Class LambertAzimuthalEqualArea

All Implemented Interfaces:
Serializable, Parameterized, LenientComparable, org.opengis.referencing.operation.MathTransform, org.opengis.referencing.operation.MathTransform2D

public class LambertAzimuthalEqualArea extends AuthalicConversion
Lambert Azimuthal Equal Area projection (EPSG code 9820). See the following references for an overview:
Since:
1.2
Version:
1.2
See Also:
  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      For cross-version compatibility.
      See Also:
    • sinβ0

      private final double sinβ0
      Sine and cosine of authalic latitude of origin. In the spherical case, the authalic latitude β and the geodetic latitude φ are the same.

      Possible simplification

      In equatorial case, sin(β₀)=0 and cos(β₀)=1. We could do special cases with simplifications in the transform(…) formulas, but the result does not seem simpler enough to worth code branching.

      In the polar case, sin(β₀)=1 and cos(β₀)=0. But the equations become indeterminate (we get 0/0) and a different set of equations must be used.

    • cosβ0

      private final double cosβ0
      Sine and cosine of authalic latitude of origin. In the spherical case, the authalic latitude β and the geodetic latitude φ are the same.

      Possible simplification

      In equatorial case, sin(β₀)=0 and cos(β₀)=1. We could do special cases with simplifications in the transform(…) formulas, but the result does not seem simpler enough to worth code branching.

      In the polar case, sin(β₀)=1 and cos(β₀)=0. But the equations become indeterminate (we get 0/0) and a different set of equations must be used.

    • polar

      private final boolean polar
      true if the projection is at a pole. This implementation does not need to distinguish between North and South pole. Formulas in this class are for the South case only, and this class handles the North case by reverting the sign of φ before conversion and y after conversion.
  • Constructor Details

    • LambertAzimuthalEqualArea

      public LambertAzimuthalEqualArea(org.opengis.referencing.operation.OperationMethod method, Parameters parameters)
      Creates a Lambert Azimuthal Equal Area projection from the given parameters.
      Parameters:
      method - description of the projection parameters.
      parameters - the parameter values of the projection to create.
    • LambertAzimuthalEqualArea

      @Workaround(library="JDK", version="1.7") private LambertAzimuthalEqualArea(Initializer initializer)
      Work around for RFE #4093999 in Sun's bug database ("Relax constraint on placement of this()/super() call in constructors").
    • LambertAzimuthalEqualArea

      LambertAzimuthalEqualArea(LambertAzimuthalEqualArea other)
      Creates a new projection initialized to the same parameters than the given one.
  • Method Details

    • initializer

      @Workaround(library="JDK", version="1.7") private static Initializer initializer(org.opengis.referencing.operation.OperationMethod method, Parameters parameters)
      Work around for RFE #4093999 in Sun's bug database ("Relax constraint on placement of this()/super() call in constructors").
    • getInternalParameterNames

      final String[] getInternalParameterNames()
      Returns the names of additional internal parameters which need to be taken in account when comparing two LambertAzimuthalEqualArea projections or formatting them in debug mode.
      Overrides:
      getInternalParameterNames in class NormalizedProjection
    • getInternalParameterValues

      final double[] getInternalParameterValues()
      Returns the values of additional internal parameters which need to be taken in account when comparing two LambertAzimuthalEqualArea projections or formatting them in debug mode.
      Overrides:
      getInternalParameterValues in class NormalizedProjection
    • transform

      public org.opengis.referencing.operation.Matrix transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate) throws ProjectionException
      Projects the specified (λ,φ) coordinates (units in radians) and stores the result in dstPts. In addition, opportunistically computes the projection derivative if derivate is true. The results must be multiplied by the denormalization matrix before to get linear distances.
      Specified by:
      transform in class NormalizedProjection
      Parameters:
      srcPts - the array containing the source point coordinates, as (longitude, latitude) angles in radians.
      srcOff - the offset of the single coordinate tuple to be converted in the source array.
      dstPts - the array into which the converted coordinates is returned (may be the same than srcPts). Coordinates will be expressed in a dimensionless unit, as a linear distance on a unit sphere or ellipse.
      dstOff - the offset of the location of the converted coordinates that is stored in the destination array.
      derivate - true for computing the derivative, or false if not needed.
      Returns:
      the matrix of the projection derivative at the given source position, or null if the derivate argument is false.
      Throws:
      ProjectionException - if the coordinates cannot be converted.
      See Also:
    • inverseTransform

      protected void inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff) throws ProjectionException
      Converts the specified (x,y) coordinates and stores the (λ,φ) result in dstPts.
      Specified by:
      inverseTransform in class NormalizedProjection
      Parameters:
      srcPts - the array containing the source point coordinates, as linear distance on a unit sphere or ellipse.
      srcOff - the offset of the point to be converted in the source array.
      dstPts - the array into which the converted point coordinates is returned (may be the same than srcPts). Coordinates will be (longitude, latitude) angles in radians.
      dstOff - the offset of the location of the converted point that is stored in the destination array.
      Throws:
      ProjectionException - if the point cannot be converted.