Class PassThroughTransform

All Implemented Interfaces:
Serializable, Parameterized, Lenient­Comparable, Math­Transform

public class PassThroughTransform extends AbstractMathTransform implements Serializable
Transform which passes through a subset of coordinates to another transform. This allows transforms to operate on a subset of coordinate values.
Example: giving (latitude, longitude, height) coordinates, Pass­Through­Transform can convert the height values from feet to meters without affecting the latitude and longitude values. Such transform can be built as below:
MathTransform feetToMetres = MathTransforms.linear(0.3048, 0);       // One-dimensional conversion.
MathTransform tr = MathTransforms.passThrough(2, feetToMetres, 0);   // Three-dimensional conversion.

Immutability and thread safety

Pass­Through­Transform is immutable and thread-safe if its subTransform is also immutable and thread-safe.

Serialization

Serialized instances of this class are not guaranteed to be compatible with future SIS versions. Serialization should be used only for short term storage or RMI between applications running the same SIS version.
Since:
0.5
See Also:

Defined in the sis-referencing module

  • Constructor Details

    • PassThroughTransform

      protected PassThroughTransform(int firstAffectedCoordinate, MathTransform subTransform, int numTrailingCoordinates)
      Constructor for sub-classes. Users should invoke the static Math­Transforms​.pass­Through(int, Math­Transform, int) factory method instead, since the most optimal pass-through transform for the given sub­Transform is not necessarily a Pass­Through­Transform instance.
      Parameters:
      first­Affected­Coordinate - index of the first affected coordinate.
      sub­Transform - the sub-transform to apply on modified coordinates.
      num­Trailing­Coordinates - number of trailing coordinates to pass through.
      See Also:
  • Method Details

    • getSourceDimensions

      public final int getSourceDimensions()
      Gets the dimension of input points. This the source dimension of the sub-transform plus the number of pass-through dimensions.
      Specified by:
      get­Source­Dimensions in interface Math­Transform
      Specified by:
      get­Source­Dimensions in class Abstract­Math­Transform
      Returns:
      the dimension of input points.
      See Also:
    • getTargetDimensions

      public final int getTargetDimensions()
      Gets the dimension of output points. This the target dimension of the sub-transform plus the number of pass-through dimensions.
      Specified by:
      get­Target­Dimensions in interface Math­Transform
      Specified by:
      get­Target­Dimensions in class Abstract­Math­Transform
      Returns:
      the dimension of output points.
      See Also:
    • getModifiedCoordinates

      public final int[] getModifiedCoordinates()
      Returns the ordered sequence of positive integers defining the positions in a source coordinate tuple of the coordinates affected by this pass-through operation.
      API note: this method is final for now because most of Apache SIS code do not use the modified­Coordinates array. Instead, SIS uses the first­Affected­Coordinate and num­Trailing­Coordinates information provided to the constructor. Consequently overriding this method may be misleading since it would be ignored by SIS. We do not want to make the "really used" fields public in order to keep the flexibility to replace them by a modified­Coordinates array in a future SIS version.
      Returns:
      Zero-based indices of the modified source coordinates.
      See Also:
    • getSubTransform

      public final MathTransform getSubTransform()
      Returns the sub-transform to apply on the modified coordinates. This is often the sub-transform specified at construction time, but not necessarily.
      Returns:
      the sub-transform.
      See Also:
    • isIdentity

      public boolean isIdentity()
      Tests whether this transform does not move any points. A Pass­Through­Transform is identity if the sub-transform is also identity.
      Specified by:
      is­Identity in interface Math­Transform
      Overrides:
      is­Identity in class Abstract­Math­Transform
      Returns:
    • transform

      public Matrix transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate) throws TransformException
      Transforms a single coordinate in a list of ordinal values, and opportunistically computes the transform derivative if requested.
      Specified by:
      transform in class Abstract­Math­Transform
      Parameters:
      src­Pts - the array containing the source coordinate (can not be null).
      src­Off - the offset to the point to be transformed in the source array.
      dst­Pts - the array into which the transformed coordinate is returned. May be the same than src­Pts. May be null if only the derivative matrix is desired.
      dst­Off - the offset to the location of the transformed point that is stored in the destination array.
      derivate - true for computing the derivative, or false if not needed.
      Returns:
      the matrix of the transform derivative at the given source position, or null if the derivate argument is false.
      Throws:
      Transform­Exception - if the sub-transform failed.
      See Also:
    • transform

      public void transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) throws TransformException
      Transforms many coordinates in a list of ordinal values.
      Specified by:
      transform in interface Math­Transform
      Overrides:
      transform in class Abstract­Math­Transform
      Parameters:
      src­Pts - the array containing the source point coordinates.
      src­Off - the offset to the first point to be transformed in the source array.
      dst­Pts - the array into which the transformed point coordinates are returned. May be the same than src­Pts.
      dst­Off - the offset to the location of the first transformed point that is stored in the destination array.
      num­Pts - the number of point objects to be transformed.
      Throws:
      Transform­Exception - if the sub-transform failed.
    • transform

