Package org.apache.sis.referencing.operation

Class DefaultConversion

java.lang.Object
org.apache.sis.io.wkt.FormattableObject
org.apache.sis.referencing.AbstractIdentifiedObject
org.apache.sis.referencing.operation.AbstractCoordinateOperation
org.apache.sis.referencing.operation.DefaultConversion
All Implemented Interfaces:
Serializable, Formattable, Parameterized, Deprecable, LenientComparable, org.opengis.referencing.IdentifiedObject, org.opengis.referencing.operation.Conversion, org.opengis.referencing.operation.CoordinateOperation, org.opengis.referencing.operation.SingleOperation
public class DefaultConversion extends AbstractCoordinateOperation implements org.opengis.referencing.operation.Conversion
A parameterized mathematical operation that converts coordinates to another CRS without any change of datum. The best-known example of a coordinate conversion is a map projection. The parameters describing coordinate conversions are defined rather than empirically derived.

This coordinate operation contains an operation method, usually with associated parameter values. In the SIS implementation, the parameter values can be either inferred from the math transform or explicitly provided at construction time in a defining conversion (see below).

Defining conversions

OperationMethod instances are generally created for a pair of existing source and target CRS. But Conversion instances without those information may exist temporarily while creating a derived or projected CRS. Those defining conversions have no source and target CRS since those elements are provided by the derived or projected CRS themselves. This class provides a constructor for such defining conversions.

After the source and target CRS become known, we can invoke the specialize(…) method for creating a math transform from the parameters, instantiate a new Conversion of a more specific type (ConicProjection, CylindricalProjection or PlanarProjection) if possible, and assign the source and target CRS to it.

Immutability and thread safety

This class is immutable and thus thread-safe if the property values (not necessarily the map itself) given to the constructor are also immutable. This means that unless otherwise noted in the javadoc, Conversion instances created using only SIS factories and static constants can be shared by many objects and passed between threads without synchronization.
Since:
0.6
Version:
1.3
Author:
Martin Desruisseaux (IRD, Geomatys)
See Also:

  • Field Summary

    Fields inherited from class org.apache.sis.referencing.AbstractIdentifiedObject

    DEPRECATED_KEY, LOCALE_KEY

    Fields inherited from interface org.opengis.referencing.operation.CoordinateOperation

    COORDINATE_OPERATION_ACCURACY_KEY, DOMAIN_OF_VALIDITY_KEY, OPERATION_VERSION_KEY, SCOPE_KEY

    Fields inherited from interface org.opengis.referencing.IdentifiedObject

    ALIAS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
     
    DefaultConversion(Map<String,?> properties, org.opengis.referencing.crs.CoordinateReferenceSystem sourceCRS, org.opengis.referencing.crs.CoordinateReferenceSystem targetCRS, org.opengis.referencing.crs.CoordinateReferenceSystem interpolationCRS, org.opengis.referencing.operation.OperationMethod method, org.opengis.referencing.operation.MathTransform transform)
    Creates a coordinate conversion from the given properties.
     
    DefaultConversion(Map<String,?> properties, org.opengis.referencing.operation.OperationMethod method, org.opengis.referencing.operation.MathTransform transform, org.opengis.parameter.ParameterValueGroup parameters)
    Creates a defining conversion from the given transform and/or parameters.
    protected
    DefaultConversion(org.opengis.referencing.operation.Conversion operation)
    Creates a new coordinate operation with the same values than the specified one.

  • Method Summary

    Modifier and Type
    Method
    Description
    static DefaultConversion
    castOrCopy(org.opengis.referencing.operation.Conversion object)
    Returns a SIS coordinate operation implementation with the values of the given arbitrary implementation.
    boolean
    equals(Object object, ComparisonMode mode)
    Compares this coordinate operation with the specified object for equality.
    Class<? extends org.opengis.referencing.operation.Conversion>
    getInterface()
    Returns the GeoAPI interface implemented by this class.
    org.opengis.referencing.operation.OperationMethod
    getMethod()
    Returns a description of the operation method, including a list of expected parameter names.
    org.opengis.parameter.ParameterDescriptorGroup
    getParameterDescriptors()
    Returns a description of the parameters.
    org.opengis.parameter.ParameterValueGroup
    getParameterValues()
    Returns the parameter values.
    <T extends org.opengis.referencing.operation.Conversion>
    T
    specialize(Class<T> baseType, org.opengis.referencing.crs.CoordinateReferenceSystem sourceCRS, org.opengis.referencing.crs.CoordinateReferenceSystem targetCRS, org.opengis.referencing.operation.MathTransformFactory factory)
    Returns a specialization of this conversion with a more specific type, source and target CRS.

