Package org.geotools.referencing.operation.transform

Class AbstractMathTransform

Object
Formattable
AbstractMathTransform
All Implemented Interfaces:
MathTransform
Direct Known Subclasses:
AbstractMathTransform.Inverse, ConcatenatedTransform, ExponentialTransform1D, GeocentricTransform, IdentityTransform, LinearTransform1D, LogarithmicTransform1D, MapProjection, MolodenskiTransform, NADCONTransform, NTv2Transform, PassThroughTransform, ProjectiveTransform, VerticalTransform, WarpTransform2D
public abstract class AbstractMathTransform extends Formattable implements MathTransform
Provides a default implementation for most methods required by the MathTransform interface. AbstractMathTransform provides a convenient base class from which other transform classes can be easily derived. In addition, AbstractMathTransform implements methods required by the MathTransform2D interface, but does not implements MathTransform2D. Subclasses must declare implements MathTransform2D themselves if they know to map two-dimensional coordinate systems.
Since:
2.0
Author:
Martin Desruisseaux (IRD)

  • Constructor Details

    • AbstractMathTransform

      protected AbstractMathTransform()
      Constructs a math transform.

  • Method Details

    • getName

      public String getName()
      Returns a name for this math transform (never null). This convenience methods returns the name of the parameter descriptors if any, or the short class name otherwise.
      Returns:
      A name for this math transform (never null).
      Since:
      2.5

    • getSourceDimensions

      public abstract int getSourceDimensions()
      Gets the dimension of input points.
      Specified by:
      getSourceDimensions in interface MathTransform
      Returns:
      The dimension of input points.

    • getTargetDimensions

      public abstract int getTargetDimensions()
      Gets the dimension of output points.
      Specified by:
      getTargetDimensions in interface MathTransform
      Returns:
      The dimension of output points.

    • getParameterDescriptors

      public ParameterDescriptorGroup getParameterDescriptors()
      Returns the parameter descriptors for this math transform, or null if unknow. This method is similar to OperationMethod.getParameters(), except that MathTransform returns parameters in standard units (usually meters or decimal degrees).
      Returns:
      The parameter descriptors for this math transform, or null.
      See Also:

    • getParameterValues

      public ParameterValueGroup getParameterValues()
      Returns the parameter values for this math transform, or null if unknow. This method is similar to Operation.getParameterValues(), except that MathTransform returns parameters in standard units (usually meters or decimal degrees). Since this method returns a copy of the parameter values, any change to a value will have no effect on this math transform.
      Returns:
      A copy of the parameter values for this math transform, or null.
      See Also:

    • isIdentity

      public boolean isIdentity()
      Tests whether this transform does not move any points. The default implementation always returns false.
      Specified by:
      isIdentity in interface MathTransform
      Returns:
      true if this MathTransform is an identity transform; false otherwise.

    • transform

      public Point2D transform(Point2D ptSrc, Point2D ptDst) throws TransformException
      Transforms the specified ptSrc and stores the result in ptDst. The default implementation invokes MathTransform.transform(double[],int,double[],int,int) using a temporary array of doubles.
      Parameters:
      ptSrc - The specified coordinate point to be transformed.
      ptDst - The specified coordinate point that stores the result of transforming ptSrc, or null.
      Returns:
      The coordinate point after transforming ptSrc and storing the result in ptDst.
      Throws:
      MismatchedDimensionException - If this transform doesn't map two-dimensional coordinate systems.
      TransformException - If the point can't be transformed.
      See Also:

    • transform

      public Position transform(Position ptSrc, Position ptDst) throws TransformException
      Transforms the specified ptSrc and stores the result in ptDst. The default implementation delegates to MathTransform.transform(double[],int,double[],int,int).
      Specified by:
      transform in interface MathTransform
      Parameters:
      ptSrc - the specified coordinate point to be transformed.
      ptDst - the specified coordinate point that stores the result of transforming ptSrc, or null.
      Returns:
      the coordinate point after transforming ptSrc and storing the result in ptDst, or a newly created point if ptDst was null.
      Throws:
      TransformException - if the point can't be transformed.

    • transform

      public void transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) throws TransformException
      Transforms a list of coordinate point ordinal values. The default implementation invokes MathTransform.transform(double[],int,double[],int,int) using a temporary array of doubles.
      Specified by:
      transform in interface MathTransform
      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 a point can't be transformed. Some implementations will stop at the first failure, wile some other implementations will fill the untransformable points with NaN values, continue and throw the exception only at end. Implementations that fall in the later case should set the last completed transform to this.

    • transform

      public void transform(double[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts) throws TransformException
      Transforms a list of coordinate point ordinal values. The default implementation invokes MathTransform.transform(double[],int,double[],int,int) using a temporary array of doubles.
      Specified by:
      transform in interface MathTransform
      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 a point can't be transformed. Some implementations will stop at the first failure, wile some other implementations will fill the untransformable points with NaN values, continue and throw the exception only at end. Implementations that fall in the later case should set the last completed transform to this.
      Since:
      2.5

    • transform

      public void transform(float[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) throws TransformException
      Transforms a list of coordinate point ordinal values. The default implementation delegates to MathTransform.transform(double[],int,double[],int,int).
      Specified by:
      transform in interface MathTransform
      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 a point can't be transformed. Some implementations will stop at the first failure, wile some other implementations will fill the untransformable points with NaN values, continue and throw the exception only at end. Implementations that fall in the later case should set the last completed transform to this.
      Since:
      2.5

    • createTransformedShape

      public Shape createTransformedShape(Shape shape) throws TransformException
      Transform the specified shape. The default implementation computes quadratic curves using three points for each shape segments.
      Parameters:
      shape - Shape to transform.
      Returns:
      Transformed shape, or shape if this transform is the identity transform.
      Throws:
      IllegalStateException - if this transform doesn't map 2D coordinate systems.
      TransformException - if a transform failed.
      See Also:

    • derivative

      public Matrix derivative(Point2D point) throws TransformException
      Gets the derivative of this transform at a point. The default implementation always throw an exception. Subclasses that implement the MathTransform2D interface should override this method. Other subclasses should override derivative(Position) instead.
      Parameters:
      point - The coordinate point where to evaluate the derivative.
      Returns:
      The derivative at the specified point as a 2×2 matrix.
      Throws:
      MismatchedDimensionException - if the input dimension is not 2.
      TransformException - if the derivative can't be evaluated at the specified point.
      See Also:

    • derivative

      public Matrix derivative(Position point) throws TransformException
      Gets the derivative of this transform at a point. The default implementation ensure that point has a valid dimension. Next, it try to delegate the work to an other method: Otherwise, a TransformException is thrown.
      Specified by:
      derivative in interface MathTransform
      Parameters:
      point - The coordinate point where to evaluate the derivative.
      Returns:
      The derivative at the specified point (never null).
      Throws:
      NullPointerException - if the derivative dependents on coordinate and point is null.
      MismatchedDimensionException - if point doesn't have the expected dimension.
      TransformException - if the derivative can't be evaluated at the specified point.

    • inverse

      public MathTransform inverse() throws NoninvertibleTransformException
      Creates the inverse transform of this object. The default implementation returns this if this transform is an identity transform, and throws a NoninvertibleTransformException otherwise. Subclasses should override this method.
      Specified by:
      inverse in interface MathTransform
      Returns:
      The inverse transform.
      Throws:
      NoninvertibleTransformException - if the transform can't be inversed.

    • hashCode

      public int hashCode()
      Returns a hash value for this transform.
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object object)
      Compares the specified object with this math transform for equality. The default implementation checks if object is an instance of the same class than this and use the same parameter descriptor. Subclasses should override this method in order to compare internal fields.
      Overrides:
      equals in class Object
      Parameters:
      object - The object to compare with this transform.
      Returns:
      true if the given object is a transform of the same class and if, given identical source position, the transformed position would be the equals.

    • formatWKT

      protected String formatWKT(Formatter formatter)
      Format the inner part of a Well Known Text (WKT) element. The default implementation formats all parameter values returned by getParameterValues(). The parameter group name is used as the math transform name.
      Overrides:
      formatWKT in class Formattable
      Parameters:
      formatter - The formatter to use.
      Returns:
      The WKT element name, which is "PARAM_MT" in the default implementation.
      See Also:

    • ensureNonNull

      protected static void ensureNonNull(String name, Object object) throws InvalidParameterValueException
      Makes sure that an argument is non-null. This is a convenience method for subclass constructors.
      Parameters:
      name - Argument name.
      object - User argument.
      Throws:
      InvalidParameterValueException - if object is null.

    • needCopy

      protected static boolean needCopy(int srcOff, int dimSource, int dstOff, int dimTarget, int numPts)
      Checks if source coordinates need to be copied before to apply the transformation. This convenience method is provided for transform(...) method implementation. This method make the following assumptions:

      • Coordinates will be iterated from lower index to upper index.
      • Coordinates are read and writen in shrunk. For example (longitude,latitude,height) values for one coordinate are read together, and the transformed (x,y,z) values are written together only after.

      However, this method does not assumes that source and target dimension are the same (in the special case where source and target dimension are always the same, a simplier and more efficient check is possible). The following example prepares a transformation from 2 dimensional points to three dimensional points: 

       public void transform(double[] srcPts, int srcOff,
                       double[] dstPts, int dstOff, int numPts)
 {
     if (srcPts==dstPts && needCopy(srcOff, 2, dstOff, 3, numPts) {
         final double[] old = srcPts;
         srcPts = new double[numPts*2];
         System.arraycopy(old, srcOff, srcPts, 0, srcPts.length);
         srcOff = 0;
     }
 }
      This method is for internal usage by the referencing module only. Do not use! It will be replaced by a different mechanism in a future GeoTools version.
      Parameters:
      srcOff - The offset in the source coordinate array.
      dimSource - The dimension of input points.
      dstOff - The offset in the destination coordinate array.
      dimTarget - The dimension of output points.
      numPts - The number of points to transform.
      Returns:
      true if the source coordinates should be copied before to apply the transformation in order to avoid an overlap with the destination array.

    • rollLongitude

      protected static double rollLongitude(double x)
      Ensures that the specified longitude stay within ±π radians. This method is typically invoked after geographic coordinates are transformed. This method may add or substract some amount of 2π radians to x.
      Parameters:
      x - The longitude in radians.
      Returns:
      The longitude in the range ±π radians.

    • normalizeAngle

      protected static double normalizeAngle(double x)
      Ensures that the specified longitude stay within 0 and {code}PI{code}.
      Parameters:
      x - An angle
      Returns:
      The normalized angle