      public void transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) throws TransformException
      Transforms many coordinates in a list of ordinal values.
      Specified by:
      transform in interface Math­Transform
      Overrides:
      transform in class Abstract­Math­Transform
      Parameters:
      src­Pts - the array containing the source point coordinates.
      src­Off - the offset to the first point to be transformed in the source array.
      dst­Pts - the array into which the transformed point coordinates are returned. May be the same than src­Pts.
      dst­Off - the offset to the location of the first transformed point that is stored in the destination array.
      num­Pts - the number of point objects to be transformed.
      Throws:
      Transform­Exception - if the sub-transform failed.
    • transform

      public void transform(double[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) throws TransformException
      Transforms many coordinates in a list of ordinal values.
      Specified by:
      transform in interface Math­Transform
      Overrides:
      transform in class Abstract­Math­Transform
      Parameters:
      src­Pts - the array containing the source point coordinates.
      src­Off - the offset to the first point to be transformed in the source array.
      dst­Pts - the array into which the transformed point coordinates are returned.
      dst­Off - the offset to the location of the first transformed point that is stored in the destination array.
      num­Pts - the number of point objects to be transformed.
      Throws:
      Transform­Exception - if the sub-transform failed.
    • transform

      public void transform(float[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) throws TransformException
      Transforms many coordinates in a list of ordinal values.
      Specified by:
      transform in interface Math­Transform
      Overrides:
      transform in class Abstract­Math­Transform
      Parameters:
      src­Pts - the array containing the source point coordinates.
      src­Off - the offset to the first point to be transformed in the source array.
      dst­Pts - the array into which the transformed point coordinates are returned.
      dst­Off - the offset to the location of the first transformed point that is stored in the destination array.
      num­Pts - the number of point objects to be transformed.
      Throws:
      Transform­Exception - if the sub-transform failed.
    • derivative

      public Matrix derivative(DirectPosition point) throws TransformException
      Gets the derivative of this transform at a point.
      Specified by:
      derivative in interface Math­Transform
      Overrides:
      derivative in class Abstract­Math­Transform
      Parameters:
      point - the coordinate point where to evaluate the derivative.
      Returns:
      the derivative at the specified point (never null).
      Throws:
      Transform­Exception - if the sub-transform failed.
    • inverse

      Creates the inverse transform of this object.
      Specified by:
      inverse in interface Math­Transform
      Overrides:
      inverse in class Abstract­Math­Transform
      Returns:
      Throws:
      Noninvertible­Transform­Exception - if the sub-transform is not invertible.
    • tryConcatenate

      protected MathTransform tryConcatenate(boolean applyOtherFirst, MathTransform other, MathTransformFactory factory) throws FactoryException
      Concatenates or pre-concatenates in an optimized way this transform with the given transform, if possible. This method applies the following special cases:
      • If the other transform is also a Pass­Through­Transform, then the two transforms may be merged in a single Pass­Through­Transform instance.
      • If the other transform discards some dimensions, verify if we still need a Pass­Through­Transform.
      Overrides:
      try­Concatenate in class Abstract­Math­Transform
      Parameters:
      apply­Other­First - true if the transformation order is other followed by this, or false if the transformation order is this followed by other.
      other - the other math transform to (pre-)concatenate with this transform.
      factory - the factory which is (indirectly) invoking this method, or null if none.
      Returns:
      the simplified transform, or null if no such optimization is available.
      Throws:
      Factory­Exception - if an error occurred while combining the transforms.
      Since:
      1.0
      See Also:
    • computeHashCode

      protected int computeHashCode()
      Computes a hash value for this transform. This method is invoked by Abstract­Math­Transform​.hash­Code() when first needed.
      Overrides:
      compute­Hash­Code in class Abstract­Math­Transform
      Returns:
      the hash code value. This value may change between different execution of the Apache SIS library.
    • equals

      public boolean equals(Object object, ComparisonMode mode)
      Compares the specified object with this math transform for equality.
      Specified by:
      equals in interface Lenient­Comparable
      Overrides:
      equals in class Abstract­Math­Transform
      Parameters:
      object - the object to compare with this transform.
      mode - the strictness level of the comparison. Default to STRICT.
      Returns:
      true if the given object is considered equals to this math transform.
      See Also:
    • formatTo

      protected String formatTo(Formatter formatter)
      Formats this transform as a Well Known Text version 1 (WKT 1) element.
      Compatibility note: Pass­Through_MT is defined in the WKT 1 specification only. If the formatter convention is set to WKT 2, then this method silently uses the WKT 1 convention without raising an error (unless this Pass­Through­Transform can not be formatted as valid WKT 1 neither).
      Overrides:
      format­To in class Abstract­Math­Transform
      Parameters:
      formatter - the formatter to use.
      Returns:
      the WKT element name, which is "Pass­Through_MT".
      See Also: