Package org.apache.sis.internal.referencing

Class PositionTransformer

java.lang.Object
org.apache.sis.io.wkt.FormattableObject
org.apache.sis.geometry.AbstractDirectPosition
org.apache.sis.geometry.GeneralDirectPosition
org.apache.sis.internal.referencing.PositionTransformer
All Implemented Interfaces:
Serializable, Cloneable, org.opengis.geometry.coordinate.Position, org.opengis.geometry.DirectPosition
public final class PositionTransformer extends GeneralDirectPosition
A direct position capable to transform another position from its arbitrary CRS to the CRS of this position. This class caches the last transform used in order to improve performance when source and target CRS do not change often. Using this class is faster than invoking CoordinateOperationFactory.createOperation(lastCRS, targetCRS) for every points.
  • Note 1: This class is advantageous on a performance point of view only if the same instance of PositionTransformer is used for transforming many points between arbitrary CRS and this position CRS.
  • Note 2: This convenience class is useful when the source and target CRS are not likely to change often. If you are sure that the source and target CRS will not change at all for a given set of positions, then using CoordinateOperation directly gives better performances. This is because this class checks if the CRS changed before every transformations, which may be costly.
This class should not appear in a public API. It is used as a helper private field in more complex classes. For example, suppose that MyClass needs to perform its internal working in some particular CRS, but we want robust API accepting whatever CRS the client uses. MyClass can be written as below: This class is not thread-safe.
Since:
1.0
Version:
1.0
Author:
Martin Desruisseaux (IRD, Geomatys)
See Also:

  • Field Details

    • defaultCRS

      public final org.opengis.referencing.crs.CoordinateReferenceSystem defaultCRS
      The default CRS to assume when transform(DirectPosition) has been invoked without associated CRS. This is often the same than the target CRS, but not necessarily.

  • Constructor Details

    • PositionTransformer

      public PositionTransformer(org.opengis.referencing.crs.CoordinateReferenceSystem defaultCRS, org.opengis.referencing.crs.CoordinateReferenceSystem targetCRS, org.opengis.referencing.operation.CoordinateOperationFactory factory)
      Creates a new position which will contain the result of coordinate transformations to the given CRS. The CRS associated with this position will be initially set to targetCRS.
      Parameters:
      defaultCRS - the CRS to take as the source when transform(position) is invoked with a position without associated CRS. If null, default to targetCRS.
      targetCRS - the CRS associated with this position. Will be the target of coordinate transformations until the next call to setCoordinateReferenceSystem(…) or setLocation. Cannot be null.
      factory - the factory to use for creating coordinate operations, or null for the default.

  • Method Details

    • setCoordinateReferenceSystem

      public void setCoordinateReferenceSystem(org.opengis.referencing.crs.CoordinateReferenceSystem targetCRS) throws org.opengis.geometry.MismatchedDimensionException
      Sets the coordinate reference system in which the coordinate is given. The given CRS will be used as:
      Overrides:
      setCoordinateReferenceSystem in class GeneralDirectPosition
      Parameters:
      targetCRS - the new CRS for this direct position.
      Throws:
      org.opengis.geometry.MismatchedDimensionException - if the specified CRS does not have the expected number of dimensions.

    • transform

      public void transform(double[] point) throws org.opengis.referencing.operation.TransformException
      Transforms the given position from the CRS of this position to the default CRS. The result is stored in the given array.
      Parameters:
      point - the coordinates of the point to transform in-place.
      Throws:
      org.opengis.referencing.operation.TransformException - if a coordinate transformation was required and failed.

    • transform

      public org.opengis.geometry.DirectPosition transform(org.opengis.geometry.DirectPosition position) throws org.opengis.referencing.operation.TransformException
      Transforms a given position from its CRS to the CRS of this PositionTransformer. If the CRS associated to the given position is null, then that CRS is assumed to be the default CRS specified at construction time. Otherwise if that CRS is not equal to the CRS associated with this position, then a coordinates transformations are applied. The result may be stored in this instance.
      Parameters:
      position - a position using an arbitrary CRS, or null. This object will not be modified.
      Returns:
      the transformed position, either this or the given position (which may be null).
      Throws:
      org.opengis.referencing.operation.TransformException - if a coordinate transformation was required and failed.

    • inverseTransform

      public org.opengis.geometry.DirectPosition inverseTransform() throws org.opengis.referencing.operation.TransformException
      Returns a new point with the same coordinates than this one, but transformed to the default CRS. This method never returns this, so the returned point does not need to be cloned.
      Returns:
      the same position as this, but transformed to the default CRS.
      Throws:
      org.opengis.referencing.operation.TransformException - if a coordinate transformation was required and failed.

    • inverseTransform

      public org.opengis.referencing.operation.Matrix inverseTransform(double[] target) throws org.opengis.referencing.operation.TransformException
      Transforms this point to the default CRS and stores the result in the given array, and returns the derivative. The target array length should be ReferencingUtilities.getDimension(defaultCRS).
      Parameters:
      target - where to store the transformed coordinates.
      Returns:
      the derivative (Jacobian matrix) at the location of this point.
      Throws:
      org.opengis.referencing.operation.TransformException - if a coordinate transformation was required and failed.