RasterFunction | References | ArcGIS Maps SDK for JavaScript

import RasterFunction from "@arcgis/core/layers/support/RasterFunction.js";

Inheritance:: RasterFunction→Accessor

Since: ArcGIS Maps SDK for JavaScript 4.0

Raster functions specify processing to be done to the image service. They allow the mosaic image service to deliver a dynamically mosaicked image and they can be used to enhance the mosaicked image product by applying processing operations such as image enhancements, and image algebra. See raster functions for a list of functions and their arguments. The following image shows a landcover ImageryLayer rendered with two chained client-side raster functions used to reclass pixel values (Remap) and assign each pixel a new color (Colormap).

Chaining raster functions is accomplished by setting the Raster argument in the functionArguments property to another defined raster function. See example below on chaining a Remap raster function with a Colormap.

let remapRF = new RasterFunction();
remapRF.functionName = "Remap";
remapRF.functionArguments = {
  InputRanges: [-3,10,11,37], // remap pixels with values -3 to 10 to now have value of 1
  OutputValues: [1,2],        // remap pixel values from 11 to 37 to have a value of 2
  Raster: "$$"  // Apply remap to the image service
};
remapRF.outputPixelType = "u8";

let colorRF = new RasterFunction();
colorRF.functionName = "Colormap";
colorRF.functionArguments = {
  Colormap: [
    [1, 255, 0, 0],  // Symbolize pixels with value of 1 using red color
    [2, 0, 255, 0]   // Symbolize pixels with value of 2 using green color
  ],
  Raster : remapRF  // Apply Colormap to output raster from the remap rasterFunction
};

imageLayer.rasterFunction = colorRF;

The following code snippet shows how convenience methods from the rasterFunctionUtils module can be used when applying a raster function to an imagery or imagery tile layer.

// apply NDVI and colormap raster function to an imagery tile layer
// use rasterFunctionUtils convenience methods to create raster functions
const ndvi = rasterFunctionUtils.bandArithmeticNDVI({
  nirBandId: 4,
  redBandId: 3,
  scientificOutput: false
});

 const colormap = rasterFunctionUtils.colormap({
  colorRampName: "NDVI3",
  raster: ndvi
});
layer.rasterFunction = colormap;

See also

Constructors

Constructor

Parameters

Parameter	Type	Description	Required
properties	`RasterFunctionProperties`

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
`declaredClass` readonly inherited	`string`	Accessor
`functionArguments`	`Record<string, any>`
`functionName`	`string \| null \| undefined`
`outputPixelType`	`RasterPixelType`
`rasterFunctionDefinition`	`any \| null \| undefined`
`variableName`	`string \| null \| undefined`

declaredClass

readonlyinherited Property

Type: string

Inherited from: Accessor

Since: ArcGIS Maps SDK for JavaScript 4.7

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

functionArguments

Property

Type: Record<string, any>

The arguments for the raster function. The structure depends on the function specified. See raster functions for a list of functions and their arguments. Also parses the arguments of RFT format.

Example

rasterFunction.functionArguments = {
  "Azimuth":215.0,
  "Altitude":75.0,
  "ZFactor":0.3
};

functionName

Property

Type: string | null | undefined

The raster function name. See raster functions for a list of functions and their arguments. The name in the raster function in RFT JSON format is also parsed to functionName.

Example

rasterFunction.functionName = "Stretched";
rasterFunction.name = "GrayScale";

outputPixelType

Property

Type: RasterPixelType

Defines the pixel type of the output image.

Default value: "unknown"

Example

rasterFunction.outputPixelType = "u8";

rasterFunctionDefinition

Property

Type: any | null | undefined

Property where Raster Function template is passed. RasterFunction template definition created by Raster Function Editor in MapViewer.

variableName

Property

Type: string | null | undefined

The variable name for the raster function.

Example

rasterFunction.variableName = "DEM";

Methods

Method	Signature	Class
`fromJSON` inherited static	`fromJSON(json: any): any`	JSONSupportMixin
`clone`	`clone(): RasterFunction`
`toJSON` inherited	`toJSON(): any`	JSONSupportMixin

fromJSON

inheritedstatic Method

Signature: fromJSON (json: any): any

Inherited from: JSONSupportMixin

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. The object passed into the input json parameter often comes from a response to a query operation in the REST API or a toJSON() method from another ArcGIS product. See the Using fromJSON() topic in the Guide for details and examples of when and how to use this function.

Parameters

Parameter	Type	Description	Required
json	`any`	A JSON representation of the instance in the ArcGIS format. See the ArcGIS REST API documentation for examples of the structure of various input JSON objects.

Returns: any
Returns a new instance of this class.

clone

Method

Signature: clone (): RasterFunction

Since: ArcGIS Maps SDK for JavaScript 4.29

Creates a deep clone of the raster function.

Returns: RasterFunction
A deep clone of the object that invoked this method.

Example

// Creates a deep clone of the layer's rasterFunction
let rasterFunction = layer.rasterFunction.clone();

toJSON

inherited Method

Signature: toJSON (): any

Inherited from: JSONSupportMixin

Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() guide topic for more information.

Returns: any
The ArcGIS portal JSON representation of an instance of this class.