dotDensity | References | ArcGIS Maps SDK for JavaScript

import { getSchemes, getSchemeByName, getSchemesByTag, cloneScheme } from "@arcgis/core/smartMapping/symbology/dotDensity.js";

Since: ArcGIS Maps SDK for JavaScript 4.12

Object containing helper methods for getting optimal symbol schemes used to create dot density visualizations. The getSchemes() returns color schemes best suited to the given basemap for this visualization style.

Functions

Name	Return Type	Object
`getSchemes`	`DotDensitySchemes \| null \| undefined`
`getSchemeByName`	`DotDensityScheme \| null \| undefined`
`getSchemesByTag`	`DotDensityScheme[]`
`cloneScheme`	`DotDensityScheme \| null \| undefined`
`GetSchemesParameters`
`GetSchemesByNameParameters`
`GetSchemesByTagParameters`

getSchemes

Function

Returns a primary scheme and secondary schemes defining symbol properties for dot density-based data-driven visualizations in a Layer. The basemap parameter determines the color of the dots used to visualize each attribute. The geometryType determines which type of symbol to return.

Signature: getSchemes (params: GetSchemesParameters): DotDensitySchemes | null | undefined

Parameters

Parameter	Type	Description	Required
params	`GetSchemesParameters`	The function parameters.

Returns: DotDensitySchemes | null | undefined
Returns an object containing the optimal type scheme to use for the given basemap; it also contains secondary schemes.

Example

// gets the primary scheme for the features of the given geometry type and basemap
const schemes = dotDensitySchemes.getSchemes({
  basemap: map.basemap,
  geometryType: featureLayer.geometryType
});

// the best default scheme for the layer and basemap
const primaryScheme = schemes.primaryScheme;

getSchemeByName

Function

Returns a dot density scheme with the provided name.

Signature: getSchemeByName (params: GetSchemesByNameParameters): DotDensityScheme | null | undefined

Parameters

Parameter	Type	Description	Required
params	`GetSchemesByNameParameters`	The function parameters.

Returns: DotDensityScheme | null | undefined
Returns the dot density scheme with the given name.

Example

// Returns the Galaxy Berries scheme
let galaxyBerriesScheme = dotDensitySchemes.getSchemeByName({
  basemap: map.basemap,
  numColors: 3,
  name: "Galaxy Berries"
});

getSchemesByTag

Function

Returns an array of dot density schemes with the provided tags. These schemes define symbol properties for dot density visualizations in any layer that can be rendered with a DotDensityRenderer.

Signature: getSchemesByTag (params: GetSchemesByTagParameters): DotDensityScheme[]

Parameters

Parameter	Type	Description	Required
params	`GetSchemesByTagParameters`	The function parameters.

Returns: DotDensityScheme[]
Returns an array of dot density schemes either including or excluding the provided tags.

Example

// Returns all the red dot density schemes
let schemes = dotDensitySchemes.getSchemesByTag({
  basemap: map.basemap,
  numColors: 2,
  includedTags: [ "reds", "dot-density" ]
});

cloneScheme

Function

Clones a dot density scheme object.

Signature: cloneScheme (scheme: DotDensityScheme | null | undefined): DotDensityScheme | null | undefined

Parameters

Parameter	Type	Description	Required
scheme	`DotDensityScheme \| null \| undefined`	The dot density scheme object to clone.

Returns: DotDensityScheme | null | undefined
Returns a clone of the given dot density scheme object.

Example

// clones the primary scheme returned from the getSchemes() method
const dotDensityScheme = primaryScheme.clone();

Type definitions

GetSchemesParameters

Type definition

numColors

Property

Type: number

The number of colors to visualize.

basemap

Property

Type: Basemap | string | null | undefined

The Esri basemap to pair with the visualization. This value indicates the best symbol colors for visualizing features against the given basemap. If you have a non-Esri basemap (e.g. a VectorTileLayer basemap with a custom style) or no basemap at all, then use the basemapTheme parameter instead of this parameter.

basemapTheme

Property

Type: BasemapTheme | null | undefined

If you have a non-Esri basemap (e.g. a VectorTileLayer basemap with a custom style) or no basemap at all, use this parameter to indicate whether the background of the visualization is light or dark.