    Methods inherited from class org.apache.sis.referencing.operation.AbstractCoordinateOperation

    castOrCopy, computeHashCode, formatTo, getCoordinateOperationAccuracy, getDomainOfValidity, getInterpolationCRS, getLinearAccuracy, getMathTransform, getOperationVersion, getScope, getSourceCRS, getTargetCRS, getWrapAroundChanges, isDefiningConversion

    Methods inherited from class org.apache.sis.referencing.AbstractIdentifiedObject

    castOrCopy, equals, formatTo, getAlias, getDescription, getIdentifiers, getName, getRemarks, hashCode, isDeprecated, isHeuristicMatchForName

    Methods inherited from class org.apache.sis.io.wkt.FormattableObject

    print, toString, toString, toWKT

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface org.opengis.referencing.operation.Conversion

    getOperationVersion, getSourceCRS, getTargetCRS

    Methods inherited from interface org.opengis.referencing.operation.CoordinateOperation

    getCoordinateOperationAccuracy, getDomainOfValidity, getMathTransform, getScope

    Methods inherited from interface org.opengis.referencing.IdentifiedObject

    getAlias, getIdentifiers, getName, getRemarks, toWKT

    Methods inherited from interface org.opengis.referencing.operation.SingleOperation

    getMethod, getParameterValues

  • Constructor Details

    • DefaultConversion

      public DefaultConversion(Map<String,?> properties, org.opengis.referencing.crs.CoordinateReferenceSystem sourceCRS, org.opengis.referencing.crs.CoordinateReferenceSystem targetCRS, org.opengis.referencing.crs.CoordinateReferenceSystem interpolationCRS, org.opengis.referencing.operation.OperationMethod method, org.opengis.referencing.operation.MathTransform transform)
      Creates a coordinate conversion from the given properties. The properties given in argument follow the same rules than for the super-class constructor. The following table is a reminder of main (not all) properties:
      Recognized properties (non exhaustive list)
      Property name Value type Returned by
      "name" Identifier or String AbstractIdentifiedObject.getName()
      "identifiers" Identifier (optionally as array) AbstractIdentifiedObject.getIdentifiers()
      "domainOfValidity" Extent AbstractCoordinateOperation.getDomainOfValidity()

      Relationship between datum

      By definition, coordinate conversions do not change the datum. Consequently, the given sourceCRS and targetCRS should use the same datum. If the datum is not the same, then the coordinate operation should probably be a transformation instead. However, Apache SIS does not enforce that condition, but we encourage users to follow it. The reason why SIS is tolerant is because some gray areas may exist about whether an operation should be considered as a conversion or a transformation.
      Example: converting time instants from a temporal CRS using the January 1st, 1950 epoch to another temporal CRS using the January 1st, 1970 epoch is a datum change, since the epoch is part of temporal datum definition. However, such operation does not have all the accuracy issues of transformations between geodetic datum (empirically determined, over-determined systems, stochastic nature of the parameters). Consequently, some users may consider sufficient to represent temporal epoch changes as conversions instead than transformations.
      Note that while Apache SIS accepts to construct DefaultConversion instances with different source and target datum, it does not accept to use such instances for derived CRS construction.
      Parameters:
      properties - the properties to be given to the identified object.
      sourceCRS - the source CRS.
      targetCRS - the target CRS, which shall use a datum equals (ignoring metadata) to the source CRS datum.
      interpolationCRS - the CRS of additional coordinates needed for the operation, or null if none.
      method - the coordinate operation method (mandatory in all cases).
      transform - transform from positions in the source CRS to positions in the target CRS.

    • DefaultConversion

      public DefaultConversion(Map<String,?> properties, org.opengis.referencing.operation.OperationMethod method, org.opengis.referencing.operation.MathTransform transform, org.opengis.parameter.ParameterValueGroup parameters)
      Creates a defining conversion from the given transform and/or parameters. This conversion has no source and target CRS since those elements are usually unknown at defining conversion construction time. The source and target CRS will become known later, at the Derived CRS or Projected CRS construction time.

      The properties map given in argument follows the same rules than for the above constructor.

      Transform and parameters arguments

      At least one of the transform or parameters argument must be non-null. If the caller supplies a transform argument, then it shall be a transform expecting normalized input coordinates and producing normalized output coordinates. See AxesConvention for more information about what Apache SIS means by "normalized".

      If the caller cannot yet supply a MathTransform, then (s)he shall supply the parameter values needed for creating that transform, with the possible omission of "semi_major" and "semi_minor" values. The semi-major and semi-minor parameter values will be set automatically when the specialize(…) method will be invoked.

      If both the transform and parameters arguments are non-null, then the latter should describe the parameters used for creating the transform. Those parameters will be stored for information purpose and can be given back by the SingleOperation.getParameterValues() method.

      Parameters:
      properties - the properties to be given to the identified object.
      method - the operation method.
      transform - transform from positions in the source CRS to positions in the target CRS, or null.
      parameters - the transform parameter values, or null.
      See Also:

    • DefaultConversion

      protected DefaultConversion(org.opengis.referencing.operation.Conversion operation)
      Creates a new coordinate operation with the same values than the specified one. This copy constructor provides a way to convert an arbitrary implementation into a SIS one or a user-defined one (as a subclass), usually in order to leverage some implementation-specific API.

      This constructor performs a shallow copy, i.e. the properties are not cloned.

      Parameters:
      operation - the coordinate operation to copy.
      See Also:

  • Method Details

    • castOrCopy

      public static DefaultConversion castOrCopy(org.opengis.referencing.operation.Conversion object)
      Returns a SIS coordinate operation implementation with the values of the given arbitrary implementation. This method performs the first applicable action in the following choices:
      • If the given object is null, then this method returns null.
      • Otherwise if the given object is an instance of Conversion, Projection, CylindricalProjection, ConicProjection or PlanarProjection, then this method delegates to the castOrCopy(…) method of the corresponding SIS subclass. Note that if the given object implements more than one of the above-cited interfaces, then the castOrCopy(…) method to be used is unspecified.
      • Otherwise if the given object is already an instance of DefaultConversion, then it is returned unchanged.
      • Otherwise a new DefaultConversion instance is created using the copy constructor and returned. Note that this is a shallow copy operation, because the other properties contained in the given object are not recursively copied.
      Parameters:
      object - the object to get as a SIS implementation, or null if none.
      Returns:
      a SIS implementation containing the values of the given object (may be the given object itself), or null if the argument was null.

    • getInterface

      public Class<? extends org.opengis.referencing.operation.Conversion> getInterface()
      Returns the GeoAPI interface implemented by this class. The default implementation returns Conversion.class. Subclasses implementing a more specific GeoAPI interface shall override this method.
      Overrides:
      getInterface in class AbstractCoordinateOperation
      Returns:
      the conversion interface implemented by this class.

    • specialize

      public <T extends org.opengis.referencing.operation.Conversion> T specialize(Class<T> baseType, org.opengis.referencing.crs.CoordinateReferenceSystem sourceCRS, org.opengis.referencing.crs.CoordinateReferenceSystem targetCRS, org.opengis.referencing.operation.MathTransformFactory factory) throws org.opengis.util.FactoryException
      Returns a specialization of this conversion with a more specific type, source and target CRS. This specialize(…) method is typically invoked on defining conversion instances, when more information become available about the conversion to create.

      The given baseType argument can be one of the following values:

      • Conversion.class
      • Projection.class
      • CylindricalProjection.class
      • ConicProjection.class
      • PlanarProjection.class
      This specialize(…) method returns a conversion which implement at least the given baseType interface, but may also implement a more specific GeoAPI interface if specialize(…) has been able to infer the type from the operation method.
      Type Parameters:
      T - compile-time type of the baseType argument.
      Parameters:
      baseType - the base GeoAPI interface to be implemented by the conversion to return.
      sourceCRS - the source CRS.
      targetCRS - the target CRS.
      factory - the factory to use for creating a transform from the parameters or for performing axis changes, or null for the default factory.
      Returns:
      the conversion of the given type between the given CRS.
      Throws:
      ClassCastException - if a contradiction is found between the given baseType, the defining conversion type and the method operation type.
      MismatchedDatumException - if the given CRS do not use the same datum than the source and target CRS of this conversion.
      org.opengis.util.FactoryException - if the creation of a MathTransform from the parameter values, or a change of axis order or units failed.
      See Also:

    • getMethod

      public org.opengis.referencing.operation.OperationMethod getMethod()
      Returns a description of the operation method, including a list of expected parameter names. The returned object does not contains any parameter value.
      Specified by:
      getMethod in interface org.opengis.referencing.operation.SingleOperation
      Returns:
      a description of the operation method.

    • getParameterDescriptors

      public org.opengis.parameter.ParameterDescriptorGroup getParameterDescriptors()
      Returns a description of the parameters. The default implementation performs the following choice:
      • If parameter values were specified explicitly at construction time, then the descriptor of those parameters is returned.
      • Otherwise if this method can infer the parameter descriptor from the math transform, then that descriptor is returned.
      • Otherwise fallback on the method parameters.
      Note: the two parameter descriptions (from the MathTransform or from the OperationMethod) should be very similar. If they differ, it should be only in minor details like remarks, default values or units of measurement.
      Specified by:
      getParameterDescriptors in interface Parameterized
      Returns:
      a description of the parameters.
      See Also:

    • getParameterValues

      public org.opengis.parameter.ParameterValueGroup getParameterValues()
      Returns the parameter values. The default implementation performs the following choice:
      Specified by:
      getParameterValues in interface Parameterized
      Specified by:
      getParameterValues in interface org.opengis.referencing.operation.SingleOperation
      Returns:
      the parameter values.
      Throws:
      UnsupportedOperationException - if the parameter values cannot be determined for the current math transform implementation.
      See Also:

    • equals

      public boolean equals(Object object, ComparisonMode mode)
      Compares this coordinate operation with the specified object for equality. If the mode argument is ComparisonMode.STRICT or BY_CONTRACT, then all available properties are compared including the domain of validity and the scope.
      Specified by:
      equals in interface LenientComparable
      Overrides:
      equals in class AbstractCoordinateOperation
      Parameters:
      object - the object to compare to this.
      mode - STRICT for performing a strict comparison, or IGNORE_METADATA for ignoring properties that do not make a difference in the numerical results of coordinate operations.
      Returns:
      true if both objects are equal for the given comparison mode.
      See Also: