SpatialReference | API Reference | ArcGIS Maps SDK for JavaScript 4.31

Defines the spatial reference of a view, layer, or method parameters. This indicates the projected or geographic coordinate system used to locate geographic features in the map. Each projected and geographic coordinate system is defined by either a well-known ID (WKID) or a definition string (WKT). Note that for versions prior to ArcGIS 10, only WKID was supported. For a full list of supported spatial reference IDs and their corresponding definition strings, see Using spatial references.

Examples

// set the spatial reference of a view to WebMercator using wkid
const view = new SceneView({
  container: "viewDiv",
  map: map,
  spatialReference: {
    wkid: 3857
  }
});

// set the spatial reference of a geometry
// to WGS84 using the WGS84 property
const point = new Point({
  x: 10.1,
  y: 47.4,
  spatialReference: SpatialReference.WGS84
});

Constructors

SpatialReference Constructor new SpatialReference(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 Watch for changes topic.

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Type	Summary	Class
SpatialReference	A convenience spatial reference instance for WGS84.	SpatialReference
SpatialReference	A convenience spatial reference instance for Web Mercator.	SpatialReference
String	The name of the class.	Accessor
Object	An image coordinate system defines the spatial reference used to display the image in its original coordinates without distortion, map transformations or ortho-rectification.	SpatialReference
Boolean	Indicates if the spatial reference refers to a geographic coordinate system.	SpatialReference
Boolean	Indicates if the wkid of the spatial reference object is `4326`.	SpatialReference
Boolean	Indicates if the wkid of the spatial reference object is one of the following values: `102113`, `102100`, `3857`.	SpatialReference
Boolean	Indicates if the spatial reference of the map supports wrapping around the International Date Line.	SpatialReference
Number	The factor to convert one unit value in the spatial reference's unit to meters.	SpatialReference
null\|String	The unit of the spatial reference.	SpatialReference
Number	The well-known ID of a spatial reference.	SpatialReference
String	The well-known text that defines a spatial reference.	SpatialReference
String	The well-known text of the coordinate system as defined by OGC standard for well-known text strings.	SpatialReference

Property Details

WGS84 Property WGS84 SpatialReferencestatic

A convenience spatial reference instance for WGS84.

Example

// returns true if the webMercatorUtils can
// project geometries from WGS84 to Web Mercator
let canProjectWGS84toWebMercator = webMercatorUtils.canProject(SpatialReference.WGS84, SpatialReference.WebMercator);

WebMercator Property WebMercator SpatialReferencestatic

A convenience spatial reference instance for Web Mercator.

Example

// returns true if the webMercatorUtils can
// project geometries from WGS84 to Web Mercator
let canProjectWGS84toWebMercator = webMercatorUtils.canProject(SpatialReference.WGS84, SpatialReference.WebMercator);

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.

imageCoordinateSystem Property imageCoordinateSystem Object Since: ArcGIS Maps SDK for JavaScript 4.13 SpatialReference since 4.0, imageCoordinateSystem added at 4.13.

An image coordinate system defines the spatial reference used to display the image in its original coordinates without distortion, map transformations or ortho-rectification. Typically, ImageryLayer is displayed in the spatialReference of the view. In some cases, converting images into map coordinates can cause your images to look skewed or distorted because of the various transformations and terrain corrections that are used. Since there is no distortion with images in the image coordinate system, it is ideal for using with oblique imagery and mensuration.

The image can be displayed in its original coordinates only in 2D MapView with a top-uprotation which is always oriented in the look of direction of the dataset. This works similarly to an in-car navigation system where the choices are often either north is at the top of the screen (therefore, not using a top up option) or the screen rotates so the travel direction is always displayed at the top.

