RasterStretchRenderer

Property Overview

Property Details

colorRamp ColorRampautocast

The stretched values are mapped to this specified color ramp. The color ramp algorithm must set when using this renderer, otherwise the cie-lab algorithm used by default.

See also

• ImageryLayer rendering

computeGamma Boolean

The computeGamma automatically calculates best gamma value to render exported image based on empirical model. This is applicable to any stretch type when useGamma is true.

Default Value:false

declaredClass Stringreadonly inherited

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

dynamicRangeAdjustment Boolean

When Dynamic Range Adjustment is true, the statistics based on the current display extent are calculated as you zoom and pan around the image.

Default Value:false

gamma Number[]

The gamma values to be used if useGamma is set to true. Gamma refers to the degree of contrast between the mid-level gray values of a raster dataset. Gamma 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 a layer. Gamma stretching is only valid with the none, standard-deviation, and min-max stretch types.

maxPercent Number

Applicable when stretchType is percent-clip. Specifies the percentage of the highest values to exclude from the stretch.

minPercent Number

Applicable when stretchType is percent-clip. Specifies the percentage of the lowest values to exclude from the stretch.

numberOfStandardDeviations Number

Applicable when stretchType is standard-deviation. Specifies the number of standard deviations to use. The values beyond the number of standard deviations become the outputMin and outputMax. The remaining values are linearly stretched between outputMin and outputMax.

outputMax Number

The outputMax denotes the output maximum, which is the highest pixel value. The outputMin and outputMax will set the range of values that will then be linearly contrast stretched. The outputMax value ranges from 0-255.

outputMin Number

The outputMin denotes the output minimum, which is the lowest pixel value. The outputMin and outputMax will set the range of values that will then be linearly contrast stretched. The outputMin value ranges from 0-255.

sigmoidStrengthLevel Number

The sigmoid strength level determines how much of the sigmoidal function will be used in the stretch. A low value such as 1 will only use the middle portion of the curve, which tends to produce dull and faint colors. A high value such as 6 will use the entire curve, which tends to produce bold and sharp colors.

statistics Number[][]|Object[]

Since: ArcGIS Maps SDK for JavaScript 4.15

The input statistics can be specified through the statistics property. If not specified, they will be retrieved from the data. If dynamicRangeAdjustment is true, these values will be ignored.

Properties

min Number The minimum pixel value.

max Number The maximum pixel value.

avg Number optional The average pixel value.

stddev Number optional The standard deviation of the pixel value.

See also

• Learn about calculating statistics

Examples

let renderer = new RasterStretchRenderer();
renderer.statistics = [
 [0, 100, 50, 10] // [<min>, <max>, <mean>, <standardDeviation>]
];

let bandStat = layer.rasterInfo.statistics[0];
let renderer = new RasterStretchRenderer();
renderer.statistics = [{
  min: valueSlider.values[0],
  max: valueSlider.values[1],
  avg: bandStat.avg,
  stddev: bandStat.stddev
}];

stretchType String

The stretch type defines a histogram stretch that will be applied to the rasters to enhance their appearance. Stretching improves the appearance of the data by spreading the pixel values along a histogram from the minimum and maximum values defined by their bit depth. For example, an 8-bit raster dataset or mosaic dataset will be stretched from 0 to 255. Different stretches will produce different results in the raster display.

The possible stretch types are listed below.

Value	Description
none	No stretch method will be applied, even if statistics exist.
standard-deviation	This stretch type applies a linear stretch between the values defined by the standard deviation value.
histogram-equalization	The pixel values are stretched to adjust the contrast using the histogram of the data.
min-max	This stretch type applies a linear stretch based on the output minimum and output maximum pixel values, which are used as the endpoints for the histogram.
percent-clip	This stretch type applies a linear stretch between the defined minPercent and maxPercent pixel values.
sigmoid	The Sigmoid contrast stretch is designed to highlight moderate pixel values in your imagery while maintaining sufficient contrast at the extremes.

Possible Values:"none"|"standard-deviation"|"histogram-equalization"|"min-max"|"percent-clip"|"sigmoid"

Default Value:none

type Stringreadonly

The type of Renderer.

For RasterStretchRenderer the type is always "raster-stretch".

useGamma Boolean

Denotes whether the gamma value should be used. When useGamma is false, the gamma is calculated from the statistics and histogram of the data. The gamma property is required if useGamma is true.

Default Value:false

Method Overview

Method Details

addHandles(handleOrHandles, groupKey)inherited

Since: ArcGIS Maps SDK for JavaScript 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(){RasterStretchRenderer}

Creates a deep clone of the renderer.

Returns

Type	Description
RasterStretchRenderer	A deep clone of the object that invoked this method.

Example

// Creates a deep clone of the first layer's renderer
let renderer = view.map.layers.getItemAt(0).renderer.clone();

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(groupKey){Boolean}inherited

Since: ArcGIS Maps SDK for JavaScript 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(groupKey)inherited

Since: ArcGIS Maps SDK for JavaScript 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(){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.