Module com.esri.arcgisruntime
Package com.esri.arcgisruntime.geometry

Class SpatialReference

java.lang.Object
com.esri.arcgisruntime.geometry.SpatialReference
All Implemented Interfaces:
JsonSerializable
public final class SpatialReference extends Object implements JsonSerializable
The spatial reference specifies how geometry coordinates relate to real-world space.

Instances of this class represent a specific coordinate system identified by a well-known ID (WKID) number or well-known text (WKT) string. There are two broad classes of coordinate systems:

  • Geographic coordinate systems use a 3-dimensional spherical surface to define locations on the earth.
  • Projected coordinate systems use a flat, 2-dimensional surface.
See https://developers.arcgis.com/documentation/spatial-references/ for more information about spatial references.

SpatialReference ensures that you can accurately view, query, and analyze the layers of a GeoModel.

The spatial reference value is available from a map or scene after loading has completed, and is immutable. If you want to set this value for a new map or scene, use the ArcGISMap(SpatialReference) or ArcGISScene(ArcGISScene.SceneViewTilingScheme) constructors.

Since:
100.0.0
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    static SpatialReference
    create(int wkid)
    Creates a new spatial reference from the given well-known ID (WKID) number.
    static SpatialReference
    create(int wkid, int verticalWkid)
    Creates a new spatial reference with the given well-known ID (WKID) numbers for both a horizontal and a vertical coordinate system.
    static SpatialReference
    create(String wkText)
    Creates a new spatial reference from the given well-known text (WKT) string.
    boolean
    equals(Object obj)
    Tests if this object is equal to a second SpatialReference object.
    static SpatialReference
    fromJson(String json)
    Creates a SpatialReference instance from a JSON string.
    SpatialReference
    getBaseGeographic()
    Gets the underlying geographic coordinate system of this spatial reference.
    double
    getConvergenceAngle(Point point)
    Gets the calculated grid convergence angle for a given point, which is the angle between True North and Grid North.
    Unit
    getUnit()
    Gets the units of measurement defined by this instance.
    Map<String,Object>
    getUnknownJson()
    SpatialReferences never have any unknown JSON so this returns an empty Map.
    Map<String,Object>
    getUnsupportedJson()
    SpatialReferences never have any unsupported JSON so this returns an empty Map.
    LinearUnit
    getVerticalUnit()
    Gets the unit of measure for the vertical coordinate system of this spatial reference.
    int
    getVerticalWkid()
    Gets the well-known ID (WKID) number of the vertical coordinate system of this instance.
    int
    getWkid()
    Gets the well-known ID (WKID) number of this instance.
    String
    getWKText()
    Gets the well-known text (WKT) representation of this instance.
    int
    hashCode()
    Generates a hash value from the SpatialReference.
    boolean
    hasVertical()
    Indicates if this instance has a vertical coordinate system set.
    boolean
    isGeographic()
    Indicates if this instance represents a geographic coordinate system.
    boolean
    isPannable()
    Indicates if an ArcGISMap with this SpatialReference can be continuously horizontally pannable.
    boolean
    isProjected()
    Indicates if this instance represents a projected coordinate system.
    String
    toJson()
    Serializes this object to a JSON string.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • create

      public static SpatialReference create(int wkid)
      Creates a new spatial reference from the given well-known ID (WKID) number.

      The WKID refers to a specific coordinate system. WKIDs are defined by standards bodies or organizations. ArcGIS supports a variety of WKIDs, typically those defined by the European Petroleum Survey Group (EPSG) or Esri, as well as a few other commonly used IDs.

      SpatialReferences can also be created from a well-known text (WKT) string using create(String). Alternatively, use the static methods on SpatialReferences to return instances of the most commonly-used SpatialReferences.

      Parameters:
      wkid - the WKID number of the required SpatialReference
      Returns:
      a SpatialReference with the given WKID number
      Since:
      100.0.0
      See Also:

    • create

      public static SpatialReference create(String wkText)
      Creates a new spatial reference from the given well-known text (WKT) string.