See also

Example

// get image coordinate system of the specified catalog item
// for example Raster.OBJECTID = 1600
layer.getCatalogItemICSInfo(imageId).then(function(info) {
// create a spatialReference object and set its
// imageCoordinateSystem property
 let sr = { // autocasts to esri/geometry/SpatialReference
   imageCoordinateSystem: { id: imageId }
 };

 // Calculate an extent for the mapview based on the image's extent
 // in its original coordinate system
 const width = document.getElementById("viewDiv").getBoundingClientRect().width;
 const height = document.getElementById("viewDiv").getBoundingClientRect().height;
 const newExt = info.icsExtent.clone();
 const scaleFactor = 5;
 newExt.xmin = (newExt.xmin + newExt.xmax - width * scaleFactor) / 2;
 newExt.xmax = newExt.xmin + width * scaleFactor;
 newExt.ymin = (newExt.ymin + newExt.ymax - height * scaleFactor) / 2;
 newExt.ymax = newExt.ymin + height * scaleFactor;
 newExt.spatialReference = sr;

 // set the MapView's spatialReference to the image's coordinate system
 // and the extent to the extent calculated above
 view = new MapView({
   container: "viewDiv",
   map: map,
   spatialReference: sr,
   extent: newExt
 });
});

isGeographic Property isGeographic Booleanreadonly

Indicates if the spatial reference refers to a geographic coordinate system.

isWGS84 Property isWGS84 Booleanreadonly

Indicates if the wkid of the spatial reference object is 4326.

isWebMercator Property isWebMercator Booleanreadonly

Indicates if the wkid of the spatial reference object is one of the following values: 102113, 102100, 3857.

isWrappable Property isWrappable Booleanreadonly

Indicates if the spatial reference of the map supports wrapping around the International Date Line. Value is true if the spatial reference is Web Mercator or WGS84.

metersPerUnit Property metersPerUnit Numberreadonly Since: ArcGIS Maps SDK for JavaScript 4.26 SpatialReference since 4.0, metersPerUnit added at 4.26.

The factor to convert one unit value in the spatial reference's unit to meters.

Examples

// Convert 1 pixel in a MapView to meters
const pixelInMeter = view.resolution * view.spatialReference.metersPerUnit;

// Measure the geodesic distance between two points in the view's unit
const distanceInViewUnit = geodesicUtils.geodesicDistance(pointA, pointB, "meters")  / view.spatialReference.metersPerUnit;

const DPI = 96
const inchesPerMeter = 39.37;

// Get the scale for an extent
function getScale(extent, viewWidth) {
  const unitValue = extent.spatialReference.metersPerUnit;
  return (extent.width / viewWidth) * unitValue * inchesPerMeter * DPI;
}

unit Property unit null |Stringreadonly Since: ArcGIS Maps SDK for JavaScript 4.26 SpatialReference since 4.0, unit added at 4.26.

The unit of the spatial reference. Returns null if no unit could be determined.

Some values of the possible values listed here cannot be used as parameters for certain functions. For example, geodesicUtils.geodesicDistance() only accepts meters, feet, us-feet. For other values, you can use the meters unit and use metersPerUnit convert to the spatial reference's unit.

See also

metersPerUnit

wkid Property wkid Number

The well-known ID of a spatial reference. See Using spatial references for a list of supported spatial references.

wkt Property wkt String

The well-known text that defines a spatial reference.

wkt2 Property wkt2 String Since: ArcGIS Maps SDK for JavaScript 4.28 SpatialReference since 4.0, wkt2 added at 4.28.

The well-known text of the coordinate system as defined by OGC standard for well-known text strings.

Method Overview

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Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
SpatialReference	Returns a deep clone of the spatial reference object.	SpatialReference
Boolean	Checks if the specified spatial reference object has the same wkid or wkt as this spatial reference object.	SpatialReference
*	Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product.	SpatialReference
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.	SpatialReference

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(){SpatialReference}

Returns a deep clone of the spatial reference object.

Returns

Type	Description
SpatialReference	Returns a deep clone of the spatial reference object.

equals Method equals(spatialReference){Boolean}

Checks if the specified spatial reference object has the same wkid or wkt as this spatial reference object.

Parameter

spatialReference SpatialReference

The spatial reference to compare to.

Returns

Type	Description
Boolean	Returns `true` if the input spatial reference object has the same wkid or wkt as this spatial reference object.

Example

require(["esri/geometry/SpatialReference"], function(SpatialReference) {
  const sr1 = new SpatialReference({ wkid: 4326 });
  const sr2 = new SpatialReference({ wkid: 4326 });
  console.log(sr1.equals(sr2)); // true
});

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.