchAttributionData (): Promise<any>

Inherited from: Layer

Fetches custom attribution data for the layer when it becomes available.

Returns: Promise<any>
Resolves to an object containing custom attribution data for the layer.

getField

Method

Signature: getField (fieldName: string): Field | null | undefined

Returns the Field instance for a field name (case-insensitive).

Parameters

Parameter	Type	Description	Required
fieldName	`string`	Name of the field.

Returns: Field | null | undefined
the matching field or undefined

getFieldDomain

Method

Signature: getFieldDomain (fieldName: string, options?: FieldDomainOptions): DomainUnion | null | undefined

Returns the Domain associated with the given field name. The domain can be either a CodedValueDomain or RangeDomain.

Parameters

Parameter	Type	Description	Required
fieldName	`string`	Name of the field.
options	`FieldDomainOptions`	An object specifying additional options. See the object specification table below for the required properties of this object.

Returns: DomainUnion | null | undefined
The Domain object associated with the given field name for the given feature.

Example

// Get a range domain associated with the first feature
// returned from queryFeatures().
//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];
sublayer.queryFeatures(query).then(function(results){
  const domain = sublayer.getFieldDomain("Height", {feature: results.features[0]});
  console.log("domain", domain)
});

hasEventListener

inherited Method

Signature: hasEventListener <Type extends EventNames<this>>(type: Type): boolean

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameters

Parameter	Type	Description	Required
type	`Type`	The name of the event.

Returns: boolean
Returns true if the class supports the input event.

isFulfilled

inherited Method

Signature: isFulfilled (): boolean

Inherited from: EsriPromiseMixin

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled, true will be returned.

Returns: boolean
Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).

isRejected

inherited Method

Signature: isRejected (): boolean

Inherited from: EsriPromiseMixin

isRejected() may be used to verify if creating an instance of the class is rejected. If it is rejected, true will be returned.

Returns: boolean
Indicates whether creating an instance of the class has been rejected.

isResolved

inherited Method

Signature: isResolved (): boolean

Inherited from: EsriPromiseMixin

isResolved() may be used to verify if creating an instance of the class is resolved. If it is resolved, true will be returned.

Returns: boolean
Indicates whether creating an instance of the class has been resolved.

load

inherited Method

Signature: load (options?: AbortOptions | null | undefined): Promise<this>

Inherited from: LoadableMixin

Loads the resources referenced by this class. This method automatically executes for a View and all of the resources it references in Map if the view is constructed with a map instance.

This method must be called by the developer when accessing a resource that will not be loaded in a View.

The load() method only triggers the loading of the resource the first time it is called. The subsequent calls return the same promise.

It's possible to provide a signal to stop being interested into a Loadable instance load status. When the signal is aborted, the instance does not stop its loading process, only cancelLoad() can abort it.

Parameters

Parameter	Type	Description	Required
options	`AbortOptions \| null \| undefined`	Additional options.

Returns: Promise<this>
Resolves when the resources have loaded.

on

inherited Method

Signature: on <Type extends EventNames<this>>(type: Type, listener: EventedCallback<this["@eventTypes"][Type]>): ResourceHandle

Type parameters: <Type extends EventNames<this>>

Inherited from: EventedMixin

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters

Parameter	Type	Description	Required
type	`Type`	An event or an array of events to listen for.
listener	`EventedCallback<this["@eventTypes"][Type]>`	The function to call when the event fires.

Returns

ResourceHandle

Returns an event handler with a remove() method that should be called to stop listening for the event(s).

Property	Type	Description
remove	Function	When called, removes the listener from the event.

Example

view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});

queryExtent

Method

Signature: queryExtent (query?: QueryProperties | null | undefined, options?: RequestOptions): Promise<{ count: number; extent: Extent | null; }>

Executes a Query against the knowledge graph service and returns the Extent of features that satisfy the query. If no parameters are specified, then the extent and count of all features satisfying the sublayer's configuration/filters are returned.

Parameters

Parameter	Type	Description	Required
query	`QueryProperties \| null \| undefined`	Specifies the attributes and spatial filter of the query. If no parameters are specified, then the extent and count of all features satisfying the sublayer's configuration/filters are returned.
options	`RequestOptions`	An object with the following properties.

Returns

Promise<{ count: number; extent: Extent | null; }>

When resolved, returns the extent and count of the features that satisfy the input query. See the object specification table below for details.

Property	Type	Description
count	Number	The number of features that satisfy the input query.
extent	Extent	The extent of the features that satisfy the query.

Examples

// Queries for the extent of all features matching the layer's configurations
// e.g. definitionExpression
//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];
sublayer.queryExtent().then(function(results){
  // go to the extent of the results satisfying the query
  view.goTo(results.extent);
});

//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];

const query = new Query();
query.where = "region = 'Southern California'";

sublayer.queryExtent(query).then(function(results){
  view.goTo(results.extent);  // go to the extent of the results satisfying the query
});

queryFeatureCount

Method

Signature: queryFeatureCount (query?: QueryProperties | null | undefined, options?: RequestOptions): Promise<number>

Executes a Query against the knowledge graph service and returns the number of features that satisfy the query. If no parameters are specified, the total number of features satisfying the sublayer's configuration/filters is returned.

Parameters

Parameter	Type	Description	Required
query	`QueryProperties \| null \| undefined`	Specifies the attributes and spatial filter of the query. If no parameters are specified, the total number of features satisfying the layer's configuration/filters is returned.
options	`RequestOptions`	An object with the following properties.

Returns: Promise<number>
When resolved, returns the number of features that satisfy the query.

Examples

// Queries for the count of all features matching the layer's configurations
// e.g. definitionExpression
//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];
sublayer.queryFeatureCount().then(function(numFeatures){
  // prints the total count to the console
  console.log(numFeatures);
});

//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];

const query = new Query();
query.where = "region = 'Southern California'";

sublayer.queryFeatureCount(query).then(function(numResults){
  console.log(numResults);  // prints the number of results satisfying the query
});

queryFeatures

Method

Signature: queryFeatures (query?: QueryProperties | null | undefined, options?: RequestOptions): Promise<FeatureSet>

Executes a Query against the feature service and returns a FeatureSet, once the promise resolves. A FeatureSet contains an array of Graphic features. See the querying section for more information on how to query features from a layer.

To query features/graphics available to or visible in the View on the client rather than making a server-side query, you must use the FeatureLayerView.queryFeatures() method.

When querying a service with z-values and no vertical coordinate system information, the z-values will automatically be converted to match the Query.outSpatialReference units. Example: The service has a horizontal spatial reference using feet units and the query is made with outSpatialReference based on meter units, then queryFeatures() automatically converts the values from feet to meter units.

Parameters

Parameter	Type	Description	Required
query	`QueryProperties \| null \| undefined`	Specifies the attributes and spatial filter of the query. If no parameters are specified, then all features satisfying the layer's configuration/filters are returned.
options	`RequestOptions`	An object with the following properties.

Returns: Promise<FeatureSet>
When resolved, a FeatureSet containing an array of graphic features is returned.

Examples

// Queries for all the features matching the layer's configurations
// e.g. definitionExpression
 //get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];
sublayer.queryFeatures().then(function(results){
  // prints the array of result graphics to the console
  console.log(results.features);
});

//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];

const query = new Query();
query.where = "STATE_NAME = 'Washington'";
query.outSpatialReference = { wkid: 102100 };
query.returnGeometry = true;
query.outFields = [ "CITY_NAME" ];

sublayer.queryFeatures(query).then(function(results){
  console.log(results.features);  // prints the array of features to the console
});

// Get a query object for the sublayer's current configuration
const queryParams = sublayer.createQuery();
// set a geometry for filtering features by a region of interest
queryParams.geometry = extentForRegionOfInterest;
// Add to the sublayer's current definitionExpression
queryParams.where = queryParams.where + " AND TYPE = 'Extreme'";

// query the sublayer with the modified params object
sublayer.queryFeatures(queryParams).then(function(results){
  // prints the array of result graphics to the console
  console.log(results.features);
});

//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];

// query all features from the layer and only return
// attributes specified in outFields.
const query = { // autocasts as Query
  where: "1=1", // select all features
  returnGeometry: false,
  outFields: ["State_Name", "City_Name", "pop2010"]
};

sublayer.queryFeatures(query).then(function(results){
  console.log(results.features);  // prints the array of features to the console
});

queryObjectIds

Method

Signature: queryObjectIds (query?: QueryProperties | null | undefined, options?: RequestOptions): Promise<ObjectId[]>

Executes a Query against the knowledge graph service and returns an array of Object IDs for features that satisfy the input query. If no parameters are specified, then the Object IDs of all features satisfying the layer's configuration/filters are returned.

Parameters

Parameter	Type	Description	Required
query	`QueryProperties \| null \| undefined`	Specifies the attributes and spatial filter of the query. If no parameters are specified, then the Object IDs of all features satisfying the sublayer's configuration/filters are returned.
options	`RequestOptions`	An object with the following properties.

Returns: Promise<ObjectId[]>
When resolved, returns an array of numbers representing the object IDs of the features satisfying the query.

