stretch | References | ArcGIS Maps SDK for JavaScript

import { createRenderer } from "@arcgis/core/smartMapping/raster/renderers/stretch.js";

Since: ArcGIS Maps SDK for JavaScript 4.20

This object contains helper methods for generating a single-band stretch visualization for raster layers (i.e. ImageryLayer, ImageryTileLayer, or WCSLayer).

The createRenderer() method in this module generates a renderer that may be applied directly to the input layer.

Type definitions

RasterStretchColorrampRendererParameters

Type definition

Supertypes: RasterRendererParameters

stretchType

Property

Type: RasterStretchType | undefined

A preferred stretch type can be provided. See RasterStretchRenderer.stretchType for more information.

bandId

Property

Type: number | undefined

The 0-based index of a selected band.

colorRamp

Property

Type: AlgorithmicColorRamp | MultipartColorRamp | undefined

The color ramp to apply to the renderer.

gamma

Property

Type: number | undefined

The gamma values to be used if useGamma is true. Gamma refers to the degree of contrast between the mid-level gray values of a raster dataset. It does not affect the black or white values in a raster dataset, only the middle values. By applying a gamma correction, you can control the overall brightness of an ImageryLayer. Gamma stretching is only valid when stretchType is none, standard-deviation, or min-max. See RasterStretchRenderer.gamma for more information.

useGamma

Property

Type: boolean | undefined

Indicates whether the gamma values should be used. When false, the gamma is calculated from the statistics and histogram of the data.

dynamicRangeAdjustment

Property

Type: boolean | undefined

When true, calculates the renderer's statistics based on the current display extent and recalculates them as you zoom and pan around the image.

estimateStatistics

Property

Type: boolean | undefined

Useful in scenarios where an image service does not have statistics. When true, this function estimates global statistics to keep a constant visual on pan and zoom, unlike dynamicRangeAdjustment which recalculates statistics on each extent change.

variableName

Property

Type: string | undefined

Only applicable to multidimensional datasets where a raster layer can contain more than one variable (such as temperature, humidity, wind speed) with different statistics. Indicate the variable name here.

RasterStretchColorrampResult

Type definition

The result object of the createRenderer() method. See the table below for details of each property.

renderer

Property

Type: RasterStretchRenderer

The RasterStretchRenderer renderer to apply to the input layer.

bandId

Property

Type: number

The zero-based index of the band represented by the renderer.

Functions

Name	Return Type	Object
`RasterStretchColorrampRendererParameters`
`RasterStretchColorrampResult`
`createRenderer`	`Promise<RasterStretchColorrampResult>`

createRenderer

Function

Generates a RasterStretchRenderer to render data from a single raster band.

Signature: createRenderer (parameters: RasterStretchColorrampRendererParameters): Promise<RasterStretchColorrampResult>

Parameters

Parameter	Type	Description	Required
parameters	`RasterStretchColorrampRendererParameters`	Input parameters for generating a single-band stretch visualization. The `colorRamp`, `gamma`, `useGamma`, `dynamicRangeAdjustment` parameters are not related to stretch type. Pass them in to preserve the existing renderer settings if desired.

Returns: Promise<RasterStretchColorrampResult>
Resolves to an object containing a stretch renderer that can be set on the input renderer.