      WKTs are full-text definitions of all of the parameters that specify a spatial reference.

      SpatialReferences can also be created from a well-known ID (WKID number) string using create(int). Alternatively, use the static methods on SpatialReferences to return instances of the most commonly-used SpatialReferences.

      Parameters:
      wkText - a string containing a well-known text representation of a SpatialReference
      Returns:
      a SpatialReference based on the given WKT string
      Since:
      100.0.0
      See Also:

    • create

      public static SpatialReference create(int wkid, int verticalWkid)
      Creates a new spatial reference with the given well-known ID (WKID) numbers for both a horizontal and a vertical coordinate system. Vertical coordinate systems are not spatial references themselves, but control how z values are displayed.
      Parameters:
      wkid - the WKID number of the required horizontal SpatialReference
      verticalWkid - the WKID number of the required vertical SpatialReference
      Returns:
      a SpatialReference with the given WKID numbers
      Since:
      100.0.0
      See Also:

    • fromJson

      public static SpatialReference fromJson(String json)
      Creates a SpatialReference instance from a JSON string.
      Parameters:
      json - a JSON string that represents a SpatialReference
      Returns:
      a SpatialReference instance
      Throws:
      IllegalArgumentException - if json is null or empty
      Since:
      100.0.0

    • toJson

      public String toJson()
      Description copied from interface: JsonSerializable
      Serializes this object to a JSON string. Note that unknown JSON is omitted from the serialized string.
      Specified by:
      toJson in interface JsonSerializable
      Returns:
      a JSON string

    • getUnknownJson

      public Map<String,Object> getUnknownJson()
      SpatialReferences never have any unknown JSON so this returns an empty Map.
      Specified by:
      getUnknownJson in interface JsonSerializable
      Returns:
      an empty unmodifiable Map
      Since:
      100.0.0

    • getUnsupportedJson

      public Map<String,Object> getUnsupportedJson()
      SpatialReferences never have any unsupported JSON so this returns an empty Map.
      Specified by:
      getUnsupportedJson in interface JsonSerializable
      Returns:
      an empty unmodifiable Map
      Since:
      100.0.0

    • getWkid

      public int getWkid()
      Gets the well-known ID (WKID) number of this instance. WKIDs are unique numbers that refer to a specific predefined coordinate system.
      Returns:
      The WKID number of the coordinate system this instance represents. Returns 0 if this instance represents a custom coordinate system, or -1 if it is invalid.
      Since:
      100.0.0
      See Also:

    • getVerticalUnit

      public LinearUnit getVerticalUnit()
      Gets the unit of measure for the vertical coordinate system of this spatial reference.

      Is null if hasVertical() is false.

      Returns:
      the unit of measure for the vertical coordinate system of this spatial reference, or null if none
      Since:
      100.14.0

    • getVerticalWkid

      public int getVerticalWkid()
      Gets the well-known ID (WKID) number of the vertical coordinate system of this instance. WKIDs are unique numbers that refer to a specific predefined coordinate system.
      Returns:
      The WKID number of the vertical coordinate system this instance represents. Returns 0 if a vertical coordinate system was not set when this instance was created. Returns -1 if an invalid vertical coordinate system was specified.
      Since:
      100.0.0
      See Also:

    • getBaseGeographic

      public SpatialReference getBaseGeographic()
      Gets the underlying geographic coordinate system of this spatial reference. Intended for use when this spatial reference is a projected coordinate system. If this spatial reference is a geographic coordinate system then a new reference to itself is returned.
      Returns:
      the underlying geographic coordinate system
      Since:
      100.1.0
      See Also:

    • hasVertical

      public boolean hasVertical()
      Indicates if this instance has a vertical coordinate system set.

      A spatial reference can optionally include a definition for a vertical coordinate system (VCS), which can be used to interpret the z values of a geometry (Point.getZ()). A VCS defines linear units of measure, the origin of z values, and whether z values are "positive up" (representing heights above a surface) or "positive down" (indicating that values are depths below a surface).