Examples

// Queries for all the Object IDs of features matching the layer's configurations
// e.g. definitionExpression
//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = knowledgeGraphLayer.layers.items[0];
sublayer.queryObjectIds().then(function(results){
  // prints the array of Object IDs to the console
  console.log(results);
});

//get the first sublayer from the parent KnowledgeGraphLayer
const sublayer = linkChartLayer.layers.items[0];

const query = new Query();
query.where = "region = 'Southern California'";

sublayer.queryObjectIds(query).then(function(ids){
  console.log(ids);  // an array of object IDs
});

refresh

inherited Method

Signature: refresh (): void

Inherited from: RefreshableLayer

Fetches all the data for the layer.

See also

Returns: void

when

inherited Method

Signature: when <TResult1 = this, TResult2 = never>(onFulfilled?: OnFulfilledCallback<this, TResult1> | null | undefined, onRejected?: OnRejectedCallback<TResult2> | null | undefined): Promise<TResult1 | TResult2>

Type parameters: <TResult1 = this, TResult2 = never>

Inherited from: EsriPromiseMixin

when() may be leveraged once an instance of the class is created. This method takes two input parameters: an onFulfilled function and an onRejected function. The onFulfilled executes when the instance of the class loads. The onRejected executes if the instance of the class fails to load.

Parameters

Parameter	Type	Description	Required
onFulfilled	`OnFulfilledCallback<this, TResult1> \| null \| undefined`	The function to call when the promise resolves.
onRejected	`OnRejectedCallback \| null \| undefined`	The function to execute when the promise fails.

Returns: Promise<TResult1 | TResult2>
Returns a new promise for the result of onFulfilled that may be used to chain additional functions.

Example

// Although this example uses MapView, any class instance that is a promise may use when() in the same way
let view = new MapView();
view.when(function(){
  // This function will execute once the promise is resolved
}, function(error){
  // This function will execute if the promise is rejected due to an error
});

Events

Name	Type
`layerview-create` inherited	CustomEvent<LayerLayerviewCreateEvent>
`layerview-create-error` inherited	CustomEvent<LayerLayerviewCreateErrorEvent>
`layerview-destroy` inherited	CustomEvent<LayerLayerviewDestroyEvent>
`refresh` inherited	CustomEvent<RefreshEvent>

layerview-create

inherited Event

layerview-create: CustomEvent<LayerLayerviewCreateEvent>

Inherited from: Layer

Fires after the layer's LayerView is created and rendered in a view.

See also

View.whenLayerView()

Example

// This function will fire each time a layer view is created for this
// particular view.
layer.on("layerview-create", function(event){
  // The LayerView for the layer that emitted this event
  event.layerView;
});

layerview-create-error

inherited Event

layerview-create-error: CustomEvent<LayerLayerviewCreateErrorEvent>

Inherited from: Layer

Fires when an error emits during the creation of a LayerView after a layer has been added to the map.

See also

View.whenLayerView()

Example

// This function fires when an error occurs during the creation of the layer's layerview
layer.on("layerview-create-error", function(event) {
  console.error("LayerView failed to create for layer with the id: ", layer.id, " in this view: ", event.view);
});

layerview-destroy

inherited Event

layerview-destroy: CustomEvent<LayerLayerviewDestroyEvent>

Inherited from: Layer

Fires after the layer's LayerView is destroyed and no longer renders in a view.

refresh

inherited Event

refresh: CustomEvent<RefreshEvent>

Inherited from: RefreshableLayer

Fires if the layer has the refreshInterval set or when refresh() method is called. The event payload indicates if the layer's data has changed.

See also

Examples

// listen to layer's refresh event to fetch the attachments
// for the updated features.
layer.on("refresh", async (event) =>{
  if (!event.dataChanged){
    return;
  }

  try {
    const query = layer.createQuery();
    const objectIds = await layer.queryObjectIds(query);
    let attachmentQuery = {
      objectIds: objectIds,
      definitionExpression: layer.definitionExpression,
      attachmentTypes: ["image/jpeg"]
    };

    const attachments = await layer.queryAttachments(attachmentQuery);

    attachmentQuery.objectIds.forEach(function (objectId) {
      if (attachments[objectId]) {
        // process the updated attachments
        let attachment = attachments[objectId];
        console.log("Attachments for objectId ", objectId, attachment);
      }
    });
  } catch (error) {
    console.log("attachment query error", error);
  }
});

// listen to layer's refresh event to fetch object ids of completed features
layer.on("refresh", function(event){
  if (event.dataChanged){
    const query = layer.createQuery();
    query.where = "Status = 'Completed'";
    layer.queryObjectIds(query).then((objectIds) => {
     // process returned features
    });
  }
});