RasterFunction

AMD: require(["esri/layers/support/RasterFunction"], (RasterFunction) => { /* code goes here */ });
ESM: import RasterFunction from "@arcgis/core/layers/support/RasterFunction.js";
Class: esri/layers/support/RasterFunction
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).

layers-imagery-rf

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

RasterFunction

Constructor
new RasterFunction(properties)
Parameter
properties Object
optional

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

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class
String

The name of the class.

Accessor
Object

The arguments for the raster function.

RasterFunction
String

The raster function name.

RasterFunction
String

Defines the pixel type of the output image.

RasterFunction
Object

Property where Raster Function template is passed.

RasterFunction
String

The variable name for the raster function.

RasterFunction

Property Details

declaredClass

Inherited
Property
declaredClass Stringreadonly
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.7 Accessor since 4.0, declaredClass added at 4.7.

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

functionArguments

Property
functionArguments Object

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
functionName String

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
outputPixelType String

Defines the pixel type of the output image.

Possible Values:"c128"|"c64"|"f32"|"f64"|"s16"|"s32"|"s8"|"u1"|"u16"|"u2"|"u32"|"u4"|"u8"|"unknown"

Default Value:unknown
Example
rasterFunction.outputPixelType = "u8";

rasterFunctionDefinition

Property
rasterFunctionDefinition Object

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

variableName

Property
variableName String

The variable name for the raster function.

Example
rasterFunction.variableName = "DEM";

Method Overview

Show inherited methods Hide inherited methods
Name Return Type Summary Class

Adds one or more handles which are to be tied to the lifecycle of the object.

Accessor
RasterFunction

Creates a deep clone of the raster function.

RasterFunction
*

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product.

RasterFunction
Boolean

Returns true if a named group of handles exist.

Accessor

Removes a group of handles owned by the object.

Accessor
Object

Converts an instance of this class to its ArcGIS portal JSON representation.

RasterFunction

Method Details

addHandles

Inherited
Method
addHandles(handleOrHandles, groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, addHandles added at 4.25.

Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.

// Manually manage handles
const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true }
);

this.addHandles(handle);

// Destroy the object
this.destroy();
Parameters
handleOrHandles WatchHandle|WatchHandle[]

Handles marked for removal once the object is destroyed.

groupKey *
optional

Key identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.

clone

Method
clone(){RasterFunction}
Since: ArcGIS Maps SDK for JavaScript 4.29 RasterFunction since 4.0, clone added at 4.29.

Creates a deep clone of the raster function.

Returns
Type Description
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();

fromJSON

Method
fromJSON(json){*}static

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.

Parameter
json Object

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
Type Description
* Returns a new instance of this class.

hasHandles

Inherited
Method
hasHandles(groupKey){Boolean}
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.

Returns true if a named group of handles exist.

Parameter
groupKey *
optional

A group key.

Returns
Type Description
Boolean Returns true if a named group of handles exist.
Example
// Remove a named group of handles if they exist.
if (obj.hasHandles("watch-view-updates")) {
  obj.removeHandles("watch-view-updates");
}

removeHandles

Inherited
Method
removeHandles(groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.

Removes a group of handles owned by the object.

Parameter
groupKey *
optional

A group key or an array or collection of group keys to remove.

Example
obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

toJSON

Method
toJSON(){Object}

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

Returns
Type Description
Object The ArcGIS portal JSON representation of an instance of this class.

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