      A SpatialReference may have a VCS set, for example if it was created using create(int, int). getVerticalWkid() and getWKText() provide more information about the specific VCS set on this instance.

      VCSs are used when projecting geometries using a HorizontalVerticalTransformation.

      Returns:
      true if this instance has a vertical coordinate system set, false otherwise.
      Since:
      100.9.0
      See Also:

    • isGeographic

      public boolean isGeographic()
      Indicates if this instance represents a geographic coordinate system. Geographic coordinate systems use angular units to define coordinates.
      Returns:
      true if this instance represents a geographic coordinate system, false otherwise
      Since:
      100.0.0
      See Also:

    • isProjected

      public boolean isProjected()
      Indicates if this instance represents a projected coordinate system. Projected coordinate systems use linear units to define coordinates.
      Returns:
      true if this instance represents a projected coordinate system; false otherwise
      Since:
      100.0.0
      See Also:

    • isPannable

      public boolean isPannable()
      Indicates if an ArcGISMap with this SpatialReference can be continuously horizontally pannable. A continuously pannable spatial reference is one of the requirements for a wrap-around map, where a user is able to continuously pan the map across the anti-meridian (approximately equal to the international date line). Only the two most common coordinate systems are continuously pannable; WGS 1984 (WKID 4326), and Web Mercator Auxilliary Sphere (WKID 102113, 102100, or 3857).
      Returns:
      true if continuously horizontally pannable; false otherwise
      Since:
      100.0.0
      See Also:

    • getWKText

      public String getWKText()
      Gets the well-known text (WKT) representation of this instance. WKTs are full-text definitions of all of the parameters that specify a spatial reference.

      SpatialReferences can be created from a WKT string using create(String).

      Returns:
      a string containing a WKT representation of this instance
      Since:
      100.0.0

    • getUnit

      public Unit getUnit()
      Gets the units of measurement defined by this instance. The Unit of the SpatialReference of a Geometry or Layer determine the units used by its coordinates.
      Returns:
      the units of measurement of this instance
      Since:
      100.0.0
      See Also:

    • getConvergenceAngle

      public double getConvergenceAngle(Point point)
      Gets the calculated grid convergence angle for a given point, which is the angle between True North and Grid North.

      This value can be used to convert a horizontal direction expressed as an azimuth in a geographic coordinate system (relative to True North) to a direction expressed as a bearing in a projected coordinate system (relative to Grid North), and vice versa.

      The grid convergence returned by this method is positive when Grid North lies east of True North, following the Gauss-Bomford convention. The formula bearing = azimuth - convergence can be used to obtain a bearing from an azimuth using the grid convergence.

      This sign convention is sometimes named the Gauss-Bomford convention. Other notes:

      • Returns 0 if the spatial reference is a geographic coordinate system
      • Returns NAN if the point is outside the projection's horizon or on error
      • If the point has no spatial reference, it is assumed to be in the given spatial reference
      • If the point's spatial reference differs from the spatial reference given, its location will be transformed automatically to the given spatial reference
      Parameters:
      point - the point at which to calculate the convergence. If this point has a different spatial reference, it will be reprojected to this spatial reference; if the spatial reference is null, the point is assumed to already be defined in this spatial reference.
      Returns:
      the convergence angle in degrees. Returns 0 if this spatial reference represents a geographic coordinate system (isGeographic() is true). Returns Double.NaN if the point lies outside this spatial reference's horizon.
      Throws:
      IllegalArgumentException - if point is null
      Since:
      100.3.0

    • hashCode

      public int hashCode()
      Generates a hash value from the SpatialReference.
      Overrides:
      hashCode in class Object
      Returns:
      a hash value based on the current SpatialReference
      Since:
      100.0.0

    • equals

      public boolean equals(Object obj)
      Tests if this object is equal to a second SpatialReference object.
      Overrides:
      equals in class Object
      Parameters:
      obj - the 2nd spatial reference to check to see if equal to the 1st
      Returns:
      true if the comparison succeeds and the objects are equal, false otherwise
      Since:
      100.0.0